Both New and Chronic Potentially Inappropriate Medications Continued at Hospital Discharge Are Associated With Increased Risk of Adverse Events

Abstract

Background: Admission to hospital provides the opportunity to review patient medications; however, the extent to which the safety of drug regimens changes after hospitalization is unclear.

Objective: To estimate the number of potentially inappropriate medications (PIMs) prescribed to patients at hospital discharge and their association with the risk of adverse events 30 days after discharge.

Design: Prospective cohort study.

Setting: Tertiary care hospitals within the McGill University Health Centre Network in Montreal, Quebec, Canada.

Participants: Patients from internal medicine, cardiac, and thoracic surgery, aged 65 years and older, admitted between October 2014 and November 2016.

Measures: Abstracted chart data were linked to provincial health databases. PIMs were identified using AGS (American Geriatrics Society) Beers Criteria®, STOPP, and Choosing Wisely statements. Multivariable logistic regression and Cox models were used to assess the association between PIMs and adverse events.

Results: Of 2,402 included patients, 1,381 (57%) were male; median age was 76 years (interquartile range [IQR] = 70-82 years); and eight discharge medications were prescribed (IQR = 2-8). A total of 1,576 (66%) patients were prescribed at least one PIM at discharge; 1,176 (49%) continued a PIM from prior to admission, and 755 (31%) were prescribed at least one new PIM. In the 30 days after discharge, 218 (9%) experienced an adverse drug event (ADE) and 862 (36%) visited the emergency department (ED), were rehospitalized, or died. After adjustment, each additional new PIM and continued community PIM were respectively associated with a 21% (odds ratio [OR] = 1.21; 95% confidence interval [CI] = 1.01-1.45) and a 10% (OR = 1.10; 95% CI = 1.01-1.21) increased odds of ADEs. They were also respectively associated with a 13% (hazard ratio [HR] = 1.13; 95% CI = 1.03-1.26) and a 5% (HR = 1.05; 95% CI = 1.00-1.10) increased risk of ED visits, rehospitalization, and death.

Conclusions: Two in three hospitalized patients were prescribed a PIM at discharge, and increasing numbers of PIMs were associated with an increased risk of ADEs and all-cause adverse events. Improving hospital prescribing practices may reduce the frequency of PIMs and associated adverse events. J Am Geriatr Soc 68:1184-1192, 2020.

Keywords: adverse drug events; hospital discharge; potentially inappropriate medications.

Figure 1

Flowchart of patient exclusions. MGH, Montreal General Hospital; RAMQ, Regiel'assurance maladie; RVH, Royal Victoria Hospital; Rx, prescription.

Figure 2

Classification of medications prescribed at discharge. PIM indicates potentially inappropriate medication.