Effects of Coffee Intake on Incident Chronic Kidney Disease: A Community-Based Prospective Cohort Study.

BACKGROUND: Drinking coffee can raise public health problems, but the association between coffee and kidney disease is unknown. We studied whether coffee intake can affect the development of chronic kidney disease in the general population. METHODS: We analyzed 8717 subjects with normal renal function recruited from the Korean Genome and Epidemiology Study (KoGES) cohort. Based on a food frequency questionnaire, coffee consumption was categorized into 5 groups: 0 per week, <1 cup per week, 1-6 cups per week, 1 cup per day, and ≥2 cups per day. The primary outcome was incident chronic kidney disease, defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2. RESULTS: The mean age (standard deviation) of study subjects was 52.0 (8.8) years, and 47.8% were male. Among the subjects, 52.8% were daily coffee consumers. During a mean follow-up of 11.3 (range, 5.9-11.5) years, 9.5% of participants developed chronic kidney disease. The incident chronic kidney disease occurred less in daily coffee consumers. Unadjusted hazard ratios (HRs) was significantly lower in daily coffee consumers. In multivariable Cox model even after adjustment of blood pressure, hypertension, cardiovascular disease, diabetes, and amount of daily intake for caffeine-containing foods such as tea and chocolate, coffee consumers with 1 cup per day (HR, 0.76; 95% confidence interval, 0.63-0.92) and ≥2 cups per day (HR, 0.80; 95% confidence interval, 0.65-0.98) were associated with a lower risk of chronic kidney disease development than nondrinkers. Time-averaged and time-varying Cox models yielded similar results. The rates of decline in glomerular filtration were lower in daily coffee consumers. CONCLUSIONS: Our findings suggest that daily coffee intake is associated with decreased risk of the development of chronic kidney disease.

Influence of ketoanalogs supplementation on the progression in chronic kidney disease patients who had training on low-protein diet.

AIM: A low-protein diet (LPD) is a conservative treatment in patients with chronic kidney disease (CKD) to improve uremic symptoms and slow the progression of renal dysfunction. However, the deleterious effects of protein restriction on nutritional status have raised concern. We investigated whether ketoanalogs supplementation in CKD patients who had training on LPD retards the progression of CKD and maintains nutritional status. METHODS: Data were collected retrospectively from 120 consecutive patients in the CKD stages III and IV. Firstly all patients were restricted to LPD alone for 6 months (LPD alone), and then ketoanalogs of essential amino acids (KA) were supplemented for 6 months. RESULTS: The adequate LPD had not achieved in both periods. The declining slopes of glomerular filtration rate (GFR) during the LPD + KA period were significantly lower than those during the LPD alone period. This improvement in GFR was apparent in both subjects with diabetics and non-diabetic patients. Mean serum total cholesterol levels decreased in LPD + KA compared with LPD alone period. However, serum albumin levels did not change. Responders showed a higher prevalence of diabetes and higher serum albumin levels during the LPD alone period. Multivariate analysis revealed that responsiveness to LPD + KA was independently related to diabetes (p = 0.006) and high serum albumin levels (p = 0.011) in the LPD alone period. CONCLUSION: KA supplementation on over LPD delayed the progression of CKD without deteriorating nutritional status, and initial serum albumin levels could be an independent factor.