Background: Medication copayment reduction can be integrated with disease management programs to incentivize patient engagement in chronic care management. While disease management programs in diabetes have been evaluated across a range of settings and designs, less is known regarding the effectiveness of copayment reduction as a component of disease management., Objective: To evaluate the short-term results of a diabetes-focused disease management program that included copayment reduction, care coordination, and patient goal setting, focusing on rates of evidence-based care processes and all-cause pharmacy and health care costs., Methods: Blue Cross Blue Shield of Rhode Island offered large employer groups the opportunity to participate in a diabetes disease management initiative that featured reduced copayments (from $7/$25/$40 for generic, tier 2, and tier 3 drugs, respectively, to $0 for generic and $0-$2 for brand drugs) for diabetes-related medications. In return for the copayment reduction, participants agreed to the following: (a) participate in care coordination with a case manager, (b) have an annual physical examination, (c) have a hemoglobin A1c blood test at least twice annually, and (d) have a low-density lipoprotein cholesterol (LDL-C) test at least once annually. Patients received personalized support provided by a registered nurse and dietician, disease-related education provided by nurses, and intensified case management services, including working with a health coach to establish healthy behavioral change goals. All study subjects were aged 18 years or older and had at least 1 ICD-9-CM code for diabetes and at least 1 claim for an antidiabetic drug during a 12-month measurement period, which was each subject's most recent 12-month period of continuous enrollment from January 1, 2008, through May 31, 2010. Administrative claims data were used to determine the percentage of intervention (participating) and nonintervention (nonparticipating) subjects from among all of the plan's employer groups who received at least once-yearly monitoring of A1c, high-density lipoprotein cholesterol (HDL-C), and LDL-C; medical attention (or drug therapy) for nephropathy; and an eye examination. We conducted multivariate logistic regression analyses to assess the effect of the intervention and other patient characteristics and comorbidities on rates of performance of these care processes, aggregating the 5 processes of care into an "all or none" single composite outcome. We also developed a propensity score-weighted model to attempt to adjust for differences between the intervention and nonintervention groups resulting from the nonrandomized study design. Additionally, we quantified average plan payments to providers less patient copayments (i.e., net plan cost) per patient per year (PPPY) for the 12-month follow-up period and compared these costs for the intervention versus nonintervention groups., Results: The study sample consisted of 9,698 patients with diabetes; 649 (6.7%) of whom participated in the intervention. 9,049 (93.3%) patients were identified by the insurer as patients with diabetes receiving usual care. Patients in the intervention and nonintervention groups were similarly likely to have all 5 recommended processes of care performed (40.1% vs. 38.9%, respectively, P = 0.543). Younger patients received all 5 recommended care processes less frequently than older patients (30.5%, 38.0%, and 47.0% for ages 18-48 years, 49-59 years, and 60 years or older, respectively, P < 0.001); in adjusted analyses, patients aged 60 years or older were approximately twice as likely to receive all 5 care processes compared with patients aged 18-48 years (odds ratio [OR] = 1.97, 95% CI = 1.75-2.21). Users of oral antidiabetic monotherapy were least likely to have these processes of care performed compared with users of multiple oral therapies (OR = 1.23, 95% CI = 1.11-1.36) and insulin (OR = 1.59, 95% CI = 1.41-1.78). PPPY prescription drug costs incurred by the plan were greater for intervention than comparison patients (means [SDs] of $3,139 [$3,426] vs. $2,854 [$3,938], respectively, P < 0.001); and the generic-dispensing ratio was slightly lower (means [SDs] of 62.1% [22.4%] and 65.4% [23.0%], respectively, P < 0.001). There were no significant differences between the intervention and comparison groups in mean [SD] PPPY all-cause medical care costs ($7,475 [$17,601] vs. $8,577 [$22,972], respectively, P = 0.213) or total all-cause costs ($10,613 [$18,590] vs. $11,431 [$24,060], P = 0.666)., Conclusions: Patients participating in this incentive program featuring diabetes medication copayment reduction and disease management components did not receive recommended care any more or less frequently than other enrolled members with diabetes. Younger patients and those utilizing oral antidiabetic monotherapy as their drug regimens were less likely to have the recommended processes of care performed. While prescription drug expenditures incurred by the plan were greater for intervention patients, between-group differences in total costs for medications and all-cause medical care were not statistically significant. Further follow-up is required to determine the success of this program over the longer term in promoting quality of care and achieving cost reductions and improved health outcomes.