Community-based study on elderly CKD subjects and the associated risk factors

Association Between Dietary Zinc Intake and Increased Renal Function in US Adults

We aimed to investigate the association between the dietary zinc intake and the risk of albuminuria, low estimated glomerular filtration rate (eGFR), and chronic kidney disease (CKD) in the US general population. This study was a cross-sectional study utilizing the data from the 2003-2018 National Health and Nutrition Examination Survey. Albuminuria was defined as urinary albumin:creatinine ratio (ACR) > 30 mg/g. Low eGFR was defined as an eGFR of less than 60 mL/min/1.73 m2. CKD is characterized by albuminuria or low eGFR. Multivariate logistic regression analysis, subgroup analyses, interaction tests, and restricted cubic spline (RCS) analysis were performed in this study. For 37,195 enrolled participants in this study, the mean dietary zinc intake was 11.85 ± 0.07 mg/day, and the rate of albuminuria, low eGFR, and CKD was 9.37%, 6.68%, and 14.10%, respectively. Participants with a higher dietary zinc intake showed a lower risk of albuminuria, low eGFR, and CKD. In the fully adjusted model, we found that participants in the highest dietary zinc intake quartile had 26% lower odds of the rate of CKD than those in quartile 1. Subgroup analyses showed that dietary zinc intake was positively associated with the risk of low eGFR in participants who were now smokers. The potential nonlinear relationship between dietary zinc intake and the risk of CKD and albuminuria was also revealed. Higher dietary zinc intake was significantly associated with a lower likelihood of CKD, which might be helpful in kidney function protection among the general population.

Octogenarians with chronic kidney disease in the nephrology clinic: Progressors vs. non-progressors

Background

The current definition of chronic kidney disease applied to patients over the age of 80 has increased the number of referrals to Nephrology. However not all of these patients may benefit from its assessment. This study aims to analyze the evolution of ≥80 years old patients referred to Nephrology.

Methods

Single-center study including patients ≥80 years old with eGFR <60 mL/min/1,73m2 who were referred to Nephrology consultation for the first time. Clinical and analytical parameters were collected retrospectively 12 months before the visit, and prospectively at baseline, and 12 and 24 months after the initial visit. We divided patients into two groups based on annual eGFR loss: progressors (>5 mL/min/1.73m2) and non-progressors (≤5 mL/min/1,73m2).

Results

A total of 318 patients were included, mean age was 84,9 ± 4 (80-97) years. Baseline serum creatinine was 1,65 ± 0,62 mg/dL, eGRF 35 (28-42) mL/min/1,73, and albumin/creatinine ratio 36 (7-229) mg/g. 55,7% of the patients met the definition of progressor at baseline (initial-progressors), 26,3% were progressors after a 12-month follow-up and 13,4% after 24 months. 21,2% and 11,4% of initial-progressors met this definition at 12 and 24 month follow up. The main risk factor for progression was albuminuria. No relationship was found between the nephrologist intervention and the evolution of renal function among initial non-progressors.

Conclusion

Elderly patients who have stable renal function at the time of referral will continue to have stable renal function over the subsequent 24 months and thus may not need to be referred to a nephrologist.

Individualized prediction of chronic kidney disease for the elderly in longevity areas in China: Machine learning approaches

Background

Chronic kidney disease (CKD) has become a major public health problem worldwide and has caused a huge social and economic burden, especially in developing countries. No previous study has used machine learning (ML) methods combined with longitudinal data to predict the risk of CKD development in 2 years amongst the elderly in China.

Methods

This study was based on the panel data of 925 elderly individuals in the 2012 baseline survey and 2014 follow-up survey of the Healthy Aging and Biomarkers Cohort Study (HABCS) database. Six ML models, logistic regression (LR), lasso regression, random forests (RF), gradient-boosted decision tree (GBDT), support vector machine (SVM), and deep neural network (DNN), were developed to predict the probability of CKD amongst the elderly in 2 years (the year of 2014). The decision curve analysis (DCA) provided a range of threshold probability of the outcome and the net benefit of each ML model.

Results

Amongst the 925 elderly in the HABCS 2014 survey, 289 (18.8%) had CKD. Compared with the other models, LR, lasso regression, RF, GBDT, and DNN had no statistical significance of the area under the receiver operating curve (AUC) value (>0.7), and SVM exhibited the lowest predictive performance (AUC = 0.633, p-value = 0.057). DNN had the highest positive predictive value (PPV) (0.328), whereas LR had the lowest (0.287). DCA results indicated that within the threshold ranges of ~0-0.03 and 0.37-0.40, the net benefit of GBDT was the largest. Within the threshold ranges of ~0.03-0.10 and 0.26-0.30, the net benefit of RF was the largest. Age was the most important predictor variable in the RF and GBDT models. Blood urea nitrogen, serum albumin, uric acid, body mass index (BMI), marital status, activities of daily living (ADL)/instrumental activities of daily living (IADL) and gender were crucial in predicting CKD in the elderly.

