Socioeconomic inequalities in polypharmacy amongst older people

Abstract

The use of multiple medications, polypharmacy, is common amongst older people and is an increasing public health challenge. The prevalence of polypharmacy across different populations has been well characterised, but what is less clear is how polypharmacy varies according to socioeconomic position. This thesis aims to address this evidence gap by exploring if there are social inequalities in polypharmacy, amongst older people. First a systematic review and meta-analysis were undertaken to synthesise international evidence on social inequalities and polypharmacy. The evidence showed people with low socioeconomic status had greater likelihood of being in receipt of polypharmacy. Education was the most commonly used socioeconomic measure, and individuals with lower levels of education had a 21% increased likelihood of polypharmacy. Second, data from longitudinal cohort studies, the two Cognitive Function and Ageing Studies (CFAS), were used to explore how socioeconomic status (measured by years of education) was associated with polypharmacy and how relationships have changed over time. Data from CFAS I (from 1991-1993) and CFAS II (2008-2009) were used in the analyses. Baseline waves of both CFAS I and CFAS II were compared. The analysis highlighted the sustained high level of polypharmacy, and multivariable logistic regression showed the widening inequalities in polypharmacy over the 20-year time period. Results from this chapter therefore informed the final analyses, to understand how inequalities in polypharmacy change across different medication groups. These analyses demonstrated that inequalities persist across different medication groups, although for some such effects (such as medications belonging to the cardiovascular group) were more pronounced than others. The work of this thesis has highlighted inequalities in polypharmacy that are widening over time. This has happened at a time when healthcare is more sophisticated and expenditure has risen, but arguably insufficient importance has been placed on prevention and public health. People working in policy and practice should consider how to address social inequalities in polypharmacy alongside current policy initiatives (e.g. the use of Structured Medication Reviews).