Chronic pain is a complex phenomenon that brings physical and emotional impairments [1], negatively impacting people’s quality of life. Due to its high prevalence, a multidimensional assessment to address its impact on quality of life and physical and emotional functionalities is needed, as well as the implementation of strategies aimed at minimizing or resolving it.

The American College of Physicians recommends the adoption of non-pharmacological interventions as the main approach to treating people with chronic back pain [2]. In this context, the adoption of interventions such as ear acupuncture (EA) and dry cupping (DC) can represent a treatment option for people with chronic back pain [3,4].

According to Traditional Chinese Medicine (TCM), EA is able to regulate the flow of Qi (vital energy) through the stimulation of specific points in the ear and, consequently, treat or prevent diseases [5]. At the neurophysiological level, symptoms of diseases are projected on specific parts of the ear, since this is one of the few anatomical structures formed by the three embryonic leaflets (endoderm, mesoderm, and ectoderm), and therefore, has the representativeness of all parts of the body [6].

Dry cupping, in turn, is another TCM intervention that also has the potential to restore the flow of Qi [7]. The mechanical stimulus triggered by tissue suction contributes to pain relief, through neural, anti-inflammatory, vasodilator, immunomodulatory and hematological mechanisms [8].

It is noteworthy that both EA and DC can be used alone or in conjunction with other treatments, possibly contributing to stronger and/or faster clinical improvements. In our previous randomized clinical trial [9] using EA as a treatment for chronic pain in people with back musculoskeletal disorders, we observed that this intervention by itself did not significantly reduce pain in the long term. Thus, we hypothesized if a local stimulus to the pain, such as the DC intervention, could improve the long-term effect of pain relief, among other outcomes, when combined with EA. Our study aims to investigate the effects of EA combined with DC on the interference of pain with the daily activities and quality of life of adults with chronic back pain.

1. Ethical considerations

This study was approved by a research ethics committee (CEAE registration number 75281317.3.0000.5149). The participants provided written consent before the start of the study.

2. Design and sample

An open-label, randomized, parallel-group controlled clinical trial study was carried out between November 2017 and December 2018, following the CONSORT statement recommendations [10]. Our target population was adults with chronic back pain who were on the waitlist for physical therapy treatment offered by the outpatient Family Health Strategies program (Estratégias de Saúde da Família) in a city in Brazil.

To screen the sample, the presence of referral to physical therapy was considered. People were contacted via telephone to check for the existence of a complaint of chronic back pain lasting three months or more [11], with a self-report of pain intensity ≥ 4 in the last seven days, which was assessed using a Numeric Ranking Scale (from 0 – no pain to 10 – pain as bad as you can imagine).

The inclusion criteria were: patients aged between 18 and 70 years and preserved cognitive function. People were excluded if: making continuous use of adjuvant drugs (antidepressants, benzodiazepines, anticonvulsants, antipsychotics, muscle relaxants) [12]; undergoing physical therapy or other energy therapies (such as massage, herbal medicine, reiki, aromatherapy, foot reflexology, homeopathy); ear infection, inflammation or injury; reporting allergy to metal or microporous tape; wearing earrings in the ears (except in the ear lobe); decreased skin turgor or lesions, inflammation or diseases on the skin in the dorsal region; serious chronic, neurological or psychiatric diseases [13]; using pacemakers and/or anticoagulants [13]; pregnant or in the puerperium [13].

People were discontinued from treatment if: they were hospitalized during treatment; made use of simple analgesics, opioids, non-steroidal anti-inflammatory and/or myorelaxant drugs, orally, 24 hours before any of the evaluations; made use of simple analgesics, opioids, non-steroidal anti-inflammatory drugs, corticoids and/or anti-rheumatic drugs, through injectable means, 72 hours before any of the evaluations; developed an allergic and/or inflammatory reaction in the ear or the suction cup application site; felt intense discomfort at the site where the needles were applied and/or at the site where the suction cups were applied; decided to discontinue the treatment; missed two consecutive sessions or exceeded an interval greater than 10 days between them.

The initial population was composed of 686 people, a total of 488 subjects did not meet the inclusion or exclusion criteria, resulting in 198 participants who were randomized into the control or experimental groups (Fig. 1).

Figure 1. Flowchart.

3. Sample size and randomization procedure

To estimate the sample size, a pre-test (n = 20) was performed using the variable “interference of pain with daily activities” from the Brief Pain Inventory [14]. The difference in averages between the groups was 2.21 points in the initial evaluation and 0.61 points in the final evaluation.

The RMASS2^® software - Repeated Measures with Attrition; Sample Sizes for 2 Groups [15] was used to estimate the sample size. For a significance of 5%, power of 90%, and average effect size of 0.5, a sample of 98 individuals per group was estimated. Our study’s final sample consisted of 182 participants, with a loss of 8.1% from the initial sample.

The participants were randomly allocated into a control group, which received EA, or an experimental group, which received EA combined with DC.

