Minimal-Resource Home Exercise Program Improves Activities of Daily Living, Perceived Health Status, and Shortness of Breath in Individuals with COPD Stages GOLD II to IV

Abstract

Home exercises (HE) with minimal resources seem to be useful in individuals with COPD. The objective was to evaluate the effects of HE, on activities of daily living (ADL), dyspnea, on the health status(CAT) and quality of life (HRQoL) of individuals with COPD GOLD II to IV. Quasi-experimental study of the effects of HE, for 2 months, 3 times a week. Individuals with COPD(n = 45) were recruited, 37 started the protocol(9 did not complete it). 28 individuals (mean age 62.04 ± 5.8 years, FEV1: 44.7 ± 2.25%, FEV1/FVC 59.8 ± 6.9%) were evaluated before and after training. We observed improvements in the ADL-Glittre (4.9 ± 1.4 vs 3.9 ± 1.1 min; mean difference: −0.9 ± 0.2 min [95%CI: −1.3 to −0.2]; p = 0.008), as well as the mMRC score(2.8 ± 1.1 vs 2.07 ± 0.81; mean difference: 0.7 ± 0.3 [95%CI: −1.20.18 to −0.2]; p = 0.009), and in the CAT (25.6 ± 4.8 vs 18.9 ± 3.1; mean difference: −6.6 ± 3.4 [95%CI: −10.6 to −1.6]; p = 0.042). Analyzing the mean change before and after the intervention, a weak correlation was observed between ADL-Glittre and mMRC (r = 0.35; [95% CI 0.09; 0.56]; p = 0.009); moderate between ADL-Glittre and CAT (r = 0.52; [95% CI 0.30; 0.69]; p < 0.001) and between ADL-Glittre and SGRQ (r = 0.50; [95% CI 0 .27; 0.67]; p < 0.001). Individuals with COPD can benefit from HE performed autonomously and with minimal resources, as this proposal improves functional capacity for ADL, health perception and dyspnea.

Keywords:

• Chronic obstructive pulmonary disease
• daily activities
• symptoms
• physiotherapy
• home-based exercises

Introduction

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition characterized by chronic respiratory symptoms (dyspnea, cough, sputum production and/or exacerbations) due to abnormalities of the airways (bronchitis,bronchiolitis) and/or alveoli (emphysema) that cause persistent, often progressive, airflow obstruction and is one of the most important causes of death in most countries. It is estimated that around three million deaths occur annually in the world due to COPD with an expected increase in its prevalence and the burden on health systems in the coming decades [1,2]. Dyspnea, fatigue, and exercise intolerance are common symptoms of COPD, with consequent worsening in health-related quality of life (HRQoL) [3]. Exercise-induced dyspnea is the most common symptom and can appear even during activities of daily living (ADL). Shortness of breath can also occur at rest, particularly in more severe cases. The reduction in ADL performance negatively impacts functionality and HRQoL [4,5]. Thus, intervention strategies that improve ADL are essential [6]. Therefore, a home exercise program performed autonomously and designed for this purpose can improve the functional limitations triggered by this clinical condition [4,5,7].

Pulmonary rehabilitation(PR) is a comprehensive intervention based on a thorough patient assessment, followed by personalized therapies that include, but are not limited to, physical training, education and behavior change, designed to improve the physical and emotional condition of people with chronic respiratory disease and to promote long-term adherence to health-enhancing behaviors, which can be performed in rehabilitation centers or even at home[4]. Despite the strong evidence of benefits, the proportion of people with COPD who have access to pulmonary rehabilitation programs is still small [8]. It is estimated that 50% of referred individuals will never attend [9,10], and treatment dropout rates range from 10-32% [11,12]. The most common barriers to adherence are the cost of traveling to rehabilitation centers and the availability of time to dedicate to treatment [9,11]. Given these difficulties, home self-care strategies seem to be an alternative that can facilitate access and adherence to treatment [13–15]. Pulmonary rehabilitation (PR) at home is an alternative, safe model that provides the essential components for the treatment, is accessible to individuals, easy to perform, and with clinical results and benefits equivalent to those achieved in reference centers [16,17]. However, there is still little evidence on the benefits of home exercises performed autonomously on ADL, symptoms, health perception, and QoL of individuals with COPD.

