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. 2023 Sep 26:10:20543581231199013.
doi: 10.1177/20543581231199013. eCollection 2023.

Prevalence of Chronic Kidney Disease of Uncertain Etiology Within Selected Farming Communities in Rural Sri Lanka

E M D V Ekanayake  1   2 , P Mangala C S De Silva  1 , T D K S C Gunasekara  1 , W A K G Thakshila  1 , S D Gunarathna  1   2 , R A I Pinipa  1 , Sudheera Jayasinghe  3 , E P S Chandana  4 , E S Wijewickrama  5 , Nishad Jayasundara  6
Affiliations

Prevalence of Chronic Kidney Disease of Uncertain Etiology Within Selected Farming Communities in Rural Sri Lanka

E M D V Ekanayake et al. Can J Kidney Health Dis. .

Abstract
in English, French

Background: Chronic kidney disease of uncertain etiology (CKDu) is an emergent health concern, particularly in tropical farming communities in several global hotspots, including Sri Lanka. This particular nephropathy is characterized by a progressive decline in kidney function in the absence of conventional chronic kidney disease (CKD) risk factors such as diabetes mellitus, hypertension, and other identifiable kidney disorders. As it is almost asymptomatic at early stages, CKDu is mostly diagnosed at late stages with significant kidney damage. Hence, the identification of disease susceptibility and vulnerable communities at the earliest possible instances is highly important for the management of the disease.

Objective: We aimed to compare kidney health across three different farming communities in Sri Lanka to identify CKDu susceptibilities.

Methods: A cross-sectional study was performed with three selected farming communities: paddy farmers (PF; N = 581), sugarcane farmers (SF; N = 550), and vegetable farmers (VF; N = 244) in comparison with an age-matched control group of nonfarming (NF; N = 225) individuals. A medical examination was performed to investigate health status and medical history, whereas a urinalysis was performed to determine creatinine and albumin contents. Estimated glomerular filtration rate (eGFR) and urinary albumin-creatinine ratio (ACR) were used for assessment of kidney function. CKDu susceptibility was determined based on eGFR, and urinary ACR adhering to the clinical practice guidelines in Sri Lanka.

Results: The median (interquartile range [IQR]) eGFR levels of PF (85 mL/min/1.73 m2 [72-97]) and SF (93 mL/min/1.73 m2 [73-112]) were significantly lower than that of the NF group (103 mL/min/1.73 m2 [87-125]) (P < .0001), whereas eGFR of VF (100 mL/min/1.73 m2 [80-111]) was not significantly different compared with NF. The median (IQR) urinary ACR levels of the study groups, PF, SF, VF, and NF, were 0.59 (0.26-1.45), 0.46 (0.28-0.88), 0.45 (0.34-0.90), and 0.44 (0.34-1.02) mg/mmol, respectively. However, urinary ACR did not differ significantly across the study groups (P > .05). The prevalence of CKDu within PF (13.60%), SF (12.54%), and VF (6.67%) communities was significantly higher (P < .05) compared with the NF (2.67%). Of the total CKD cases, CKDu susceptible cases represented 73%, 69%, 50%, and 25% in PF, SF, VF, and NF, respectively, indicating a high risk of CKDu susceptibility among farming communities. Moreover, a noteworthy association of CKDu was observed with agrochemical exposure (odds ratio [OR] = 3.11, 95% confidence interval [CI] = 1.36-7.09). Concerning the farming practices, sugarcane farming showed the highest association with CKDu prevalence (OR = 3.40, 95% CI = 1.49-7.78).

Conclusions: Compared with the nonfarming group, a significant risk of CKDu was observed in the three farming communities, particularly among paddy and sugarcane farmers. Longitudinal epidemiological studies to identify vulnerable farming communities and associated risk factors are critically needed to develop effective management strategies against CKDu within farming communities.

Contexte: L’insuffisance rénale chronique d’étiologie incertaine (IRCi) est un problème de santé émergent, en particulier dans les collectivités agricoles de plusieurs régions tropicales dans le monde, dont le Sri Lanka. Cette néphropathie particulière se caractérise par un déclin progressif de la fonction rénale en absence de facteurs de risque classiques de l’IRC comme le diabète, l’hypertension et d’autres troubles rénaux identifiables. L’IRCi étant quasi asymptomatique dans les stades précoces, elle est souvent diagnostiquée à des stades avancés et en présence de lésions rénales importantes. Il serait donc très pertinent d’identifier les populations vulnérables et d’évaluer le plus tôt possible leur prédisposition à l’IRCi, afin de faciliter la prise en charge de la maladie.

Objectif: Notre objectif était de comparer la santé rénale de trois différentes populations agricoles du Sri Lanka afin d’évaluer leur prédisposition à l’IRCi.

