Estimated Prevalence Of Chronic Kidney Disease Research Articles

Worldwide growing epidemic of CKD: fact or fiction?

Chronic kidney disease (CKD) is recognized as a major noncommunicable disease of growing epidemic dimension worldwide. However, recent surveys have shown a marked heterogeneity of CKD prevalence in the general population, from ∼5% to 13% across countries. Methodological issues, genetic diversity, and dietary factors may all play a role. An important, currently emerging aspect of CKD epidemiology is the variability of CKD trends over time, with some countries showing a stable or even a decreased prevalence.

Exploration of chronic kidney disease prevalence estimates using new measures of kidney function in the health survey for England.

BackgroundChronic kidney disease (CKD) diagnosis relies on glomerular filtration rate (eGFR) estimation, traditionally using the creatinine-based Modification of Diet in Renal Disease (MDRD) equation. The Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) equation performs better in estimating eGFR and predicting mortality and CKD progression risk. Cystatin C is an alternative glomerular filtration marker less influenced by muscle mass. CKD risk stratification is improved by combining creatinine eGFR with cystatin C and urinary albumin to creatinine ratio (uACR). We aimed to identify the impact of introducing CKDEPI and cystatin C on the estimated prevalence and risk stratification of CKD in England and to describe prevalence and associations of cystatin C.Methods and FindingsCross sectional study of 5799 people in the nationally representative 2009 and 2010 Health Surveys for England. Primary outcome measures: prevalence of MDRD, CKDEPI and cystatin C-defined eGFR<60ml/min/1.73m2; prevalence of CKD biomarker combinations (creatinine, cystatin C, uACR). Using CKDEPI instead of MDRD reduced the prevalence of eGFR<60ml/min/1.73m2 from 6.0% (95% CI 5.4–6.6%) to 5.2% (4.7–5.8%) equivalent to around 340,000 fewer individuals in England. Those reclassified as not having CKD evidenced a lower risk profile. Prevalence of cystatin C eGFR<60ml/min/1.73m2 was 7.7% and independently associated with age, lack of qualifications, being an ex-smoker, BMI, hypertension, and albuminuria. Measuring cystatin C in the 3.9% people with CKDEPI-defined eGFR<60ml/min/1.73m2 without albuminuria (CKD Category G3a A1) reclassified about a third into a lower risk group with one of three biomarkers and two thirds into a group with two of three. Measuring cystatin C in the 6.7% people with CKDEPI eGFR >60ml/min/1.73m2 with albuminuria (CKD Category G1-2) reclassified almost a tenth into a higher risk group.LimitationsCross sectional study, single eGFR measure, no measured (‘true’) GFR.ConclusionsIntroducing the CKDEPI equation and targeted cystatin C measurement reduces estimated CKD prevalence and improves risk stratification.

Chronic kidney disease in lithium-treated older adults: a review of epidemiology, mechanisms, and implications for the treatment of late-life mood disorders.

Lithium is an important medication in the treatment of mood disorders. However, clinicians are hesitant to use lithium in older adults for fear of its medical effects, particularly kidney disease. This review describes the current understanding of the epidemiology and mechanisms underlying chronic kidney disease (CKD) in older lithium users, with recommendations for using lithium safely in late life. Prevalence estimates of CKD in older lithium users range from 42-50%, which does not differ greatly from the 37.8% rates seen in community-dwelling non-lithium using, non-psychiatric populations. Clinical and pre-clinical data suggest a variety of synergistic mechanisms contributing to CKD in older lithium users, including aging, cardiovascular factors, oxidative stress, inflammation, nephrogenic diabetes insipidus, acute kidney injury, and medication interactions. With regards to CKD, lithium can be used safely in many older adults with mood disorders. Compared to patients with pre-existing CKD, those with an estimated glomerular filtration rate >60 mL/min/1.73 m(2) are probably not as susceptible to lithium-associated renal decline. Using lithium concentrations <0.8 mmol/L; monitoring lithium concentrations and renal function every 3-6 months; being vigilant about concurrent medication use (e.g., diuretics, anti-inflammatories); as well as preventing/treating acute kidney injury, nephrogenic diabetes insipidus, diabetes mellitus, hypertension, smoking, and coronary artery disease can all help prevent CKD and further renal decline in older lithium users.

Chronic kidney disease in US adults with type 2 diabetes: an updated national estimate of prevalence based on Kidney Disease: Improving Global Outcomes (KDIGO) staging.