Therefore, the objectives of this study were: to evaluate the effects of a home exercise program, performed autonomously, on the (i) functional capacity for ADL, (ii) dyspnea, (iii) health status and HRQoL of individuals with COPD, (iv) comparing the results of the home intervention with individuals in GOLD II stages to the IV and (v) verify the correlation between these results after the program.

Methods

Participants

A quasi-experimental (before-and-after) study was performed, including individuals with a diagnosis of COPD, classified as GOLD II-IV [1], recruited at the Newton Bethlem Health Post of the City of Rio de Janeiro, and the Rehabilitation center of the Military Police (CFRPM), in the State of Rio de Janeiro, Brazil. According to the recommendations of the Helsinki Declaration, the protocol was approved by the Research Ethics Committee of the Augusto Motta University Center (UNISUAM)/Brazil Platform, (CAAE: 64805317.7.0000.5235), and all participants signed an informed consent form.

Intervention

The home exercise program lasted two months and consisted of breathing exercises(deep breathing), stretching, muscle strengthening, balance training, and aerobic training (illustrated in booklet format).

Education regarding the use of the illustrated exercise booklet

After an initial assessment, this material was delivered in person, and the execution of the proposed exercises was demonstrated, clarified, and trained by a senior physical therapist specializing in exercise science. Individuals were instructed to perform the activities for at least three days/a week. The exercise program was designed to be simple and fully free of charge for the participants .

Equipments

Training equipment was not provided; materials contained in the patient’s own home were used to produce training load in the patient’s own home, such as a chair and a 1 to 4 kg pack of groceries. All individuals were instructed to perform the exercises prefereably at the same time of the day (chosen by the participant), wearing comfortable clothes.

Exercise sessions

Daily exercise sessions were organized sequentially by stretching followed by free exercises for global mobility. Subsequently, the individuals performed exercises for strengthening, localized muscular resistance and aerobic training. At the end, the subjects performed ventilatory control, relaxation and mindfulness exercises. Each session was planned to last approximately 90 to 120 min. Weekly telemonitoring was carried out to checklist the performance of tasks and adjust, if necessary, specific guidelines on certain tasks or exercises.

Stretching exercises

The daily exercise sessions started with a set of stretching exercises for the muscles of the neck, shoulders, upper limbs, trunk and lower limbs, sustaining thirty seconds in the stretching position and thirty seconds of rest, followed by free exercises for the mobility of the upper limbs, lower limbs and trunk. These steps lasted ten minutes.

Strength exercises

The volunteers performed strength and localized muscular resistance training, in three series of 8-10 repetitions, for all exercises using household utensils and their own body weight as a load. Strengthening of the upper limbs was performed in an orthostatic position with shoulder abduction exercises in the scapula plane, shoulder flexion with an extended elbow, and elbow flexion followed by shoulder flexion above the head. Subsequently, lying down, they performed adduction of the upper limbs in the horizontal plane. For the lower limbs, strengthening exercises were performed in a closed kinetic chain, performing squats in bipedal support and load supported by a backpack on the back or holding a weight in the hands, followed by platinum flexion and stair climbing exercises. These strengthening steps lasted around 30 to 45 min.

Aerobic training

In addition to muscle strengthening exercises, all individuals were instructed to walk freely for thirty minutes at a step speed enough of producing an effort capable of maintaining the sensation of dyspnea and fatigue on the modified Borg scale(contained in the available booklet) between 4 and 6 BORG [18].

Ventilatory control strategies

In the end, all individuals underwent ventilatory control, relaxation and mindfulness exercises.

Assessments

Spirometry analysis was conducted following the standard protocols of the American Thoracic Society/European Respiratory Society [19] The analyzed parameters were the forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), the FEV1/FVC ratio. These parameters were expressed as absolute values and as a percentage of the predicted values, and the reference values were obtained from the equations of Pereira et al. [20]. Lung function data were collected at post-bronchodilator test.

The home exercises were weekly telemonitored by phone contact from the same professional. This telemonitoring accompanied the execution of the exercise protocols, as well as resolved doubts that could arise, guiding the load progression and encouraging the execution of the tasks proposed in the study. Individuals were instructed to increase weight and repetitions whenever the effort intensity was <4 by the Borg scale, as well as they were asked to reduce weight and repetitions or increase the rest interval between exercises if they presented severe dyspnea (equivalent to Borg ≥7) [4]. Those who completed 70% of the sessions of the home training program were included as adherents [16,21,22].

