The ageing of the population, while a societal success, presents many challenges to healthcare systems. One such challenge relates to prescribing practices for older people. While many older people remain robust and independent, others become frail, suffer chronic diseases, receive multiple medications, and are susceptible to adverse drug events (ADEs). Prescribing is further influenced by age-related changes in drug pharmacokinetics and pharmacodynamics. Identifying ways for optimising prescribing and minimizing harm in this vulnerable population is increasingly a priority for health care providers and policy makers.
The overall aim of this thesis was to determine how to optimise medication prescribing in frail older people. Four connected study phases were conducted to address the overall aim and to inform the development of a best practice guideline for prescribing in frail older people.
The first part of this thesis explored the relationship between polypharmacy and adverse outcomes among older hospital inpatients stratified according to their frailty status. This was a secondary analysis of a prospective study of 1418 patients, aged 70 and older, admitted to 11 hospitals across Australia. Patients had a mean (SD) age of 81 (6.8) years and 55% were female. Polypharmacy (5-9 drugs per day) was observed in 684 (48.2%) and hyper-polypharmacy (≥10 drugs) in 497 (35.0%) patients. In total, 591 (42.5%) patients experienced at least one adverse outcome. The only adverse outcome associated with polypharmacy was delirium. Within each polypharmacy category, frailty was associated with adverse outcomes and the lowest overall incidence was among robust patients prescribed 10 or more drugs. While polypharmacy may be a useful signal for medication review, in this study it was not an independent predictor of adverse outcomes for older inpatients. Assessing the frailty status of patients better appraised risk. Extensive de-prescribing programs in all older inpatients may not be an intervention that directly improves outcomes.
The second part of this thesis assessed the frequency and nature of risk factors for potentially inappropriate prescribing (PIP) in patients discharged to residential aged care facilities (RACF) (from the larger cohort of 1418 patients in the previous study). The study revealed that 54.4% of patients were on at least one potentially inappropriate medication (PIM) at admission to hospital with a non-significant trend to fewer PIMs on discharge (49.5%). The frailty status of patients and in-hospital cognitive decline were the only significant predictors of the number of PIMs received at both admission and discharge. The findings of this study provided a basis for designing interventions to rationalize prescribing in frail older patients in RACFs.
In third part of this thesis, the recommendations on medication by specialist geriatricians were evaluated in a prospective observational study conducted on residents in four RACFs in Queensland, Australia via video-conferencing (VC). Four geriatricians assessed a total of 153 patients. They were prescribed a mean (SD) of 9.6 (4.2) regular medications. Of total 1469medications prescribed, geriatricians recommended withdrawal of 145 (9.8%) and dose alteration of 51 (3.5%). New medications were initiated in 73 (47.7%) patients. Of the 151 (10.3%) medications considered as potentially inappropriate, 26 (17.2%) were stopped and the dose altered in 4 (2.6%). Geriatricians made relatively few changes, suggesting either that, on balance, prescription of these medications was appropriate or, because of other factors, there was a reluctance to adjust medications. A structured medication review using an algorithm for withdrawing medications of high disutility might help optimise medications in frail patients. A follow up study on 50 patients was also conducted to review the impact of these recommendations 3 months after the initial consultation to determine the extent to which the medication changes had been implemented and maintained. A total of 126 recommendations were made by a geriatrician of which only 17 (13.5%) were not followed.
In the final part of this thesis, we developed a pragmatic, easily applied algorithm for medication review to help clinicians identify and discontinue potentially inappropriate medications that predispose older patients, particularly those who are frail, to develop various geriatrics syndromes. The algorithm captures a range of different clinical situations in relation to PIMs and offers an evidence-based approach to identifying and, if appropriate, discontinuing such medications. Decision support resources were developed to complement the algorithm in ensuring a systematic and patient-centred approach to medication discontinuation. Further studies are required to evaluate the effects of the algorithm on prescribing decisions and ultimately, patient outcomes.
In conclusion, optimising prescribing in frail older people is achievable by accurate identification of frail patients in clinical settings and individualisation of medication prescribing based on each patient’s own goals of care and frailty status. Future work should focus on the incorporation of frailty measures into clinical studies to improve medication use in frail older people. A routine use of a medication review algorithm may improve the quality of prescribing.