Effects of inspiratory muscle training in COPD patients: A systematic review and meta-analysis.

In chronic obstructive pulmonary disease (COPD), quality of life and exercise capacity are altered in relationship to dyspnea. Benefits of inspiratory muscle training (IMT) on quality of life, dyspnea, and exercise capacity were demonstrated, but when it is associated to pulmonary rehabilitation (PR), its efficacy on dyspnea is not demonstrated. The aim of this systematic review with meta-analysis was to verify the effect of IMT using threshold devices in COPD patients on dyspnea, quality of life, exercise capacity, and inspiratory muscles strength, and the added effect on dyspnea of IMT associated with PR (vs. PR alone). This systematic review and meta-analysis was conducted on the databases from PubMed, Science direct, Cochrane library, Web of science, and Pascal. Following key words were used: inspiratory, respiratory, ventilatory, muscle, and training. The searching period extended to December 2017. Two reviewers independently assessed studies quality. Forty-three studies were included in the systematic review and thirty-seven studies in the meta-analysis. Overall treatment group consisted of six hundred forty two patients. Dyspnea (Baseline Dyspnea Index) is decreased after IMT. Quality of life (Saint George's Respiratory Questionnaire), exercise capacity (6 min walk test) and Maximal inspiratory pressure were increased after IMT. During PR, no added effect of IMT on dyspnea was found. IMT using threshold devices improves inspiratory muscle strength, exercise capacity and quality of life, decreases dyspnea. However, there is no added effect of IMT on dyspnea during PR (compared with PR alone).

Beaumont M ，Forget P ，Couturaud F ，Reychler G ... -  《-》

Inspiratory muscle training, with or without concomitant pulmonary rehabilitation, for chronic obstructive pulmonary disease (COPD).