After all the home sessions, the individuals reported in the diary contained in the booklet their effort before, during, and after the exercises, the days of the week in which they performed the activities, and the difficulties encountered during the execution.

The ADL-Glittre test was used to assess functional capacity, which was performed according to the protocol proposed by Skumlien et al. [23]. It consists of performing five laps of a task circuit and carrying a backpack (2.5 kg for women and 5 kg for men). The course consists of a 10 m corridor and involves the following activities: from the sitting position, the individual walks on a flat path, interposed in its half by a box with three steps (17 cm high x 27 cm wide) to up and down; at the end of the corridor, the individual moves three objects of 1 kg each, positioned at shelf most high (height From shoulders) from a bookcase, one by one, to the lowest bracket (waist height) and then to the floor; the objects are then replaced on the lowest shelf and later on the highest shelf; the individual then returns, doing the course in reverse and sitting down in the chair. This sequence corresponds to one lap. Immediately after completing it, the individual gets up from the chair and starts another turn. This sequence should be performed in the shortest possible time, and the shorter the time spent on the ADL-Glittre test, the faster the individual will have performed the test and this represents a better functional capacity to perform ADL [23,24]. During the initial assessment and reassessment, all individuals performed two tests, with an interval of 60 min between them, to ensure full recovery of the patient between tests and thus prevent any worse performance in the second test as a consequence of the tiredness and fatigue produced by the first test. Same. The test with the least time spent was considered for the analysis [23]. The ADL-Glittre test is valid and reliable for assessing the functional capacity of individuals with COPD during ADL [23], responsive to a pulmonary rehabilitation program [23,24], with a reduction of 0.38 min (23 s) in its execution time considered the minimal important difference (MID) [24].

The COPD Assessment Test (CAT) was applied through an interview to assess the health status. It consists of eight items, with the patient reporting a score from 0 to 5 for each item [25]. The total score ranges from 0 to 40, and the higher its value, the worse the patient’s health ­status. This questionnaire is validated for the Brazilian population [26] and has an MID of −3.8 to −1.0 points [27].

Dyspnea was assessed using the modified Medical Research Council scale (mMRC), which has five scores (0 to 4), with higher scores reflecting more significant dyspnea related to ADL [28]. The scale is valid for the Brazilian population, and its MID is −1 point [29].

QoL was assessed using the modified Brazilian version of the Saint George Respiratory Questionnaire (SGRQ), which addresses aspects related to three domains: activities, symptoms, and psychosocial factors. The score ranges from 0 to 100%, and higher values reflect the worse quality of life. Changes ≥ 4% after an intervention indicate a clinically relevant difference in HRQOL [30,31].

Statistical analysis

Statistical analysis of the data was performed using the JASP software (JASP Team (2019), version 0.10.2). The sample calculation was performed using the R software (https://www.r-project.org/), “pwr” package (https://CRAN.R-project.org/package=pwr) [32]. For the calculation, we considered an average reduction in time spent on ADL-Glittre test equal to an MID of −0.38 min [24] and power based on the Cohen model [32] of 0.88 with a standard deviation of 0.46. Assuming α = 0.05, β = 0.8, standard deviation = 0.46 and “margin” set at −0.38 min, the minimum number of individuals required for this study was 11.

The Shapiro-Wilk test was used to verify data distribution. The data showed a normal distribution. The paired Student’s t-test was used to compare the means of time spent on the ADL-Glittre test, CAT, and SQRQ scores before and after the intervention. We calculated all pvalue adjusting for the false discovery rate (FDR method). Pearson’s correlation coefficient was used to verify a correlation between the changes (post-pre) after the intervention in the ADL-Glittre test, CAT, and SGRQ. The following classification was considered: 0.9 − 1 very strong correlation; 0.7 − 0.9 strong; 0.5 − 0.7 moderate; 0.3 − 0.5 weak and 0 − 0.3 correlation negligible [33]. The significance level adopted for all analyzes was 5%.

Results

Initially, 45 individuals with COPD, former smokers, were recruited, thirty-seven individuals started the protocol, but nine did not finish it (dropout 24.3%). The reasons for exclusions and losses are described in Figure 1. Therefore, twenty-eight individuals(mean age of 62.04 ± 5.8 years, FEV₁: 44.7 ± 2.25%, FEV₁/FVC 59.8 ± 6.9% predicted and BMI: 22.9 ± 5.4 kg/m²), with COPD completed the study, 39.3%, 32.1%, and 28.6% classified how GOLD II, III, and IV, respectively. The sample’s demographic characteristics at the beginning of the study are summarized in Table 1.

