Analysis of the validation status of quality of life and functional disability measures in pulmonary arterial hypertension related to systemic sclerosis: results of a systematic literature analysis by the Expert Panel on Outcomes Measures in Pulmonary Arterial Hypertension related to Systemic Sclerosis (EPOSS).

OBJECTIVE

We aimed to assess the current validity status of the Health Assessment Questionnaire-Disability Index (HAQ-DI) and the 36-item Medical Outcomes Study Short Form Health Survey (SF-36).

METHODS

Studies using HAQ-DI and/or SF-36 in patients with pulmonary arterial hypertension (PAH) associated with systemic sclerosis (PAH-SSc) were identified through a systematic literature review and assessed according to the Outcome Measures in Rheumatology Clinical Trials (OMERACT) consensus group criteria.

RESULTS

Both HAQ-DI and SF-36 were considered credible (having face validity) and feasible. Based on expert opinion, neither HAQ-DI nor SF-36 was specific for PAH-SSc since their results may be influenced by other aspects of SSc (judged "unclear" with respect to the content validity criterion). In the overall SSc population, there was significant albeit weak correlation between physical component SF-36 scores and pulmonary artery systolic pressure (PASP) by echocardiography (Kendall tau b = -0.2, p < 0.01). Although HAQ-DI also correlated with PASP by echocardiography, there were no significant correlations in SSc patients with PAH proven by right heart catheterization between changes in HAQ-DI over time and changes in other PAH measures including 6-min walk distance (r = -0.04, p = 0.86), expert global assessment (r = 0.06, p = 0.97), and New York Heart Association functional class (r = 0.38, p = 0.39), indicating lack of construct validity for HAQ-DI in PAH-SSc. No studies enabling assessment of criterion validity or discrimination of HAQ-DI or SF-36 in PAH-SSc could be identified.

CONCLUSION

Further validation of HAQ and SF-36 in PAH-SSc is needed. Alternatively, more specific assessments for functional disability or quality of life in PAH-SSc might be required.