Determination of the minimal important difference for inspiratory muscle strength in people with severe and very severe COPD.

OBJECTIVE: Inspiratory muscle training is recommended for people with chronic obstructive pulmonary disease (COPD) with inspiratory muscle weakness. Clinical interpretation of changes in inspiratory muscle strength could be helped by the determination of cut-off values. The aim of this study was to estimate the minimal important difference for inspiratory muscle strength assessed with maximal inspiratory pressure (MIP) in people with COPD. DESIGN: Post hoc analysis of a randomized controlled trial (EMI2 study) including people with severe to very severe COPD undergoing a pulmonary rehabilitation program was conducted. The determination of the minimal important difference was realized using both anchor-based and distribution-based methods. SETTING: The study includes patients admitted to the rehabilitation program unit of the Centre Hospitalier des Pays de Morlaix (Morlaix, France) between March 5, 2014 and September 8, 2016. PARTICIPANTS: Seventy-three people with severe to very severe COPD (age 62.2 ± 8.0 years, forced expiratory volume in 1 s 36.4 ± 9.5% of theoretical) were analyzed. INTERVENTION: Patients followed a standardized pulmonary rehabilitation program 5 days a week for 4 weeks. The program included aerobic training, ground-based outdoor walking training, and strengthening of lower and upper limb muscles. MAIN MEASURES: At the end of the pulmonary rehabilitation program, MIP improved by 14.8 ± 14.9 cmH2O (p < 0.05). Regarding the anchor-based method, only the modified Medical Research Council was selected as an appropriate anchor. The receiver operating characteristic curve analysis reported a minimal important difference of 13.5 cmH2O (sensibility: 75% specificity: 67.5%). Using distribution-based methods, the estimate of minimal important difference was 7.9 cmH2O (standard error of measurement method) and 10.9 cmH2O (size effect method). RESULTS: The estimations proposed by this study ranged from 7.9 to 13.5 cmH2O. CONCLUSIONS: The measurement of minimal important difference is a simple tool for assessing the changes of inspiratory muscle strength during a pulmonary rehabilitation program. We propose a minimal important difference of 13.5 cmH2O for the improvement of MIP. Further studies are needed to confirm this estimation.ClinicalTrials.gov identifier: NCT02074813.

Responsiveness and Minimally Important Difference of the 6-Minute Stepper Test in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: The validity and reproducibility of the 6-minute stepper test (6MST) have already been demonstrated in patients with chronic obstructive pulmonary disease (COPD). OBJECTIVES: The aim of this study was to evaluate the responsiveness of the 6MST to pulmonary rehabilitation (PR) in patients with COPD, to determine a minimal important difference (MID) for the 6MST, and to compare the 6MST and the 6-minute walk test (6MWT). METHODS: Sixty-two patients with COPD were included in a prospective experimental study. Participants underwent a 3-week inpatient PR program. The primary outcome was the change in the number of steps during the 6MST measured before and after PR. The secondary outcome included the change in the 6-minute walking distance (6MWD) pulse oximetry, heart rate, dyspnea, and leg discomfort during the tests measured before and after PR. MID was determined by anchor-based and distribution approaches. RESULTS: After PR, we observed a significant increase in the number of steps during the 6MST (22.5 steps; 95% CI 13.8-31.3; p < 0.0001) and in the 6MWD (26.6 m; 95% CI 17.6-35.5; p < 0.0001). The 6MST and 6MWT were improved by 10.1 and 6.5%, respectively. The number of steps during the 6MST was significantly correlated with the 6MWD before (r = 0.72; p < 0.0001) and after PR (r = 0.66; p < 0.0001). MID was estimated to be around 20 steps. CONCLUSION: The 6MST appears to be as responsive as the 6MWT in assessing functional improvement during PR in patients with COPD. The 6MST is a low-cost assessment and requires limited space.

Characteristics and Predictors of Postural Control Impairment in Patients With COPD Participating in a Pulmonary Rehabilitation Program.

