Evidence-Based Deprescribing: Reversing the Tide of Potentially Inappropriate Polypharmacy

In this narrative review, we aim to detail the ADE risk of polypharmacy, the process of deprescribing and evidence of its efficacy in reducing potentially inappropriate polypharmacy, the enablers and barriers to deprescribing, and patient and system of care level strategies that can be employed in enhancing deprescribing.

Polypharmacy As a Risk Factor for Medicine-Related Harm

The number of medicines a patient is taking is the single most important predictor of medicine-related harm [15]. One report estimated the risk of ADEs as a contributory cause of patients presenting acutely to hospital emergency departments to be 13% for 2 drugs, 38% for 4 drugs, and 82% for 7 drugs or more [16]. The more medicines an individual takes, the greater their risk of experiencing an adverse drug reaction, a drug-drug interaction, a drug-disease interaction, cascade prescribing (where more medicines are added to counteract side effects of existing medicines), nonadherence, and drug errors (wrong drug, wrong dose, missed doses, erroneous dosing frequency) [17–20]. Once the number of regular medicines rises above 5 (commonly regarded as the threshold for defining polypharmacy), observational data suggest that additional medicines independently increase the risk of frailty, falling, and hospital admission [21].

The benefits of many medicines in frail older people remain unquantified. As many as 50% of clinical trials have a specific upper age limit and approximately 80% of clinical trials exclude people with comorbidities [22,23]. Single-disease treatment guidelines based on such trials are often extrapolated to older people with multimorbidity despite an absence of evidence for benefit [24] and with little consideration of the potential burdens and harms of polypharmacy resulting from treating multiple diseases in the one patient [25]. By contrast, the risks from many medicines in older people are well known. Older people are at high risk of ADEs and toxicity due to reduced renal and liver function and age-related changes in physiological reserve, body composition, and cellular metabolism [26]. While the adverse effects of polypharmacy or of comorbidities targeted for treatment are difficult to separate, the burden of medicine-induced decline in function and quality of life is becoming better defined and appreciated [27].

Defining Evidence-Based Deprescribing

While many definitions have been proposed [28], we define evidence-based deprescribing as follows: the active process of systematically reviewing medicines being used by individual patients and, using best available evidence, identifying and discontinuing those associated with unfavorable risk–benefit trade-offs within the context of illness severity, advanced age, multi-morbidity, physical and emotional capacity, life expectancy, care goals, and personal preferences [29]. An enlarging body of research has demonstrated the feasibility, safety and patient benefit of deprescribing, as discussed further below. It employs evidence-based frameworks that assist the prescriber [30] and are patient-centered [31].

Importantly, deprescribing should be seen as part of the good prescribing continuum, which spans medicine initiation, titrating, changing, or adding medicines, and switching or ceasing medicines. Deprescribing is not about denying effective treatment to eligible patients. It is a positive, patient-centered intervention, with inherent uncertainties, and requires shared decision-making, informed patient consent and close monitoring of effects [32]. Deprescribing involves diagnosing a problem (use of a PIM), making a therapeutic decision (withdrawing it with close follow-up) and altering the natural history of the problem (reducing incidence of medicine-related adverse events).