Randomization was performed by a researcher masked to the study design, in the proportion of 1:1, through randomization.com^®. Each number in the random sequence was placed in an opaque envelope and given to the interventionist only in the first treatment session.

4. Data collection and instruments

Evaluations were carried out in three moments, by the same trained examiners. The first was before the first treatment session (EV0), the second was one week after the last session (EV1), and finally seven days after the final evaluation (EV2).

Sociodemographic (sex, age, marital status, and occupation) and clinical (time and cause of the pain) information were collected using a form for individual characterization. The form was created by the authors and evaluated as to content and relevance by three experts in the area of pain.

Interference of pain with daily activities was verified by the Brief Pain Inventory [16]. This instrument has numerical scales, graded from zero (without interference) to 10 (total interference), to measure the interference of pain with general activities, locomotion capacity, job, humor, relationships with other people, the pleasure of living, and sleep [16]. The average score of these items represents the general interference of pain with daily activities. This instrument was translated to Brazilian Portuguese and adapted to the Brazilian culture and has adequate psychometric properties [17].

Quality of life was verified by the World Health Organization Quality of Life-BREF (WHOQOL-BREF) [18]. This instrument consists of 26 questions: two general questions on perception of quality of life and satisfaction with health, and the other questions distributed under four domains (physical, social, psychological, and environment). Each question has a score from one to five, on a Likert scale, which is transformed into a linear scale from zero (less favorable quality of life) to 100 points (more favorable quality of life). The instrument was translated and validated to the Brazilian Portuguese version and has adequate psychometric properties [18].

5. Interventions

The EA and DC protocols followed the recommendations of the Standards for Reporting Interventions in Clinical Trials of Acupuncture (Table 1) [19] and the Standards for Reporting Interventions in Clinical Trials of Cupping (Table 2) [20].

Table 1

Ear Acupuncture intervention protocol according to the Standards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA) [19].

Item	Detail	Description
1. Acupuncture rationale	a) Style of acupuncture	Ear acupuncture according to Traditional Chinese Medicine
	b) Reasoning for treatment provided, based on historical context, literature sources, and/or consensus methods, with references where appropriate	According to Traditional Chinese Medicine, ear acupuncture is able to regulate the flow of Qi (vital energy) through the stimulation of specific points in the ear and, consequently, treat or prevent diseases [5]. At the neurophysiological level, symptoms of diseases are projected on specific parts of the ear, since this is one of the few anatomical structures formed by the three embryonic leaflets (endoderm, mesoderm and ectoderm), and therefore, has the representativeness of all parts of the body [6]
	c) Extent to which treatment was varied	Not applicable
2. Details of needling	a) Number of needle insertions per subject per session (mean and range where relevant)	A maximum of 9 semi-permanent, sterile and disposable needles were used in each participant per session
	b) Names (or location if no standard name) of points used (uni/bilateral)	Shénmén (TF4); Shèn (CO10); Jiaogan (AH6); Pizhixia (AT4); Pangguang (CO9); Gan (COI2); Jlngzhui (AH13); Xiongzhui (AH11); Yaodfzhui (AH9). The choice of the referred acupoints varied according to the site of the pain. The acupoints were applied unilaterally, shifting the ear at each session
	c) Depth of insertion, based on a specified unit of measurement, or on a particular tissue level	The needles were inserted 1.5 mm (the size of the needle) in the ear
	d) Response sought (e.g. de qi or muscle twitch response)	Not applicable
	e) Needle stimulation (e.g. manual, electrical)	The needles were not stimulated
	f) Needle retention time	Seven days
	g) Needle type (diameter, length, and manufacturer or material)	Semi-permanent, sterile, and disposable needles, size 0.20 × 1.5 mm (Complementar Agulhas®)
3. Treatment regimen	a) Number of treatment sessions	Five sessions
	b) Frequency and duration of treatment sessions	Once a week, for approximately 20 minutes, for five weeks
4. Other components of treatment	a) Details of other interventions administered to the acupuncture group (e.g. moxibustion, cupping, herbs, exercises, lifestyle advice)	Ear acupuncture was administered to the control group and a combination of ear acupuncture and dry cupping was administered to the experimental group
	b) Setting and context of treatment, including instructions to practitioners, and information and explanations to patients	Only one acupuncturist administered ear acupuncture for all participants during the study. Each participant was informed about the needles used during the procedure, the treatment regiment, the ear acupoints used, and potential side effects, including brief pain in the application site. The procedure was conducted using the aseptic technique, with sterile and disposable equipment
5. Practitioner background	Description of participating acupuncturists (qualification or professional affiliation, years in acupuncture practice, other relevant experience)	Nurse specialist in acupuncture, with six years of experience in the area
6. Control or comparator interventions	a) Rationale for the control or comparator in the context of the research question, with sources that justify this choice	This study was conducted with two groups: a control group, which received ear acupuncture, and an experimental group, which received ear acupuncture combined with dry cupping. This study hypothesized that dry cupping can enhance the effects of ear acupuncture
	b) Precise description of the control or comparator. If sham acupuncture or any other type of acupuncture-like control is used, provide details as for Items 1 to 3 above	The description can be found in Table 2

1) Cervical region: BL10: Tianzhu 天柱 and BL11: Dazhu 大杼;.

