Prevalence of low glomerular filtration rate, proteinuria and associated risk factors in North India using Cockcroft-Gault and Modification of Diet in Renal Disease equation: an observational, cross-sectional study

Abstract

BackgroundChronic kidney disease (CKD) is increasingly being recognized as an emerging public health problem in India. However, community based estimates of low glomerular filtration rate (GFR) and proteinuria are few. Validity of traditional serum creatinine based GFR estimating equations in South Asian subjects is also debatable. We intended to estimate and compare the prevalence of low GFR, proteinuria and associated risk factors in North India using Cockcroft-Gault (CG) and Modification of Diet In Renal Disease (MDRD) equation.MethodsA community based, cross-sectional study involving multistage random cluster sampling was done in Delhi and its surrounding regions. Adults ≥ 20 years were surveyed. CG and MDRD equations were used to estimate GFR (eGFR). Low GFR was defined as eGFR < 60 ml/min/1.73 m2. Proteinuria (≥ 1+) was assessed using visually read dipsticks. Odds ratios, crude and adjusted, were calculated to ascertain associations between renal impairment, proteinuria and risk factors.ResultsThe study population had 3,155 males and 2,097 females. The mean age for low eGFR subjects was 54 years. The unstandardized prevalence of low eGFR was 13.3% by CG equation and 4.2% by MDRD equation. The prevalence estimates of MDRD equation were lower across gender and age groups when compared with CG equation estimates. There was a strong correlation but poor agreement between GFR estimates of two equations. The survey population had a 2.25% prevalence of proteinuria. In a multivariate logistic regression analysis; age above 60 years, female gender, low educational status, increased waist circumference, hypertension and diabetes were associated with low eGFR. Similar factors were also associated with proteinuria. Only 3.3% of subjects with renal impairment were aware of their disease.ConclusionThe prevalence of low eGFR in North India is probably higher than previous estimates. There is a significant difference between GFR estimates derived from CG and MDRD equations. These equations may not be useful in epidemiological research. GFR estimating equations validated for South Asian populations are needed before reliable estimates of CKD prevalence can be obtained. Till then, primary prevention and management targeted at CKD risk factors must play a critical role in controlling rising CKD magnitude. Cost-benefit analysis of targeted screening programs is needed.

Screening of a Population at Risk of Chronic Kidney Disease: Analysis of Factors Associated with Low eGFR and Microalbuminuria

“…Almost one half of them had at least one of the three markers: 25% had only MAU and/or proteinuria but not diminished eGFR, while 21% had eGFR below 60 mL/min/1.73 m 2 -14% without MAU and proteinuria and 7% with MAU and/or proteinuria. These results cannot be compared with those obtained in several massive screenings carried out in the general population where the prevalence of GFR below 60 mL/min/1.73 m 2 was between 3.2 and 11.2% 2,11,17,26,27 and albuminuria between 2.4 and 15.6%. 2,11,[26][27][28][29] The almost twice as high prevalence of CKD markers found here, where three groups of patients at increased risk of CKD were involved, is comparable to values determined in studies that also targeted different at-risk populations.…”

“…Age, hypertension, and diabetes were reported as significant variables associated with reduced eGFR in both developed 2,11,37 and developing countries. 17,26,27 The lack of diabetes as a significant predictor of reduced eGFR in our study might be partly explained by the low proportion of diabetics included. As already mentioned, most patients with diabetes are not monitored by the general practitioners who recruited patients for our screening study but in special advice centers for diabetics.…”

“…In addition to age, hypertension, and diabetes, a high BMI 2,26 and obesity 17,27 were reported as significant predictors of reduced eGFR. That was not found here, although the prevalence of overweight and obese persons was at a similar level.…”

Underestimation of Impaired Kidney Function with Serum Creatinine

“…Our study is in harmony with Duncan et al [8] study reported that (13.9%) patients had misplaced with SCr concentration method. Yet another Indian study also forwarded similar results [11]. For this study, we chose a cut-off for abnormal renal function of \60 ml/min to reduce the likelihood of elderly patients being erroneously classified has having abnormal renal function.…”

Does angiotensin-converting enzyme-1 (ACE-1) gene polymorphism lead to chronic kidney disease among hypertensive patients?

“…But, our study showed that subjects having DD genotype were at 1.42 times higher risk for the progression of chronic kidney disease as compared with II genotype, but it was not found statistically significant. In a study by Singh et al 18 , estimated and compared the prevalence of low Glomerular Filtration Rate (GFR), proteinuria and associated risk factors in North India using Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) equation. They found that unstandardized prevalence of low eGFR was 13.3% by CG equation and 4.2% by MDRD equation.…”