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*242. Predicting Costs of VA Health Care for Gulf War Veterans

ML Maciejewski, Seattle HSR&D, VA Puget Sound Health Care System; J Tackett, VA Puget Sound Health Care System; R Richardson, VA Puget Sound Health Care System; M McFall, VA Puget Sound Health Care System; S Hunt, VA Puget Sound Health Care System

Objectives: With the proliferation in the number of generic and condition-specific health status measures, there is debate about which type of measure is appropriate for different applications. This cohort study explores whether condition-specific or generic mental health status measures are better predictors of outpatient health care costs for Gulf War veterans seeking primary care for medically unexplained symptoms.

Methods: Study participants were 117 Gulf War veterans enrolled in the VA PSHCS Gulf War Primary Care Medicine Clinic at the Veterans Affairs Puget Sound Health Care System (VAPSHCS). Participants were consecutive admissions to the Clinic during 1998 – 1999. Survey data on demographics, employment, number of environmental toxins and hazards were obtained at the time of admission to the Gulf War clinic. Two mental health specific measures – PTSD Checklist and the Depression subscale of the Brief Symptom Inventory (BSI-D) – were collected. In addition, the Global Symptom Index (GSI) and the Mental Health Index (MHI-5) – were the two generic mental health measures used to compare with the specific measures. Costs of health care utilization were derived from the Department of Veterans Affairs Decision Support System (DSS), a computerized cost-accounting system that tracks cost of care at the individual patient level, for the 6-month interval following participants’ clinic enrollment. Total health care costs were partitioned into components reflecting outpatient mental health use, outpatient medicine services, and outpatient pharmacy charges. Outpatient medical costs included services for primary care as well as specialty medical clinic consultations. A series of least squares regression analyses were computed in order to explain variation in 6-month outpatient health care costs from mental health variables, after controlling for a number of patient characteristics. Outpatient mental health costs, outpatient medicine (non-mental health), and outpatient pharmacy costs were the three dependent variables used in these analyses. Adjusted R2 and t-statistics were used to compare the four regressions for the three dependent variables on cost.

Results: Both generic mental health status measures were significant predictors of outpatient mental health costs, but the PTSD Checklist was the only specific measure that was significant (p < 0.05). All three models had the same adjusted R-squared (0.69). The two generic measures were significant predictors of outpatient medicine costs and the BSI-D was also significant, with similar adjusted R-squared (0.20-0.21) in the three models. None of the four mental health status variables were particularly good predictors of outpatient pharmacy costs.

Conclusions: Generic mental health status measures are at least as good at predicting outpatient costs for Gulf War veterans seeking primary care as specific measures about PTSD and depression. Outpatient pharmacy costs are explained by factors other than mental health status. Clinicians interested in screening patients who may be intensive mental health and medicine service users can use well-validated mental health status measures. The use of generic measures allows comparisons across various population and condition types.

Impact: Mental health status measures may be useful as diagnostic tools for providers interested in identifying veterans who may be high users of mental health services and medical (non-mental health) services