EMPIRIC INVESTIGATION ON DIRECT COSTS-OF-ILLNESS AND HEALTH-CARE UTILIZATION OF MEDICAID PATIENTS WITH DIABETES-MELLITUS

Objective: To determine total direct costs-of-illness and to study the influence of different factors affecting these costs. In addition, we examined each type of service (eg, hospitalization, outpatient care, prescription drugs, physician encounters, and laboratory tests) for di abetic Medicaid patients to provide evidence about the relationship be tween diabetic patients' healthcare utilization and their related pred ictors. Patients and Methods: A total of 7931 patients with diabetes w ho were 65 years or younger in the Alabama Medicaid program from 1992 to 1995 were studied. Using a relational database created from Medicai d claims, multiple regression and canonical correlation methods were u sed to analyze the patients' direct costs-of-illness, including the co sts associated with each healthcare service used by each patient. Resu lts: The costs of hospitalization, outpatient care, prescription drugs , and physician encounters were the four largest components of the dir ect costs-of-illness for diabetic Medicaid patients, comprising 29.9%, 21.3%, 28.2%, and 14.3%, respectively. After controlling for other fa ctors in an empiric model, the direct costs-of-illness for a patient w ith insulin-dependent diabetes mellitus was $5160 higher than for a pa tient with noninsulin-dependent diabetes mellitus during the 3-year st udy. The cost for a patient with renal dysfunction was $59,920 higher than for other diabetic patients. Each increase in the number of diffe rent prescribing physicians per patient was associated with a cost inc rease of $450. Each additional comorbidity increased the cost by $735 per patient. The cost for a male patient was $2140 higher than that fo r a female patient, and the cost for a white patient was $1330 higher than that for a nonwhite patient. For a patient who relied on diet to control diabetes, there were $2750 less in costs compared with other p atients during the study period. More than 20% of the variability in p atients' healthcare utilization costs was explained by the set of pred ictive factors. Conclusions: The direct costs-of-illness and healthcar e utilization for Medicaid diabetic patients were significantly accoun ted for by the number of comorbidities, the number of different physic ians visited, insulin-dependent diabetes mellitus, and complications ( especially renal dysfunction). Patients who relied on dietary therapy and exercise to control their diabetes had lower healthcare costs and utilization than other patients: A significant amount of healthcare co sts and utilization might be controlled or reduced if diabetes disease management can successfully be aimed at preventing diabetic complicat ions, controlling comorbidities, and minimizing the number of differen t physicians visited.