Associations of Long-Term Visit-to-Visit Blood Pressure Variability With Subclinical Kidney Damage and Albuminuria in Adulthood: a 30-Year Prospective Cohort Study

Abstract

Background: Recent evidence indicates that long-term visit-to-visit blood pressure variability (BPV) may be associated with risk of cardiovascular disease. We, therefore, aimed to determine the potential associations of long-term BPV from childhood to middle age with subclinical kidney damage (SKD) and albuminuria in adulthood.

Methods: Using data from the ongoing cohort of Hanzhong Adolescent Hypertension study, which recruited children and adolescents aged 6 to 18 years at baseline, we assessed BPV by SD and average real variability (ARV) for 30 years (6 visits). Presence of SKD was defined as estimated glomerular filtration rate between 30 and 60 mL/min per 1.73 m² or elevated urinary albumin-to creatinine ratio at least 30 mg/g. Albuminuria was defined as urinary albumin-to creatinine ratio ≥30 mg/g.

Results: During 30 years of follow-up, of the 1771 participants, 204 SKD events occurred. After adjustment for demographic, clinical characteristics, and mean BP during 30 years, higher SD_SBP , ARV_SBP , SD_DBP , ARV_DBP , SD_MAP , ARV_MAP , and ARV_PP were significantly associated with higher risk of SKD. When we used cumulative exposure to BP from childhood to adulthood instead of mean BP as adjustment factors, results were similar. In addition, greater long-term BPV was also associated with the risk of albuminuria. Long-term BPV from childhood to middle age was associated with higher risk of SKD and albuminuria in adulthood, independent of mean BP or cumulative exposure to BP during follow-up.

Conclusions: Identifying long-term BPV from early age may assist in predicting kidney disease and cardiovascular disease in later life.

Keywords: albuminuria; blood pressure; cardiovascular diseases; cohort studies; kidney.

Figure 1.

The example of individual follow-up data of systolic blood pressure (SBP) across 6 visits (Y₀–Y₃₀). The absolute differences of BP between successive SBP measurements are shown as Δ1−Δ5. For example, Δ1 represents the difference in SBP between visit 1 and visit values. Average real variability is calculated as (Δ1+Δ2+Δ3+Δ4+Δ5)/5. The mean BP between successive BP measurements is shown as A1−A5. Cumulative exposure to BP was calculated as (A1×2 y+A2×3 y+A3×3 y+A4×18 y+A5×4) and is shown by the dotted area, representing in mm Hg×y. Mean SBP and SD were calculated from all 6 BP values from visit 1 to visit 6 for each individual, and coefficient of variation was calculated as SD/mean BP. The variability independent of the mean (VIM) of SBP was defined as the intraindividual SD of SBP across examinations (M/x)^p, where x is individual mean SBP across visits, M is the mean of individual mean SBP in the overall population, and p is the regression coefficient on the basis of regressing the natural logarithm of SD on the natural logarithm of the multiplication of x and M.

Figure 2.

Flow diagram showing the selection of the study population.