Low-priced generic drugs most likely to have shortages

(HealthDay)—The lowest-priced generic drugs are more likely to experience shortages, according to a study published in the November issue of Value in Health.

Chintan V. Dave, Pharm.D., Ph.D., from Brigham and Women's Hospital in Boston, and colleagues analyzed 1.3 billion outpatient prescription claims from commercial health plans between 2008 and 2014 to estimate the probability of experiencing a drug shortage based on drug-specific competition levels, market sizes, formulations (e.g., capsules), and drug prices. Additionally, the model estimated the percentage change in drug prices from baseline depending on the duration of the drug shortage.

In a cohort of 1,114 generic drugs, the researchers found that just over one-quarter (28 percent) experienced a shortage. Low-priced generic drugs were at a higher risk for drug shortages versus medium-priced and high-priced generic drugs (odds ratio, 0.60 and 0.72, respectively). Compared with periods of no shortage, drug shortages lasting less than six months had price increases of 6.0 percent compared with 10.9 percent increases for 6- to 12-month shortages, 14.2 percent for 12- to 18-month shortages, and 14.0 percent for >18-month shortages. However, the authors warn that these findings may not be generalizable to drugs that became generic after 2008 or those commonly used in inpatient settings.

"Although drug shortages have been associated with some well-publicized examples of rising generic drug prices, the low prevalence of drug shortages in recent years coupled with their modest association with price increases in our study demonstrate that other factors, such as market competition levels, are more important contributors to this phenomenon," Dave said in a statement.