Objectives
This systematic review aimed to describe medication non-adherence
among people living with multimorbidity according to the current
literature, and synthesise predictors of non-adherence in this
population.
Methods
A systematic review was conducted according to the Preferred
Reporting Items for Systematic reviews and Meta-Analyses. PubMed,
EMBASE, CINAHL and PsycINFO were searched for relevant articles
published in English language between January 2009 and April 2019.
Quantitative studies reporting medication non-adherence and/or
predictors of non-adherence among people with two or more chronic
conditions were included in the review. A meta-analysis was conducted
with a subgroup of studies that used an inclusive definition of
multimorbidity to recruit participants, rather than seeking people with
specific conditions. Remaining studies reporting prevalence and
predictors of non-adherence were narratively synthesised.
Results
The database search produced 10â998 records and a further 75 were
identified through other sources. Following full-text screening, 178
studies were included in the review. The range of reported non-adherence
differed by measurement method, at 76.5% for self-report, 69.4% for
pharmacy data, and 44.1% for electronic monitoring. A meta-analysis was
conducted with eight studies (n=8949) that
used an inclusive definition of multimorbidity to recruit participants.
The pooled prevalence of non-adherence was 42.6% (95% CI: 34.0 - 51.3%,
k=8,
I2=97%,
p<0.01). The overall range of
non-adherence was 7.0%â83.5%. Frequently reported correlates of
non-adherence included previous non-adherence and treatment-related
beliefs.
Conclusions
The review identified a heterogeneous literature in terms of
conditions studied, and definitions and measures of non-adherence used.
Results suggest that future attempts to improve adherence among people
with multimorbidity should determine for which conditions individuals
require most support. The variable levels of medication non-adherence
highlight the need for more attention to be paid by healthcare providers
to the impact of multimorbidity on chronic disease
self-management.
PROSPERO registration number
CRD42019133849.