2) Thoracic region: BL12: Fengmen 風(风)門(门), BL17: Geshu 膈兪(俞), BL21: Weishu 胃兪(俞);.

3) Lumbar region: BL23: Shenshu 腎兪(俞), BL24: Qihaishu 氣(气,気)海(海)兪(俞), BL25: Dachangshu 大腸兪(俞).

d. Number of cupping units and/or cupping time per location (mean or range where relevant)A maximum of 22 cupping units was used in each participant per session. The cups were applied in 11 acupoints bilaterally and fixed for 10 minutese. Procedure and technique for cupping (e.g., weak/light cupping, medium cupping, strong cupping, moving cupping, light-moving cupping, needle cupping, hot needle and moxa cupping, empty/flash cupping, bleeding/wet/full cupping, herbal cupping, water cupping and ice cupping)Medium cupping: a manual suction pump activated the acrylic cups until the skin rose 1.5 centimeters inside the cup (three or four manual pumps)f. Responses sought from participants (e.g., warm feeling, skin reddening, ring mark, etc.)Warm feeling and skin reddeningg. Precautionary measures to adverse events (e.g., skin blister, scald, or bleeding), and management, if anyIn case of blisters or skin lesions, the participant would see a trained health care professional and receive the appropriate topical treatment until the lesions had completely healed. The dry cupping procedure was performed using the aseptic technique3. Treatment regimenNumber, frequency and duration of the cupping sessionsFive sessions, once a week, for five weeks. The session with combined ear acupuncture and dry cupping lasted for 40 minutes4. Other components of treatmenta. Details of other interventions administered to the cupping group (e.g., acupuncture, moxibustion, massage, herbs, exercises, lifestyle advice)The experimental group received ear acupuncture combined with dry cupping. A detailed description can be found in Table 1b. Setting and instruction of treatment to the cupping providers and the participantsOnly one professional administered the dry cupping for all participants during the study. Each participant was informed about the cupping units used during the procedure, the treatment regiment, the systemic acupoints used, and potential side effects, including brief pain in the application site, warm feeling, skin reddening, and purple spots/marks. The spots could take between seven and 15 days to disappear. It was also explained to the participants that, in case of blisters or skin lesions, the participant would be referred to a health care professional for treatment5. Treatment provider backgroundDescription of treatment provider(s) (qualification or professional affiliation, years in cupping practice, and other relevant experience for professional)Nurse specialist in cupping therapy, with six years of experience in the area6. Control or comparator of cuppinga. Rationale for the choice of control or comparator of cuppingThis study was conducted with two groups: a control group, which received ear acupuncture, and an experimental group, which received ear acupuncture combined with dry cupping. This study hypothesized that dry cupping can enhance the effects of ear acupunctureb. Precise description of the control or comparator. If another form of cupping or cupping-like control is used, provide details as for Items 1 to 3 aboveThe information about ear acupuncture can be found in Table 1&md=tbl&idx=2' data-target="#file-modal"">Table 2

Dry Cupping intervention protocol according to the Standards for Reporting Interventions in Clinical Trials of Cupping (STRICTOC) [20].

