Interventions to Enhance Medication Adherence in Older Heart Failure Patients - A Systematic Review

Introduction: While there is clear evidence that medications improve survival and reduce hospitalisation rates due to heart failure, there is also evidence that adherence to medication is sub-optimal. The aim of this systematic review was to determine the effect of interventions promoting adherence in heart failure patients.

Methods: We conducted a systematic review of randomised controlled trials searching for all-language publications in electronic databases (Medline, CINAHL, Embase, Cochrane Central Register of Controlled Trials and PsychINFO) up to the end of April 2015. Trials describing interventions intended to enhance adherence to self-administered medications in the treatment of heart failure were eligible. Two independent reviewers examined lists of retrieved articles extracting study characteristics and results for adherence. Methodological quality was examined using the Cochrane Collaboration risk of bias tool. Studies were critically reviewed and assessed for validity of their findings.

Results: We included 21 trials containing data on 4346 patients (average age 56 to 85 years). Heterogeneity of interventions and outcome measures precluded meta-analysis of
results. Medication adherence improvement was reported in 8 of 21 trials. 14 of 21 trials evaluated intensified patient care, via either direct patient contact interventions (9 trials) or telephone / tele-monitoring programs (5 trials). 5 of 9 direct patient contact interventions reported enhanced medication adherence versus 1 of 5 telephone / tele-monitoring programs. None of the 3 trials evaluating patient education reported enhanced adherence, however while 2 of the 3 studies examining complex behavioral approaches reported enhanced adherence, a large trial involving >900 participants reported no effect. One trial solely targeting simplification of the drug regime did not find evidence of enhanced adherence.

Conclusions: While it is possible to improve medication adherence in heart failure patients, heterogeneity in both intervention techniques and measurement methodology leave us unable to identify reliable and efficacious intervention approaches. Future studies should aim to build on the methodologically stronger studies in this literature so that a cumulative set of findings can emerge.