Reduced Kidney Function and Relative Hypocalciuria-Observational, Cross-Sectional, Population-Based Data

The case for a ketogenic diet in the management of kidney disease

Ketogenic diets have been widely used for weight loss and are increasingly used in the management of type 2 diabetes. Despite evidence that ketones have multiple positive effects on kidney function, common misconceptions about ketogenic diets, such as high protein content and acid load, have prevented their widespread use in individuals with impaired kidney function. Clinical trial evidence focusing on major adverse kidney events is sparse. The aim of this review is to explore the effects of a ketogenic diet, with an emphasis on the pleiotropic actions of ketones, on kidney health. Given the minimal concerns in relation to the potential renoprotective effects of a ketogenic diet, future studies should evaluate the safety and efficacy of ketogenic interventions in kidney disease.

Renal complications in chronic hypoparathyroidism - a systematic cross-sectional assessment

Context

Although renal long-term complications are acknowledged in chronic hypoparathyroidism (HPT), standardized investigations are scarce.

Objective

To systematically investigate renal complications and their predictors in hypoparathyroid patients compared to matched individuals.

Design

Prospective observational study in 161 patients with chronic HPT.

Methods

Patients received renal ultrasound, clinical and laboratory assessments. An individual 1:3 matching with participants from the German population-based Study of Health in Pomerania was performed.

Results

Of 161 patients (92% postoperative HPT), prevalence of eGFR <60ml/min/1.73m2 was 21%, hypercalciuria 41%. Compared to healthy individuals, HPT patients had a significantly lower eGFR (74.2 vs. 95.7 ml/min/1.73m², p<0.01). Renal ultrasound revealed calcifications in 10% (nephrocalcinosis in 7% and calculi in 3%). Patients with renal calcifications had higher levels of 24-hour urine calcium excretion (8.34 vs. 5.08 mmol/d, p=0.02), spot urine calcium excretion (4.57 vs. 2.01 mmol/L, p=0.01) and urine calcium-to-creatinine ratio (0.25 vs. 0.16, p<0.01) than patients without calcifications. Albumin-corrected calcium, phosphate, calcium-phosphate product, 25-hydroxyvitamin D in serum, eGFR, daily calcium intake or disease duration were not significantly different between these two groups. Including patients receiving rhPTH therapy, a lower serum phosphate concentration (odds ratio 1.364 [95% confidence interval (CI) 1.049-1.776], p<0.05) and a longer disease duration of HPT (odds ratio 1.063 [95% CI 1.021-1.106], p<0.01) were significant predictors for renal calcifications. Excluding patients receiving rhPTH therapy, a higher 24-hour urine calcium excretion (odds ratio 1.215 [95% CI 1.058-1.396], p<0.01) was a significant predictor for renal calcifications but not serum magnesium or disease duration.

Conclusions

Prevalence of impaired renal function among patients with chronic HPT is increased and independent from visible renal calcifications. Depending on exclusion of patients with rhPTH therapy, regression analysis revealed disease duration and serum phosphate or disease duration and 24-hour urinary calcium excretion as predictors for renal calcifications.

Clin Trials Identifier

NCT05585593.

Relationship of the Intake of Water and Other Beverages With Renal Endpoints: Cross-Sectional and Longitudinal Data-Observational, Population-Based Study

OBJECTIVES

The relationship of water intake with kidney function in the population is uncertain. This study investigated cross-sectionally and longitudinally the relationship of the intake of water and other beverages with kidney function within an adult Italian population sample.

METHODS

In 4,554 Gubbio Study examinees (54.4% women, age 18-95 years), data collection at baseline included demographics, anthropometry, questionnaires on habitual intakes of water and other beverages (non-water fluids), a timed overnight urine collection, estimated glomerular filtration rate (eGFR), decreased eGFR (<60 mL/minute/1.73 m²), and other variables including urinary markers of diet. At 15-year follow-up, the incidence of renal/kidney replacement therapy, the eGFR change from baseline, and the incidence of decreased eGFR were used as indices of kidney function change over time.

