(200) Developing a drug shortages predictive model using real-world Canadian drug utilization

Background: Drug shortages are an ongoing challenge for the healthcare system but approaches to quantifying shortage risk are lacking. Current research has focused on factors associated with supply chain issue reports, but reporting at the manufacturer supply level does not reflect downstream population-level drug utilization. Therefore, it is essential to determine the impact of shortage events on drug utilization trends and identify shortage predictors associated with decreases in drug use to ascertain shortage risk and inform future policy prioritization.

Objectives: To develop a predictive model to anticipate shortage risk using characteristics associated with meaningful supply decreases following shortage events.

Methods: We conducted a matched cross-sectional study analyzing monthly trends in drug utilization using IQVIA MIDAS data from 2017-2021. Incidence density sampling was used to match each drug with a supply chain event (cases) to 10 drugs without an event (controls). Shortage reports were obtained from Drug Shortages Canada. A logistic regression model with random effects was used to compare the odds of a meaningful supply decrease (33%) within 2 quarters following the report for cases and controls. To assess the impact of drug characteristics on the incidence of meaningful supply decreases, we included interaction terms for drug class, formulation, unit price, number of manufacturers, sales, provider administered drugs, World Health Organization (WHO) essential medicine status, availability of therapeutic equivalents, time on market, number of active pharmaceutical ingredients, Tier-3 status, number of DINs, drug schedule and ODB coverage.

Results: Of 1589 drugs, 998 (63%) unique drugs were exposed to 1959 supply chain events. Meaningful supply decreases (≥33%) were experienced by 11% of cases, compared to 7% of controls. Drugs with sales less than $100,000, anti-infectives (ATC class J) and drugs with unit prices greater than $100 had a higher odds of experiencing meaningful supply decreases (OR: 4.03, 3.16, 2.79 respectively).

Conclusions: Our findings highlight factors strongly associated with supply issue-related decreases in drug supply and indicate that only 1 in 10 supply chain events led to a meaningful decrease in drug supply. These can be used to develop a predictive model to score shortage risk of Canadian drugs and develop a national at-risk medicines list accounting for both supply chain and clinical risk. Our work will guide policy decisions aimed at managing drug shortages, improving patient outcomes and healthcare delivery.