Blood Pressure is Associated with Rapid Kidney Function Decline in a Very Elderly Hypertensive Chinese Population

Pulse pressure modifies the association between diastolic blood pressure and decrease in kidney function: the Japan Specific Health Checkups Study

Background

Unlike systolic blood pressure (SBP), the prognostic value of diastolic blood pressure (DBP) in kidney function has not been established. We hypothesized that pulse pressure (PP), which is associated with arteriosclerosis, would affect the prognostic value of DBP.

Methods

This longitudinal study used data from the Japan Specific Health Checkups Study was conducted between 2008 and 2014. The participants were stratified into three PP subgroups (low PP ≤39, normal PP 40-59 and high PP ≥60 mmHg). The exposures of interest were SBP and DBP, and the association between SBP/DBP and kidney outcomes (30% decline in the estimated glomerular filtration rate from baseline) was examined in each PP subgroup using a Cox proportional hazards model.

Results

Among 725 022 participants, 20 414 (2.8%) developed kidney outcomes during a median follow-up period of 34.6 months. Higher SBP was consistently associated with a higher incidence of kidney outcome in all PP subgroups. Although DBP had a positive linear association with the incidence of kidney outcome in low- and normal-PP subgroups, both lower (≤60 mmHg) and higher (≥101 mmHg) DBP were associated with a higher incidence of kidney outcome in the high-PP subgroup, with a U-shaped curve. Hazard ratios (95% confidence intervals) of ≤60 mmHg (reference: 61-80 mmHg in normal-PP subgroup) and ≥101 mmHg were 1.26 (1.15-1.38) and 1.86 (1.62-2.14), respectively.

Conclusions

In this large population-based cohort, DBP was differently associated with kidney outcome by PP level; lower DBP was significantly associated with a higher incidence of kidney outcome in the high-PP subgroup but not in the low- and normal-PP subgroups.

Effect of Orthostatic Hypotension on Kidney Function

BACKGROUND

The association between orthostatic hypotension (OH) and long-term changes in kidney function in the general population is not yet well known.

METHODS

We performed a population-based cohort study based on data from the Korean Genome and Epidemiology Study (KoGES). The primary exposure was the presence of classic OH, defined as a postural drop in blood pressure (systolic blood pressure ≥20 mm Hg and/or diastolic blood pressure ≥10 mm Hg) at 2 min of standing after 5 min of supine rest. The primary outcome was a 12-year change in kidney function, assessed by subtracting the baseline estimated glomerular filtration rate (eGFR) from the eGFR at 12 years of follow-up.

RESULTS

Our study included 5,905 participants (median [interquartile range] age, 49 [44-58] years; 46% males) who met inclusion and exclusion criteria. Classic OH was detected in 268 (4.5%) of the total participants. In the regression analyses, participants with classic OH had a greater decline in eGFR over 12 years compared with those without classic OH; the fully adjusted beta coefficient and 95% confidence intervals (95% CIs) were -1.74 (-3.07, -0.40). Furthermore, classic OH was associated with 27% greater risk of a 30% decline in kidney function compared with those without classic OH; fully adjusted hazard ratio and 95% CIs were 1.27 (1.07, 1.49).

CONCLUSIONS

Classic OH can negatively affect long-term kidney function in the general population.

Nomogram to predict rapid kidney function decline in population at risk of cardiovascular disease

BACKGROUND

To develop a reliable model to predict rapid kidney function decline (RKFD) among population at risk of cardiovascular disease.

METHODS

In this retrospective study, key monitoring residents including the elderly, and patients with hypertension or diabetes of China National Basic Public Health Service who underwent community annual physical examinations from January 2015 to December 2020 were included. Healthy records were extracted from regional chronic disease management platform. RKFD was defined as the reduction of estimated glomerular filtration rate (eGFR) ≥ 40% during follow-up period. The entire cohort were randomly assigned to a development cohort and a validation cohort in a 2:1 ratio. Cox regression analysis was used to identify the independent predictors. A nomogram was established based on the development cohort. The concordance index (C-index) and calibration plots were calculated. Decision curve analysis was applied to evaluate the clinical utility.

RESULTS

A total of 8455 subjects were included. During the median follow-up period of 3.72 years, the incidence of RKFD was 11.96% (n = 1011), 11.98% (n = 676) and 11.92% (n = 335) in the entire cohort, development cohort and validation cohort, respectively. Age, eGFR, hemoglobin, systolic blood pressure, and diabetes were identified as predictors for RKFD. Good discriminating performance was observed in both the development (C-index, 0.73) and the validation (C-index, 0.71) cohorts, and the AUCs for predicting 5-years RKFD was 0.763 and 0.740 in the development and the validation cohort, respectively. Decision curve analysis further confirmed the clinical utility of the nomogram.

CONCLUSIONS

Our nomogram based on five readily accessible variables (age, eGFR, hemoglobin, systolic blood pressure, and diabetes) is a useful tool to identify high risk patients for RKFD among population at risk of cardiovascular disease in primary care. Whereas, further external validations are needed before clinical generalization.