Item	Detail	Description
1. Cupping rationale	a. Style of cupping (e.g., Chinese medicine, dry cupping, wet cupping, etc.)	Dry cupping
	b. Reasoning for cupping provided, based on historical context, literature sources, and/or consensus methods, with references where appropriate	Dry cupping is a Traditional Chinese Medicine intervention that has the potential to restore the flow of Qi [7]. The mechanical stimulus triggered by tissue suction contributes to pain relief, through neural, anti-inflammatory, vasodilator, immunomodulatory and hematological mechanisms [8]
	c. Whether the cupping treatment is individualized or not	The cupping treatment is not individualized
2. Details of cupping	a. Patient posture during the cupping	The participant was positioned on a stretcher, in a prone position with arms flexed at the head height
	b. Devices used for cupping, such as type of cupping set, size, manufacturer, and material (e.g., herbal, needle, moxa, water) inside the cup, if any	Acrylic cups of 4.5, 3, or 2.3 centimeters in diameter were used (DongYang®), depending on the application site. Local asepsis was performed, and the cups were applied bilaterally to the dorsal region
	c. Name and number of acupoints/meridians/locations (if no official name) used for cupping	The acupoints used were the Gallbladder Meridian (GB21: Jianjing 肩井; GB30: Huantiao 環(环)跳) and the Liver Meridian (LR8: Ququan 曲泉). In addition, the following acupoints of the Bladder Meridian were used depending on the site of the pain: 1) Cervical region: BL10: Tianzhu 天柱 and BL11: Dazhu 大杼;. 2) Thoracic region: BL12: Fengmen 風(风)門(门), BL17: Geshu 膈兪(俞), BL21: Weishu 胃兪(俞);. 3) Lumbar region: BL23: Shenshu 腎兪(俞), BL24: Qihaishu 氣(气,気)海(海)兪(俞), BL25: Dachangshu 大腸兪(俞).
	d. Number of cupping units and/or cupping time per location (mean or range where relevant)	A maximum of 22 cupping units was used in each participant per session. The cups were applied in 11 acupoints bilaterally and fixed for 10 minutes
	e. Procedure and technique for cupping (e.g., weak/light cupping, medium cupping, strong cupping, moving cupping, light-moving cupping, needle cupping, hot needle and moxa cupping, empty/flash cupping, bleeding/wet/full cupping, herbal cupping, water cupping and ice cupping)	Medium cupping: a manual suction pump activated the acrylic cups until the skin rose 1.5 centimeters inside the cup (three or four manual pumps)
	f. Responses sought from participants (e.g., warm feeling, skin reddening, ring mark, etc.)	Warm feeling and skin reddening
	g. Precautionary measures to adverse events (e.g., skin blister, scald, or bleeding), and management, if any	In case of blisters or skin lesions, the participant would see a trained health care professional and receive the appropriate topical treatment until the lesions had completely healed. The dry cupping procedure was performed using the aseptic technique
3. Treatment regimen	Number, frequency and duration of the cupping sessions	Five sessions, once a week, for five weeks. The session with combined ear acupuncture and dry cupping lasted for 40 minutes
4. Other components of treatment	a. Details of other interventions administered to the cupping group (e.g., acupuncture, moxibustion, massage, herbs, exercises, lifestyle advice)	The experimental group received ear acupuncture combined with dry cupping. A detailed description can be found in Table 1
	b. Setting and instruction of treatment to the cupping providers and the participants	Only one professional administered the dry cupping for all participants during the study. Each participant was informed about the cupping units used during the procedure, the treatment regiment, the systemic acupoints used, and potential side effects, including brief pain in the application site, warm feeling, skin reddening, and purple spots/marks. The spots could take between seven and 15 days to disappear. It was also explained to the participants that, in case of blisters or skin lesions, the participant would be referred to a health care professional for treatment
5. Treatment provider background	Description of treatment provider(s) (qualification or professional affiliation, years in cupping practice, and other relevant experience for professional)	Nurse specialist in cupping therapy, with six years of experience in the area
6. Control or comparator of cupping	a. Rationale for the choice of control or comparator of cupping	This study was conducted with two groups: a control group, which received ear acupuncture, and an experimental group, which received ear acupuncture combined with dry cupping. This study hypothesized that dry cupping can enhance the effects of ear acupuncture
	b. Precise description of the control or comparator. If another form of cupping or cupping-like control is used, provide details as for Items 1 to 3 above	The information about ear acupuncture can be found in Table 1

Interventions were performed in five sessions, once a week, by a nurse specialist in acupuncture, with six years of experience in the area [3,4].

1) Ear acupuncture

Ear acupuncture was performed using semi-permanent, sterile, and disposable needles, size 0.20 × 1.5 mm, alternating the ears at each session [4].

Antisepsis of the ear was performed before the intervention. A Chinese map [20] and an acupoint locator (EL30 Finder NKL Basic^®) with a red differential pen were used for the location of the acupoints.

The following ear acupoints were used (Fig. 2) [4,21]: Shénmén (TF₄); Shèn (CO₁₀); Jiaogan (AH₆); Pizhixia (AT₄); Pangguang (CO₉); Gan (CO_I2); Jlngzhui (AH₁₃); Xiongzhui (AH₁₁); Yaodfzhui (AH₉). The choice of the referred acupoints varied according to the site of the pain.

Figure 2. Ear acupoints.

2) Dry cupping

Acrylic cups of 4.5, 3, or 2.3 centimeters in diameter were used, depending on the application site. A manual suction pump activated the acrylic cups until the skin rose 1.5 centimeters inside the cup [22].

Local asepsis was performed and the cups were applied bilaterally to the dorsal region and fixed for 10 minutes [23]. The acupoints used [24] were the Gallbladder Meridian (GB21: Jianjing; GB30: Huantiao) and the Liver Meridian (LR8: Ququan). In addition, the following acupoints of the Bladder Meridian were used depending on the site of the pain [24]: 1) cervical region: BL10: Tianzhu and BL11: Dazhu; 2) thoracic region: BL12: Fengmen, BL17: Geshu, BL21: Weishu; 3) lumbar region: BL23: Shenshu, BL24: Qihaishu, BL25: Dachangshu (Fig. 3).

Figure 3. Cupping acupoints.

6. Data analysis

The Statistical Package for the Social Sciences^® software (version 23.0) was used for data analysis. Homogeneity between groups by sociodemographic and clinical variables was verified using the Chi-square and Mann-Whitney tests at a 5% significance level.

