Abstract
Abstract Background and Aims The common etiologies of CKD are diabetes, hypertension and glomerulonephritis. Prevalence of CKD of unknown (CKDu) etiology is being increasingly considered as an emerging etiology, especially in the developing countries, with environmental predisposition to hot humid climate, dehydration and toxic metal contaminations. The aim was to identify the frequency of CKDu as an etiology in a rural population with environmental exposure. Method In this observational study subjects were selected from a geographically defined rural population in Bangladesh. Baseline information was recorded by the translated WHO STEP wise approach surveillance- Instrument v.3.1 (Core and Expanded). Blood Pressure was measured by digital blood pressure monitor. Serum creatinine was measured by enzymatic method using assays traceable to isotope dilution mass spectrometry (IDMS). A fasting blood sample and spot urine was collected. BP ≥140/90mmHg; FBS > 5.6 mmol/l and HbA1c ≥6.5%; and eGFR< 60ml/min (CKD-EPI equation) or urine ACR > 30mg/g was taken as diagnostic cut-offs for hypertension, diabetes and nephropathy respectively. From diagnosed CKD patients CKDu group was further identified by stepwise approach of WHO criteria as suspected and probable stages. Results The mean age was 41.3 ± 12.7 years with male/female ratio 37/63 in preliminary 303 study subjects. They were 12.5% diabetic, 21% hypertensive and 75% had some form of dyslipidemia. Among all 51 subjects (16.8%) were diagnosed as CKD based on single measurement of eGFR and ACR. Of these 30 study subjects (58%) met the criteria of suspected CKDu. After repeat measures of eGFR and ACR at 3 months, prevalence of CKD came down to 10.2% persisting in 31 subjects (G1:5.3%, G2:2.3% and G3: 2.6%). Of these 7 study subjects (23%) met the criteria of probable CKDu. The main etiologies of CKD among these subjects were diabetic nephropathy (48%) followed by CKDu. The frequency of CKDu in total study population as a whole was 2.3%.The pattern of environmental exposures like types of farming, use of pesticide-fertilizer, NSAIDs intakes, water sources, amount of drinking water per day, duration of work under direct sun, pattern of fish-meat intakes, etc. were not different between subjects with CKDu versus the others. Conclusion The prevalence of chronic kidney disease in a rural area of Bangladesh is one in ten (10.2%). Among these nearly one-fourth (23%) of the subjects belonged to probable CKDu category. This alarmingly high frequency of CKDu needs further extensive evaluation to identify the predisposing factors responsible.