Figure 1. CONSORT diagram of patient enrollment into the study.

Table 1. Demographic data of the sample at the time of the initial assessment.

	General group – Baseline	GOLD 2	GOLD 3	GOLD 4
No, groups	28	11	9	8
Age, years	62.3 ± 5.4	58.0 ± 3.2	60.2 ± 4.6^a	64.4 ± 4.6^b,c
Male, %(n)	57.1(16)	45.4(5)	44.4(4)	87.5(7)^c
BMI, kg/m^2	22.9 ± 5.4*	24.9 ± 6.4	22.3 ± 4.4	20.9 ± 4.7^b,c
Smoking load, packs/year	51.9 ± 20.2	36.4 ± 11.8	51.9 ± 20.2^a	58.0 ± 12.8^b,c
FEV1, L	1.23 ± 0.06	1.77 ± 0.08	1.06 ± 0.05^a	0.68 ± 0.04^b,c
FEV1, %	44.7 ± 2.25*	65.1 ± 2.0	39.6 ± 1.0^a	24.2 ± 4.0^b,c
FVC, L	2.92 ± 0.21	3.36 ± 0.19	2.62 ± 0.18^a	2.35 ± 0.24^b,c
FVC, %	75.8 ± 4.1	93.2 ± 4.3	77.2 ± 4.4^a	56.3 ± 3.6^b,c
FEV1/FVC, %	59.8 ± 6.9*	55.2 ± 1.9	42.8 ± 2.2^a	28.4 ± 2.6^b,c
CAT	25.4 ± 3.7	20.6 ± 4.3	25.2 ± 3.6^a	30.6 ± 2.2^b,c
mMRC	2.8 ± 1.1	2.2 ± 0,6	2.9 ± 0,4^a	3.3 ± 0,3^b,c
Exacerbations/year	0.8 ± 1.1	0.3 ± 1.2	0.6 ± 0.5^a	1.7 ± 0.9^b,c
Hospitalizations/year	0.4 ± 0.39	0	0.32 ± 0,28	0.8 ± 0.5^b,c

Results expressed as mean ± SD or number. GOLD: Global Initiative for Chronic Obstructive Lung Disease; BMI: body mass index; FEV _1: forced expiratory volume in the first second; FVC: forced vital capacity. *Significant difference at baseline between individuals with COPD GOLD II, III and IV. Adjusted p- value for the false discovery rate (FDR method). ^aSignificant difference compared with patients with COPD stage II (adjusted pvalue = 0.001); ^bSignificant difference compared with patients with COPD stage II (adjusted pvalue = 0.001); ^cSignificant difference compared with patients with COPD stage III (adjusted pvalue = 0.001).

After the home exercise program, there was a reduction in the time spent on the ADL-Glittre test (mean difference: −0.9 ± 0.2 min [95%CI: −1.3 to −0.2]; p = 0.008), as well as the mMRC score (mean difference: 0.7 ± 0.3 [95%CI: −1.20.18 to −0.2]; p = 0.009), and in the COPD assessment test (CAT) (mean difference: −6.6 ± 3.4 [95%CI: −10.6 to −1.6]; p = 0.042) (Table 2). There was no statistically significant difference either in the global SGRQ score or in the domains for the 28 individuals with COPD pre and post intervention, were as follow: mean difference: 12.6 ± 6.7 [95%CI −26.1 to −1.88]; p = 0.06, “symptoms”, “activities” and “psychosocial impacts” domains also showed no statistically significant difference (mean difference: 15.0 ± 7.2 [95%CI −26.1 to −0.6]; p = 0.06, mean difference: −14.1 ± 6.4 [95%CI: −27.1 to −1.2]; p = 0.06 and mean difference: 11.4 ± 7.3; p = 0.06), respectively (Table 4).

Table 2. The difference in ADL- Glittre time, CAT, and mMRC pre and post-intervention.

