Characteristics of adult primary care patients as predictors of future health services charges

BACKGROUND. Utilization risk assessment is potentially useful for allocatio n of health care resources, but precise measurement is difficult. OBJECTIVE. Test the hypotheses that health-related quality of life (HRQOL), severity of illness, and diagnoses at a single primary care visit are comp arable case-mix predictors of future 1-year charges in all clinical setting s within a large health system, and that these predictors are more accurate in combination than alone. RESEARCH DESIGN. Longitudinal observational study in which subjects' charac teristics were measured at baseline, and their outpatient clinic visits and charges and their inpatient hospital days and charges were tracked for 1 y ear. SUBJECTS. Adult primary care patients. MEASURES. Duke Health Profile for HRQOL, Duke Severity of Illness Checklist for severity of illness, and Johns Hopkins Ambulatory Care Groups for diag nostic groups classification. RESULTS. Of 1,202 patients, 84.4% had follow up in the primary care clinic, 63.2% in subspecialty clinics, 14.8% in the emergency room, and 9.6% in th e hospital. Of $6,290,775 total charges, $779,037 (12.2%) was for follow-up primary care. The highest accuracy was found for predicting primary care c harges, where R-2 for predictors ranged from 0.083 for medical record audit or-reported severity of illness to 0.107 for HRQOL. When predictors were co mbined, the highest R-2 of 0.125 was found for the combination of HRQOL and diagnostic groups. CONCLUSIONS. Baseline HRQOL, severity of illness, and diagnoses were compar able predictors of 1-year health services charges in all clinical sites but most predictive for primary care charges, and were more accurate in combin ation than alone.