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Background The SingHypertension primary care clinic intervention, which consisted of clinician training in hypertension management, subsidized single‐pill combination medications, nurse‐delivered motivational conversations and telephone follow‐ups, improved blood pressure control and cardiovascular disease (CVD) risk scores relative to usual care among patients with uncontrolled hypertension in Singapore. This study quantified the incremental cost‐effectiveness, in terms of incremental cost per unit reduction disability‐adjusted life years, of SingHypertension relative to usual care for patients with hypertension from the health system perspective. Methods and Results We developed a Markov model to simulate CVD events and associated outcomes for a hypothetical cohort of patients over a 10‐year period. Costs were measured in US dollars, and effectiveness was measured in disability‐adjusted life years averted. We present base‐case results and conducted deterministic and probabilistic sensitivity analyses. Based on a willingness‐to‐pay threshold of US $55 500 per DALY averted, SingHypertension was cost‐effective for patients with hypertension (incremental cost‐effectiveness ratio: US $24 765 per disability‐adjusted life year averted) relative to usual care. This result held even if risk reduction was assumed to decline linearly to 0 over 10 years but not sooner than 7 years. Incremental cost‐effectiveness ratios were most sensitive to the magnitude of the reduction in CVD risk; at least a 0.13% to 0.16% point reduction in 10‐year CVD risk is required for cost‐effectiveness. Probabilistic sensitivity analysis indicates that SingHypertension has a 78% chance of being cost‐effective at the willingness‐to‐pay threshold. Conclusions SingHypertension represents good value for the money for reducing CVD incidence, morbidity, and mortality and should be considered for wide‐scale implementation in Singapore and possibly other countries. Registration Information REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02972619.

Abstract Introduction Cardiovascular disease (O'Lone E, Viecelli AK, Craig JC, Tong A, Sautenet B, Herrington WG, et al., Am J Kidney Dis 76(1):109–20, 2020) remains the leading cause of death in Singapore. Uncontrolled hypertension confers the highest attributable risk of CVD and remains a significant public health issue with sub-optimal blood pressure (BP) control rates. The aim of the trial is to evaluate the effectiveness and cost-effectiveness of a multicomponent intervention (MCI) versus usual care on lowering BP among adults with uncontrolled hypertension visiting primary care clinics in Singapore. This article describes the statistical analysis plan for the primary and secondary objectives related to intervention effectiveness. Methods The study is a cluster randomized trial enrolling 1000 participants with uncontrolled hypertension aged ≥ 40 years from eight primary care clinics in Singapore. The unit of randomization is the clinic, with eight clusters (clinics) randomized in a 1:1 ratio to either MCI or usual care. All participants will be assessed at baseline, 12 months, and 24 months with measurements of systolic and diastolic BP, antihypertensive and statin medication use, medication adherence, physical activity level, anthropometric parameters, smoking status, and dietary habits. The primary objective of this study is to assess the effectiveness of MCI versus usual care on mean SBP at the 2-year follow-up. The primary outcome is SBP at 24 months. SBP at baseline, 12, and 24 months will be modeled at the subject level using a likelihood-based, linear mixed-effects model repeated measures (MMRM) analysis with treatment group and follow-up as fixed effects, random cluster (clinic) effects, Gaussian error distribution, and adjustment to degrees of freedom using the Satterthwaite approximation. Secondary outcomes will be analyzed using a similar modeling approach incorporating generalized techniques appropriate for the type of outcome. Discussion The trial will allow us to determine whether the MCI has an impact on BP and cardiovascular risk factors over a 2-year follow-up period and inform recommendations for health planners in scaling up these strategies for the benefit of society at large. A pre-specified and pre-published statistical analysis plan mitigates reporting bias and data driven approaches. Trial registration ClinicalTrials.gov NCT02972619 . Registered on 23 November 2016.

An amendment to this paper has been published and can be accessed via the original article.