PURPOSE: Postural control impairment has been identified as a potential extrarespiratory manifestation in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to identify clinical factors that characterize patients with reduced postural control, to examine the correlation between clinical factors and postural control and to determine predictors of an impaired postural control among COPD participants enrolled in a pulmonary rehabilitation (PR) program. METHODS: This study is a secondary analysis of an observational study (PARACHUTE). The baseline assessment of the PR program was used for the analysis. Postural control impairment was defined using the Brief BESTest score (BBT). RESULTS: Participants (n = 73) were included in the analysis, 43 of them were classified in the reduced postural control group. The between-group comparison (non-reduced vs reduced postural control) identified differences for partial pressure in oxygen (Pa O2 ), Saint George Respiratory Questionnaire (SGRQ) total score and subscores (SGRQ-Symptoms, SGRQ-Activities, and SGRQ-Impact), COPD assessment test (CAT), and anxiety score of the Hospital Anxiety and Depression Scale. The BBT score was significantly correlated with maximal inspiratory pressure (MIP), SGRQ, SGRQ-Symptoms, SGRQ-Impact, Falls Efficacy Scale, modified Medical Research Council Scale, 6-min walk test, and Pa O2 . Logistic regression identified SGRQ-Symptoms, Pa O2 , MIP, and body mass index (BMI) as predictors of the presence of reduced postural control. CONCLUSION: Low quality of life (QoL) and Pa O2 and high anxiety seem to be discriminative characteristics of patients with COPD with reduced postural control. Furthermore, QoL, Pa O2 , inspiratory muscle strength, and BMI seem to be acceptable predictors of the presence of postural control impairment.

Impairment and characteristics of postural control sub-components in people with COPD: a scoping review.

PURPOSE: Impairment of postural control is common in people with COPD. However, the precise characteristics of this alteration are not clearly known. The "Systems Framework for Postural Control" which define postural control sub-components, represents an interesting tool to explore this field. The main aim of this review was to identify which postural control sub-components are impaired in people with COPD and to summarise characteristics for each sub-component. A secondary aim was to precise the relation between postural control and activities of daily living (ADL). MATERIALS AND METHODS: A scoping review was conducted, according to the JBI methodology. Medline, Cochrane Library, Scielo, Google Scholar, OpenGrey, and HAL were searched from inception to May 2022. The search was performed in English and French. RESULTS: Eighty-nine articles were included. There was evidence of a potential impairment for most of the postural control sub-components. Characteristics of every sub-component alteration were heterogeneous. Reduced postural control could be associated with difficulties in ADL. CONCLUSIONS: People with COPD may have impairment in a wide range of postural control sub-components. Further research is needed to clarify if a common pattern of modification exits for this alteration and to precise the link with ADL.Implications for rehabilitationImpairment of postural control is a common extra-respiratory manifestation in people with COPD and so clinicians must include it in their clinical reasoning.Numerous postural control sub-components could be altered in people with COPD, suggesting that postural control assessment must be holistic.This scoping review shows that characteristics of postural control impairment are varied and that there may be no common pattern at the COPD population level.The relationship between impaired postural control and activities of daily living remains unclear, but clinicians should be alert to potential negative interactions between these two areas.

Influence of Speech and Cognitive Load on Balance and Timed up and Go.

The interaction between oral and/or mental cognitive tasks and postural control and mobility remains unclear. The aim of this study was to analyse the influence of speech production and cognitive load levels on static balance and timed up and go (TUG) during dual-task activities. Thirty healthy young subjects (25 ± 4 years old, 17 women) participated in this study. A control situation and two different cognitive arithmetic tasks were tested: counting backward in increments of 3 and 7 under oral (O) and mental (M) conditions during static balance and the TUG. We evaluated the dual-task cost (DTC) and the effect of speech production (SP) and the level of cognitive load (CL) on these variables. There was a significant increase in the centre of pressure oscillation velocity in static balance when the dual task was performed orally compared to the control situation The DTC was more pronounced for the O than for the M. The SP, but not the CL, had a significant effect on oscillation velocity. There was an increase in TUG associated with the cognitive load, but the mental or oral aspect did not seem to have an influence. Mobility is more affected by SP when the cognitive task is complex. This may be particularly important for the choice of the test and understanding postural control disorders.

Determination of the minimal important difference for Dyspnoea-12 questionnaire in patients with COPD, after pulmonary rehabilitation.

