Measurement properties of functional status and health related quality of life questionnaires in interstitial lung disease

Background: People with interstitial lung diseases (ILD) present a decline in functional status and health related quality of life (HRQoL). The American Thoracic Society considers the assessment of these domains as a priority. There are several instruments to assess these domains however, their measurement properties for specific populations, as ILD, and for European Portuguese are unknown. Aim: To assess the reliability and validity -of the King’s Brief Interstitial Lung Disease (KBILD), the Canadian Occupational Performance Measure (COPM) and the Pulmonary Functional Status and Dyspnea Questionnaire - modified version (PFSDQ-M) for people with ILD. Methods: An observational cross-sectional study was conducted with people with ILD recruited from routine pulmonology appointments. Sociodemographic and clinical data [lung function and 6-minute walk test (6MWT)] were retrieved from the participants’ medical notes and/or with a structured specific questionnaire. At baseline (1st moment), the assessment protocol was also applied [COPM, KBILD, St. George’s Respiratory Questionnaire for idiopathic pulmonary fibrosis (SGRQ-I), PFSDQ-M, London Chest Activities of Daily Living (LCADL)]. COPM, KBILD, and PFSDQ-M were repeated 48h-72h after, via phone call, by two raters (2nd moment and 2nd rater). Reliability was assessed using Cronbach’s α (internal consistency), intraclass correlation coefficient (test-retest, intra-rater and inter-rater reliability), and Bland&Altman method (agreement), standard error of measurment (SEM), minimal detectable change (MDC95), and floor and ceiling effects. Additionally, for COPM, two raters classified all activities mentioned by the International Classification of Functioning, Disability and Health (ICF) two level classification. Inter-rater agreement was assessed through Cohen’s kappa. Spearman’s Rho (ρ) was used to assess criterion validity (between SGRQ-I and KBILD; LCADL and COPM and PFSDQ-M) and construct/divergent validity (between lung function, 6MWT and KBILD, COPM, and PFSDQ-M; LCADL and KBILD; SGRQ-I and COPM and PFSDQ-M). Results: 114 people with ILD (63.2±13.9 years old; 52% male; FVCpp 85.6±19.6; DLCOpp 61±20.1) participated in the study. KBILD has shown good to excellent internal consistency (α=0.81-0.94), good to excellent test-retest and inter-rater reliability (ICC=0.78-0.94) and good agreement between raters, without evidence of systematic bias. SEM and MDC95 ranged between 0.19-1.25 and 0.53-3.46, respectively. Correlations between KBILD and: i) SGRQ-I were significant, negative and moderate to high (ρ=-0.60 to -0.85; p<0.01); ii) LCADL were significant, negative and moderate (ρ=-0.51 to -0.69; p<0.01); iii) lung function and 6MWT were significant, positive and small to moderate (ρ=0.22 a 0.46; p<0.01). COPM showed excelent vallues of testretest/ intra-rater and inter-rater reliability on performance domain (ICC=0.91, 0.94), and good (ICC=0.79, 0.78) on satisfaction. SEM and MDC95 ranged between 0.33-0.52 and 0.92-1.43, respectively. Interrater agreement for the COPM’s classification using ICF two-level was almost perfect (k=0.81). Correlations between COPM and: i) SGRQ-I were significant, negative and moderate (ρ=-0.45 to -0.62; p<0.01); ii) LCADL were significant, negative and moderate (ρ=-0.45 to -0.58; p<0.01); and, iii) lung function and 6MWT were mainly no significant (p>0.05). The PFSDQ-M showed excellent internal consistency (α=0.94-0.98) and moderate to good test-retest and inter-rater reliability (ICC=0.74-0.86). SEM and MDC95 ranged between 0.78-3.20 and 2.17-8.90, respectively. Correlations between PFSDQ-M and: i) SGRQ-I were significant, positive and moderate to high (ρ=0.56-0.78; p<0.01); ii) LCADL were significant, positive and moderate to high (ρ=0.68-0.75; p<0.01); iii) lung function were significant, negative and small to moderate (ρ=-0.23 to 0.42; p<0.01), except for diffusion capacity of carbon monoxide (p>0.05); iv) 6MWT were significant, negative and small to moderate (ρ=-0.36 to - 0.44; p<0.01). Only PFSDQ-M showed a floor effect. Conclusion: KBILD, COPM, and PFSDQ-M seem to be reliable and valid measurement tools to assess functional status and HRQoL in adult people with ILD.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.