The burden of non-adherence to cardiovascular medications among the aging population in Australia : A meta-analysis

Background
Non-adherence to cardiovascular medications is a problem worldwide, even in Australia, which has a socialized medical system, Medicare.

Objective
The aim of this systematic review was to evaluate the burden of non-adherence to cardiovascular medications and factors thereof in Australia.

Data Sources
Pubmed, Embase, CINAHL, PsycInfo, Cochrane Library databases were searched.

Eligibility Criteria
Articles were included if they were in English, peer-reviewed and provided empirical data on adherence to cardiovascular medication for an Australian cohort.

Methods
A meta-analysis of prevalence of medication non-adherence using the double arcsine square root transformed proportion was undertaken. Studies were pooled in homogenous prevalence groups and factors that differed across groups were ascertained.

Results
Five studies, including eight datasets and 76,867 subjects were analyzed. Three more or less homogenous prevalence categories were discernable: low [19 %, 95 % confidence interval (CI) 15–24], moderate (26 %, 95 % CI 23–29) and high (43 %, 95 % CI 43–44; this was a single study) prevalence of non-adherence. There were minimal clear patterns across groups in relation to typical factors of non-adherence (patient, condition, healthcare system or socioeconomic factors). Measurements used for non-adherence were similar for six of the eight included datasets, suggesting this did not affect prevalence of non-adherence or inclusion in a prevalence group.

Conclusions
Non-adherence to cardiovascular medications is a serious problem in the aging Australian setting with an overall prevalence of between 14 and 43 %. The lack of patterns in the typical factors of non-adherence suggests that another factor, such as patients’ beliefs about their conditions and medications, may be playing a stronger role in their non-adherence than clinical or sociodemographic factors. This is an area for further research.