Medication-related risk factors and its association with repeated hospital admissions in frail elderly: A case control study

Abstract

Background: Repeated hospital admissions are prevalent in older people. The role of medication in repeated hospital admissions has not been widely studied. The hypothesis that medication-related risk factors for initial hospital admissions were also associated with repeated hospital admissions was generated.

Objectives: To examine the association between medication-related risk factors and repeated hospital admissions in older people living with frailty.

Method: A retrospective case-control study was carried out with 200 patients aged ≥75 years with unplanned medical admissions into a large teaching hospital in England between January and December 2015. Demographic, clinical, and medication-related data were obtained from review of discharge summaries. Statistical comparisons were made between patients with 3 or more hospital admissions during the study period (cases) and those with 2 or fewer admissions (controls). Regressions were performed to establish independent predictors of repeated hospital admissions.

Results: Participants had a mean age of 83.8 years (SD 5.68) and 65.5% were female. There were 561 admission episodes across the sample, with the main reasons for admissions recorded as respiratory problems (25%) and falls (17%). Univariate logistic regression revealed five medication-related risks to be associated with repeated hospital admissions: Hyper-polypharmacy (defined as taking ≥10 medications) (OR 2.50, p < 0.005); prescription of potentially inappropriate medications (PIMs) (OR 1.89; p < 0.05); prescription of a diuretic (OR 1.87; p < 0.05); number of high risk medication (OR 1.29; p < 0.05) and the number of 'when required' medication (OR 1.20; p < 0.05). However, the effects of these risk factors became insignificant when comorbid disease was adjusted for in a multivariable model.

Conclusion: Medication-related risk factors may play an important role in future repeated admission risk prediction models. The modifiable nature of medication-related risks factors highlights a real opportunity to improve health outcomes.

Keywords: Medication risks; Polypharmacy; Potentially inappropriate medication; Prediction model; Repeated hospital admissions.