Kidney dysfunction: prevalence and associated risk factors in a community-based study from the North West Province of South Africa

γ-Gammaglutamyl transferase predicts all-cause mortality within three-year intervals in patients undergoing peritoneal dialysis

OBJECTIVES

Peritoneal dialysis (PD) serves as a vital renal replacement therapy for patients with end-stage kidney disease (ESKD). γ-Gamma-glutamyl transferase (γ-GGT) is a recognized predictor of oxidative stress and mortality. This study aimed to assess the prognostic significance of γ-GGT in predicting all-cause and cardiovascular mortality among PD patients.

METHODS

A retrospective study was conducted, enrolling 640 PD patients from a single center. The one-year, three-year, and five-year mortality rates for all causes and cardiovascular causes were evaluated. Kaplan-Meier survival analysis and multivariate Cox regression analysis were performed.

RESULTS

Within five years of initiating PD, the observed all-cause mortality rates at one, three, and five years were 11.72%, 16.09%, and 23.44%, while cardiovascular mortality rates were 2.97%, 7.34%, and 11.09%, respectively. Lower γ-GGT levels were associated with decreased all-cause mortality during one-, three-, and five-year follow-ups, along with reduced cardiovascular mortality in the first and third years, as indicated by Kaplan-Meier analysis on median γ-GGT groupings. Multivariate Cox regression analysis showed significantly decreased hazard ratios (HRs) for one- to five-year all-cause mortality and cardiovascular mortality in the lower γ-GGT group compared to higher groups. However, when sex differences were eliminated using separate tertile groupings for males and females, only the one- and three-year all-cause mortality rates demonstrated significantly reduced hazard ratios (HRs) in the lower γ-GGT groups.

CONCLUSION

This retrospective study suggests that γ-GGT levels have prognostic significance in predicting one- and three-year all-cause mortality among PD patients when accounting for sex differences.

Global disease burden attributable to kidney dysfunction, 1990-2019: A health inequality and trend analysis based on the global burden of disease study

OBJECTIVE

This study aimed to evaluate the burden of kidney dysfunction (KD), assess socioeconomic inequalities, and project trends in the future.

METHODS

Data on deaths, disability-adjusted life years (DALYs), years lived with disability (YLDs), and years of life lost (YLLs) were from Global Burden of Disease Study 2019. The Joinpoint regression model was utilized to analyze the temporal trend by the annual percentage change (APC). The slope index and concentration index were employed to evaluate cross-country disparities. The future trend was predicted using an age-period-cohort analysis.

RESULTS

In the past three decades, the death numbers of KD increased from 1,571,720 to 3,161,552, DALYs from 42,090,331 to 76,486,945, YLDs from 5,003,267 to 11,282,484, and YLLs from 37,087,065 to 65,204,461, respectively. The age-standardized rate (ASR) of deaths, DALYs, and YLLs exhibited a declining trend. The ASR of YLDs increased until 2017, then decreased. The slope index and concentration index for DALYs increased from 248.1 to 351.9 and from 40.70 to 57.8. In the future, the ASR of deaths, DALYs, YLDs, and YLLs will remain stable, while their numbers will continue to rise, except for YLLs.

CONCLUSIONS

The disease burden of KD remained serious. Tailored interventions should be developed based on national contexts.

Laboratory-based surveillance of chronic kidney disease in people with private health coverage in Brazil

BACKGROUND

Although approximately 25% of Brazilians have private health coverage (PHC), studies on the surveillance of chronic kidney disease (CKD) in this population are scarce. The objective of this study was to estimate the prevalence of CKD in individuals under two PHC regimes in Brazil, who total 8,335,724 beneficiaries.

METHODS

Outpatient serum creatinine and proteinuria results of individuals from all five regions of Brazil, ≥ 18 years of age, and performed between 10/01/2021 and 10/31/2022, were analyzed through the own laboratory network database. People with serum creatinine measurements were evaluated for the prevalence and staging of CKD, and those with simultaneous measurements of serum creatinine and proteinuria were evaluated for the risk category of the disease. CKD was classified according to current guidelines and was defined as a glomerular filtration rate (GFR) < 60 ml/min/1.73 m² estimated by the 2021 CKD-EPI equation.

