Significance of blood pressure variability in normotensive individuals as a risk factor of developing hypertension.

PURPOSE: Visit-to-visit blood pressure variability is a strong predictor of the incidence of cardiovascular events and target organ damage due to hypertension. The present study investigated whether year-to-year blood pressure variability predicts the risk of hypertension in the Japanese general population. MATERIALS AND METHODS: This study analysed 2806 normotensive individuals who participated in our physical check-up program for five years in a row from 2008 to 2013. The average, standard deviation, coefficient of variation, average real variability, and highest value of systolic blood pressure in the five consecutive visits were determined and used as baseline data. The participants were followed up for the next 6 years with the development of 'high blood pressure', an average blood pressure level of ≥140/90 mmHg or the use of antihypertensive medications, as the endpoint. RESULT: During follow-up, 'high blood pressure' developed in 389 participants (13.9%, 29.5 per 1 000 person-years). The incidence increased across the quartiles of standard deviation and average real variability, while the average and highest systolic blood pressure had the most prominent impact on the development of 'high blood pressure'. Multivariate logistic regression analysis adjusted for possible risk factors indicated that the average, standard deviation, average real variability, and highest blood pressure, but not the coefficient of variation of systolic blood pressure, were significant predictors of 'high blood pressure'. CONCLUSION: Increased year-to-year blood pressure variability predicts the risk of hypertension in the general normotensive population. The highest blood pressure in the preceding years may also be a strong predictor of the risk of hypertension.

What is the context A relatively high blood pressure level recorded by chance is not usually examined further, especially in cases where the blood pressure values recorded in different opportunities were within normal levels.However, high blood pressure observed by chance may be a result of increased blood pressure variability.Increased blood pressure variability predicts incident hypertension in patients with diabetes, but clinical significance of increased blood pressure variability in the general population with normal blood pressure has not been studied.What is new The impact of blood pressure variability on the development of hypertension in the normotensive general population was investigated.The present study demonstrated that increased blood pressure variability was the significant predictor of the development of hypertension in the general population.What is the impact Increased year-to-year blood pressure variability as well as the highest blood pressure observed by chance in the preceding years is a strong predictor of the development of hypertension in the general normotensive population.

Urinary Na/K ratio is a predictor of developing chronic kidney disease in the general population.

Chronic kidney disease (CKD) is a major risk factor for cardiovascular diseases as well as end-stage kidney disease. Increased dietary sodium (Na) or decreased dietary potassium (K) deteriorates kidney function; however, findings regarding the association of dietary Na/K ratio with kidney function are limited and conflicting. Therefore, the present study investigated the impact of urinary Na/K ratio on the development of CKD, defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2, in the Japanese general population. In total, 14,549 subjects without CKD who participated in our medical checkup were enrolled. The urinary Na/K ratio was measured using a sample of overnight urine. The subjects were followed up until the endpoint (onset of CKD). During the median follow-up period of 61.4 months, CKD developed in 2096 participants (25.9 per 1000 person-years). The risk of developing CKD increased across the quartiles of baseline urinary Na/K ratio in the Kaplan-Meier analysis (log-rank, P < 0.001). In multivariate Cox proportional hazard regression analysis, urinary Na/K ratio was a significant predictor of new-onset CKD after adjustment for important factors including eGFR at baseline (hazard ratio, 2.013; 95% confidence interval, 1.658-2.445; p < 0.001). Moreover, baseline urinary Na/K ratio was found to be independently correlated with yearly decline in eGFR. Similar results were obtained in subgroups of participants with and without hypertension. Thus, urinary Na/K ratio is significantly associated with the development of CKD in the general population.