What is the relationship between hospitalisation and potentially inappropriate prescribing among older people in primary care?
Potentially inappropriate prescribing (PIP), use of a medication where the risks are likely to outweigh the benefits, is frequent among older people, who often have complex health needs and associated healthcare utilisation. Most studies to date have focussed on patient and GP characteristics as risk factors for PIP. There has been little evaluation of how hospitalisation, and the resultant intensification of healthcare, can impact on PIP. This study aims to determine if hospitalisation is associated with PIP, and among patients hospitalised, to determine if the likelihood of PIP varied in the post-hospitalisation period relative to pre-hospitalisation.
This repeated cross-sectional study of a dataset collected retrospectively includes Irish general practice patients aged ≥65 years between the years 2012 and 2015. Data were collected from 44 general practices in Ireland using the patient software management system Socrates (www.socrates.ie) and included prescribing, demographic, clinical and hospitalisation records. The outcome was prevalence of PIP assessed using 45 criteria from the Screening Tool for Older Persons’ Prescription (STOPP) version 2. This was analysed both as number of distinct PIP (using Poisson regression) and binary presence of PIP (using logistic regression). The exposure of interest was admission to hospital (comparing those with any hospitalisation versus none). Among those hospitalised, prevalence of PIP in the post-hospitalisation period was also compared to pre-hospitalisation. Analyses were repeated by study year and adjusted for patient characteristics.
Overall 40,816 patients were included, and during 2012, the mean age was 76.8 years (SD 8.2), and 43% were male. Each year, 10.4%-15.0% of patients had ≥1 hospital admission. The overall prevalence of PIP ranged from 45.3% of patients in 2012 to 50.9% in 2015. Independent of age, gender, number of prescription items, co-morbidity, and health cover, hospitalisation was associated with higher number of distinct PIP e.g. adjusted rate ratio for hospitalisation in 2012 was 1.33 (95%CI 1.28, 1.39). This association was consistent across study years, 2013: 1.26 (1.22, 1.30), 2014: 1.24 (1.20, 1.28), 2015: 1.23 (1.19, 1.28). Among hospitalised patients, the likelihood of PIP post-hospitalisation was higher than pre-hospitalisation, independent of patient characteristics, e.g. adjusted odds ratio for post-hospitalisation in 2012 was 1.75 (95%CI 1.53, 1.96), and again, this was consistent across study years.
In this study, hospitalisation was independently associated with PIP. This is significant for older adults who may have frequent hospital admissions, and for their GPs who provide overall management of their medications, including those initiated in secondary care. It is important to determine how hospital admission may affect appropriateness of prescribing for older people and how potential adverse consequences of hospitalisation can be minimised. Enhanced quality of communication between secondary and primary care and transitional care interventions may improve prescribing appropriateness post-discharge.