INTRODUCTION: The authors of the international task force about the management of Dyspnoea recommend assessing sensory and affective components of dyspnoea. The Dyspnoea-12 questionnaire (D-12) allows to assess both components of dyspnoea. D-12 is valid and reliable but its sensitivity to pulmonary rehabilitation was not studied. The aim of this study was to estimate the minimal important difference (MID) for D-12 in COPD patients undergoing a pulmonary rehabilitation programme (PRP). METHODS: Severe or very severe COPD patients undergoing a PRP were included. Dyspnoea was assessed using D-12, MMRC dyspnoea scale, London chest of Activity of Daily Living questionnaire (LCADL). Quality of life was assessed using Saint-George respiratory questionnaire (SGRQ) and COPD assessment Test (CAT); exercise capacity using 6-Minute walk Test (6MWT) and 1-minute sit to-stand test (1STST). The MID was evaluated using distribution and anchor-based methods. RESULTS: Sixty patients (age: 64.4 ± 8.2; FEV1 (%): 28.6 ± 8.1) were included. At the end of the PRP, patients had significantly decreased their dyspnoea measured with D-12, MMRC, LCADL (D-12:23.9 ± 8.9 to 17.6 ± 9.4; MMRC: 3 ± 0.7 to 2.2 ± 1.1, LCADL: 38 ± 13.9 to 31.6 ± 11; p < 0.0001). Using the distribution-based analysis, MID of -2.67 (standard error of measurement) or -4.45 (standard deviation) was found. According to methodology, we could only use SGRQ as anchor. With SGRQ as anchor, the receiver operating characteristic curve identified MID for the change in D-12 at -6.1 (sensibility: 58%, specificity: 79%). The correlation with SGRQ was modest (r = 0.33), so the calculated MID should be interpreted with caution. CONCLUSION: D-12 is a good tool to assess the decrease of dyspnoea after PR. We propose MID of -6 points. However, Future estimates of MID for the D-12 should use anchors that are more strongly correlated with it.

One minute sit-to-stand test is an alternative to 6MWT to measure functional exercise performance in COPD patients.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is frequently associated with a reduced functional exercise performance. Even if this parameter is routinely evaluated using 6-minute walking test (6MWT), new field tests are regularly investigated as alternative tests. The aim of this study was to compare functional exercise performance evaluation by sit-to-stand test (STST) and 6MWT and to evaluate reliability and repeatability of the STST in COPD patients. METHOD: Forty-two COPD patients performed randomly two tests: 6MWT and STST. Each test was repeated two times. Distance (6MWD) and number of repetitions were measured. Cardiorespiratory parameters, dyspnea and lower limb fatigue (Borg) were recorded before and after the tests. RESULTS: Sit-to-stand repetitions (19 ± 6) and 6MWD (441 ± 104 m) were correlated (r = .716; P < .001). Good repeatability was found for STST and 6MWT. Good reliability was observed for STST (ICC = 0.902). Variations of heart rate and pulsed oxygen saturation were significantly different between these two tests (23% ± 17% vs 13% ± 11%; P = .022 and -7.6% ± 4.6% vs -0.7% ± 2.7%; P < .001 for 6MWT and STST, respectively). Variations of dyspnea and lower limb fatigue were similar between both tests (P = .827 and P = .467). CONCLUSION: The one minute sit-to-stand test is a valuable alternative to 6MWT to estimate functional exercise performance in COPD patients. The cardiorespiratory demand is different between both tests although the variation of dypsnea is similar. No learning effect was observed for STST.

Validation of the French version of the London Chest Activity of Daily Living scale and the Dyspnea-12 questionnaire.

Introduction: Eighty percent of COPD patients experience dyspnea during activities of daily life (ADL). To the best of our knowledge, the Modified Medical Research Council (MMRC) dyspnea scale is the only validated scale designed to quantify dyspnea during ADL available in the French language. Two other instruments are only available in English versions: the London Chest Activity of Daily Living (LCADL) scale that allows a specific evaluation of dyspnea during ADL and the Dyspnea-12 questionnaire that evaluates the affective (emotional) and sensory components of dyspnea in daily life. The aim of this study was to translate and validate French versions of both LCADL and Dyspnea-12 questionnaires and to determine the reliability of these versions for the evaluation of dyspnea in severe to very severe COPD patients. Methods: Both translation and cultural adaptation were based on Beaton's recommendations. Fifty consecutive patients completed the French version of LCADL and Dyspnea-12 and other questionnaires (MMRC, Saint George's Respiratory Questionnaire [SGRQ], Hospital Anxiety and Depression [HAD]), at a 2-week interval. Internal consistency, validity, and reliability of LCADL and Dyspnea-12 were evaluated. Results: The French version of LCADL and Dyspnea-12 demonstrated good internal consistency with Cronbach's α of, respectively, 0.84 and 0.91. LCADL was correlated significantly with item activity of SGRQ (ρ=0.55, p<0.001), total score of SGRQ (ρ=0.63, p<0.001), item impact of SGRQ (ρ=0.57, p<0.001), and HAD-depression (HAD-D) (ρ=0.47, p=0.001); and Dyspnea-12 was correlated significantly with MMRC (ρ=0.39, p<0.001), HAD-anxiety (ρ=0.64, p<0.001), and HAD-D (ρ=0.64, p<0.001). The French version of LCADL and Dyspnea-12 demonstrated good test-retest reliability with, respectively, intraclass coefficient =0.84 (p<0.001) and 0.91 (p<0.001). Conclusion: The French versions of LCADL and Dyspnea-12 questionnaires are promising tools to evaluate dyspnea in severe to very severe COPD patients.