Inspiratory muscle training (IMT) aims to improve respiratory muscle strength and endurance. Clinical trials used various training protocols, devices and respiratory measurements to check the effectiveness of this intervention. The current guidelines reported a possible advantage of IMT, particularly in people with respiratory muscle weakness. However, it remains unclear to what extent IMT is clinically beneficial, especially when associated with pulmonary rehabilitation (PR).   OBJECTIVES: To assess the effect of inspiratory muscle training (IMT) on chronic obstructive pulmonary disease (COPD), as a stand-alone intervention and when combined with pulmonary rehabilitation (PR). We searched the Cochrane Airways trials register, CENTRAL, MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCO, Physiotherapy Evidence Database (PEDro) ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform on 20 October 2021. We also checked reference lists of all primary studies and review articles. We included randomized controlled trials (RCTs) that compared IMT in combination with PR versus PR alone and IMT versus control/sham. We included different types of IMT irrespective of the mode of delivery. We excluded trials that used resistive devices without controlling the breathing pattern or a training load of less than 30% of maximal inspiratory pressure (PImax), or both. We used standard methods recommended by Cochrane including assessment of risk of bias with RoB 2. Our primary outcomes were dyspnea, functional exercise capacity and health-related quality of life.  MAIN RESULTS: We included 55 RCTs in this review. Both IMT and PR protocols varied significantly across the trials, especially in training duration, loads, devices, number/ frequency of sessions and the PR programs. Only eight trials were at low risk of bias. PR+IMT versus PR We included 22 trials (1446 participants) in this comparison. Based on a minimal clinically important difference (MCID) of -1 unit, we did not find an improvement in dyspnea assessed with the Borg scale at submaximal exercise capacity (mean difference (MD) 0.19, 95% confidence interval (CI) -0.42 to 0.79; 2 RCTs, 202 participants; moderate-certainty evidence).   We also found no improvement in dyspnea assessed with themodified Medical Research Council dyspnea scale (mMRC) according to an MCID between -0.5 and -1 unit (MD -0.12, 95% CI -0.39 to 0.14; 2 RCTs, 204 participants; very low-certainty evidence).  Pooling evidence for the 6-minute walk distance (6MWD) showed an increase of 5.95 meters (95% CI -5.73 to 17.63; 12 RCTs, 1199 participants; very low-certainty evidence) and failed to reach the MCID of 26 meters. In subgroup analysis, we divided the RCTs according to the training duration and mean baseline PImax. The test for subgroup differences was not significant. Trials at low risk of bias (n = 3) demonstrated a larger effect estimate than the overall. The summary effect of the St George's Respiratory Questionnaire (SGRQ) revealed an overall total score below the MCID of 4 units (MD 0.13, 95% CI -0.93 to 1.20; 7 RCTs, 908 participants; low-certainty evidence).  The summary effect of COPD Assessment Test (CAT) did not show an improvement in the HRQoL (MD 0.13, 95% CI -0.80 to 1.06; 2 RCTs, 657 participants; very low-certainty evidence), according to an MCID of -1.6 units.  Pooling the RCTs that reported PImax showed an increase of 11.46 cmH2O (95% CI 7.42 to 15.50; 17 RCTs, 1329 participants; moderate-certainty evidence) but failed to reach the MCID of 17.2 cmH2O.  In subgroup analysis, we did not find a difference between different training durations and between studies judged with and without respiratory muscle weakness.  One abstract reported some adverse effects that were considered "minor and self-limited". IMT versus control/sham Thirty-seven RCTs with 1021 participants contributed to our second comparison. There was a trend towards an improvement when Borg was calculated at submaximal exercise capacity (MD -0.94, 95% CI -1.36 to -0.51; 6 RCTs, 144 participants; very low-certainty evidence). Only one trial was at a low risk of bias. Eight studies (nine arms) used the Baseline Dyspnea Index - Transition Dyspnea Index (BDI-TDI). Based on an MCID of +1 unit, they showed an improvement only with the 'total score' of the TDI (MD 2.98, 95% CI 2.07 to 3.89; 8 RCTs, 238 participants; very low-certainty evidence). We did not find a difference between studies classified as with and without respiratory muscle weakness. Only one trial was at low risk of bias. Four studies reported the mMRC, revealing a possible improvement in dyspnea in the IMT group (MD -0.59, 95% CI -0.76 to -0.43; 4 RCTs, 150 participants; low-certainty evidence). Two trials were at low risk of bias. Compared to control/sham, the MD in the 6MWD following IMT was 35.71 (95% CI 25.68 to 45.74; 16 RCTs, 501 participants; moderate-certainty evidence). Two studies were at low risk of bias. In subgroup analysis, we did not find a difference between different training durations and between studies judged with and without respiratory muscle weakness.  Six studies reported theSGRQ total score, showing a larger effect in the IMT group (MD -3.85, 95% CI -8.18 to 0.48; 6 RCTs, 182 participants; very low-certainty evidence). The lower limit of the 95% CI exceeded the MCID of -4 units. Only one study was at low risk of bias. There was an improvement in life quality with CAT (MD -2.97, 95% CI -3.85 to -2.10; 2 RCTs, 86 participants; moderate-certainty evidence). One trial was at low risk of bias. Thirty-two RCTs reported PImax, showing an improvement without reaching the MCID (MD 14.57 cmH2O, 95% CI 9.85 to 19.29; 32 RCTs, 916 participants; low-certainty evidence). In subgroup analysis, we did not find a difference between different training durations and between studies judged with and without respiratory muscle weakness.   None of the included RCTs reported adverse events. IMT may not improve dyspnea, functional exercise capacity and life quality when associated with PR. However, IMT is likely to improve these outcomes when provided alone. For both interventions, a larger effect in participants with respiratory muscle weakness and with longer training durations is still to be confirmed.

Ammous O ，Feki W ，Lotfi T ，Khamis AM ，Gosselink R ，Rebai A ，Kammoun S ... -  《Cochrane Database of Systematic Reviews》

Effect of inspiratory muscle training on dyspnea-related kinesiophobia in chronic obstructive pulmonary disease: A randomized controlled trial.

