Background and objectives: To assess the association between potentially inappropriate prescribing (PIP) and adverse patient outcomes (mortality, hospitalization, and emergency department (ED) visits) in a large, population-based cohort of older adults, using previously codified Screening Tool of Older Persons' Prescriptions (STOPP) - Screening Tool to Alert to Right Treatment (START) and Beers criteria.
Methods: We conducted a population-based, retrospective cohort study using linked health administrative data from Ontario, Canada. The cohort included all Ontario residents aged 65 years or older who received at least one prescription between April 1, 2003, and March 31, 2017 (N = 2,937,927). PIP was identified using subsets of the 2014 STOPP-START and 2015 Beers criteria applicable to health administrative data. Associations between PIP and outcomes were examined using multivariable logistic regression.
Results: Of the 2,937,927 patients, 2,410,626 (82.1%) had the outcome of death, hospitalization, or ED visit. Among those with an outcome, 2,002,651 (83.1%) and 1,412,278 (58.6%) had at least one instance of potentially inappropriate prescribing as identified by the STOPP-START and Beers criteria, respectively. After multivariable adjustment, the presence of any instance of potentially inappropriate prescribing identified by STOPP-START criteria was significantly associated with increased odds of mortality (adjusted odds ratio (aOR): 3.68, 95% CI: 3.65-3.72), hospitalization (aOR: 4.86, 95% CI: 4.83-4.90), ED visits (aOR: 4.12, 95% CI: 4.09-4.14), and of the composite outcome (ie, any one of ED visit, hospitalization, and/or mortality) (aOR: 4.59, 95% CI: 4.55-4.62). For the Beers criteria, any instance of potentially inappropriate prescribing was similarly associated with increased odds of mortality (aOR: 1.74, 95% CI: 1.73-1.75), hospitalization (aOR: 2.93, 95% CI: 2.91-2.94), ED visits (aOR: 4.29, 95% CI: 4.26-4.32), and the composite outcome (aOR: 4.44, 95% CI: 4.40-4.47). A strong dose-response relationship was observed with the adjusted odds of all adverse outcomes increasing progressively with each additional PIP compared to one instance of potentially inappropriate prescribing. For example, 5 or more STOPP-START PIP were associated with a nearly 15-fold increase in the odds of death.
Conclusion: In this large, population-based study, PIP was strongly and independently associated with an increased risk of ED visits, hospitalization, and mortality in older adults. The risk escalated significantly with an increasing number of instances of potentially inappropriate prescribing. These findings highlight the value of using codified medication appropriateness criteria to identify PIP as a modifiable risk factor for adverse outcomes at a population level.
Plain language summary: Inappropriate prescribing may be linked to adverse patient outcomes in older adults. In this 14-year study of nearly 3 million older adults in Ontario, Canada, we found that receiving even one potentially inappropriate prescription or combination of prescriptions was strongly linked to a higher risk of ED visit, hospitalization, and death. This risk increased substantially with each additional inappropriate medication a person was prescribed. These findings suggest that systematically identifying and reducing inappropriate prescribing is a critical public health priority that could prevent significant harm to older adults.
Keywords: Beers criteria; Health administrative data; Inappropriate prescribing; Medication safety; PIP; Population health; Potentially inappropriate prescribing; STOPP-START criteria.
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