OBJECTIVES

Non-adherence of patients to pharmacological treatments for cardiovascular disease (CVD) is a common theme in the medical literature. However, the information about its economic consequences is more erratic. The objective was to summarise and critically apprise the medical literature on the costs of poor adherence to CVD medications.

METHODS

Systematic search of publications (up to July 31, 2018) conducted in several electronic databases (PubMed, Scopus, DARE and CINAHL). Search terms were combined to identify papers related to the costs of poor adherence to medications for CVD. Data from comparable studies were combined for meta-analysis. Fixed-effects or random-effects models were used depending on the heterogeneity of studies. All costs were converted to US$ (American dollars, 2016 values). Strength of evidence and the risk of bias were assessed with the GRADE and the ROBINS-I tools.

RESULTS

33 publications met the inclusion criteria; 25 were conducted in North America; 32 reported direct medical costs only; 31 papers referred to statins and antihypertensives. Based on comparable studies (n=10), 38 out of 100 patients adhered poorly (MPR < 80%) to therapies (0.38; 95% CI: 0.33; 0.42). The mean annual direct medical costs of a non-adherent patient with a CVD reached a maximum of US$ 33,609.00 (SD: 18,648.09) (year 2016) during year 1 of treatment. Higher medical costs were associated to a greater risk of adhering poorly to medications (RR = 0.58; 95% CI: 0.52; 0.65, p < 0.01). Studies were highly heterogeneous; evidence was of moderate strength.

CONCLUSIONS

Poor adherence to CVD treatments is costly to healthcare systems. More robust studies with a societal perspective are needed to reach a more comprehensive understanding of its full economic consequences.