Regional disparities in blood pressure control after hypertension treatment initiation in Japan: a real-world data analysis

This study assessed regional variations in blood pressure (BP) control after antihypertensive treatment and explored the associations with healthcare resource indicators across Japan. Using nationwide health check-up data from the Japan Health Insurance Association between 2015 and 2022, we analyzed 1,318,437 individuals aged 40-74 who initiated antihypertensive treatment based on consecutive health check-ups. We evaluated prefecture-level differences in post-treatment BP control rates (systolic BP [SBP]/diastolic BP [DBP] <130/<80 mmHg). Prefecture-level ecological analyses examined the associations between adjusted BP control rates and cerebrovascular disease mortality rates and six healthcare resource indicators, including the Physician Uneven Distribution Index (PUDI). Mean SBP/DBP decreased from 148.3/92.4 mmHg to 134.1/83.1 mmHg following treatment initiation. Only 26.7% of patients achieved the target BP (<130/<80 mmHg). This level is the universal target in the Japanese Society of Hypertension Guidelines for the Management of Elevated Blood Pressure and Hypertension 2025, highlighting a significant public health challenge. Unadjusted BP control rates varied by 10.2% across prefectures, narrowing to 7.4% after adjusting for individual-level patient characteristics. Pre-treatment SBP was the strongest predictor of post-treatment BP control. Ecological analysis revealed that each 1% increase in patients achieving the target BP of <130/<80 mmHg was associated with 3.5 fewer cerebrovascular disease deaths per 100,000 population in both sexes. PUDI showed a significant positive association with BP control rate (weighted Pearson's r = 0.47; p < 0.001). In conclusion, substantial regional disparities in BP control persist across Japan, which are significantly influenced by physician availability and associated with differences in stroke mortality. Using Japanese nationwide health check-up data from 1.3 million individuals initiating antihypertensive treatment, only 26.7% achieved the target BP (<130/<80 mmHg). Adjusted BP control rates varied by 7.4% across prefectures and were positively associated with physician availability and inversely with stroke mortality, indicating the impact of regional healthcare resource disparities.