Recipients of a haematopoietic stem cell transplantation (HSCT) may experience issues
in medication adherence (MA) when discharged. The primary aim of this review was to describe
the oral MA prevalence and the tools used to evaluate it among these patients; the secondary aims
were to summarise factors affecting medication non-adherence (MNA), interventions promoting MA,
and outcomes of MNA. A systematic review (PROSPERO no. CRD42022315298) was performed by
searching the Cumulative Index of Nursing and Allied Health (CINAHL), Cochrane Library, Excerpta
Medica dataBASE (EMBASE), PsycINFO, PubMed and Scopus databases, and grey literature up
to May 2022 by including (a) adult recipients of allogeneic HSCT, taking oral medications up to
4 years after HSCT; (b) primary studies published in any year and written in any language; (c) with
an experimental, quasi-experimental, observational, correlational, and cross-sectional design; and
(d) with a low risk of bias. We provide a qualitative narrative synthesis of the extracted data. We
included 14 studies with 1049 patients. The median prevalence of MA was 61.8% and it has not
decreased over time (immunosuppressors 61.5% [range 31.3–88.8%] and non-immunosuppressors
65.2% [range 48–100%]). Subjective measures of MA have been used most frequently (78.6%) to date.
Factors affecting MNA are younger age, higher psychosocial risk, distress, daily immunosuppressors,
decreased concomitant therapies, and experiencing more side effects. Four studies reported findings
about interventions, all led by pharmacists, with positive effects on MA. Two studies showed an
association between MNA and chronic graft-versus-host disease. The variability in adherence rates
suggests that the issues are relevant and should be carefully considered in daily practice. MNA has a
multifactorial nature and thus requires multidisciplinary care models.
