The Association Between Potentially Inappropriate Prescribing and Medication-Related Hospital Admissions in Older Patients: A Nested Case Control Study.

INTRODUCTION: Medication-related problems can cause serious adverse drug events (ADEs) that may lead to hospitalization of the patient. There are multiple screening methods to detect and reduce potentially inappropriate medications (PIMs) and potential prescribing omissions (PPOs). Whether this will result in less medication-related hospitalizations is unknown. The study objective was to assess the risk of preventable medication-related hospital admissions associated with potentially inappropriate prescribing, using the Beers 2012 and the Screening Tool of Older Person's Prescriptions and the Screening Tool to Alert doctors to Right Treatment (STOPP & START) 2008 criteria.

DESIGN, SETTING AND PARTICIPANTS: A nested case-control study was conducted with a subset of Dutch participants from the Hospital Admissions Related to Medication (HARM) study. Cases were defined as patients aged ≥65 years with a potentially preventable medication-related hospital admission. For each case, one control was selected, matched for age and sex. The primary determinant was the presence of one or more PIMs according to the Beers 2012 and STOPP 2008 criteria. The secondary determinant was the presence of one or more PIMs and PPOs according to the STOPP & START 2008 criteria. The strength of the association between inappropriate prescribing and medication-related hospital admission was evaluated with multivariate logistic regression and expressed as odds ratios (ORs) with 95 % confidence intervals (CIs).

RESULTS: The prevalence of Beers 2012 criteria PIMs in the total cohort was 44.4 %. The prevalence of STOPP & START 2008 criteria PIMs and PPOs were, respectively, 34.1 and 57.7 %. STOPP 2008 criteria PIMs were associated with preventable medication-related hospital admissions [OR adjusted for number of drugs and comorbidities (ORadj) 2.30, 95 % CI 1.30-4.07], whereas there was no association with Beers 2012 criteria PIMs (ORadj 1.49, 95 % CI 0.90-2.47). STOPP PIMs and START PPOs together were also associated with preventable medication-related hospital admissions (ORadj 3.47, 95 % CI 1.70-7.09).

CONCLUSION: Our study shows that patients with potentially inappropriate prescribing detected with the STOPP & START 2008 criteria are at risk of preventable medication-related hospital admissions. The STOPP & START 2008 criteria can be used to identify older people at risk of medication-related problems.