How effective are interventions to support shared decision making for hypertension? A systematic review.
Hypertension is a common risk factor for cardiovascular events. Control of hypertension is sub-optimal. Shared decision making (SDM) is a process by which healthcare professionals and patients work together to make decisions about healthcare choices. It has been described as an essential component of high quality healthcare. Increasing the involvement of patients in healthcare choices has been proposed as a mechanism for improving hypertension control, based on an assumption that involvement will improve blood pressure control. We aimed to systematically review primary studies evaluating the effect of interventions to support SDM for hypertension, to describe their underlying concept of SDM and the hypothesised link with outcomes.
A systematic review of controlled studies. Searches were conducted in six databases without language or publication restrictions. References were screened against predefined in/exclusion criteria independently by two reviewers. Disagreements at each stage were resolved by discussion. Data from included studies were extracted by one reviewer and checked by a second. Risk of bias was assessed independently by two reviewers. Meta-analysis was considered appropriate where studies were at low risk of bias and reported similar interventions and outcomes. The underlying conceptualisation of SDM was summarised for each study by one reviewer and checked by another.
5402 references were identified for title and abstract screening; 66 were retained for full text screening and 8 reports of 6 studies were included in the final review. All studies were based in primary care. Of the 6 included studies, 4 were RCTs (2 cluster RCTs), 2 were controlled studies. The interventions were heterogeneous: 2 included training for general practitioners, 3 included a decision aid, and 1 included a patient leaflet. 2 studies were considered at high risk of bias. Outcomes assessed were also heterogeneous and meta-analysis was not appropriate. We found no high quality evidence of an effect of SDM on clinical outcomes including prescribing of anti-hypertensives and blood pressure. The effect of the intervention on shared decision making was reported in 3 of the 6 studies; the interventions had inconsistent effects on shared decision making. A descriptive report of the conceptualisation of SDM and its link with outcomes will be presented.
There is little high quality evidence to inform use of interventions to support SDM for hypertension. The hypothesis that shared decision making results in improved hypertension outcomes is not supported by our review. There is a lack of conceptual clarity underpinning evaluated interventions, reflected in the heterogeneous outcome measures chosen to report the effect of interventions. Moreover, the assumption that SDM should be a tool for improving hypertension treatment concordance, rather than an end in itself, is problematic.