Continuous variables were compared using a longitudinal model based on a Generalized Estimation Equation (GEE) to evaluate the effect of group allocation, adjusting the effect of time and interaction (group * time). Gamma distribution and logarithmic link function were used. Several covariance (independent, AR (1), interchangeable and unstructured) matrices were evaluated and the model with the lowest Quasi Likelihood Under Independence Model Criterion and the best fit was considered for selection of the final statistical model (unstructured or interchangeable). For significant effects at 5%, the post hoc t-test protected by Bonferroni was used to compare means.

1. Participants baseline demographic and clinical characteristics

Table 3 shows the comparison between groups according to demographic and pain characteristics, highlighting the homogeneity between them (p > 0.05).

^aMann-Whitney test; ^bChi-Square test; ^cPain due to emotional factors, age, overweight, or previous cancer treatment ^dIntervertebral disc degeneration, vertebral axis rotational changes, degenerative spine conditions, nerve root compression; CG = control group; EG = experimental group; EA = ear acupuncture; DC = dry cupping; _x = mean; sd = standard deviation; p = percentile..

&md=tbl&idx=3' data-target="#file-modal"">Table 3

Patient demographics and pain characteristics.

Variables	CG (EA) (n = 94)	EG (EA plus DC) (n = 88)	p-value
Age			0.885a
x ± sd (yr)	47.87 ± 13.18	48.20 ± 11.62
Median (p25-p75) (yr)	50 (40.0-59.0)	48 (40.0-56.0)
Gender			0.870b
Male (%)	16.00	16.90
Female (%)	84.00	83.10
Marital status			0.929b
Single (%)	24.50	24.70
Married/Cohabiting (%)	60.60	62.90
Widowed (%)	5.30	3.40
Divorced (%)	9.60	9.00
Occupation (%)	58.50	55.1	0.637b
Time of pain			0.566a
x ± sd (months)	96.37 ± 117.47	102.19 ± 116.25
Median (p25-p75) (months)	48 (16.5-168.0)	60 (13.5-126.0)
Cause of pain
Fall (%)	12.80	10.10	0.573b
Sedentarism (%)	3.20	4.50	0.646b
Physical (%)	57.40	61.80	0.549b
Otherc (%)	7.40	12.40	0.487b
Pathologies diagnosed through imaging testsd (%)	73.40	60.70	0.067b

^aMann-Whitney test; ^bChi-Square test; ^cPain due to emotional factors, age, overweight, or previous cancer treatment ^dIntervertebral disc degeneration, vertebral axis rotational changes, degenerative spine conditions, nerve root compression; CG = control group; EG = experimental group; EA = ear acupuncture; DC = dry cupping; _x = mean; sd = standard deviation; p = percentile..

2. Intervention effects

There were significant reductions in the interference of general pain with daily activities between EV0 and EV1, and between EV0 and EV2, in the control group and experimental group. Between EV1 and EV2, there was no change. Thus, the reduction achieved in EV1 remained constant until EV2. Also, a greater number of variables showed statistical changes over time in the experimental group. However, no differentiation between groups was observed (Table 4).

^aConfidence interval for difference set at 95%; ^bMean Difference: Control - Experimental; *Statistical significance - the post-hoc t-test protected by Bonferroni was used to compare means (according to Generalized Estimation Equation model)..

EV0 = First evaluation; EV1 = Evaluation one week after the last intervention session; EV2 = Evaluation seven days after the final evaluation; CG = control group; EG = experimental group..

&md=tbl&idx=4' data-target="#file-modal"">Table 4

Analyses of pain interference in daily activities in the two groups.

