Comparing generic and disease-specific measures of physical and role functioning: results from the Veterans Health Study.

OBJECTIVES: This study compared the performance of generic measures of Medical Outcome Study Short Form 36-Item Health Survey physical functioning and role limitations with disease-specific measures of physical functioning and role limitations using specific disease attributions for chronic lung disease, chronic low back pain, and osteoarthritis of the knee.
METHODS: Data were analyzed from the Veterans Health Study among patients receiving Veteran's Administration ambulatory care. Patients identified as having one of the three study conditions were included in the study (n = 932).
RESULTS: The study revealed that the generic physical functioning and role limitations scales had higher correlations with other generic SF-36 scales, whereas disease-specific attribution measures had larger R2 values in explaining variability in symptom-based disease severity and larger t statistic values in discriminating the impacts of patients taking medications and having surgery.
CONCLUSIONS: The generic measures of physical functioning and role limitations were more applicable in assessing a broad array of health-related quality-of-life issues, whereas disease-specific measures of physical functioning and role limitations were more useful in evaluating clinical management and limitations associated with specific disease conditions. The results of the study suggest that the use of disease-specific attribution assessments was more cost-efficient than the development of new disease-specific instruments. Disease-specific attribution could be used to complement generic measures in assessing patient outcomes.