Development and psychometric properties of the Pulmonary-specific Quality-of-Life Scale in lung transplant patients

Abstract

BACKGROUND The Pulmonary-specific Quality-of-Life Scale (PQLS) was developed to measure quality of life (QoL) among patients awaiting lung transplant. The objective of this study was to determine the psychometric properties of the PQLS, identify empirically derived sub-scales, and examine ability to detect changes in pulmonary-specific QoL scores after lung transplantation. METHODS Data were derived from the INSPIRE trial, a dual-site randomized controlled trial of coping skills training in 389 lung transplant candidates (obstructive [48.3%], restrictive [24.2%], cystic fibrosis [13.6%], and other [13.9%]). Cronbach alpha was calculated to assess the internal reliability of the PQLS (n = 388). Test-retest reliability was assessed with correlation coefficients between baseline and 12-week post-baseline scores for the usual care control condition (n = 140). Convergent validity was assessed with correlation coefficients between the PQLS and established measures of QoL and emotional distress, 6-minute walk test distance, forced expiratory volume in 1 second, and use of supplemental oxygen at rest (n = 388). Change from baseline to 6 months post-transplantation was assessed with repeated measures analysis of variance (n = 133). RESULTS The PQLS was internally reliable and stable across 12 weeks. The PQLS correlated strongly with QoL measures (e.g., Shortness of Breath Questionnaire, r = 0.78, p < 0.0001), moderately with mood and anxiety (e.g., Beck Depression Inventory-II, r = 0.59, p < 0.0001), and modestly with lung disease severity (e.g., 6-minute walk test, r = −0.41, p < 0.0001). PQLS scores improved by nearly 2 SDs after transplant. CONCLUSIONS These results demonstrated the reliability, validity, and sensitivity to change of the PQLS for measuring pulmonary QoL among patients with advanced lung disease and the responsiveness of the PQLS to changes in QoL after lung transplantation.

Effect of Lung Transplantation on Health-Related Quality of Life in the Era of the Lung Allocation Score: A U.S. Prospective Cohort Study

“…Other studies (from the pre-LAS era) have identified a slow, relentless HRQL decline after the first post-operative year, although rarely declining to the low levels observed before lung transplantation. (33, 48, 49) Further, we found that improvements were achieved within the first 3 post-operative months, which contrasts to prior studies that found improvements continuing through the first year. (49, 50)…”

“…Efforts to understand why some groups, such as cystic fibrosis, derive larger benefits may inform interventions to improve HRQL in others. (45, 48, 52)…”

“…Ongoing efforts to meet this challenge may help to more fully realize the true clinical aims of lung transplantation. (42, 48, 52)…”

“…While some have been validated in this population, all fail to some extent to measure certain health domains important in lung transplant recipients. (18, 42, 48, 55, 56) Although we repeatedly measured HRQL, the state or trajectory of HRQL in between sampling periods is unknown and estimates might have been different with different sampling timeframes. Also, although we considered disability as an upstream predictor of HRQL, the SF12-PCS, AQ20-R, and EQ5D all include items that do query physical functioning.…”

Depressive symptoms and early mortality following lung transplantation: A pilot study

“…Lower scores indicate better pulmonary‐specific QoL. The PQLS has good convergent validity (−.74) with the SF‐36 and has high internal consistency (.87) and has been validated among lung transplant recipients University of San Diego Shortness of Breath Questionnaire (SOBQ) .…”