		Mean ± SD	Difference between means ± standard error	95%CI	Adjusted p value #	Cohen’s D
ADL –Glittre time, min	Pre- Intervention	4.9 ± 1.4
	Post - Intervention	3.9 ± 1.1	−0.9 ± 0.2	(-1.3; −0.2)	0.013*	0.74
CAT	Pre- Intervention	25.6 ± 7.76
	Post - Intervention	18.9 ± 9.1	−6.6 ± 3.4	(-10.6; −1.6)	0.040*	0.63
mMRC	Pre- Intervention	2.8 ± 1.1
	Post - Intervention	2.07 ± 0.81	−0.7 ± 0.3	(-1.2; −0.2)	0.013*	0.72

Results expressed as mean ± SD or number. CI: confidence interval. Cohen’s d: effect size measure for comparing differences between means. CAT: COPD assessment test; mMRC: Medical Resource Council modified dyspnea scale.* Statistically significant compared to pre-intervention. # Adjusted p-value for the false discovery rate (FDR method).

Table 3. Comparative analysis between the means of variation of time after intervention (min) of the ADL- Glittre time and the score of the COPD Assessment test (CAT) among COPD individuals with different severity profiles.

	GOLD	Difference between means ± standard error	Adjusted p value*	Cohen’s D	95% CI
Δ ADL –Glittre time, min	2-3^#	0.2 ± 0.3	0.809	0.18	(−0.6; 1.1)
	2-4^#	−1.3 ± 0.4	0.002	−1.01	(−2.2; −0.4)
	3-4^#	−1.5 ± 0.4	0.002	−1.45	(−2.4; −0.6)
Δ CAT	2-3	−9.9 ± 1.7	0.002	−1.05	(−14.0; −5.7)
	2-4	−18.9 ± 1.8	0.002	−1.55	(−23.2; −14.5)
	3-4	−11.1 ± 1.7	0.002	−1.26	(−13.1; −5.0)

Results expressed as mean ± standard error. CI: confidence interval. Cohen’s d: effect size measure for comparing differences between means; GOLD: Global Initiative for Chronic Obstructive Lung Disease CAT: COPD Assessment Test. ^#Statistically significant relative to baseline. *Adjusted p-value for the false discovery rate (FDR method).

Table 4. Quality of life analysis by the SGRQ and its subdomains before and after the intervention.

		Mean ± SD	Difference between means ± standard deviation	Adjusted p value*	Cohen’s D	95% CI
SGRQ - Symptoms	Pre- Intervention	65.5 ± 12.5
	Post - Intervention	60. 5 ± 10.5	15.0 ± 7.2	0.06	0.67	−29.5; −0.6;
SGRQ - Activities	Pre- Intervention	53.5 ± 11.0
	Post - Intervention	49.5 ± 9.1	14.1 ± 6.4	0.06	0.69	−27.1; −1.2;
SGRQ- Psychosocial Impacts	Pre- Intervention	37.4 ± 17.5
	Post - Intervention	33.8 ± 16.4	11.4 ± 7.3	0.06	0.12	−1.2; 25.0
Total SGRQ	Pre- Intervention	50.6 ± 17.7
	Post - Intervention	46.2 ± 12.8	12.6 ± 6.7	0.06	0.68	−26.1; −1.9;

Results expressed as mean ± standard deviation. CI: confidence interval. Cohen’s d: effect size measure for comparing differences between means; SGRQ: Saint George’s Hospital questionnaire on respiratory disease. *Adjusted p- value for the false discovery rate (FDR method).

It is noted that when the ADL were analyzed among individuals with different stages of severity by GOLD, there is a statistically significant difference in the ADL-Glittre test only in individuals GOLD 3 (p = 0.012) and 4 (p < 0.001), which does not occur in individuals classified as GOLD 2 (p = 0.696) (Figure 2).

Figure 2. Comparative analysis of the intervention in the duration of the ADL-Glittre in COPD individuals with different GOLD classification criteria. *Statistically significant compared to baseline (adjusted p – value = 0.012) Adjusted p- value for the false discovery rate (FDR method. **Statistically significant compared to baseline (adjusted p – value = 0.002) Adjusted p- value for the false discovery rate (FDR method).

Comparing the responses to the intervention (mean of the differences = intervention - pre-intervention) grouping the individuals according to the GOLD classification, it was observed that the most severe individuals (GOLD 4) presented more significant variations after the intervention when compared to the GOLD 2 individuals and the GOLD 3 ([CI 95% (-2.19;-0.43); p = 0.002] and [CI 95% (-2.45;-0.60); p < 0.001], respectively) (Table 3).

