Medication adherence in older adults with cognitive impairment: a systematic evidence-based review

Background: Cognitive impairment challenges the ability to adhere to the complex medication regimens needed to treat multiple medical problems in older adults.

Objective: Our aim was to conduct a systematic evidence-based review to identify barriers to medication adherence in cognitively impaired older adults and interventions aimed at improving medication adherence.

Methods: A search of MEDLINE, EMBASE, PsycINFO, GoogleDocs, and CINAHL for articles published between 1966 and February 29, 2012 was performed. Studies included older adults with a diagnosis of cognitive impairment of any degree (mild cognitive impairment or mild, moderate, or severe dementia). To identify barriers to adherence, we reviewed observational studies. To identify relevant interventions, we reviewed clinical trials targeting medication adherence in cognitively impaired older adults. We excluded studies lacking a measure of medication adherence or lacking an assessment of cognitive function, case reports or series, reviews, and those focusing on psychiatric disorders or infectious diseases. Population demographics, baseline cognitive function, medication adherence methods, barriers to adherence, and prospective intervention methodologies were extracted.

Results: The initial search identified 594 articles. Ten studies met inclusion criteria for barriers to adherence and three met inclusion criteria for interventional studies. Unique barriers to adherence included understanding new directions, living alone, scheduling medication administration into the daily routine, using potentially inappropriate medications, and uncooperative patients. Two studies evaluated reminder systems and showed no benefit in a small group of participants. One study improved adherence through telephone and televideo reminders at each dosing interval. The results of the review are limited by reviewing only published articles, missing barriers or interventions due to lack of subgroup analysis, study selection and extraction completed by 1 reviewer, and articles with at least an abstract published in English.

Conclusions: The few studies identified limit the assessment of barriers to medication adherence in the cognitively impaired population. Successful interventions suggest that frequent human communication as reminder systems are more likely to improve adherence than nonhuman reminders.