Impact of the COVID-19 Pandemic on Drug Shortage Incidence in the United States

Background: Drug shortages are a major public health concern due to their increasing frequency, duration and negative consequences on patient outcomes. The COVID-19 pandemic has had a major impact on the global drug supply chain, but it remains unclear to what extent it affected drug shortages.

Objectives: To determine the impact of the COVID-19 pandemic on the true incidence of meaningful drug shortages in the United States.

Methods: Supply chain reports were identified using FDA and ASHP's websites. We used data from IQVIA MIDAS to calculate changes in purchased units in each 3-month period with an active issue, relative to the 3 months preceding the initial report. Our outcomes were the incidence of meaningful and severe shortages, defined ≥33% or ≥66% decreases in units purchased. To mitigate the impact of seasonality unrelated to shortages, we compared outcomes for drugs with and without supply reports. We employed a difference-in-difference approach using multivariable Poisson models and predictive marginal effects to compare the incidence of drug shortages pre (1/2018-1/2019) vs. during (5/2020- 9/2021) the pandemic for drugs with a report versus comparison drugs, adjusting for essential medicine status, parenteral formulation, generic status, medication age, single-source status, and sales volume. February-April 2020 were excluded to control for temporary increases in purchasing in anticipation of the pandemic.

Results: There were 1711 medications in the MIDAS dataset. Of these, 644 (37.6%) had any supply issue report from 2018-2021. Nearly one third (36%) were discontinuations, 56.4% were shortages, and 9.2% were recalls. Manufacturers did not provide a reason for 33.1% and 23.6% were manufacturing delays. Older, parenteral generics were over-represented. Pre-pandemic, 15.6% (95% CI: 14.4, 16.8%) of drugs with a report experienced meaningful shortages vs. 4.6% (95% CI: 4.3, 4.8%) of comparison drugs. During the pandemic, the incidence of meaningful shortages increased to 16.3% (95% CI: 14.9, 17.7%) among drugs with a report and decreased among comparison drugs (4.0%, 95% CI: 3.7, 4.2%). The difference-in-difference estimate found that the change was not significant (1.3%, 95% CI: -0.005, 3.2%). Severe shortages increased non-significantly from an incidence of 6.3% (95% CI: 5.5, 7.1%) to 7.2% (95% CI: 6.5, 8.4%) for drugs with reports.

Conclusions: This national analysis identified minimal, statistically insignificant increases in drug shortages in the first year of the COVID-19 pandemic. New policies may have mitigated the impact of drug shortages. Our results highlight the importance of ongoing work by FDA and other federal agencies to mitigate the impact of unexpected events like pandemics on U.S. pharmaceutical supply.