Generic drug discount programs: are prescriptions being submitted for pharmacy benefit adjudication?

In 2006, pharmacies began offering select generic prescription drugs at discount prices (e.g., $4 for a 30-day supply) through nonmembership and membership programs. As part of the contract in membership generic drug discount programs, the member agrees to forgo submission of the claim to the insurance company. Claims not submitted for insurance adjudication may result in incomplete pharmacy benefit manager (PBM) and health plan data, which could negatively influence adherence reporting and clinical programs. To address potentially missing claims data, the Centers for Medicare Medicaid Services (CMS) encourages Medicare Part D sponsors to incentivize network pharmacies to submit claims directly to the plan for drugs dispensed outside of a member's Part D benefit, unless a member refuses. The extent of PBM and health plan claims capture loss due to generic drug discount programs is unknown.

To identify changes in levothyroxine utilizers' prescription claims capture rate following the advent of generic drug discount membership and nonmembership programs.

This retrospective concurrent cohort study used claims data from 3.5 million commercially insured members enrolled in health plans located in the central and southern United States with Prime Therapeutics pharmacy benefit coverage. Members were required to be 18 years or older and younger than 60 years as of January 1, 2006, and continuously enrolled from January 1, 2006, through December 31, 2010. Members utilizing generic levothyroxine for at least 120 days during January 1, 2006, through June 30, 2006 (baseline period) from the same pharmacy group with supply on July 1, 2006, were placed into 1 of 3 pharmacy groups: (1) nonmembership (Walmart, Sam's Club, Target, Kroger, City Market, and King Soopers pharmacies), (2) membership (Walgreens, CVS, Albertsons, and Savon pharmacies), or (3) the reference group of all other pharmacies. The index date was defined as July 1, 2006. The levothyroxine claim providing supply on July 1, 2006, was the index claim. Members with a Kmart pharmacy index claim were excluded, since the Kmart membership drug discount program began prior to July 1, 2006. Levothyroxine claims capture nonpersistency, defined as the occurrence of a claim supply end date prior to a 180-day gap, was the primary outcome variable and was assessed from July 1, 2006, through June 30, 2010 (follow-up period). The odds of levothyroxine claims capture nonpersistency by pharmacy group were assessed using a logistic regression analysis adjusted for the following covariates: age, gender, median income in the ZIP code of residence (binomial for ≤ $50,000 vs. greater than $50,000), switch to a brand levothyroxine product during the follow-up period, index levothyroxine claim supply of 90 days or more, and index levothyroxine claim member cost share per 30-day supply in tertiles (≤ $5.00, $5.01-$7.99, ≥ $8.00).

Of 2,632,855 eligible members aged 18 years or older, 13,427 met all study eligibility criteria. The baseline pharmacy groups were membership with 3,595 (26.8%), nonmembership with 1,919 (14.3%), and all other pharmacies with 7,913 (58.9%) members. The rates of levothyroxine claims capture persistency throughout the 4-year follow-up period were 85.4% for nonmembership (P = 0.593 vs. all other pharmacies), 77.7% for the membership group (P  less than  0.001 vs. all other pharmacies), and 85.9% for all other pharmacies. The Kaplan-Meier comparison of claims capture persistency found nearly identical claims capture loss for the nonmembership compared with all other pharmacies group, and when compared in a multivariate logistic regression model, there was no difference in the odds of levothyroxine claims capture over 4 years follow-up (OR = 1.01, 95% CI = 0.88-1.16, P = 0.900). The membership generic drug discount programs (Walgreens, CVS, Alberstons, and Savon pharmacies) had a statistically significant 61% higher odds (OR = 1.61, 95% CI = 1.45-1.79, P  less than  0.001) of levothyroxine claims capture nonpersistency. The onset of the difference between the membership group and the all other pharmacies group was temporally associated with the launch of the membership programs. In comparison to index levothyroxine member cost of ≤ $5.00 per 30-day supply, higher cost shares were associated with higher levothyroxine claims capture nonpersistency ($5.01 to $7.99 OR 1.34, 95% CI 1.19-1.52 and ≥ $8.00 OR 1.60, 95% CI 1.40-1.82).

Among levothyroxine utilizers in 2006 (prior to the advent of drug discount programs), those with claims from a pharmacy that subsequently implemented a nonmembership generic drug discount program did not appear to have a different rate of levothyroxine claims capture than members from the reference group when followed through June 2010. Utilizers with claims from a pharmacy that subsequently implemented a membership program had a significantly lower levothyroxine claims capture rate. Increasing index levothyroxine member cost was associated with higher levothyroxine claims capture loss. Because the analysis could not directly measure claims capture loss associated with members who switched to a new pharmacy group without presenting their insurance information (e.g., membership discount programs), further research is needed to confirm these findings.