The JNC-7 and ADA recommend a goal BP of < 130/80mmHg in diabetes mellitus (DM) patients. Clinical trials suggest most DM patients require ≥ 2 antihypertensive medications to achieve BP goal. OBJECTIVES: Compare differences in BP and healthcare costs by CCB type (dihydropyridine [DHP] vs. (nondihydropyridine [NDHP]) added to an antihypertensive regimen. Proportion of patients tested for proteinuria was also assessed. METHODS: Administrative claims data were obtained from Western and Southeastern US health plans. Patients were identified (N = 5551) with DM and HTN initiated on CCB therapy from January 1, 2000 through June 30, 2002, with eligibility 6 months prior and 1 year post-index, no CCB prescriptions within 6 months pre-index date, and medication possession ratio > 50% in the 1 year post-index period. Costs attributable to DM or HTN were analyzed. A random sample was targeted for medical chart review. Testing for proteinuria was identified from both claims and medical charts. RESULTS: Majority of patients initiated on CCB received other antihypertensive medications; 86% and 76% in the DHP and NDHP groups, respectively. The NDHP group had lower annual attributable costs ($1637 [95% CI, $1479-$1813] vs. $1989 [95% CI, $1823-$2170]; P <0.004). A total of 313 medical charts were reviewed (DHP=242, NDHP=71). Both groups had similar pre- and post-index BP values; mean changes in SBP and DBP were not statistically significant between groups. Percentages of patients achieving BP goal were low in both groups; < 25% achieved SBP goal of < 130mmHg, and 36%-37% achieved DBP goal of < 80mmHg. Less than 45% of patients were tested for proteinuria during the study period. CONCLUSIONS: Patients initiated on an NDHP attained similar BP reductions compared to DHP at lower total costs. Opportunities exist for more aggressive management of BP and testing for proteinuria in DM patients with HTN.