RESULTS

In multivariable analyses, higher water intake is independently related to higher urine flow (beta = 0.163, P < .001), lower urine osmolality (beta = 0.184, P < .001), lower eGFR (beta = 0.030, P = .002), and higher prevalence of decreased eGFR (logistic coefficient ± standard error = 1.13 ± 0.32, P < .001). Water intake did not relate to kidney function change over time. Intake of non-water fluids did not independently relate to urinary indices nor to kidney function.

CONCLUSIONS

In the general population, water intake relates cross-sectionally to urine flow, urine concentration, and kidney function but it does not relate to kidney function change over time. The intake of other beverages does not relate to urinary indices or kidney function. Results do not support a role of water intake in kidney function decline over time in the population.

Urinary Potassium and Kidney Function Decline in the Population-Observational Study

Background-Some data suggest favorable effects of a high potassium intake on kidney function. The present population-based study investigated cross-sectional and longitudinal relations of urinary potassium with kidney function. Methods-Study cohort included 2027 Gubbio Study examinees (56.9% women) with age ≥ 18 years at exam-1 and with complete data on selected variables at exam-1 (1983-1985), exam-2 (1989-1992), and exam-3 (2001-2007). Urinary potassium as urinary potassium/creatinine ratio was measured in daytime spot samples at exam-1 and in overnight timed collections at exam-2. Estimated glomerular filtration rate (eGFR) was measured at all exams. Covariates in analyses included demographics, anthropometry, blood pressure, drug treatments, diabetes, smoking, alcohol intake, and urinary markers of dietary sodium and protein. Results-In multivariable regression, urinary potassium/creatinine ratio cross-sectionally related to eGFR neither at exam-1 (standardized coefficient and 95%CI = 0.020 and -0.059/0.019) nor at exam-2 (0.024 and -0.013/0.056). Exam-1 urinary potassium/creatinine ratio related to eGFR change from exam-1 to exam-2 (0.051 and 0.018/0.084). Exam-2 urinary potassium/creatinine ratio related to eGFR change from exam-2 to exam-3 (0.048 and 0.005/0.091). Mean of urinary potassium/creatinine ratio at exam-1 and exam-2 related to eGFR change from exam-1 to exam-3 (0.056 and 0.027/0.087) and to incidence of eGFR < 60 mL/min per 1.73 m² from exam-1 to exam-3 (odds ratio and 95%CI = 0.78 and 0.61/0.98). Conclusion-In the population, urinary potassium did not relate cross-sectionally to eGFR but related to eGFR decline over time. Data support the existence of favorable effects of potassium intake on ageing-associated decline in kidney function.

A report on the Gubbio Study thirty-eight years after its inception

BACKGROUND

The Gubbio Population Study ("Gubbio Study") is a prospective epidemiological study carried out on the resident population of the city of Gubbio, Italy. The study's objectives are both of public health nature (the control and awareness of hypertension), and experimental (the role of electrolyte handling at the cellular membrane level and its relation to hypertension). Additional objectives were addressed during the 30+ year activity of the study, in particular the role of kidney dysfunction.

METHODS

Three active screenings ('Exams') were performed beginning 38 years ago; the first (Exam 1) in 1983-1986 (5376 individuals - response rate 92%) and two follow-up exams, were completed between 1989-92 (Exam 2) and 2001-2007 (Exam 3). Data collected include demographics, personal and family medical history, lifestyle (smoking, alcohol, diet and physical activity), education, type of work, anthropometry, blood pressure, pulse rate, blood biochemistry, urine biochemistry and special investigations on cellular electrolyte handling. Additional measurements were performed in selected sub-groups of participants. Data on hospitalizations, mortality and causes of death were collected after the completion of Exam 1.

RESULTS

The main results of the study, presented in this paper, identify new variables to consider in screening for cardiovascular risk factors, and show the impact that the focused and coordinated effort of a longitudinal program can have on a free-living population'.

CONCLUSIONS

The data are of relevance to Public Health and to experimental medicine alike, and vouch to the importance of the control of risk factors at the community level.