OBJECTIVE -To describe the direct medical costs associated with type 2 diabetes, as well as its treatments, complications, and comorbidities.RESEARCH DESIGN AND METHODS -We studied a random sample of 1,364 subjects with type 2 diabetes who were members of a Michigan health maintenance organization. Demographic characteristics, duration of diabetes, diabetes treatments, glycemic control, complications, and comorbidities were assessed by surveys and medical chart reviews. Annual resource utilization and costs were assessed using health insurance claims. The log-transformed annual direct medical costs were fitted by multiple linear regression to indicator variables for demographics, treatments, glycemic control, complications, and comorbidities.RESULTS -The median annual direct medical costs for subjects with diet-controlled type 2 diabetes, BMI 30 kg/m 2 , and no microvascular, neuropathic, or cardiovascular complications were $1,700 for white men and $2,100 for white women. A 10-kg/m 2 increase in BMI, treatment with oral antidiabetic or antihypertensive agents, diabetic kidney disease, cerebrovascular disease, and peripheral vascular disease were each associated with 10 -30% increases in cost. Insulin treatment, angina, and MI were each associated with 60 -90% increases in cost. Dialysis was associated with an 11-fold increase in cost. T he worldwide prevalence of diabetes is increasing (1), as is the demand for and cost of medical care (2). Many studies have described the economic impact diabetes has on the health system and society (3-6) and have compared the health care utilization of patients with and without diabetes (7-10). Only a few studies have assessed the relationship between patient characteristics, complications, and costs using patientlevel data (11-16) and most have examined the relationship for aggregated end points (12,13,15,16). The purpose of this study was to describe the relationship between direct medical costs and individual demographic characteristics, treatments, glycemic control, complications, cardiovascular risk factors, and comorbidities in patients with type 2 diabetes.
CONCLUSIONSPrevious models have assigned costs to specific diabetes-related health states (17)(18)(19)(20). This approach is most appropriate for acute health states where interactions with other conditions are absent or clearly identifiable and of limited duration (21). A complex chronic disease like diabetes impacts many other apparently unrelated health problems and the resources used in their treatment. Therefore, it is important to extend the scope of a cost model beyond the direct complications of diabetes to include total direct medical costs. Only in this way can the true economic burden of diabetes be assessed.
RESEARCH DESIGN AND METHODS -The study was reviewed and approved by the University of Michigan Institutional Review Board. All subjects were enrolled in commercial, Medicare, or Medicaid managed care programs offered by a large Michigan health maintenance organization (HMO). Subjects thus represented ...