Background The successful management of hypertension requires sustained engagement in self-care behaviour such as adhering to medication regimens and diet. Bandura’s Social Cognitive Theory suggests that self-efficacy is a major determinant of engagement in self-care behaviour. Self-efficacy refers to an individual’s belief in their capacity to execute behaviours necessary to produce specific performance attainments. This systematic review of observational studies aims to summarise and evaluate the quality of evidence available to support the association between self-efficacy and engagement in self-care behaviour in hypertension. Methods Searches were performed of the Pubmed, MEDLINE, CINAHL and OpenSIGLE databases from database inception to January 2020. Reference lists and individual journals were also hand searched. Observational studies in English quantifying self-efficacy and self-care behaviour in hypertensive adults were included. The quality of included articles was assessed with the National Institute of Health Quality Assessment Tool for observational studies. Results The literature search identified 102 studies, of which 22 met the inclusion criteria for full-text review. There were 21 studies which reported that higher self-efficacy was associated with engagement in self-care behaviours including medication adherence (n = 9), physical activity (n = 2) and dietary changes (n = 1). Of these, 12 studies were rated as ‘good’ on the quality assessment tool and 10 were ‘fair’. A common limitation in these studies was a lack of objectivity due to their reliance on self-reporting of engagement in self-care behaviour. Conclusion Our review suggests an association between self-efficacy and self-care. However, the evidence supporting this association is of low to medium quality and is limited by heterogeneity. Our findings suggest the need for further well-designed interventional studies to investigate this association.

Introduction: Practice guidelines advise caution on the use of metformin in patients with type 2 diabetes mellitus with chronic kidney disease (CKD). This review aims to examine the evidence for the benefits and risks of metformin use in patients with T2DM and CKD. Methods: The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials and PubMed were searched; the references of selected papers were hand searched. Systematic reviews, randomised controlled trials, cohort studies, case series and case-control studies were included. The full text of selected articles was reviewed. The outcomes studied were all-cause mortality, cardiovascular complications, lactic acidosis and worsening of renal function. Recommendations were graded according to the Scottish Intercollegiate Guidelines Network system. Results: A total of 139 unique articles were identified, 14 of which met the inclusion criteria and were selected for full-text review. Four cohort studies reported an association between metformin use and improved all-cause mortality in CKD stage 4 and better. Two cohort studies reported improved cardiovascular outcomes with metformin use. Four cohort studies, 1 case series and 1 case-control study reported no significant association between metformin use and an increased risk of lactic acidosis in CKD. There is a moderate level of evidence to support reduced mortality, improved cardiovascular outcomes and a low risk of lactic acidosis with metformin use in patients with T2DM and with CKD stage 4 and above. Conclusion: Existing recommendations to restrict metformin use in diabetes patients with CKD need to be reviewed in light of emerging evidence supporting its overall benefits in these patients. Keywords: Chronic renal insufficiency, metformin, type 2 diabetes mellitus