RESULTS

The number of adults with serum creatinine results was 1,508,766 (age 44.0 [IQR, 33.9-56.8] years, 62.3% female). The estimated prevalence of CKD was 3.8% (2.6%, 0.8%, 0.2% and 0.2% in CKD stages 3a, 3b, 4 and 5, respectively), and it was higher in males than females (4.0% vs. 3.7%, p < 0.001, respectively) and in older age groups (0.2% among 18-29-year-olds, 0.5% among 30-44-year-olds, 2.0% among 45-59-year-olds, 9.4% among 60-74-year-olds, and 32.4% among ≥ 75-year-olds, p < 0.001) Adults with simultaneous results of creatinine and proteinuria were 64,178 (age 57.0 [IQR, 44.8-67.3] years, 58.1% female). After adjusting for age and gender, 70.1% were in the low-risk category of CKD, 20.0% were in the moderate-risk category, 5.8% were in the high-risk category, and 4.1% were in the very high-risk category.

CONCLUSION

The estimated prevalence of CKD was 3.8%, and approximately 10% of the participants were in the categories of high or very high-risk of the disease. While almost 20% of beneficiaries with PHC had serum creatinine data, fewer than 1% underwent tests for proteinuria. This study was one of the largest ever conducted in Brazil and the first one to use the 2021 CKD-EPI equation to estimate the prevalence of CKD.

Chronic kidney disease of unknown aetiology in Africa: A review of the literature

During the last two decades, an epidemic of a severe form of chronic kidney disease (CKD) unrelated to traditional risk factors (diabetes and hypertension) has been recognized in low- to middle-income countries. CKD of unknown aetiology (CKDu) mainly affects young working-age adults, and has become as an important and devastating public health issue. CKDu is a multifactorial disease with associated genetic and environmental risk factors. This review summarizes the current epidemiological evidence on the burden of CKDu and its probable environmental risk factors contributing to CKD in Africa. PubMed/Medline and the African Journals Online databases were searched to identify relevant population-based studies published in the last two decades. In the general population, the burden of CKD attributable to CKDu varied from 19.4% to 79%. Epidemiologic studies have established that environmental factors, including genetics, infectious agents, rural residence, low socioeconomic status, malnutrition, agricultural practise and exposure to agrochemicals, heavy metals, use of traditional herbs, and contaminated water sources or food contribute to the burden of CKD in the region. There is a great need for epidemiological studies exploring the true burden of CKDu and unique geographical distribution, and the role of environmental factors in the development of CKD/CKDu.

Proteomic insights into the pathophysiology of hypertension-associated albuminuria: Pilot study in a South African cohort

BACKGROUND

Hypertension is an important public health priority with a high prevalence in Africa. It is also an independent risk factor for kidney outcomes. We aimed to identify potential proteins and pathways involved in hypertension-associated albuminuria by assessing urinary proteomic profiles in black South African participants with combined hypertension and albuminuria compared to those who have neither condition.

METHODS

The study included 24 South African cases with both hypertension and albuminuria and 49 control participants who had neither condition. Protein was extracted from urine samples and analysed using ultra-high-performance liquid chromatography coupled with mass spectrometry. Data were generated using data-independent acquisition (DIA) and processed using Spectronaut™ 15. Statistical and functional data annotation were performed on Perseus and Cytoscape to identify and annotate differentially abundant proteins. Machine learning was applied to the dataset using the OmicLearn platform.

RESULTS

Overall, a mean of 1,225 and 915 proteins were quantified in the control and case groups, respectively. Three hundred and thirty-two differentially abundant proteins were constructed into a network. Pathways associated with these differentially abundant proteins included the immune system (q-value [false discovery rate] = 1.4 × 10- 45), innate immune system (q = 1.1 × 10- 32), extracellular matrix (ECM) organisation (q = 0.03) and activation of matrix metalloproteinases (q = 0.04). Proteins with high disease scores (76-100% confidence) for both hypertension and chronic kidney disease included angiotensinogen (AGT), albumin (ALB), apolipoprotein L1 (APOL1), and uromodulin (UMOD). A machine learning approach was able to identify a set of 20 proteins, differentiating between cases and controls.

CONCLUSIONS

The urinary proteomic data combined with the machine learning approach was able to classify disease status and identify proteins and pathways associated with hypertension-associated albuminuria.