Utilization and costs for compliant patients initiating therapy with pioglitazone or rosiglitazone versus insulin in a Medicaid fee-for-service population.

OBJECTIVE: To compare health care utilization and costs for type 2 diabetes patients initiating therapy with one of two thiazolidinediones (TZDs, pioglitazone or rosiglitazone) or insulin in a Medicaid population.

METHODS: The study used a retrospective cohort design and included type 2 diabetes patients who initiated therapy with TZDs or insulin treatment during the 3-year period (1999-2001). These patients were identified from a Medicaid administrative claims database for approximately 230,000 fee-for-service Medicaid recipients using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes: 250.0x-250.9x, where x = 0 or 2). The first pharmacy claim for a TZD or insulin was treated as an index pharmacy claim, and utilization and costs were assessed for each patient for a 12-month follow-up period after the index date of the first pharmacy claim. A 12-month preperiod without a pharmacy claim for a TZD or insulin confirmed that the patient was newly prescribed with these medications. Analysis was restricted to a compliant sample receiving at least 6 pharmacy claims for either TZD or insulin in the 12-month follow-up period. The propensity matching technique was used to control for selection bias and potential imbalances between these groups at baseline. Patients initiating therapy with insulin or TZD were matched on the basis of demographics, year of index pharmacy claim, presence of microvascular/macrovascular complications, comorbidity, type 2 diabetes-related medical utilization and costs in the 12-month preperiod, overall health care utilization and costs in the preperiod, and type of oral hypoglycemic agents/other medications in the preperiod. Nonparametric bootstrapping was used to estimate the impact of therapy on both overall and type 2 diabetes-related health care utilization and costs in the matched sample.

RESULTS: A total of 2,842 patients with type 2 diabetes patients met the inclusion criteria prior to exclusion of 881 patients (31.0%) who did not receive at least 6 pharmacy claims for either TZD or insulin in the 12 months following the index pharmacy claim, leaving 1,961 type 2 diabetes patients who initiated therapy with one of the two TZDs or insulin in the 3-year enrollment period (TZDs = 1,523; insulin = 438). Propensity matching eliminated 1,271 patients (64.8%), resulting in a final sample consisting of 690 patients.345 patients per treatment group.with comparable demographic and utilization parameters at baseline. In the 12-month follow-up period for the measures of overall utilization, patients initiated on TZDs did not differ significantly in the number of emergency room (ER)/hospitalization episodes and the number of pharmacy claims compared with the patients initiated on insulin, but they did have an average of 1.2 fewer physician office visits (9.3 vs. 10.5, P <0.05). Compared with the insulin group, the TZD group incurred 35% lower costs for ER visits/hospitalization (dollar 3,727 vs. dollar 5,793, P <0.01) and 18% lower total health care costs (dollar 12,737 vs. dollar 15,563, P <0.05). No significant differences were observed between the groups in overall outpatient and pharmacy costs. When the analysis was restricted to type 2 diabetes-related utilization and costs, patients initiating therapy with TZDs had 0.8 fewer physician office visits (3.6 vs. 4.4, P <0.05). However, TZD patients had 2.7 (14.1%) more diabetes pharmacy claims than patients initiating therapy with insulin (P <0.01), but there was no difference in the number of type 2 diabetes-related ER visits/hospitalizations between the groups. The TZD group had 53% higher type 2 diabetes-related pharmacy costs than the insulin group (dollar 1,678 vs. dollar 1,096, P <0.01). However, these costs were offset by lower costs for ER visits and hospitalization for the TZD group as compared with the insulin group (dollar 2,855 vs. dollar 5.090, P <0.01) resulting in 25% lower total type 2 diabetes-related costs for the TZD group compared with the insulin group (dollar 5,425 vs. dollar 7,255, P <0.05).

CONCLUSION: Medicaid fee-for-service patients initiated on either pioglitazone or rosiglitazone incurred higher diabetes-related pharmacy costs, which were offset by lower total type 2 diabetes-related medical costs, contributed primarily by lower costs for ER visits and hospitalizations in this 12-month analysis.