Economic Outcomes Associated with Microvascular Complications of Type 2 Diabetes Mellitus: Results from a US Claims Data Analysis

Background: Patients with diabetes mellitus have been shown to be at high risk for both macrovascular and microvascular complications (MVC). Recent studies have focused on MVC and their effect on the healthcare system, but limited published data exist on long-term costs associated with MVC in patients with type 2 diabetes mellitus (T2DM).

Objective: The objective of this study was to compare resource utilization and medical costs over a 12-month period among patients diagnosed with T2DM with versus without MVC in a managed-care population.

Methods: Patients aged >/=18 years, diagnosed with T2DM between 1 January 2003 and 31 December 2004 were identified in an administrative claims database of approximately 55 million beneficiaries in private and public health plans. The date of the first T2DM diagnosis during this period was the 'index date' for each patient. All patients had to have a minimum of 12 months of continuous enrolment both prior to and following the index date. MVC was identified during the 12 months prior to the first T2DM diagnosis and these patients were matched (1 : 2) by age, sex and ten co-morbid conditions to those with no evidence of MVC during the entire study period.

Results: Among the 15 326 MVC patients included in the study, 61% had a history of peripheral neuropathy, 28% diabetic retinopathy and 19% nephropathy. Compared with 30 652 patients without MVC, the MVC patients were more likely to use oral antidiabetics and insulin and had a higher co-morbidity score. Over 12 months, patients with MVC had more (mean 0.3 vs 0.2; p < 0.001) and longer (mean length of stay 1.79 days vs 0.85 days; p < 0.001) hospital stays; physician office visits (19.7 vs 13.7; p < 0.001); and prescriptions for oral antidiabetic (6.3 vs 5.6 scripts; p < 0.001) and insulin (0.7 vs 0.2 scripts; p < 0.001) use. Average total costs per patient over 12 months were $US14 414 with MVC versus $US8669 without MVC (p < 0.001).

Conclusions: This study indicates that in patients with T2DM, MVC is associated with significant consumption of healthcare resources. Mean total costs with MVC were almost double those of patients without MVC over a 12-month period.