Conclusion

The ML model could successfully capture the linear and nonlinear relationships of risk factors for CKD in the elderly. The decision support system based on the predictive model in this research can help medical staff detect and intervene in the health of the elderly early.

Hyperuricemia prevalence and its association with metabolic disorders: a multicenter retrospective real-world study in China

Background

The prevalence of hyperuricemia (HUA) and gout continues to increase in China. Research suggests that HUA may be related to many diseases other than gout. However, further population research is required to investigate the association between HUA and metabolic syndromes. This study sought to investigate the prevalence of HUA in an average population in China, and the association between serum uric acid (UA) levels and related metabolic disorders.

Methods

This multicenter retrospective real-world study examined the hospital information system data of 4 tertiary hospitals in 3 provinces in China. The data of patients aged between 18 and 80 years, who had attended at least 1 medical appointment at which their UA level was recorded, were analyzed to evaluate associations between UA levels and metabolic disorders.

Results

Among the 374,506 enrolled subjects (49.7% male; mean age 51.5 years old), the overall prevalence of HUA and gout were 14.8% and 0.5%, respectively. The prevalence was higher among males than females (17.6% vs. 12.0%, 0.8% vs. 0.1%; both P<0.001). Groups exhibiting higher UA levels had increased adjusted odds ratios for dyslipidemia and chronic kidney disease (CKD) in both sexes. Changes in UA levels from the baseline were negatively correlated with changes in the estimated glomerular filtration rate and hemoglobin A1c among both sexes (all P<0.001), and were positively correlated with changes in total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) (all P<0.05) among males, and changes in TC, TG, LDL-C and glucose (all P<0.001) among females.

Conclusions

HUA is associated with dyslipidemia and CKD both cross-sectionally and longitudinally. Similar phenomena were observed in both sexes.

Time spent outside of the hospital, CKD progression, and mortality: a prospective cohort study

PURPOSE

Home time-being out of any healthcare facility-has been proposed as a patient-centered outcome. This novel measure has not been investigated in patients with chronic kidney disease (CKD). The aim of this study is to determine whether there was an association between home time and occurrence of end-stage renal disease (ESRD) or all-cause mortality during 1 year of follow-up.

METHODS

We assembled a prospective cohort of patients with CKD not requiring dialysis at the Nephrology Center of First Affiliated Hospital of Jiaxing University between May 2014 and April 2017 and followed up for 1 year. Home time was calculated as the number of days spent out of a hospital, rehabilitation facility, or skilled nursing facility. Outcomes included progression to ESRD and all-cause mortality.

RESULTS

Among 943 patients, 882 (93.5%) had complete follow-up through 1 year. Mean home time was 246.9 ± 126.7 days. In regression analysis, several patient characteristics were associated with significantly reduced home time, including diabetes mellitus, cardiovascular disease, and albuminuria. Home time was strongly correlated with time-to-event endpoints of ESRD (τ=0.324) and all-cause mortality (τ=0.785).

CONCLUSIONS

Home time is significantly reduced for patients with CKD not requiring dialysis and is highly correlated with traditional time-to-event endpoints. Home time serves as a novel, easily calculated, patient-centered outcome that may reflect effect of interventions on future CKD research.

Gender-specific association between uric acid level and chronic kidney disease in the elderly health checkup population in China

Objective: To evaluate the association between serum uric acid (SUA) levels with CKD in elderly health checkup population and explore the gender difference.

Methods: A total of 4242 subjects were included in the cross-sectional study. All of the subjects participated in the annual checkup between June 2016 and June 2017. Chronic kidney disease (CKD) was defined by estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m². We examined the association between SUA levels and CKD. Multivariate binary logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) by comparing association between the SUA level and CKD. The models were adjusted for age, gender, body mass index (BMI), hypertension, diabetes, triglyceride and high-density lipoprotein cholesterol (HDL-C).

Result: The prevalence of hyperuricemia was 22.2%, and it was significantly higher in male than in female (25.2% vs. 17%, p < .001). The prevalence of hyperuricemia increased with age, especially in the female. The prevalence of CKD was 27.8% in male and 20.2% in female (p < .001). Compared with the SUA first quartile, the multivariate-adjusted odds for CKD of fourth quartiles were 6.05 (95%CI: 4.32–8.49) in male and 8.21(95%CI: 5.37–12.54) in female.

Conclusion: Our finding showed gender-specific differences in the association between high SUA and an increased risk of CKD in the elderly population. The association of SUA and CKD was independent of other potential confounding factors including age, glucose, hypertension, HDL, TG and BMI.