Variation in US private health plans' coverage of orphan drugs

To compare coverage of orphan and nonorphan drugs, to examine variation in orphan drug coverage across the largest US private plans, and to evaluate factors influencing coverage decisions.

Database and regression analyses.

We analyzed a data set of private health plan coverage decisions for specialty drugs (N = 5000) in 3 ways. First, we compared the frequency with which plans applied restrictions in their decisions for orphan and nonorphan drugs. Second, we examined variation in the frequency with which 17 of the largest 20 private plans applied coverage restrictions for orphan drugs. Third, we used multivariate regression to examine factors associated with restricted orphan drug coverage.

Health plans are less likely to restrict orphan drugs compared with nonorphan drugs. Of orphan drug decisions (n = 2168), plans did not apply coverage restrictions in 70% of cases, applied restrictions in 29%, and did not cover in 1%. In contrast, of nonorphan drug decisions (n = 2832), plans did not apply coverage restrictions in 53% of cases, applied restrictions in 41%, and did not cover in 6%. The frequency of restrictions for orphan drugs varied from 11% to 65% across plans. The attributes of orphan drugs that were more likely to be associated with restrictions than others included drugs for noncancer diseases, drugs with alternatives, self-administered drugs, drugs indicated for diseases with a higher prevalence, and drugs with higher annual costs (all P <.05).

Health plans restrict access to orphan drugs approximately one-third of the time, and restrictions vary considerably across plans. Plans more often add restrictions for orphan drugs that are indicated for diseases with a higher prevalence and that have higher annual costs.