Measuring patient and clinician perspectives to evaluate change in health-related quality of life among patients with chronic obstructive pulmonary disease.

Context: Many treatments aim to improve patients' health-related quality of life (HRQoL), and many care guidelines suggest assessing symptoms and their impact on HRQoL. However, there is a lack of consensus regarding which HRQoL outcome measures are appropriate to assess, and how much change on those measures depict significant HRQoL improvement.

Objective: We used triangulation methods to identify and understand clinically important differences (CIDs) for the amount of change in HRQoL that reflects both health professionals and patients' values, among patients with chronic obstructive pulmonary disease (COPD).

Design, Setting, And Participants: We incorporated three perspectives: (1) an expert panel of physicians familiar with the measurement of HRQoL in COPD patients; (2) 610 primary care COPD outpatients who completed baseline and bimonthly follow-up HRQoL interviews over the 12-month study; and (3) the primary care physicians (PCPs; n = 43) of these outpatients who assessed their patients' disease at baseline and at subsequent PCP visits during the year long study.

Measurements: The Chronic Respiratory Disease Questionnaire (CRQ), the Medical Outcomes Study Short Form 36-item survey (SF-36, version 2.0), and global assessments of change from each of the three perspectives for all HRQoL domains.

Results: With few exceptions, the CRQ was able to detect small changes at levels reported by the patients (1-2 points) and their PCPs (1-5 points). These results confirm minimal important difference standards developed in 1989 by Jaeschke et al. anchored on patient-perceived changes in HRQoL. In general, the expert panel and PCP CIDs were larger than the patient CIDs.

Conclusion: This triangulation methodology yielded improved interpretation, understanding, and insights on stakeholder perspectives of CIDs for patient-reported outcomes.