Measuring potentially inappropriate prescribing in vulnerable older adults using routinely collected interRAI data

Abstract

Introduction and background Potentially inappropriate prescribing (PIP) of medicines is prevalent and has potential for causing adverse health outcomes in older adults. Older adults are at higher risk of inappropriate prescribing because of multimorbidity and changes in pharmacokinetics and pharmacodynamics which make them more sensitive to adverse drug events. Monitoring prescribing appropriateness is important to guide improvement in prescribing quality. interRAI (international Resident Assessment Instrument) is a tool that is routinely used to assess healthcare needs for more than 50,000 older adults across New Zealand each year. interRAI collects information on patients' health needs and includes their usual medicines. It can be readily and digitally extracted making interRAI a promising information source for auditing of PIP. It is unclear however, whether it is possible to use interRAI data for the detection of PIP. Aim To investigate PIP in vulnerable older adults using routinely-collected interRAI data and examine the association of PIP with selected adverse health outcomes. Methods An electronic algorithm based on the STOPP/START criteria for PIP was designed to be applied to interRAI data to identify PIP. All people with at least one medication recorded in their interRAI assessment from 1 June 2016 to 31 October 2016 were included in the cohort. The cohort was followed-up for up to 18 months after interRAI assessment to identify adverse health outcomes which were then analysed for association with PIP status. Results The median age of the cohort (n = 30,469) was 85 years and was 65% female. In total 58,322 instances of PIP were found among 25,653 people. Having one or more STOPP PIP was associated with a higher risk of emergency department visit (hazard ratio (HR) 1.05 95% confidence interval (CI) = 1.01 - 1.10) and having one or more START PIP was associated with an increased risk of both emergency department visit (HR 1.07, 95% CI = 1.03 - 1.11) and acute hospitalisation (HR 1.09, 95% CI = 1.05 - 1.13). There was no association between STOPP PIP (HR 1.02, 95% CI = 0.94 - 1.10) or START PIP (HR 0.95, 95% CI = 0.89 - 1.02) with entry to residential aged care. There was also no association between STOPP PIP (HR 0.99, 95% CI = 0.94 - 1.04) or START PIP (HR 1.04, 95% CI = 0.99 - 1.08) and mortality. Conclusion Using interRAI data and an electronic algorithm a high prevalence of PIP was found in interRAI's population of vulnerable older adults. This method could be used to routinely screen for PIP in interRAI assessments to facilitate medication reviews for individuals with PIP to improve their care.