The Ambulatory Diabetes Outreach Program (ADOP): Rigorous Evaluation of a Pharmacist and Nurse-Led Care Model.

Background: Although several systematic reviews found that ambulatory diabetes mellitus (DM) interventions involving pharmacists generally yielded better outcomes than the ones that did not, existing studies have limitations in rigor and study design.

Objective: To examine the intention-to-treat effects of the Ambulatory Diabetes Outreach Program (ADOP) on participants' A1c values and healthcare utilization over a 52-month follow-up period.

Design: Difference-in-differences with staggered adoption. Specifically, we employed the Callaway and Sant'Anna's "group-time average treatment effect" estimator using not-yet treated as controls adjusting for patient's age, BMI, sex, race, comorbidity, payor, and socio-economic status.

Participants: All patients with at least one ADOP treatment encounter from July 2017 to October 2021, regardless of program completion or length of exposure to the program.

Intervention: ADOP, a collaborative population health program led by pharmacists and nurse specialists to provide individualized type 2 DM management and education within a large and diverse health system.

Main measures: Patients' A1c values and healthcare utilization, including inpatient admission, inpatient days, and numbers of visits to the emergency department, urgent care, and primary care in recent 6 months.

Key results: ADOP participation was associated with an overall average reduction of 1.04 percentage points (95%CI - 1.12, - 0.95) in A1c level. Similar A1c reductions were also observed in the subgroups by sex and race/ethnicity. An average of 2 months were required to reach the overall average effect, which persisted over 4 years. Compared to the respective utilization levels pre-intervention, participants also had average reductions in inpatient admissions by 32.4%, inpatient days by 81.6%, visits to the emergency department by 21.6%, and primary care by 17.9%.

Conclusions: The results suggest that a collaborative model of pharmacist and nurse-led type 2 DM intervention was effective in improving A1c outcomes and reducing healthcare utilization in the long term.