Evaluation of a pharmacist-led medication management program in high-risk diabetic patients: impact on clinical outcomes, medication adherence, and pharmacy costs

Diabetes mellitus is a group of metabolic disorders caused by a relative or absolute lack of insulin. Currently, 23.6 million Americans have diabetes. Diabetes can lead to serious microvascular and macrovascular complications, such as cardiovascular disease, blindness, kidney disease, lower-limb amputations, and premature death. Due to the potential cardiovascular complications and the high prevalence of co-morbid hypertension and/or hyperlipidemia in patients with diabetes, diabetes management should include close monitoring of blood glucose, blood pressure, and cholesterol levels.

Medical management of diabetic patients is costly; approximately 1 in every 10 health care dollars is currently spent treating diabetes. Studies have shown that in chronic conditions such as diabetes, increased medication use results in demonstrable improvements in health outcomes, reduced hospitalization rates, and decreased direct health care costs. To date no studies have evaluated the impact of a pharmacist-led intervention on diabetic medication adherence.

The purpose of this investigation was to analyze the impact of a pharmacist-led medication management program on medication adherence and pharmacy costs and to evaluate clinical measures of diabetes, hypertension, and hyperlipidemia. This study was a quasi-experimental, longitudinal, pre-post study, with a control group. Scott & White Health Plan (SWHP) patients with diabetes (type 1 or type 2), poor glycemic control (most recent A1C >7.5%), and living within 30 miles of participating pharmacies were invited to participate in the intervention which consisted of monthly appointments with a clinical pharmacist and a co-payment waiver for all diabetes medications and testing supplies. A total of 118 patients met study inclusion criteria and were enrolled in the intervention between August 2006 and July 2008. Intervention patients were matched on sex and age to SWHP patients with poor diabetes control living more than 30 miles from a participating pharmacy. To measure the impact of the intervention, medical and pharmacy data were evaluated for one year before and after the study enrollment date.

A significant difference was seen in the percentage of patients with type 1 diabetes in the intervention group (14) and the control group (3). The medication management program significantly improved A1C levels in intervention patients relative to controls (-1.1% vs. 0.6%) and was more effective in lowering A1Cs in type 2 diabetics than type 1 patients. Although the generalized linear model did not show that the intervention significantly improved the percentage of patients achieving the ADA goal A1C of <7% compared to controls, the multivariate logistic regression, which controlled for factors such as diabetes type, showed that patients participating in the intervention were 8.7 times more likely to achieve the A1C goal. Persistence with diabetic medications and the number of medications taken significantly increased in the intervention group; however, adherence rates, as measured by medication possession ratio (MPR), did not significantly improve relative to controls. The expenditure on diabetic medications and testing supplies increased substantially more in the intervention group than in the control group.

The percentage of patients adherent with antihypertensive medications (MPR ≥80%) increased from 76% to 91% in the intervention group and decreased from 68% to 63% in the control group (P<0.05); no significant difference in blood pressure control was observed. For hyperlipidemia medications, adherence and persistence increased and pharmacy costs decreased in both groups, likely due to the introduction of the first generic HMG-CoA reductase inhibitor into the market during the study period. Future research is needed on the impact of the intervention on medical resource utilization and costs.