A Systematic Study of the Prevalence and Risk Factors of CKD in Uddanam, India

Abstract

Introduction: Despite reports of a high prevalence of chronic kidney disease (CKD) from the coastal Uddanam region of Andhra Pradesh, India, there are no accurate data on the distribution of kidney function abnormalities and CKD risk factors in this region.

Methods: A total of 2419 participants were recruited through multistage cluster random sampling from 67 villages. Serum creatinine and urine protein creatinine ratio were measured using validated methodologies. All abnormal estimated glomerular filtration rate (eGFR) and urine protein creatinine ratio values were reconfirmed after 3 months. A range of sociodemographic factors were evaluated for their association with CKD using Poisson regression.

Results: Of 2402 eligible subjects (mean ± SD age, 45.67 ± 13.29 years; 51% female), 506 (21.07%) had CKD (mean ± SD age, 51.79 ± 13.12 years; 41.3% female). A total of 246 (10.24%) had eGFR <60 ml/min/1.73 m², whereas 371 (15.45%) had an elevated urine protein creatinine ratio (>0.15 g/g). The poststratified estimates, adjusted for age and sex distribution of the region for CKD prevalence, are 18.7% (range, 16.4%-21.0%) overall and 21.3% (range, 18.2%-24.4% ) and 16.2% (range, 13.7%-18.8%) in men and women, respectively. Older age, male sex, tobacco use, hypertension, and family history of CKD were independently associated with CKD. Compared with those with higher eGFR, those with eGFR <60 ml/min/1.73m² were older, were more likely to be uneducated, manual laborers/farmers, or tobacco users, and were more likely to have hypertension, a family history of CKD, a diagnosis of heart disease, and a lower body mass index. Among those with low eGFR, there was no difference between those with urine protein creatinine ratio <0.15 or >0.15, except a lower frequency of males in the former.

Conclusion: We confirmed the high prevalence of CKD in the adult population of Uddanam. The cause was not apparent in a majority. Subjects with a low eGFR with or without elevated proteinuria were phenotypically distinct from those with proteinuria and preserved eGFR. Our data suggest the need to apply a population-based approach to screening and prevention and studies to understand the causes of CKD in this region.

Keywords: CKD of unknown etiology; Uddanam; chronic kidney disease; hypertension; proteinuria; risk factors.

Graphical abstract

Figure 1

Flow of subjects through the Study to Test and Operationalize Preventive approaches for CKD of uncertain etiology study. ∗Confirmed CKD includes those with abnormal values plus deaths due to CKD plus patients on dialysis. CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; IHD, ischemic heart disease; uPCR, urine protein creatinine ratio.

Figure 2

Distribution of estimated glomerular filtration rate and urine protein creatinine ratio in the study population.

Figure 3

Prevalence of chronic kidney disease across mandals, by sex. The darker shaded areas indicate chronic kidney disease not associated with diabetes and longstanding hypertension.

Figure 4

Chronic kidney disease classification as per Kidney Disease: Improving Global Outcomes risk categories in the population. eGFR, estimated glomerular filtration rate.