Differences in All-Cause Health Care Utilization and Costs in a Type 2 Diabetes Mellitus Population with and Without a History of Cardiovascular Disease

BACKGROUND: Multiple studies have reported that type 2 diabetes mellitus (T2DM) is a major risk factor for cardiovascular diseases (CVD), and presence of T2DM and CVD increases risk of death. There is growing interest in examining the effects of antidiabetic treatments on the reduction of cardiovascular events in T2DM adults with a history of CVD and thus at higher risk of cardiovascular events. OBJECTIVE: To estimate the incremental all-cause health care utilization and costs among adults with T2DM and a history of CVD compared with adults without a history of CVD, using a national linked electronic medical records (EMR) and claims database. METHODS: Adults aged ≥ 18 years with evidence of at least 1 T2DM-related diagnosis code or antidiabetic medication (date of earliest occurrence was defined as the index date) in calendar year 2012 were identified. The population was divided into 2 cohorts (with and without a history of CVD) and followed until the end of their enrollment coverage, death, or 12 months, whichever came first. Multivariable generalized linear models were used to assess differences in health care utilization and per patient per month (PPPM) total costs (plan- and patient-paid amount for health care services) between the 2 groups during the post-index year, while adjusting for an a priori list of demographic and clinical characteristics. RESULTS: A total of 138,018 adults with T2DM was identified, of which 16,547 (12%) had a history of CVD. The unadjusted resource utilization (outpatient: 27.5 vs. 17.8; emergency room [ER]: 0.8 vs. 0.4; inpatient: 0.4 vs. 0.2 days; and total unique drug prescriptions: 10.1 vs. 8.3) and PPPM total health care costs ($2,655.1 vs. $1,435.0) were significantly higher in T2DM adults with a history of CVD versus T2DM adults without a history of CVD. The adjusted models revealed that T2DM adults with a history of CVD had a 31% higher number of ER visits (rate ratio [RR] = 1.31, 95% CI = 1.25-1.37); 27% more inpatient visits (RR = 1.27, 95% CI = 1.21-1.34); 15% longer mean inpatient length of stay (RR = 1.15, 95% CI = 1.06-1.25); and 11% more outpatient visits (RR = 1.11, 95% CI = 1.09-1.13) compared with T2DM adults without a history of CVD. Furthermore, the difference in total PPPM health care cost was found to be 16% ($200) higher in adults with a history of CVD (RR = 1.16, 95% CI = 1.13-1.19). PPPM costs associated with outpatient and ER visits were approximately 21% and 19% higher among adults with a history of CVD, respectively (P < 0.0001), while costs for inpatient visits were similar between the 2 groups. In addition, a subgroup analysis revealed that adjusted differences in PPPM total cost was larger in the younger age group (56% higher cost in those aged < 45 years) and diminished in the older age group (only 2% higher in those aged ≥ 65 years). CONCLUSIONS: Study findings showed that resource utilization and costs remains significantly higher in T2DM patients with a history of CVD compared with patients without a history of CVD even after controlling for significant patient comorbid and demographic characteristics. Also, younger age groups had higher differences in outcomes compared with older age groups. This study underscores the importance of cost-effective interventions that may reduce economic burden in this T2DM population with a history of CVD.