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Aveiro Institute of Biomedicine

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Establishing a minimal clinically important difference in pulmonary rehabilitation: Digging in the methods
Publication . Paixão, Cátia; Rebelo, Patrícia; Oliveira, Ana; Jácome, Cristina; Cruz, Joana; Marques, Alda
COPD profiles and treatable traits using minimal resources: Identification, decision tree and stability over time
Publication . Marques, Alda; Souto-Miranda, Sara; Machado, Ana; Oliveira, Ana; Jácome, Cristina; Cruz, Joana; Enes, Vera; Afreixo, Vera; Martins, Vitória; Andrade, Lília; Valente, Carla; Ferreira, Diva; Simão, Paula; Brooks, Dina; Tavares, Ana Helena
Background and objective: Profiles of people with chronic obstructive pulmonary disease (COPD) often do not describe treatable traits, lack validation and/or their stability over time is unknown. We aimed to identify COPD profiles and their treatable traits based on simple and meaningful measures; to develop and validate a decision tree and to explore profile stability over time. Methods: An observational, prospective study was conducted. Clinical characteristics, lung function, symptoms, impact of the disease (COPD Assessment Test—CAT), health-related quality of life, physical activity, lower-limb muscle strength and functional status were collected cross-sectionally and a subsample was followed-up monthly over six months. A principal component analysis and a clustering procedure with k-medoids were applied to identify profiles. A decision tree was developed and validated cross-sectionally. Stability was explored over time with the ratio between the number of timepoints that a participant was classified in the same profile and the total number of timepoints (i.e., 6). Results: 352 people with COPD (67.4 ± 9.9 years; 78.1% male; FEV1 = 56.2 ± 20.6% predicted) participated and 90 (67.6 ± 8.9 years; 85.6% male; FEV1 = 52.1 ± 19.9% predicted) were followed-up. Four profiles were identified with distinct treatable traits. The decision tree included CAT (< 18 or ≥ 18 points); age (< 65 or ≥ 65 years) and FEV1 (< 48 or ≥ 48% predicted) and had an agreement of 71.7% (Cohen’s Kappa = 0.62, p < 0.001) with the actual profiles. 48.9% of participants remained in the same profile whilst 51.1% moved between two (47.8%) or three (3.3%) profiles over time. Overall stability was 86.8 ± 15%. Conclusion: Four profiles and treatable traits were identified with simple and meaningful measures possibly available in low-resource settings. A decision tree with three commonly used variables in the routine assessment of people with COPD is now available for quick allocation to the identified profiles in clinical practice. Profiles and treatable traits may change over time in people with COPD hence, regular assessments to deliver goal-targeted personalised treatments are needed.
Minimal Clinically Important Difference for Quadriceps Muscle Strength in People with COPD Following Pulmonary Rehabilitation
Publication . Oliveira, Ana; Rebelo, Patrícia; Paixão, Cátia; Jácome, Cristina; Cruz, Joana; Martins, Vitória; Simão, Paula; Brooks, Dina; Marques, Alda
Quadriceps strength training is a key component of pulmonary rehabilitation (PR). Clinical interpretability of changes in muscle strength following PR is however limited due to the lack of cut-off values to define clinical improvement. This study estimated the minimal clinically important difference (MCID) for the isotonic and isometric quadriceps muscle strength assessed with the one-repetition maximum (1RM) and hand-held dynamometry (HHD) in people with chronic obstructive pulmonary disease (COPD) following PR. A secondary analysis of a real life non-randomised controlled study was conducted in people with COPD enrolled in a 12-week community-based PR programme. Anchor and distribution-based methods were used to compute the MCIDs. The anchors explored were the St. George's respiratory questionnaire (SGRQ) and the six-minute walk test (6MWT) using Pearson's correlations. Pooled MCIDs were computed using the arithmetic weighted mean (2/3 anchor, 1/3 distribution-based methods) and reported as absolute and/or percentage of change values. Eighty-nine people with COPD (84% male, 69.9 ± 7.9 years, FEV1 49.9 ± 18.9% predicted) were included. No correlations were found between changes in 1RM and the SGRQ neither between changes in HHD and the SGRQ and 6MWT (p > 0.05). Thus, anchor-based methods were used only in the MCID of the 1RM with the 6MWT as the anchor. The pooled MCIDs were 5.7Kg and 26.9% of change for the isotonic quadriceps muscle strength with 1RM and 5.2KgF for isometric quadriceps muscle strength assessed with HHD. The MCIDs found are estimates to improve interpretability of community-based PR effects on quadriceps muscle strength and may contribute to guide interventions.