The major symptom of chronic obstructive pulmonary disease (COPD) is dyspnea, which causes dyspnea-related kinesiophobia resulting in avoidance of activities associated with dyspnea or compensation by reducing the rate of activity. The aim of this study was to assess dyspnea-related kinesiophobia and determine the effect of inspiratory muscle training (IMT) on dyspnea-related kinesiophobia in COPD. Forty COPD subjects were randomly allocated to either the IMT or sham group. Both groups' maximal inspiratory pressure (MIP) was assessed weekly. All patients were instructed to perform the training exercises for 15 min twice a day, 5 days a week for a total of 8 weeks. In the IMT group, intensity was set at 30% of MIP and adjusted according to weekly MIP value. In the sham group, intensity remained constant at 15% of initial MIP. Pulmonary function test (PFT), respiratory muscle strength, 6-min walk test (6 MWT), Breathlessness Beliefs Questionnaire (BBQ), Modified Medical Research Council scale (MMRC), modified Borg scale, Hospital Anxiety and Depression Scale (HADS), Saint George's Respiratory Questionnaire (SGRQ), and COPD Assessment Test (CAT) were assessed before and after the intervention. BBQ scores ranged from 18 to 51, with mean values in the IMT and sham groups of 39.80 ± 7.62 and 43.00 ± 6.58, respectively. When between-group differences of all outcome scores were compared, there was a statistically significant improvement in the IMT group than in the sham group (p < 0.05). After IMT, statistically significant decreases in BBQ and modified Borg scores were observed in within groups (p ≤ 0.001). These decreases were significantly greater in the IMT group (p ≤ 0.001). MMRC decreased significantly only in the IMT group (p < 0.001). There was a statistically significant increase in PFT values in the IMT group (p = 0.007-0.045), but no difference in the sham group (p = 0.129-0.886). Both groups showed statistically significant improvement in respiratory muscle strength, 6 MWT distance, and CAT score after 8 weeks (p < 0.05). All HADS and SGRQ scores decreased significantly in the IMT group (p < 0.001), whereas only the SGRQ activity score decreased significantly in the sham group (p = 0.017). Our study provides data on the presence and level of dyspnea-related kinesiophobia in COPD patients. All patients had BBQ scores higher than 11, indicating dyspnea-related kinesiophobia. IMT reduced BBQ score and improved respiratory function, and exercise capacity. Our results also support the other known benefits of IMT such as reduced dyspnea and symptom perception, decreased anxiety and depression, and improved quality of life.

Saka S ，Gurses HN ，Bayram M 《-》

Inspiratory Muscle Training in Patients With Heart Failure: What Is New? Systematic Review and Meta-Analysis.

The benefits of inspiratory muscle training (IMT) have already been demonstrated in patients with heart failure (HF), but the best mode of training and which patients benefit from this intervention are not clear. The purpose of this study was to review the effects of IMT on respiratory muscle strength, functional capacity, pulmonary function, quality of life, and dyspnea in patients with HF; IMT isolated or combined with another intervention (combined IMT), the presence of inspiratory muscle weakness, training load, and intervention time were considered. The search included the databases MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Physiotherapy Evidence Database, and LILACS database through September 2019. The review included randomized studies that assessed IMT in isolation or combined with another intervention-in comparison with a control group, a placebo, or another intervention-in patients with HF. Fourteen studies were included, 13 for meta-analysis (10 for isolated IMT and 3 for combined IMT). Isolated IMT demonstrated an increase in maximal inspiratory pressure (MIP) (25.12 cm H2O; 95% CI = 15.29 - 34.95), 6-Minute Walk Test (81.18 m; 95% CI = 9.73 - 152.63), maximum oxygen consumption (12 weeks: 3.75 mL/kg/min; 95% CI = 2.98 to 4.51), and quality of life (-20.68; 95% CI = -29.03 to -12.32). The presence of inspiratory muscle weakness, higher loads, and longer intervention times resulted in greater increases in MIP. IMT combined with another intervention demonstrated an increase only in MIP. Isolated IMT resulted in an increase in inspiratory muscle strength, functional capacity, and quality of life. IMT combined with another intervention resulted only in a small increase in inspiratory strength. Isolated IMT with higher loads can be considered an adjuvant intervention, especially for those who do not adhere to conventional rehabilitation and who have respiratory muscle weakness. A systematic review was necessary to review the effects of IMT on respiratory muscle strength, lung function, functional capacity, quality of life, and dyspnea in patients with HF. Various clinical issues important for a better training prescription were considered; these included whether the performance of the training IMT as a form of isolated training benefits patients with HF, whether the combination of IMT with another intervention has additional effects, whether any patient with HF can benefit from IMT (alone or combined with another intervention), and whether only patients who already have respiratory muscle weakness benefit. Also important was establishing which training load provides the best result and the best intervention time, so that health care can be provided more efficiently. For people with heart failure, IMT by itself, without being combined with other exercise, can improve ease of breathing, increase the amount of distance that they can walk, and improve quality of life. Inspiratory training with higher loads might be helpful for those with respiratory muscle weakness who are unable to do conventional exercise.

Azambuja ACM ，de Oliveira LZ ，Sbruzzi G 《-》

Cycle ergometer and inspiratory muscle training offer modest benefit compared with cycle ergometer alone: a comprehensive assessment in stable COPD patients.

Wang K ，Zeng GQ ，Li R ，Luo YW ，Wang M ，Hu YH ，Xu WH ，Zhou LQ ，Chen RC ，Chen X ... -  《International Journal of Chronic Obstructive Pulmonary Disease》