Assessment of basal insulin adherence using 2 methodologies among Texas Medicaid enrollees with type 2 diabetes.

BACKGROUND: Basal insulin is often recommended as the initial therapy for patients with type 2 diabetes who require insulin treatment. Adequate adherence is critical to diabetes management, yet suboptimal insulin adherence has been reported. Second-generation long-acting (SGLA) insulin has higher dosing flexibility and lower hypoglycemia risk and may improve adherence. However, little is known regarding adherence to SGLA insulin and how adherence to SGLA insulin compares with intermediate-acting neutral protamine Hagedorn (NPH) and first-generation long-acting (FGLA) insulin. Measurement of insulin adherence is challenging because of the inaccuracies of recorded days supply of insulin, and traditional medication possession ratio (MPR) may be negatively affected. Adjusted MPR (aMPR) has been developed in an effort to address this issue. OBJECTIVE: To examine the unadjusted and adjusted associations between basal insulin type and adherence to basal insulin using MPR and aMPR. METHODS: This retrospective database study used Texas Medicaid prescription claims from January 1, 2014, through June 30, 2017. The index date was the date of the first basal insulin prescription without the same prescription 6 months before (pre-index), and all patients were followed for 12 months (post-index). Patients aged 18-63 years with ≥ 1 pre-index prescription of an oral hypoglycemia agent (OHA) or a glucagon-like peptide-1 receptor agonist (GLP-1 RA), without any post-index prescription of premixed insulin or a basal insulin different from index insulin, and with continuous enrollment throughout the pre- and post-index periods, were included. The dependent variable was basal insulin adherence over 12 months, measured using MPR and aMPR. Unadjusted and adjusted adherence comparisons were conducted by basal (background) insulin type (NPH, FGLA, and SGLA). Covariates included age, gender, baseline use of basal insulins and comorbid medications, total number of medications, OHA adherence, post-index number of OHAs, and use of bolus insulins and GLP-1 RAs. Analysis of variance, chi-square tests, and multiple logistic regression analyses were performed. RESULTS: Of the 5,034 patients included, NPH, FGLA, and SGLA insulin users accounted for 3.7%, 89.8%, and 6.5%, respectively. The overall mean (SD) age was 50.9 (9.9) years, and 65.9% were female. In the unadjusted bivariate analyses, SGLA insulin users had significantly higher adherence, using either MPR (SGLA 0.68 [0.25] vs. FGLA 0.59 [0.27] vs. NPH 0.55 [0.27]; P < 0.0001) or aMPR (0.83 [0.23] vs. 0.78 [0.26] vs. 0.73 [0.28]; P = 0.0001). After controlling for covariates, insulin type was not significantly associated with the likelihood of being adherent (MPR or aMPR ≥ 0.8) using either measure. CONCLUSIONS: Adherence to SGLA insulin was not different from adherence to other basal insulins after controlling for patient characteristics. Yet, MPR and aMPR have limitations and warrant further confirmation of the study findings. Before new adherence measures for insulin therapy are developed, MPR and aMPR should be used with caution. DISCLOSURES: No specific funding was received for this manuscript. The authors report no potential conflicts of interest. Part of the data from this study was presented as posters at the American Pharmacists Association 2020 Annual Meeting & Exposition, March 20-23, 2020, in National Harbor, MD, and at the International Society for Pharmacoeconomics and Outcomes Research 2020 Conference, May 16-20, 2020, in Orlando, FL.

Prediction of Change in Prescription Ingredient Costs and Co-payment Rates under a Reference Pricing System in South Korea.

BACKGROUND: The reference pricing system (RPS) establishes reference prices within interchangeable reference groupings. For drugs priced higher than the reference point, patients pay the difference between the reference price and the total price. OBJECTIVES: To predict potential changes in prescription ingredient costs and co-payment rates after implementation of an RPS in South Korea. METHODS: Korean National Health Insurance claims data were used as a baseline to develop possible RPS models. Five components of a potential RPS policy were varied: reference groupings, reference pricing methods, co-pay reduction programs, manufacturer price reductions, and increased drug substitutions. The potential changes for prescription ingredient costs and co-payment rates were predicted for the various scenarios. RESULTS: It was predicted that transferring the difference (total price minus reference price) from the insurer to patients would reduce ingredient costs from 1.4% to 22.8% for the third-party payer (government), but patient co-payment rates would increase from a baseline of 20.4% to 22.0% using chemical groupings and to 25.0% using therapeutic groupings. Savings rates in prescription ingredient costs (government and patient combined) were predicted to range from 1.6% to 13.7% depending on various scenarios. Although the co-payment rate would increase, a 15% price reduction by manufacturers coupled with a substitution rate of 30% would result in a decrease in the co-payment amount (change in absolute dollars vs. change in rates). CONCLUSIONS: Our models predicted that the implementation of RPS in South Korea would lead to savings in ingredient costs for the third-party payer and co-payments for patients with potential scenarios.

Retrospective evaluation of the impact of copayment increases for specialty medications on adherence and persistence in an integrated health maintenance organization system.

BACKGROUND: Specialty drugs are generally defined as high-cost injectable, infused, oral, or inhaled drugs that require close monitoring. Specialty drugs account for an increasing percentage of total drug expenditures, and management of specialty drugs has become a priority. A Central Texas-based integrated health maintenance organization system implemented a specialty drug benefit to manage expensive specialty drug costs. OBJECTIVES: Our objective was to measure and compare the change in adherence and persistence after implementation of copayment increases for select specialty medications used on a long-term basis (at least 2 years). METHODS: Patients who were long-term users of anti-inflammatory, immunosuppressant, cancer, and multiple sclerosis medications were selected. The intervention group consisted of those whose out-of-pocket payment for specialty medications increased, and the control group consisted of those whose out-of-pocket costs did not change. Adherence, defined by proportion of days covered, was measured every 3 months for 12 months before and after the change. Individual growth model analysis evaluated the changes in adherence. Cox regression analysis determined the difference in persistence between groups. RESULTS: There were 178 and 202 patients in the intervention and control groups, respectively. The growth model showed a small but statistically significant decrease in proportion of days covered of 0.040 after copay changes in the intervention versus control group (P < 0.001) for immunosuppressants. The Cox regression analysis indicated a higher probability of intervention patients on anti-inflammatory drugs (hazard ratio [HR] = 2.53; 95% CI, 1.38-4.62) and immunosuppressants (HR = 3.01; 95% CI, 1.20-7.56) would be nonpersistent compared with those in their control groups. CONCLUSIONS: The move to the specialty formulary allows for closer scrutiny of specialty utilization by pharmacists, who actively monitor utilization and access. Despite the minimal adherence decrease and significant persistence changes with certain drug types, the results indicated relatively more stability with specialty drug use than reported with traditional pharmaceuticals.