Construct validity and reliability of the Informal Caregiver Burden Assessment Questionnaire (QASCI) in caregivers of patients with COPD
Publication . Hipólito, Nádia; Martins, Sara; Ruivo, Adriana; Flora, Sofia; Silva, Cândida G.; Marques, Alda; Brooks, Dina; Cruz, Joana
Introduction: COPD often leads to loss of independence in daily activities which may increase the dependency on the informal caregiver, resulting in caregiving burden. Several instruments have been used to assess caregiving burden in COPD; however, their measurement properties have been poorly investigated in this population. This study assessed the construct validity and reliability of the Informal Caregiver Burden Assessment Questionnaire (QASCI) in informal caregivers of patients with COPD. Methods: Participants completed the QASCI (higher scores indicate higher burden) and the following questionnaires to assess construct validity: Zarit Burden Interview (ZBI), Hospital Anxiety and Depression Scale (HADS) and World Health Organization Quality of Life Instrument – Short Form (WHOQOL-Bref). QASCI was completed again one week later to assess test-retest reliability. Statistical analyses included: Pearson’s (r) or Spearman’s (ρ) correlations (construct validity); Cronbach’s α (internal consistency); Intraclass Correlation Coefficient (ICC2,1, test-retest reliability) and Standard Error of Measurement (SEM), Minimal Detectable Change (MDC95) and Bland and Altman 95% Limits of Agreement (LoA). Results: Fifty caregivers (62.7 ± 9.8 years, 88% female; patients’ FEV1 = 45.2 ± 21.3%predicted) participated. QASCI mean score was 28.5 ± 19.8 (moderate burden). QASCI was positively correlated with ZBI (r = 0.908; p < 0.01), HADS anxiety (r = 0.613; p < 0.01) and depression (ρ = 0.634; <0.01) and negatively correlated with WHOQOL-Bref (􀀀 0.476 to 􀀀 0.739) (all p < 0.01). Cronbach’s α was 0.793 for the QASCI total score (subscales: 0.747–0.932). The ICC2,1 was 0.924, SEM 2.8 and MDC95 7.8, and the LoA were 􀀀 18.3 to 11.1. Conclusions: The QASCI seems to be a promising measure to assess burden levels associated with informal caregiving in COPD.
Test-retest reliability, agreement and construct validity of the International Physical Activity Questionnaire short-form (IPAQ-sf) in people with COPD
Publication . Flora, Sofia; Marques, Alda; Hipólito, Nádia; Morais, Nuno; Silva, Cândida G.; Januário, Filipa; Rodrigues, Fátima; Carreira, Bruno P.; Cruz, J.
Introduction This study assessed the test-retest reliability/agreement and construct validity of the International Physical Activity Questionnaire short-form (IPAQ-sf) in patients with chronic obstructive pulmonary disease (COPD). It also explored differences in its validity according to age, sex and GOLD airflow obstruction levels. Methods 62 participants (68 ± 8 years, 53 males, FEV1 51 ± 23%pred) completed the Portuguese IPAQ-sf, wore an accelerometer for 7 days and completed a second IPAQ-sf. Test-retest reliability/agreement was assessed with Intraclass Correlation Coefficient (ICC2,1), 95% Limits of Agreement (LoA), standard error of measurement (SEM) and minimal detectable change (MDC95) for continuous variables, and percentage of agreement (%agreement) for categories (“active”/“inactive”). Validity was assessed with 95% LoA and Spearman's correlations (ρ) between IPAQ-sf 2 (METs-min/week, time in vigorous [VPA], moderate PA [MPA] and walking) and accelerometry (time in MVPA, VPA, MPA and step counts) for continuous variables; %agreement, Cohen's kappa, and sensitivity specificity and±predictive values for categories. Correlations were also performed for age, sex and GOLD airflow obstruction grades. Results Reliability was good (ICC2,1 = 0.707) with wide LoA (-6446—6409 METs-min/week). SEM and MDC95 were 1840 and 4971 METs-min/week, respectively. %agreement between the two IPAQ-sf was 84% (kappa = 0.660). Positive, moderate and significant correlations were found between IPAQ-sf and accelerometry (0.396 ≤ ρ ≤ 0.527, p < 0.001), except for VPA (p > 0.05). The strongest correlations were found in age (<65 years) and male (0.466 ≤ ρ ≤ 0.653, p < 0.05). %agreement between tools was 65% (kappa = 0.313), with high sensitivity (0.830) but low specificity (0.500). Conclusions The IPAQ-sf seems valid to be used in COPD but caution on its widespread use is recommended as its accuracy may be limited.

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Funding agency

Fundação para a Ciência e a Tecnologia

Funding programme

6817 - DCRRNI ID

Funding Award Number

UIDB/04501/2020

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