Potentially Inappropriate Medication Prescribing and Risk of Unplanned Hospitalization among the Elderly: A Self-Matched, Case-Crossover Study.

Abstract

An association between potentially inappropriate medication (PIM) use and adverse events has been established. However, PIM criteria for elderly patients and medical circumstance vary in different countries. We investigated the association between PIM use according to Japanese guidelines and unplanned hospitalization among elderly patients. A case-crossover study was conducted. We used the Japanese Medical Data Vision database of 17.9 million people from 270 acute care hospitals across Japan. Records from 247,897 patients aged ≥ 65years with unscheduled admissions between January 2009 and December 2015 were analyzed. We defined PIM use according to the Japanese Guidelines for Medical Treatment and Its Safety in the Elderly and used conditional logistic regression analysis to fit self-matched case-crossover models and compared each patient's PIM use over five case periods (1, 2, 4, 8, and 12weeks) prior to each unplanned hospitalization. We found the highest odds ratios (ORs) of unscheduled admission related to PIM use in the 1-week case period [OR 4.15; 95% confidence interval (CI) 4.05-4.25], followed by the 2-week (OR 3.01; 95% CI 2.95-3.07), 4-week (OR 3.91; 95% CI 3.83-4.00), 8-week (OR 2.00; 95% CI 1.96-2.05), and 12-week case periods (OR 1.48; 95% CI 1.44-1.51). Elderly patients commonly used PIMs, especially antidiabetics and diuretics. PIM use was associated with a 1.5- to 4-fold increase in the ORs of unplanned hospitalization among them.