Méthodologie: Une étude transversale a été réalisée auprès de trois populations agricoles, soit les cultivateurs de riz (CR; n=581), de canne à sucre (CCS; n=550) et de légumes (CL; n=244). Les groupes étudiés ont été comparés à un groupe témoin d’individus non-agriculteurs (NA; n=225) d’âge similaire. Les sujets se sont soumis à un examen de leur état de santé et leurs antécédents médicaux, ainsi qu’à une analyse d’urine pour déterminer leurs taux urinaires de créatinine et d’albumine. Le débit de filtration glomérulaire estimé (DFGe) et le rapport albumine-créatinine urinaire (RAC) ont servi à évaluer la fonction rénale. La prédisposition à l’IRCi a été établie sur la base du DFGe et du RAC urinaire, conformément aux recommandations de pratique clinique au Sri Lanka.

Résultats: Le DFGe médian (ÉIQ) des CR (85 ml/min/1,73 m2 [72-97]) et des CCS (93 ml/min/1,73 m2 [73-112]) était significativement inférieur à celui du groupe témoin (103 ml/min/1,73 m2 [87-125]) (p < 0.0001); aucune différence significative n’a été observée pour le groupe des CL (100 ml/min/1,73 m2 [80-111]). Le RAC urinaire médian (ÉIQ) s’établissait à 0,59 mg/mmol (0,26-1,45) pour les CR, à 0,46 mg/mmol (0,28-0,88) pour les CCS, à 0,45 mg/mmol (0,34-0,90) pour les CL et à 0,44 mg/mmol (0,34-1,02) pour le groupe témoin; soit aucune différence significative pour le RAC urinaire entre les groupes à l’étude (p > 0.05). La prévalence de l’IRCi dans les populations de CR (13,60 %), de CCS (12,54 %) et de CL (6,67 %) était significativement plus élevée (p < 0.05) que dans le groupe témoin (2,67 %). Sur le total des cas d’IRC, ceux qui montraient une prédisposition à l’IRCi représentaient 73 % (CR), 69 % (CCS), 50 % (CL) et 25 % (NA) des cas d’IRC de chaque groupe, ce qui indique un risque élevé de prédisposition à l’IRCi dans les communautés agricoles. On a en outre observé une association notable entre l’IRCi et l’exposition aux agents agrochimiques (RC : 3,11 [IC 95 % : 1,36-7,09]). En ce qui concerne les différentes pratiques agricoles, la culture de la canne à sucre a montré la plus forte association avec la prévalence d’IRCi (RC : 3,40 [IC 95 % : 1,49-7,78]).

Conclusion: Un risque significativement plus élevé d’IRCi a été observé dans les trois communautés agricoles par rapport au groupe des non-agriculteurs, en particulier chez les cultivateurs de riz et de canne à sucre. Il est essentiel de procéder à des études épidémiologiques longitudinales visant à identifier les communautés agricoles vulnérables et les facteurs de risque associés, afin d’élaborer des stratégies efficaces pour prévenir l’IRCi au sein de ces communautés.

Keywords: CKDu; Sri Lanka; farming communities; kidney diseases.

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Conflict of interest statement

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.
Figure 1.
Epidemiology of chronic kidney diseases, including CKDu, in Sri Lanka. Note. The prevalence is expressed as the number of reported CKD/CKDu patients at Divisional Secretariat levels, where the majority of reported cases are CKDu, as per the analysis by Ranasinghe et al. (2019). Residential areas of the communities that participated in the study (Wasgamuwa, Nuwara Eliya, and Buttala) are represented on the map. CKD = chronic kidney disease; CKDu = chronic kidney disease of uncertain etiology.
Figure 2.
Figure 2.
An overview of the study design and sampling strategy. Note. Study groups: PF = paddy farmers; SF = sugarcane farmers; VF = vegetable farmers; NF = nonfarmers; GND = Grama Niladhari Divisions.*applicable only for the farming groups.
Figure 3.
Figure 3.
Biomarkers of kidney function of the study groups. (a) urinary ACR. (b) eGFR. Note. Graphs illustrate distributions with median and interquartile distance for each study group. Study groups: PF = paddy farmers; SF = sugarcane farmers; VF = vegetable farmers; NF = nonfarmers. ACR = albumin-to-creatinine ratio; eGFR = estimated glomerular filtration rate.
Figure 4.
Figure 4.
Effect of selected risk factors on the likelihood of having suspected CKD and CKDu. Note. The graphs represent the odds ratios with 95% confidence intervals. CKD = chronic kidney disease; CKDu = chronic kidney disease of uncertain etiology; BMI = body mass index.
See this image and copyright information in PMC

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