Patient-based measures of illness severity in the Veterans Health Study

The Veterans Health Study (VHS) was designed to produce patient-based measures of health status suitable for monitoring the health of men served by the Veterans Health Administration. This article summarizes the objectives, conceptual framework, and results of 6 substudies of the VHS that were designed to develop disease-focused measures of illness severity, that is, patient-perceived, clinically significant manifestations of disease processes that are associated with decrements in health-related quality of life. Developmental psychometric studies used cross-sectional survey data from the baseline comprehensive evaluations conducted in the VHS. Patients who screened positive for the 6 study medical conditions in the VHS (osteoarthritis of the knee, n = 511; type 2 diabetes, n = 425; chronic lung disease, n = 352; hypertension, n = 996; chronic low-back pain, n = 574; and alcohol-related disorder, n = 175) were administered structured interview modules that assessed symptoms and complications of these chronic diseases. Psychometric analyses were conducted to identify internally coherent and reliable indices, which were validated with respect to their correlations with measures of health-related quality of life (eg, Short Form-36) and the utilization of health services. We constructed 6 indices of illness severity. The severities of osteoarthritis of the knee and chronic lung disease were defined by brief (12 and 6 items, respectively) assessments of symptoms (eg, knee pain and dyspnea). Since diabetes and hypertension are largely asymptomatic, illness severity for these conditions was assessed by ascertaining complications such as angina and vascular disorders. Alcohol-related disorder, which involves both behavioral symptoms and physical complications, was assessed by separate scales for these 2 dimensions of its severity. Chronic low-back pain required a unique solution. Rather than assessing the intensity of back pain, it is more productive to construct a measure that focuses on manifestations of radiculopathy, that is, whether back pain radiated down the leg to below the knee. The 5 symptoms or complication indices and the assessment of radiculopathy in chronic low-back pain were significantly correlated with Short Form-36 scores and intensity of recent use of health services. The 6 measures may complement measures of health-related quality of life in providing more comprehensive assessments of health status in Veterans Affairs patients.