Analyzing the behavior of the CAT variation before and after the intervention (mean difference = intervention - pre-intervention) between each GOLD profile, it is evident statistically different responses of the intervention in relation to the CAT in individuals with COPD classified as GOLD 2 vs GOLD 3, GOLD 2 vs GOLD 4 individuals and GOLD 3 vs. GOLD 4 ([CI 95% −14.02; −5.70]; p < 0.001; [CI 95% −23.24; −14.53]; for <0.001; [CI 95% −13.05; −4.99]; to <0.001), respectively) (Table 3).

Based on these results, we jointly analyzed the mean variation before and after the intervention, in the time to perform the ADL-Glittre test, in the CAT and mMRC scores to analyze whether the impacts of home exercises, with low resources, performed autonomously, present similar responses in activities of daily living, in the perception of health status, in symptoms and in quality of life. In this context, we observed a weak and statistically significant correlation between the mean variation (pre and post-intervention) of the time to perform the ADL-Glittre test and the mMRC (r = 0.35; [95% CI 0.09; 0.56]; p = 0.009), and a moderate and statistically significant correlation between the mean variation of the ADL-Glittre test and the CAT (r = 0.52; [95% CI 0.30; 0.69]; p < 0.001), and between the mean difference of the ADL-Glittre test and the SGRQ score (r = 0.50; [95% CI 0.27;0.67]; p < 0.001) and a correlation strong and statistically significant difference between the mean CAT score difference and the mean SGRQ difference before and after the intervention. (r = 0.86; [95% CI 0.77;0.91]; p < 0.001) (Figure 3).

Figure 3. Correlation matrix (pearson’s correlation) between the mean variation (pre and post-intervention) in the time to perform the ADL-Glittre test, min, in the COPD assessment test (CAT), in the Medical resource Council modified dyspnea scale (mMRC), and the Saint George’s Hospital questionnaire on respiratory disease (SGRQ). r = Pearson’s correlation coefficient, CI: 95% confidence interval. * statistically significant correlation. Adjusted p- value for the false discovery rate (FDR method

Discussion

The main result of the present study demonstrated that a low-cost, performed autonomously home exercise program, guided by an illustrated task booklet, had an impact on the improvement of functional capacity for ADL, dyspnea, health status a in individuals with COPD in GOLD stages II to IV. However, no statistically significant differences were found in the SGRQ Global and your domains Score. Although individuals with COPD GOLD I present symptoms and eventually limitations in ADL, we took into account the profile of individuals commonly admitted to our supervised pulmonary rehabilitation program. Thus, the objective of the study was to evaluate the impacts of performed autonomously home exercises, guided by a booklet for individuals with COPD stages from GOLD II to IV and for this reason, individuals classified as mild COPD were excluded.Several studies have already evaluated the impact of pulmonary rehabilitation based on home exercises on the functional capacity of individuals with COPD [15,16,21,22,34–38]. However, few studies have analyzed the effects of low-resource home interventions, centered on performed autonomously exercises guided by an illustrated booklet. on ADL, symptoms, perception of health status, and QoL of individuals with COPD. The difference in this study lies in the low-resource, self-performed interventions at home and the use of objective measures to assess ADL after the proposed home intervention. The use of a booklet with instructions for home exercises, previously validated [39], was well tolerated by individuals through reports described in the logbook contained in the guidance booklet and in the weekly telephone contacts that were made by the rehabilitation team. These low-resource interventions, performed autonomously by individuals at home resulted in significant improvements in ADL performance, symptoms and perception of health status, in individuals with COPD especially in the most critically ill individuals. The main result of this study was the response of the intervention in everyday tasks, identified by the reduction of time in the ADL-Glittre test which represents better functional capacity, as previously described [40]. Other studies also recognized a reduction in the time of this test after a supervised rehabilitation program [23,24], however, no further research has evaluated the effects of home exercise on ADL using the ADL-Glittre test in COPD individuals.

The ADL-Glittre test is sensitive to the response after a PR program [5,23,24]. In addition, minimal clinically relevant differences from −0.38 min (22.8 s) [23] to −0.89 min (53 s) [23,24] after a PR program has been previously described. In our study, in addition to identifying a statistically significant reduction in the time of the ADL-Glittre test after eight weeks of home exercises, we also observed a decrease of −0.93 min (55.8 s), above the previously established minimal important difference, which suggests a clinical improvement with a positive impact on ADL. Clinical improvement represents an essential change for individuals after an intervention [41,42] and has been a significant challenge for PR programs [43].

