INTRODUCTION
Polypharmacy is the use of multiple medications by a single patient (most commonly defined as five or more concomitant regular medications).1 Individuals over the age of 60 years are commonly seen to be taking several medications. The main contributor to this is multimorbidity, with most adults over 65 years having at least two chronic conditions.2 From 2009-2016, 37% of patients over 65 years of age attending US Physician offices were found to be taking over 5 medications.3 Similarly high rates of polypharmacy in have also been found in other countries4,5 Within residential care, studies have found that there may be as many as 91% of patients taking more than five medications and up to 74% of patients taking in excess of nine medicines.6
Polypharmacy itself has been clearly associated with a broad range of negative clinical consequences.7 These consequences include a decrease in compliance, increased risk of adverse drug events, falls, impaired cognition, decrease in physical function, hospital admission and increased frailty.8,9 The World Health Organization has highlighted polypharmacy as one of the key areas to prioritize in the mission to reduce medication harm.10
Depending on the individual, polypharmacy can be viewed as appropriate (where the clinical benefits from medication outweigh the risk of harm) or inappropriate. Achieving the desired balance between benefit and risk in patients with multimorbidity can often be challenging, given that evidence-based guidelines are usually for single health conditions. A medication that poses a greater risk of harm than benefit (particularly where there are safer or more effective alternatives) is termed a potentially inappropriate medication (PIM). A significant positive association has been described between the number of medications taken by an individual and the likelihood of a PIM being used.11 Multimorbidity, compounded by age-related pharmacodynamic and pharmacokinetic changes all increase the use of PIMS in the older population.12
Use of potentially inappropriate medications is commonplace. It is estimated that one in five community dwelling individuals older than 65 years are prescribed at least one medication that is considered inappropriate.13 It has also been estimated that over a 5-year period, a quarter of all older Australians will be hospitalized for an adverse drug reaction.14
Interventions to reduce polypharmacy and enhance the deprescription of potentially inappropriate medications are the focus of current research. The process of deprescribing can often be complicated and requires individualization. While there are opportunities for intervention that start from the time of prescribing, it is still unclear how best to organize and implement processes to achieve a meaningful reduction in inappropriate polypharmacy. There have been several systematic reviews looking at the efficacy of deprescribing interventions within primary care,15,16 within residential care,17,18 and for hospital-inpatients.19 However, another area that has been less well researched is the impact of interventions delivered within medical specialist outpatient clinics. Specialist clinics, such as general medicine, geriatric, oncology, cardiology, and haematology clinics, are likely to encounter patients with a high medication burden and increased risk of medication-related problems due to advancing age and multimorbidity. In patients reviewed at a heart failure clinic, 72% were taking eleven or more medications.20 A recent study, found that 41% of people who attended a memory clinic were taking an inappropriate drug choice.21 Similarly, a study of 248 geriatric oncology patients at an outpatient clinic found PIM use in 51% of individuals.22 Although the patient may not be referred to a specialist outpatient clinic for a comprehensive assessment of all medications, there may be a possible opportunity here to promote deprescribing. This review aims to examine studies to date on the feasibility and effectiveness of deprescribing interventions implemented within specialist outpatient clinics.