Potentially inappropriate prescribing and its association with health outcomes in middle-aged people: a prospective cohort study in Ireland

OBJECTIVES: To determine the prevalence of potentially inappropriate prescribing (PIP) in a cohort of community-dwelling middle-aged people and assess the relationship between PIP and emergency department (ED) visits, general practitioner (GP) visits and quality of life (QoL). DESIGN: Prospective cohort study. SETTING: The Irish Longitudinal Study on Ageing (TILDA), a nationally representative cohort study of ageing. PARTICIPANTS: Individuals aged 45–64 years recruited to TILDA who were eligible for the means-tested General Medical Services scheme and followed up after 2 years. EXPOSURE: PIP was determined in the 12 months preceding baseline and follow-up TILDA data collection by applying the PRescribing Optimally in Middle-aged People’s Treatments (PROMPT) criteria to participants’ medication dispensing data. OUTCOME MEASURES: At follow-up, the reported rates of ED and GP visits over 12 months (primary outcome) and the CASP-R12 (Control Autonomy Self-realisation Pleasure) measure of QoL (secondary outcome). ANALYSIS: Multivariate negative binomial (rates) and linear regression (CASP-R12) models controlling for potential confounders. RESULTS: At 2-year follow-up (n=808), PIP was detected in 42.9% by the PROMPT criteria. An ED visit was reported by 18.7% and 94.4% visited a GP (median 4 visits, IQR 2–6). Exposure to ≥2 PROMPT criteria was associated with higher rates of healthcare utilisation and lower QoL in unadjusted regression. However, in multivariate analysis, the associations between PIP and rates of ED visits (adjusted incidence rate ratio (IRR) 0.92, 95% CI 0.53 to 1.58), and GP visits (IRR 1.06, 95% CI 0.87 to 1.28), and CASP-R12 score (adjusted β coefficient 0.35, 95% CI −0.93 to 1.64) were not statistically significant. Numbers of medicines and comorbidities were associated with higher healthcare utilisation. CONCLUSIONS: Although PIP was prevalent in this study population, there was no evidence of a relationship with ED and GP visits and QoL. Further research should evaluate whether the PROMPT criteria are related to these and other adverse outcomes in the general middle-aged population.