Predictors for unplanned hospital admissions in community dwelling adults: A dynamic cohort study

Background: Polypharmacy and inappropriate medication use are associated with unplanned hospital admissions. Targeted interventions might reduce the hospitalization risk. Yet, it remains unclear which patient profiles derive the largest benefit from such interventions.Objective: The aim of this study was to determine independent risk factors, among which polypharmacy, for unplanned hospital admissions in a cohort of community dwelling adults.Methods: A retrospective study was performed using a large general practice registry and an insurance database in Flanders, Belgium. Community dwelling adults aged 40 years or older with data for 2013-2015 were included. The index date was the last general practitioner contact in 2014. Determinants were collected during the preceding year. Unplanned hospital admissions were determined during the year after the index date. Univariable logistic regression models were fitted on each risk factor for an unplanned hospital admission as the primary outcome. Two multivariable models were derived.Results: In total, 40411 patients were included and 2126 (5.26%) experienced an unplanned hospital admission. Mean age was 58.3 (+/- 12.3) years. The two models identified the following determinants for an unplanned hospital admission: excessive polypharmacy, older age, male sex, number of comorbidities, atrial fibrillation, chronic obstructive pulmonary disease or stroke, low hemoglobin, use of hypnotics, antipsychotics, antidepressants or antiepileptics and prior hospital and general practitioner visits. Prior hospital visits was the largest determinant.Conclusions: In our study we identified and confirmed the presence of known determinants for unplanned hospital admissions in community dwelling adults, most of which align with a geriatric phenotype. Our findings can inform the allocation of interventions aiming to reduce unplanned hospital admissions.