DISCUSSION
The participants in all included studies had a high prevalence of
polypharmacy (mean number of medications ranged from 4.6 to 23.2 [SD
4.7]), multimorbidity, and use of PIMS. The studies were heterogenous
with regards to how medication count was captured. Some studies
incorporated ‘when required (pro re nata, PRN) ’ medications or
self-prescribed (over-the-counter) medications. Pill burden (as assessed
by a living with medicines questionnaire) and tablet count was examined
in one study.36 The definition of polypharmacy was
consistent between studies with five or more medicines classified as
polypharmacy. The mean number of medications for study participants
varied between settings, with medication load being highest for
individuals attending the heart-failure clinic and renal dialysis
units.35,38 Polypharmacy and increase in pill burden
has previously been associated with reduced compliance and quality of
life scores in dialysis patients50 and negative
medication interactions in heart-failure patients.51 A
high medication burden was also notable for oncology patients ≥65 years,
where polypharmacy and use of PIM is associated with an increased risk
of postoperative complications, lower adherence to medication, and
increased chemotherapy toxicity.52
The prevalence of PIM use between settings varied from 55% to 100% of
patients depending on the assessment tools used.26,34It is known that the sole use of explicit tools such as Beers or STOPP
is insufficient to address all medication concerns. Use of a combination
of three validated instruments (STOPP, Beers, and MAI) was found to be
superior and identified significantly more PIMS than a single instrument
alone when reviewed in the oncology setting.34 Another
recent study in an oncology unit noted that while 46% of patients were
identified as taking a PIM using Beers criteria, the number of patients
identified with ‘drug-related problems’ was 95%.53‘Drug related problems’ not revealed using explicit tools may include
under treatment, dosing concerns, lack of monitoring, and compliance
with therapy. It should be noted that adverse drug-reactions may also
occur with so called ‘appropriate medications’; anticoagulants,
antiplatelets, and antidiabetics (both oral and insulin) have been found
to be more frequently implicated in hospital admissions, than the usual
‘medications to avoid’ lists.54 Thus, accurately
assessing the medication burden and appropriateness of medication for
each individual is a complicated process.
The identified studies could be grouped into those where the
deprescribing intervention was physician-led and implemented, delivered
from a multidisciplinary team with pharmacist support, or
pharmacist-led, physician implemented.