The impact of blood pressure on kidney function in the elderly: a cross-sectional study.

BACKGROUND/AIMS: Intensive blood pressure (BP) target decreases blood perfusion of kidneys that attenuates the benefits of BP treatment in elderly hypertensive individuals. The optimal BP goal for renal function in the hypertensive elderly has been unclear. We investigated the impact of BP on renal function to define the appropriate BP target in the elderly. METHODS: A total of 28,258 elderly subjects were categorized into normotensive (Norm), hypotensive (Hypo) and hypertensive (Hyper) groups according to BP levels. Systolic, diastolic and pulse BP (SBP, DBP and PBP) were further stratified by 10 mmHg. Blood urea nitrogen, serum creatinine, uric acid, glomerular filtration rate (GFR), renal insufficiency prevalence (RIP) and proteinuria prevalence (PP) were compared among different groups and BP strata. The RIP and PP in the elderly with obesity, hyperlipidemia or diabetes in Norm, Hypo and Hyper groups were evaluated. RESULTS: GFR in Hypo and Hyper groups was significantly lower than that in Norm group. The RIP and PP was higher in Hypo and Hyper groups than that in the Norm group. Proteinuria became more prevalent when SBP was >140 mmHg or <90 mmHg. DBP>80 mmHg increased PP while DBP<70 mmHg increased RIP. PBP>60 mmHg led to an increased RIP and PP. Obesity or hyperlipidemia only combined with hypertension caused a significantly increased RIP and PP. Diabetes independent of hypertension contributed to higher RIP and PP. CONCLUSIONS: The most beneficial BP target for kidney function in the elderly may be SBP of 90-140 mmHg and DBP of 70-80 mmHg. PBP <60 mmHg may be appropriate.

Gender-specific association between metabolic syndrome and decreased glomerular filtration rate in elderly population.

PURPOSE: Few studies have investigated the association between metabolic syndrome (MS) and chronic kidney disease in the elderly. Accordingly, the aim of this study was to examine the sex-specific association between MS and decreased glomerular filtration rate (GFR) in a Chinese elderly population. METHODS: We performed cross-sectional analyses of older (age ≥60 years) males (n = 19,015) and females (n = 23,310) classified as 0, 1, 2, 3, 4, and 5 component(s) or MS group based on the presenting MS component(s). Sex-specific relationship of decreased GFR with MS component(s) was analyzed by logistic regression models. RESULTS: Compared with participants with 0 component of MS, males with 1, 2, 3, 4, and 5 component(s) had 1.40-, 1.79-, 2.41-, 3.29-, and 4.09-fold risks for decreased GFR; females with 1, 2, 3, 4, and 5 component(s) had 1.65-, 1.71-, 1.88-, 2.32-, and 1.96-fold risks for decreased GFR, respectively. The multivariate-adjusted odds ratios for decreased GFR in males and females with MS compared with those without MS were 1.79 and 1.25, respectively. For participants without hypertension and diabetes, the association of MS with decreased GFR was still significant. CONCLUSIONS: In this study of 42,325 Chinese participants aged ≥60 years, MS was significantly associated with decreased GFR, and the association was more profound for males than females.

Association between high-density lipoprotein cholesterol and renal function in elderly hypertension: a cross-sectional study in Chinese population.

Few studies have yet investigated the possible association between high-density lipoprotein cholesterol (HDL-C) and kidney function in elderly patients with primary hypertension. Accordingly, the aim of the present study was to evaluate the relationship between HDL-C and kidney function in elderly hypertension. A total of 14,644 elderly hypertensive subjects were enrolled in our cross-sectional study. The patients were categorized based on serum HDL-C level and glomerular filtration rate (GFR) value, respectively. One-way analysis of variance was used to compare the parameters among different groups. Bonferroni correction was performed for multiple comparisons. Analysis of covariance was used to control for confounding factors. The significance of difference between 3 groups and more was determined by chi-square test for categorical variables. Serum creatinine and uric acid were negatively related to HDL-C level, whereas GFR was positively related to HDL-C level in elderly hypertensive patients according to tertiles of HDL-C and tertiles of HDL-C/total cholesterol ratio (all P for trends <0.05). The male elderly hypertensive patients showed stronger relationship between HDL-C and renal function than the female elderly hypertensive subjects. Low HDL-C was associated with renal insufficiency and proteinuria in the hypertensive elderly (P < 0.05). The elderly "renal-hyperfiltrator" appeared to have lower HDL-C level, compared with the "normal renal-filtrator" (P < 0.05). There was an inverse "V" shape between HDL-C and GFR by GFR strata. Our results point out that there is an association of low HDL-C level with impaired kidney function in elderly hypertensive patients. Glomerular hyperfiltration may also affect HDL-C level and sex might be an influential factor for the association of HDL-C with kidney function in elderly hypertension.