Group	Mean Difference (CIa)
	Assessments
	EV0	EV1	EV2	EV0-EV1	EV1-EV2	EV0-EV2
Interference of pain
CG (n = 94)	–0.08b (–0.77; 0.62)	0.78b (–0.31; 1.87)	0.87b (–0.08; 1.82)	1.82 (0.79 ; 1.86)*	–0.36 (–1.33; 0.61)	1.47 (0.68; 2.25)*
EG (n = 88)				2.68 (1.75; 3.62)*	–0.28 (–1.21; 0.65)	2.41 (1.49; 3.33)*
Activities
CG (n = 94)	–0.53b (–1.28; 0.23)	–0.78b (–2.20; 0.64)	0.59b (–0.54; 1.71)	1.52 (0.32; 2.72)*	–1.81 (–3.11; –0.52)*	–0.29 (–1.34; 0.76)
EG (n = 88)				1.27 (–0.04; 2.57)	–0.44 (–1.78; 0.89)	0.82 (–0.33; 1.98)
Locomotion capacity
CG (n = 94)	0.15b (–0.64; 0.94)	–0.19b (–1.84; 1.45)	1.19b (–0.03; 2.40)	1.02 (–0.46; 2.50)	–1.00 (–2.75; 0.76)	0.02 (–1.06; 1.11)
EG (n = 88)				0.68 (–0.87; 2.23)	0.38 (–1.30; 2.07)	1.06 (–0.10; 2.23)
Work
CG (n = 94)	–0.03b (–0.63; 0.68)	–0.58b (–1.81; 0.65)	0.30b (–0.80; 1.41)	1.67 (0.66; 2.67)*	–0.75 (–1.78; 0.28)	0.92 (–0.08; 1.94)
EG (n = 88)				1.11 (–0.08; 2.30)	0.14 (–1.05; 1.32)	1.25 (0.16; 2.33)*
Mood
CG (n = 94)	–1.03b (–1.81; –0.25)	–0.47b (–2.40; 1.46)	0.30b (–1.16; 1.76)	1.02 (–0.98; 3.03)	–0.88 (–2.99; 1.23)	0.15 (–1.22; 1.52)
EG (n = 88)				1.58 (0.36; 2.81)*	–0.10 (–1.40; 1.20)	1.48 (0.30; 2.67)*
Relationships
CG (n = 94)	–0.57b (–1.67; 0.54)	–1.69b (–5.00; 1.61)	1.32b (–0.64; 3.28)	1.89 (–1.93; 5.72)	–2.18 (–5.84; 1.48)	–0.28 (–2.50; 1.93)
EG (n = 88)				0.77 (–1.34; 2.88)	0.84 (–1.23; 2.90)	1.61 (0.27; 2.12)*
Pleasure of living
CG (n = 94)	–0.20b (–1.04; 0.65)	–1.42b (–3.53; 0.69)	0.65b (–1.24; 2.55)	1.18 (–0.74; 3.10)	–0.71 (–3.57; 2.15)	0.47 (–1.47; 2.41)
EG (n = 88)				–0.04 (–1.83; 1.75)	1.36 (–0.48; 3.20)	1.32 (–0.08; 2.71)
Sleep
CG (n = 94)	–0.34b (–0.93; 0.26)	–0.49b (–1.92; 0.94)	0.18b (–1.15; 1.51)	1.32 (–0.29; 2.92)	–0.70 (–2.79; 1.39)	0.62 (–0.66; 1.90)
EG (n = 88)				1.17 (0.17; 2.16)*	–0.03 (–1.34; 1.28)	1.14 (0.09; 2.18)*

^aConfidence interval for difference set at 95%; ^bMean Difference: Control - Experimental; *Statistical significance - the post-hoc t-test protected by Bonferroni was used to compare means (according to Generalized Estimation Equation model)..

EV0 = First evaluation; EV1 = Evaluation one week after the last intervention session; EV2 = Evaluation seven days after the final evaluation; CG = control group; EG = experimental group..

The perception of quality of life improved in the control and experimental groups, between EV0 and EV1. Only the experimental group presented a significant increase between EV0 and EV2. The changes that occurred in EV1 remained constant until EV2 (Table 5).

^aConfidence interval for difference set at 95%; ^bMean Difference: Control - Experimental; *Statistical significance - the post-hoc t-test protected by Bonferroni was used to compare means (according to Generalized Estimation Equation model)..

EV0 = First evaluation; EV1 = Evaluation one week after the last intervention session; EV2 = Evaluation seven days after the final evaluation; CG = control group; EG: experimental group..

&md=tbl&idx=5' data-target="#file-modal"">Table 5

Analyses of quality of life in the two groups.

Group	Mean Difference (CIa)
	Assessments
	EV0	EV1	EV2	EV0-EV1	EV1-EV2	EV0-EV2
General perception of quality of life
CG (n = 94)	0.80b (–4.04; 5.64)	–1.15b (–5.47; 3.18)	–5.82b (1.16; 10.48)*	–5.85 (–9.71; –1.98)*	2.95 (–0.69; 6.60)	–2.90 (–7.03; 1.24)
EG (n = 88)				–7.80 (–12.43; –3.16)*	–1.72 (–5.50; 2.05)	–9.52 (–13.79; –5.25)*
Satisfaction with health
CG (n = 94)	1.27b (–4.23; 6.78)	–5.22b (–10.43; –0.01)*	–2.54b (–8.29; 3.19)	–7.82 (–12.49; –3.13)*	0.27 (–3.40; 3.94)	–7.54 (–12.04; –3.04)*
EG (n = 88)				–14.31 (–19.05; –9.57)*	2.94 (–1.98; 7.87)	–11.37 (–16.94; –5.80)*
Physical domain
CG (n = 94)	0.76b (–3.33; 4.86)	–3.82b (–8.01; 0.36)	–2.68b (–7.28; 1.91)	–9.46 (–12.41; –6.50)*	0.39 (–2.23; 3.00)	–9.07 (–12.31; –5.82)*
EG (n = 88)				–14.04 (–17.20; –10.88)*	1.52 (–1.68; 4.73)	–12.52 (–16.01; –9.02)
Psychological domain
CG (n = 94)	0.12b (–4.77; 5.00)	–0.47b (–5,00; 4,05)	–2.28b (–6,56; 1,98)	–3.01 (–6.29; 0.27)	0.30 (–2.25; 2.85)	–2.71 (–5.49; 0.70)
EG (n = 88)				–3.60 (–6.92; –0.28)*	–1.51 (–4.00; 0.98)	–5.12 (–8.56; –1.67)*
Social relationships
CG (n = 94)	–0.43b (–4.96; 4.09)	0.81b (–3.75; 5.37)	–2.52b (–7.05; 2.00)	–2.83 (–5.62; –0.04)*	2.27 (–0.75; 5.31)	–0.55 (–3.48; 2.36)
EG (n = 88)				–1.59 (–4.63; 1.44)	–1.05 (–3.74; 1.63)	–2.64 (–5.61; 0.32)
Environment
CG (n = 94)	–3.47b (–6.82; 0.12)	–2.78b (–6.06; 0.48)	–2.65b (–5.97; 0.68)	–2.16 (–4.40; 0.08)	–0.06 (–2.02; 1.88)	1.03 (–4.70; 0.25)
EG (n = 88)				–1.47 (–3.78; 0.84)	0.08 (–2.09; 2.25)	–1.39 (–3.82; 1.03)

