Clinical Decision Support System, Antihypertensive Treatment Intensification, and Blood Pressure Control: A Post Hoc Secondary Analysis of a Cluster Randomized Trial.

Importance: Clinical decision support systems (CDSSs) are increasingly used to improve guideline-based hypertension care; however, their association with antihypertensive treatment intensification and blood pressure (BP) control in primary care practices remains unclear. Objectives: To evaluate whether CDSS implementation was associated with improvement in antihypertensive treatment intensification and BP control in primary care practices and to examine the association between treatment intensification and BP change. Design, Setting, and Participants: This post hoc secondary analysis used the data from a pragmatic cluster randomized clinical trial conducted from August 1, 2019, to July 31, 2022, in urban primary care practices in China among 4612 adult patients with hypertension and uncontrolled BP at baseline. Data analysis was conducted from August 1, 2024, to September 1, 2025. Interventions: Practices randomized to the intervention group used a real-time, guideline-based CDSS for guiding antihypertensive treatment, while control practices delivered usual care. Main Outcomes and Measures: Treatment intensification rate, defined as the percentage of clinic visits with uncontrolled BP during which there was an increase in the class or dose of antihypertensive medication. Among patients with uncontrolled BP at baseline, treatment intensification was assessed at visits with uncontrolled BP, and BP control was evaluated at the last follow-up visit. Treatment intensity was summarized using a treatment intensification score reflecting the frequency of medication intensification relative to guideline expectations. Results: Among 4612 patients with uncontrolled BP at baseline (median age, 63 years [IQR, 52-74 years]; 2648 men [57.4%]; 2134 [46.3%] in CDSS group and 2478 [53.7%] in control group) from 93 practices, treatment intensification rates were higher in the CDSS group than in the usual care group (47.3% [95% CI, 40.1%-54.6%] vs 11.6% [95% CI, 8.9%-14.9%]; adjusted odds ratio [OR], 6.87 [95% CI, 4.90-9.64]; P < .001). The median treatment intensification score was higher in the CDSS group than in the usual care group (-0.25 [IQR, -0.50 to 0] vs -0.50 [IQR, -0.75 to -0.30]; mean difference, 0.22 [95% CI, 0.17-0.28]). Each 0.22-point increase in the treatment intensification score was associated with a mean systolic BP change of -3.8 mm Hg (95% CI, -4.1 to -3.5 mm Hg). BP control rates were similar between groups. Conclusions and Relevance: In this post hoc analysis of a cluster randomized clinical trial, CDSS implementation was associated with increased treatment intensification but was not associated with improvements in overall BP control. These findings suggest that stronger implementation strategies may be needed to translate treatment intensification into improved BP outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT03636334.