Regional variation in pre-dialysis blood pressure and its association with cardiovascular mortality rates in Japanese patients undergoing dialysis

Adequate blood pressure (BP) management poses a significant challenge in improving the prognosis of patients undergoing dialysis. We aimed to investigate the relationship between pre-dialysis systolic blood pressure (SBP) and underlying disease in Japanese patients undergoing dialysis, based on prefectural location, and assess the association between pre-dialysis SBP and cardiovascular disease (CVD) mortality rate. We extracted the basic information of 336,182 patients who were undergoing dialysis in 2021 from the Web-based Analysis of Dialysis Data Archives database. Data on average pre-dialysis SBP were analyzed according to sex, prefectural location, and diabetic status, and the CVD mortality rate for each prefecture was calculated. The mean pre-dialysis SBP of the patients (males, 66.3%; mean age, 69.7 ± 12.5 years) was 151.9 ± 24.7 mmHg. Overall, 133,037 patients had underlying diabetic kidney disease (DKD). The patients with DKD were younger, had a shorter dialysis duration, and a higher pre-dialysis SBP than those with non-DKD comorbidities. The prefecture-based mean pre-dialysis SBP values were all higher than 140 mmHg. At the prefectural level, CVD mortality rate was positively correlated with pre-dialysis SBP (r = 0.3127, p = 0.0324) and diastolic blood pressure (r = 0.3378, p = 0.0202) among female patients. At the prefectural level, pre-dialysis SBP is >140 mmHg in Japanese patients undergoing dialysis, especially in those with DKD. The positive association between pre-dialysis SBP and CVD mortality rate suggests that optimal BP management at the prefectural level may reduce CVD mortality rates. At the prefectural level, pre-dialysis SBP is higher than 140 mmHg in Japanese patients undergoing dialysis, especially higher in those with DKD.