^aConfidence interval for difference set at 95%; ^bMean Difference: Control - Experimental; *Statistical significance - the post-hoc t-test protected by Bonferroni was used to compare means (according to Generalized Estimation Equation model)..

EV0 = First evaluation; EV1 = Evaluation one week after the last intervention session; EV2 = Evaluation seven days after the final evaluation; CG = control group; EG: experimental group..

Satisfaction with health and the physical and psychological domains also improved between EV0 and EV1, and between EV0 and EV2. Between EV1 and EV2, both groups remained constant over time. The social relations domain improved only in the control group between EV1 and EV2. There was no difference over time in the environment domain (Table 5).

Differentiation between groups was observed in EV2 in the perception of quality of life and EV1 in satisfaction with health, with a significant improvement for the experimental group (Table 5).

In our study, both EA and EA combined with DC treatments had a positive impact on most of the variables investigated, especially in the quality of life.

The Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT) recommends that physical and emotional functionalities, which are central components of health-related quality of life, be evaluated in all randomized clinical trials (RCT) of treatments for chronic pain [25]. Changing a point on the scale of interference of pain with daily activities is reasonable to identify small but clinically important changes [25]. In this study, a reduction of 1.82 points in EV1 and 1.47 points in EV2 in relation to EV0 was seen in the control group, and of 2.68 and 2.41, respectively, in the experimental group, reaffirming the positive effects of the interventions.

It is known that chronic pain can compromise work productivity. In the present study, EA reduced the interference of pain with work productivity by 1.67 points between EV0 and EV1 in the control group. In the experimental group, we observed that EA combined with DC reduced the interference of pain with work productivity by 1.25 points between EV0 and EV2. Our results demonstrate the potential of EA in reducing the interference of pain in work productivity and its lasting effects on the population under study.

Another study described that fear of performing work activities dropped by 2 points in the group that received four sessions of ear acupressure with seeds [26]. Cupping therapy can also bring positive results in relation to work given its contribution to reducing the level of pain, and consequently, physical disability [27], leading to the resumption of activities. To date, no randomized controlled trial has been identified that assessed the impact of DC on work activity, which is secondary to pain relief, demonstrating the innovations in terms of knowledge obtained in the present study.

An improvement in the relationship with other people in the experimental group was also observed, like pain, when intense and disabling, can cause social and family isolation [28]. It is noteworthy that no study with EA or DC applied to patients with pain discussing such a relationship was found.

Regarding mood changes, depression and anxiety stand out, as they can be triggered by chronic pain or can act as risk factors for its development [29]. These mood changes have an impact on the quality of life of people with chronic back pain who do not have an effective assessment, monitoring, and therapeutic resources for their treatment/control.

Ear acupuncture has been shown to be effective for controlling emotional changes. As in the present study, research has shown that patients with chronic low back pain who received ear acupressure reported decreased anxiety after four weeks from baseline, compared to a sham group [26]. In relation to DC, a study carried out with workers with cervical pain found a reduction in psychological symptoms in the group that received the cupping therapy compared to the group that received the heating pad [29]. Such results suggest that, although this intervention can be used for the treatment of painful and emotional conditions.

Sleeping is also affected by chronic pain [30]. In this study, there was a reduction in the interference pain with sleep in the experimental group, whereas the change observed in the control group was not significant. The DC in addition to EA contributed to improving the quality of sleep.

Researchers found a reduction in the symptoms of insomnia in groups treated with cupping therapy and benzodiazepines [31]. Thus, DC proved to be a promising therapeutic resource for sleep disorders, and even better results are expected when associated with EA.

