Construct validity and reliability of the Informal Caregiver Burden Assessment Questionnaire (QASCI) in caregivers of patients with COPD

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 (ICC_2,1, 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 ICC_2,1 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.