According to the GOLD severity classification, we also observed that the individuals with the most significant pulmonary impairment were those who presented the greatest variation in the reduction in the time to perform the ADL-Glittre test after home training. Studies indicate that more severe individuals have a better response after a PR program when compared to those classified as mild and moderate [36,44–46]. We did not observe alteration in the time of the ADL-Glittre test after home exercises in individuals classified as GOLD 2, possibly because, although they present symptoms and limitations in the HRQOL, they did not present reduction of the functional capacity for the ADLs. Thus, those with less functional alteration did not present relevant alterations in ADL after the intervention. Our study observed a significant improvement in dyspnea, expressed by the reduction in the mean mMRC score after the home intervention. These results are widely described in the literature and reinforce that low-cost, self-performing interventions can improve the subjective sensation of dyspnea, which is a critical objective in the therapeutic management of COPD. In addition, there is a significant improvement in the perception of disease-related health status, expressed by a substantial decrease in the CAT score, regardless of the GOLD severity classification. The CAT is a questionnaire used to assess the impact of the disease on the lives of individuals with COPD, where a higher score represents a worse health status [25,27]. Therefore, our study’s reduction in the CAT score reflects an improved perception of health status after training with home exercise guidance in COPD individuals [27,36].

The HRQoL evaluated with the SGRQ, after the home exercises, did not show a significant improvement either in the total score or in the domains “symptoms”, “activity” and social impacts. However, note that although the adjusted pvalue is not capable of refuting the null hypothesis, the 95% confidence interval in an analysis evidences this possibility, including the difference means present variation greater than 10%, which is the minimum clinically important difference. These results suggest that the use of a booklet with home exercise guidelines perhaps improved the perception of quality of life, agreeing with those found in the literature, which showed an improvement in QOL after home-based PR programs in individuals with COPD [35–37,44]. Possibly, there was no change in the global score of the SGRQ or in its subdomains, as it is a training program in which individuals perform the exercises alone, with only the interaction of their family members. Interacting with other patients in the same treatment condition (or even the simple fact of leaving home more often to carry out activities) could perhaps have influenced more intensely the domains and total score of the SGRQ.

Our results showed moderate and strong correlations between the CAT, the ADL-Glittre test, the mMRC and the SGRQ. These correlations suggest that more symptomatic individuals (higher CAT and mMRC scores) have the worst performance on ADLs (longer time to complete the ADL-Glittre test), as well as worse QoL (higher SGRQ scores). The observed associations suggest that the longer the time to complete the ADL-Glittre test, the worse the disease severity, the worse the health status, the worse the QoL and the greater the dyspnea [45,46]. In addition, these individuals have a three times greater risk of developing severe exacerbations during the year compared to those who have it for a shorter time [37,46]. However, no other study has evaluated the effects of home-based training for self-execution in ADLs using the ADL-Glittre test in individuals with COPD.

As with any study, ours also has some limitations. First, because there is no effective guarantee of the level of intensity performed, except for the self-report of the participants, second, because there was a reasonable number of volunteers who did not adhere to the proposal (24.3% did not complete the minimum of 75% of the exercise days; n = 9), after receiving the booklet and instructions for use. Another limitation present in any unsupervised study is the lack of guarantee of the faithful fulfillment of the tasks, even knowing that we make weekly contact for the telemonitoring of the activities, the absence of a control group to serve as a comparator for the proposed intervention and the impossibility of controlling some possible confounders such as diet and other aspects that could affect ADL and functional capacity.

The results of this study demonstrated that individuals with COPD can benefit from performing self-performed home exercises, guided by an illustrated booklet, as this proposal improves ADLs, symptoms, health perception and quality of life in this population. This could, in another analysis, indicate a functional improvement in these individuals.

Thus, considering the results presented, a program of home exercises performed autonomously can be recommended for this population, since, because they are safe, low cost and easy to access, they constitute an alternative that can democratize access rehabilitation and thus expand the results of this therapeutic modality for the population of individuals with COPD.

Declaration of interest

No competing interest declared.

Additional information

Funding

This study was supported by the Fundação Carlos Chagas Filho de Apoio à Pesquisa do Estado do Rio de Janeiro (FAPERJ, no. E-26/211.104/2021) and Coordenação de Aperfeiçoamento de Pessoal (CAPES, Finance Code 001; no. 88881.708719/2022-01, and no. 88887.708718/2022-00).