Shared decision making in hypertension: the impact of patient preferences on treatment choice

Background. Recent guidelines for treatment of hypertension advocate a multifactorial approach based on absolute risk of a cardiovascular event. However, this does not take any account of individual patient values or preferences for health outcomes that result from having hypertension. Objective. Our aim was to investigate the impact of patient preferences on treatment recommendations for hypertension using individual decision analysis. Methods. We carried out an observational study based on interviews with 52 hypertensive patients. Patient preferences were measured using the standard gamble method. Associations between outcome of the individual decision analyses (recommendation to accept or decline antihypertensive medication) and treatment guidelines based on blood pressure and absolute cardiovascular risk were investigated. Adherence to medication during the 6 months following the interview was also assessed. Results. Individual patient preferences have a substantial impact on the proportion of patients for whom drug treatment would be recommended. In 52 patients interviewed, decision analysis indicated that 29 [56%, 95% confidence interval (Cl) 41-70] should be treated, compared with 27 (52%, 38-66) using a cardiovascular risk of greater than or equal to 10% over 5 years and 19 (37%, 24-51) using a systolic blood pressure of greater than or equal to 160 mmHg. There was marked disagreement between the decision analysis and these recommendations (kappas 0.18 or less). There was no relationship between outcome of the decision analysis and adherence to medication [chi-square (1 d.f.) = 0.5, P = 0.5]. Conclusions. Quantifying patients' preferences and using decision analysis as a shared decision-making aid appears to have an impact on whether patients would be recommended for antihypertensive medication. Further evaluation of this method as a shared decision-making tool is warranted.