Health care costs associated with escalation of drug treatment in type 2 diabetes mellitus.

The cost of different intensities of therapy in HMO patients with type 2 diabetes mellitus was studied. Health care utilization data from 1995 were obtained for 12,200 registrants from the Kaiser Permanente Northwest Diabetes Registry who had type 2 diabetes mellitus. The data were used to determine costs associated with the escalation of antidiabetic therapies in persons with type 2 diabetes mellitus. The total annual costs (in 1993 dollars) associated with no drug therapy, a sulfonylurea only, metformin, a sulfonylurea plus insulin, and insulin alone were $4400, $4187, $4838, $8856, and $7365, respectively. Per patient total costs were higher for patients who had received antidiabetic therapy in 1995 or previously than for those who had not ($5303 versus $4365) and for patients who had received insulin therapy than for those who had not ($7379 versus $4117). Macrovascular complications accounted for 62-89% of the cost associated with inpatient treatment of diabetes-related complications. The total cost of treating patients with type 2 diabetes mellitus at an HMO increased as antidiabetic therapies escalated.