Impact of a Clinical Pharmacy Program on Changes in Hemoglobin A1c, Diabetes-Related Hospitalizations, and Diabetes-Related Emergency Department Visits for Patients with Diabetes in an Underserved Population

BACKGROUND: Diabetes mellitus is associated with substantial morbidity and mortality. With the rise in prevalence of diabetes, there has been an increased need for clinical pharmacy services focused on diabetes management in ambulatory clinics. However, more data IS needed to determine the overall impact that clinical pharmacists have on preventing diabetes-related inpatient admissions and emergency department (ED) visits for patients with diabetes, especially in an underserved population. OBJECTIVES: To assess the impact of clinical pharmacy services on the change in hemoglobin A1c measurements, the number of diabetes-related hospitalizations, and the number of diabetes-related ED visits for patients with uncontrolled diabetes. METHODS: This was a retrospective study that evaluated outcomes for patients referred to a clinical pharmacist for management of diabetes, compared with patients who were not seen by a clinical pharmacist. Adult patients aged between 18 and 89 years with a diagnosis of type 1 or type 2 diabetes mellitus were identified, using the electronic medical records from CommUnityCare outpatient clinics in central Texas during the period July 1, 2007, through July 1, 2011. Patients enrolled had poor glycemic control, defined as an A1c ≥ 9% at baseline (index), with at least 3 visits with a clinical pharmacist or 3 visits to usual care. Patients with at least 1 year of pre-index data, 1 year of post-index follow-up, and a post-index A1c measure were included in the study. Propensity score (PS) matching was used to create a 1:1 cohort. T-tests were used to calculate results for the main outcome variables (change in A1c, change in number of diabetes-related hospitalizations, and change in number of diabetes-related ED visits). In addition, general linear models (GLM) were used to control for baseline demographic and clinical characteristics. RESULTS: A total of 782 patients met inclusion criteria, 557 in the usual care (control) group and 225 in the clinical pharmacy (intervention) group. PS matching provided a 1:1 matched sample of 220 patients per cohort. When assessing the change in the number of diabetes-related hospitalizations from the pre-index year to the post-index year, patients in the control group had an increase of 8 hospitalizations (8 visits per 220 patients, mean = 0.036, SD = 0.284), while the intervention group had a decrease of 1 hospitalization (-1 visit per 220 patients, mean = - 0.005, SD=0.278). Both the t-test (P = 0.06) and GLM model (P = 0.06) indicated that the difference was statistically significant. When assessing the change in the number of diabetes-related ED visits from the pre-index year to the post-index year, we found patients in the control group had an increase of 16 ED visits (16 visits per 220 patients, mean = 0.073, SD = 0.584), while the intervention group had an increase of 4 ED visits (4 visits per 220 patients, mean = - 0.018, SD=0.641). Both the t-test (P = 0.18) and GLM model (P = 0.28) indicated that the difference was not statistically significant. A1c levels were reduced in the post-index period for both groups. For the control group, A1c reduction was 1.50 (from 11.17 to 9.67, SD = 2.49). For the intervention group, A1c reduction was 1.90 (from 11.09 to 9.19, SD = 2.44). Both the t-test (P = 0.04) and GLM model (P = 0.05) indicated that the A1c difference was statistically significant. CONCLUSIONS: Underserved patients with baseline uncontrolled diabetes who were managed by a clinical pharmacist in the outpatient setting had a higher decrease in A1c compared with usual care. The changes in diabetes-related hospitalizations and diabetes-related ED visits were in the hypothesized direction, but the comparison for ED visits was not statistically significant.