Abstract
IMPORTANCE: Patient adherence to antidiabetic medications, especially insulin, remains poor, leading to adverse outcomes and increased costs. Most adherence interventions have only been modestly effective, partly because they are not targeted to patients who could benefit most. OBJECTIVE: To evaluate whether delivering more intensive insulin-adherence interventions only to individuals with type 2 diabetes predicted to benefit most was more effective than delivering a lower-intensity intervention to a larger group of unselected individuals. DESIGN, SETTING, AND PARTICIPANTS: This 3-arm pragmatic randomized clinical trial used data from Horizon, the largest health insurer in New Jersey, on 6000 participants 18 years or older with type 2 diabetes who were receiving basal insulin. Patients were excluded if they were insured by Medicaid or Medicare or had fewer than 3 months of continuous enrollment. The study was conducted from July 7, 2016, through October 5, 2017. Analyses were conducted from February 5 to September 24, 2018. INTERVENTIONS: Eligible patients were randomized to 3 arms in a 1:1:1 ratio. Randomization was stratified based on baseline availability of 1 or more glycated hemoglobin A1c (HbA1c) test values. All arms were designed to cost the same, and each cohort received a tailored pharmacist telephone consultation varying based on (1) proportion receiving the intervention and (2) intensity, including follow-up frequency and cointerventions. Arm 1 offered a low-intensity intervention to all patients. Arm 2 offered a moderate-intensity intervention to 60% of patients based on their predicted risk of insulin nonadherence. Arm 3 offered a high-intensity intervention to 40% of patients based on glycemic control and predicted risk of insulin nonadherence. MAIN OUTCOMES AND MEASURES: The primary outcome was insulin persistence. Secondary outcomes were changes in HbA1c level and health care utilization. Outcomes were evaluated in arms 2 and 3 vs arm 1 using claims data, intention-to-treat principles, and multiple imputation for missing values in the 12-month follow-up. RESULTS: Among 6000 participants, mean (SD) age was 55.9 (11.0) years and 3344 (59.8%) were male. Compared with arm 1, insulin nonpersistence did not differ in arm 2 (relative risk, 0.88; 95% CI, 0.75-1.03) or arm 3 (relative risk, 0.91; 95% CI, 0.77-1.06). Glycemic control was similar in arm 2 and arm 1 (absolute HbA1c level difference, -0.15%; 95% CI, -0.34% to 0.05%) but was better in arm 3 (absolute HbA1c level difference, -0.25%; 95% CI, -0.43% to -0.06%). Total spending and office visits did not differ, but arm 2 (moderate intensity intervention) had more hospitalizations (odds ratio, 1.22; 95% CI, 1.06-1.41) and emergency department visits (odds ratio, 1.38; 95% CI, 1.24-1.53) than did arm 1 (low intensity intervention). CONCLUSIONS AND RELEVANCE: Compared with an untargeted low-intensity intervention, delivering a highly targeted high-intensity intervention did not improve insulin persistence but modestly improved mean glycemic control. A partially targeted moderate-intensity intervention did not change insulin persistence or HbA1c level but was associated with a small increase in hospitalizations. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02846779.