BACKGROUND

Medical complications are the key drivers of the direct medical costs of treating patients with type 2 diabetes mellitus. However, the published literature shows great variability across studies in the number and type of sources from which these costs for diabetes are obtained.

OBJECTIVE

To provide to researchers a set of costs for type 2 diabetes complications, originally developed for input into an established diabetes model, that are empirically based, clearly and consistently defined and applicable to a large segment of managed care patients in the US.

METHODS

Patients with 1 of 24 diabetes-related complications between 1 January 2003 and 31 December 2004 and with evidence of type 2 diabetes were identified using a nationally representative US commercial insurance claims database. Therapy utilization and complication cost data were extracted for all patients for the 12 months following the first identified complication; data for months 13-24 were obtained for a subset of patients with at least 24 months of follow-up enrollment. Medical costs included both the amounts charged by medical providers and the health plan contracted allowed amounts. Costs were expressed as $US, year 2007 values.

RESULTS

A total of 44 021 patients with a minimum of 12 months of continuous follow-up enrollment were identified, with a mean age of 56 years; a subset of 32 991 patients with at least 24 months of continuous health-plan enrollment was also identified. Among the aggregate sample, 74% of patients were receiving oral antidiabetics, 26% were receiving insulin, 43% were receiving ACE inhibitors and 50% were receiving antihyperlipidaemics/HMG-CoA reductase inhibitors (statins) during the first 12 months following the index complication. The majority of patients had at least one physician office visit (99.8%), laboratory diagnostic test (96.2%) and other outpatient visit (97.5%). Six complications (angina pectoris, heart failure, peripheral vascular disease, renal disease, nonproliferative retinopathy and neuropathy) had a prevalence of at least 10%. Allowed amounts for most complications were 30-45% of charges. Myocardial infarction, heart failure and renal disease had the greatest fiscal impact because of the total number of patients experiencing them (7.2%, 14.0% and 11.0%, respectively) and their associated costs; 12-month mean allowed amounts were $US 14,853, $US 11,257 and $US 13,876, respectively, and 12-month mean charged amounts were $US 41,695, $US 30, 066 and $US 34,987, respectively. Similarly, in the subset of 32 991 patients, these three complications had higher allowed and charged amounts over months 13-24 compared with the majority of other complications of interest.

CONCLUSION

These costing results provide an important resource for economic modelling and other types of costing research related to treating diabetes-related complications within the US managed care system.