Date of Award
PhD (Doctor of Philosophy)
Dr Gráinne Cousins
Professor Tom Fahey
Professor Paul Gallagher
RCSI School of Pharmacy (Clement Archer Scholarship)
Alcohol; Medication; Older Adults; Interactions; Adverse Outcomes
The aim of this thesis was to develop an explicit list of potentially serious alcohol medication interactions for use in older adults and to determine the prevalence and magnitude of risk associated with exposure to these interactions. The influence of life course transitions on alcohol consumption were also examined.
The thesis consists of five main studies; a systematic review was conducted to investigate the prevalence of concurrent use of alcohol and medications among older adults and associated adverse outcomes, followed by a Delphi consensus study in which an explicit list of potentially serious alcohol-medication interactions for use in older adults (POSAMINO criteria) was developed. Three observational studies were then conducted using the first three waves of the Irish Longitudinal Study on Ageing (TILDA) dataset. The first study examined trajectories of alcohol consumption among adults ≥ 50 years, with gender-specific multilevel models used to investigate the frequency of consumption (ordered logistic regression (odds ratios (ORs)), weekly quantity (incidence rate ratios (IRRs)) and heavy episodic drinking (odds ratios). Following this, the longitudinal prevalence of potentially serious alcohol-medication interactions among older adults ≥ 65 years was evaluated using multilevel models. The association between these interactions and falls in community dwelling older adults at 2- and 4-year follow-up were investigated in the final study.
The findings from the systematic review suggest that there is a high propensity for alcohol-medication interactions among older adults, with between one-in-five (21%) and one-in-three (35%) older adults at risk. Yet, across the included studies, there was a lack of consensus regarding what constitutes an alcohol interactive (AI) medication. From the Delphi consensus study, an explicit list of 38 potentially serious alcohol-medication interactions in older adults (POSAMINO criteria) was derived: central nervous system (CNS) (n=15), cardiovascular system (CVS) (n=9), endocrine (n=5), musculoskeletal (n=3), infections (n=3), malignant disease and immunosuppression (n=2) and respiratory (n=1). 15 Longitudinal TILDA analysis highlighted that over time, both men and women drank more frequently, with frequency decreasing with age for women. In contrast, average weekly consumption decreased over time and with increasing age. Transitions in self-rated health, particularly those reflecting poorer health, were associated with lower frequency and weekly consumption. Heavy episodic drinking decreased with age, with men who were retired across all waves more likely to engage in heavy episodic drinking at baseline (wave 1). An estimated 18% of older adults were at risk of potentially serious alcohol medication interactions at baseline, according to the POSAMINO criteria (8% at risk of one potentially serious alcohol-medication interaction, and 10% at risk of two or more). The prevalence of any POSAMINO or number of POSAMINO did not change over the four years. The risk of any or number of potentially serious interactions were associated with younger age, male sex and number of medications and chronic conditions. The final study, investigating the association between POSAMINO criteria and falls, found that exposure to central nervous system (CNS) POSAMINO, was positively associated with the risk of falls (aRR:1.62; 95% CI: 1.03-2.55) and injurious falls (aIRR:1.48; 95% CI: 0.97-2.25) at four year follow-up.
Overall, this thesis adds to the growing body of evidence investigating alcohol-related harms among older adults and the prevalence of potentially serious alcohol-medication interactions in later life. The principal findings from this thesis suggest that there is a high propensity for potentially serious alcohol-medication interactions among older adults, and that this risk does not reduce over time, suggesting that patients are unaware or that they are not screened. Finally, exposure to the CNS POSAMINO criteria is associated with an increased risk of falling and injurious falls at four-year follow-up. Future research is required to validate the POSAMINO criteria further and critically examine the individual and public health impact on serious alcohol-medication interactions among older adults.
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Holton A. The POSAMINO Study: Development and Validation of Explicit Criteria for Potentially Serious Alcohol Medication Interactions in Older Adults [PhD Thesis]. Dublin: Royal College of Surgeons in Ireland; 2018.
Available for download on Sunday, November 15, 2020