Potentially high-risk medication categories and unplanned hospitalizations: a case–time–control study

Empirical data of medication-related hospitalization are very limited. We aimed to investigate the associations between 12 high risk medication categories (diabetic agents, diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), anticoagulants, antiplatelets, antihypertensives, antiarrhythmics, anticonvulsants, antipsychotics, antidepressants, benzodiazepine (BZD)/Z-hypnotics, and narcotics) and unplanned hospitalizations. A population-based case–time–control study was performed using Taiwan’s National Health Insurance Research Database. Patients who experienced an unplanned hospitalization (index visit) were identified as index subjects and matched to a randomly selected reference visit within users of a specific category of high-risk medication. An unplanned hospitalization was defined as a hospital admission immediately after an emergency department visit. Discordant exposures to the high-risk medication during the case period (1–14 days before the visit) and the control period (366–379 days before the visit) were examined in both index and reference visits. Antipsychotics was associated with the highest risk of unplanned hospitalizations (adjusted OR: 1.54, 95% CI [1.37–1.73]), followed by NSAIDs (1.50, [1.44–1.56]), anticonvulsants (1.34, [1.10–1.64]), diuretics (1.24, [1.15–1.33]), BZD/Z-hypnotics (1.23, [1.16–1.31]), antidepressants (1.17, [1.05–1.31]) and antiplatelets (1.16, [1.07–1.26]). NSAIDs and narcotics were associated with the highest risks of unplanned hospitalizations with a length of stay ≥10 days. These medication categories should be targeted for clinical and policy interventions.