Quality of life is also affected by pain. A study conducted with 17,249 people reported significant associations between the indicators of physical and mental health and the presence of pain and a significant reduction in quality of life [32].

In the present study, the general perception of quality of life improved significantly between EV0 and EV1 in both groups, and between EV0 and EV2 only in the experimental group. Also, in EV2, the experimental group improved 8.86% more than the control group. In other words, the association of DC with EA also enhanced the health-related quality of life.

A study [26] that evaluated the quality of life in people with chronic low back pain found no difference in the group that received ear acupressure with seeds when compared to the sham group. Perhaps the application with seeds contributed to this, for superior effects of EA are found when performed with invasive devices [33].

Dry cupping was able to enhance the scores of the perception of quality of life when compared to the application of EA by itself, in addition to the maintenance of this effect one week after the end of the treatment. A systematic review concluded that cupping therapy is associated with improved quality of life in patients with cervical pain. However, due to the low quality of the evidence, the review did not present definitive conclusions [34].

In the present study, an improvement in the physical domain was also observed in both groups. It is noteworthy that, this domain not only encompasses physical mobility but also issues related to energy, fatigue, activities of daily living, dependence on medication, and ability to work [18]. Thus, its evaluation in a study comparing treatments for chronic pain is important.

A randomized clinical trial found that, after two sessions, the EA associated with obstetric treatment improved the physical domain of quality of life in pregnant women with low back pain [35]. However, to date, no recent evidence has been found addressing the effect of EA in this domain in people with chronic back pain. In relation to DC, a RCT also found that the pulsatile modality was able to improve the physical component of quality of life in people with chronic low back pain, with the effect lasting up to eight weeks after treatment [36]. Such findings underscore the importance of performing RCT with a longer follow-up period.

Chronic pain also affects the quality of life through the psychological component [37]. In this study, there was an improvement in this domain only in the experimental group. Conversely, a study by Lauche et al. [38], which also applied five DC sessions, found no significant psychological changes, which may have been due to the study’s small sample size.

In addition to the emotional impact, people with chronic pain face difficulties to maintain work and leisure activities and tend to slow down social life. In this study, there was an improvement of 4.18% between the beginning and the end of the treatment only in the control group. It is noteworthy that a month of treatment is a short period to find significant differences in this variable. Therefore, it is necessary to further investigate the changes that occurred in the social relations domain related to a longer treatment period.

A RCT pointed out an improvement in the social domain in people with chronic low back pain who received four sessions of ear acupressure [26]. It is believed that, in the present study, a longer time of application of the intervention would be necessary to bring more expressive results, both in the control and experimental groups.

Finally, there was no difference over time and between groups in the environment domain of the WHOQOL-BREF. Pain relief can contribute to improving well-being, disposition, and social interaction, and these factors can influence some aspects that are assessed in the environmental domain, such as the opportunity to acquire new information, and skills, and participation in recreation and leisure activities. However, data collection and the interventions sessions of our study were conducted during seven weeks, which is a time considered short for changes of this magnitude. Perhaps longer periods of treatment and follow-up time may reveal positive changes in this dimension of quality of life.

The limitations of this study are: 1) due to the nature of the DC intervention and the marks left on the skin after the procedure, it was not possible to blind the participants and researchers to the intervention being performed; however, the statistician in the team conducted blinded analyzes; 2) the application of fixed protocols for interventions, which may go against the basic precepts of a RCT; however, satisfactory and significant results were achieved; 3) Regarding DC, no acupoints of the second branch of the Urinary Bladder meridian, which have emotional functions, were used, besides points of the Governing Vessel meridian, which benefit the lower back, and Small Intestine meridian points, which act in the cervical and thoracic regions; 4) no placebo or waitlist control group was used.

In view of the results found in our study, it is evident the great potential of long-lasting effects of EA and DC in reducing the interference of pain on daily activities, physical and psychological aspects, and social relationships, the perception of quality of life, and satisfaction with their health for those suffering from chronic pain. These interventions can represent adjuvant or even the main therapeutic approach, in addition to enabling holistic and less medicalized care. Therefore, the implementation of these resources in clinical practice becomes valuable.

EA and EA combined with DC positively impacted the performance of daily activities and the quality of life of people with chronic back pain. The use of the interventions EA in association with DC showed better results in terms of a general perception of quality of life and satisfaction with health.

This work was supported by the Fundação de Amparo a Pesquisa de Minas Gerais (FAPEMIG) [grant number: APQ-01681-18] and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) [financing code 001].

C.C.M, E.C.L.C and T.C.M.C conceived the study. C.C.M, C. A, GAP and HMS conducted the data collection. C. C. M, D.H.I and T.C.M.C did funding acquisition. D.A.N conduced the statistical analysis. C.C.M and T.G.R.M. writing the original draft. All authors have read and approved the final manuscript.

The data set generated and analyzed during the study are available from the corresponding author on reasonable request.

The authors declare no conflict of interest.