BackgroundKidney Disease Improving Global Outcomes (KDIGO) 2013 updated the classification and risk stratification of chronic kidney disease (CKD) to include both the level of renal function and urinary albumin excretion (UAE). The update subclassifies the previous category of moderate renal impairment. There is currently limited information on the prevalence of CKD based on this new classification in United States (US) adults with type 2 diabetes mellitus (T2DM). The objective of this study was to provide such estimates, for T2DM both overall and in those ≥ 65 years of age. We used the continuous National Health and Nutrition Examination Survey (NHANES) 1999–2012 to identify participants with T2DM. Estimated glomerular filtration rate (eGFR) and UAE were calculated using laboratory results and data collected from the surveys, and categorized based on the KDIGO classification. Projections for the US T2DM population were based on NHANES sampling weights.ResultsA total of 2915 adults diagnosed with T2DM were identified from NHANES, with 1466 being age ≥ 65 years. Prevalence of CKD based on either eGFR or UAE was 43.5% in the T2DM population overall, and 61.0% in those age ≥ 65 years. The prevalence of mildly decreased renal function or worse (eGFR < 60/ml/min/1.73 m2) was 22.0% overall and 43.1% in those age ≥ 65 years. Prevalence of more severe renal impairment (eGFR < 45 ml/min/1.73 m2) was 9.0% overall and 18.6% in those age ≥ 65 years. The prevalence of elevated UAE (> 30 mg/g) was 32.2% overall and 39.1% in those age ≥ 65 years. The most common comorbidities were hypertension, retinopathy, coronary heart disease, myocardial infarction, and congestive heart failure.ConclusionsThis study confirms the high prevalence of CKD in T2DM, impacting 43.5% of this population. Additionally, this study is among the first to report US prevalence estimates of CKD based on the new KDIGO CKD staging system.

Estimating Prevalence of CKD Stages 3-5 Using Health System Data

The feasibility of using health system data to estimate prevalence of chronic kidney disease (CKD) stages 3-5 was explored. Cohort study. A 5% national random sample of patients from the Veterans Affairs (VA) health care system, enrollees in a managed care plan in Michigan (M-CARE), and participants from the 2005-2006 National Health and Nutrition Examination Survey (NHANES). Observed CKD prevalence estimates in the health system population were calculated as patients with an available outpatient serum creatinine measurement with estimated glomerular filtration rate <60 mL/min/1.73 m(2), among those with at least one outpatient visit during the year. A logistic regression model was fitted using data from the 2005-2006 NHANES to predict CKD prevalence in those untested for serum creatinine in the health system population, adjusted for demographics and comorbid conditions. Model results then were combined with the observed prevalence in tested patients to derive an overall predicted prevalence of CKD within the health systems. Patients in the VA system were older, had more comorbid conditions, and were more likely to be tested for serum creatinine than those in the M-CARE system. Observed prevalences of CKD stages 3-5 were 15.6% and 0.9% in the VA and M-CARE systems, respectively. Using data from NHANES, the overall predicted prevalences of CKD were 20.4% and 1.6% in the VA and M-CARE systems, respectively. Health system data quality was limited by missing data for laboratory results and race. A single estimated glomerular filtration rate value was used to define CKD, rather than persistence over 3 months. Estimation of CKD prevalence within health care systems is feasible, but discrepancies between observed and predicted prevalences suggest that this approach is dependent on data availability and quality of information for comorbid conditions, as well as the frequency of testing for CKD in the health care system.

Age, eGFR, and CKD Complications

Age, eGFR, and CKD Complications

Estimating glomerular filtration rate: comparison of the CKD-EPI and MDRD equations in a large UK cohort with particular emphasis on the effect of age

The chronic kidney disease (CKD)-Epidemiology Collaboration (CKD-EPI) equation was developed to address the underestimation of measured glomerular filtration rate (GFR) by the Modification of Diet in Renal Disease (MDRD) equation at levels >60 mL/min/1.73 m(2). To assess the impact of the CKD-EPI equation on the estimation of GFR in a large adult UK population (n = 561,400), particularly looking at the effect of age. Serum creatinine results (ID-MS-aligned enzymatic assay) were extracted from the pathology database during 1 year on adult (≥ 18 years) patients from primary care. The first available creatinine result from 174,448 people was used to estimate GFR using both equations and agreement assessed. Median CKD-EPI GFR was significantly higher than median MDRD GFR (82 vs. 76 mL/min/1.73 m(2), P < 0.0001). Overall mean bias between CKD-EPI and MDRD GFR was 5.0%, ranging from 13.0% in the 18-29 years age group down to -7.5% in those aged ≥ 90 years. Although statistically significant at all age groups the difference diminished with age and the agreement in GFR category assignment increased. Age-adjusted population prevalence of CKD Stages 3-5 was lower by CKD-EPI than by MDRD (4.4% vs. 4.9%). CKD-EPI produces higher GFR and lower CKD estimates, particularly among 18-59 year age groups with MDRD estimated GFRs of 45-59 mL/min/1.73 m(2) (Stage 3A). However, at ages >70 years there is very little difference between the equations, and among the very elderly CKD-EPI may actually increase CKD prevalence estimates.

Single Estimated Glomerular Filtration Rate and Albuminuria Measurement Substantially Overestimates Prevalence of Chronic Kidney Disease

Background/Aims: Guidelines require repeatedly diminished estimated glomerular filtration rate (eGFR) and/or albuminuria to diagnose chronic kidney disease (CKD), and advise screening only in select populations. Many estimates of CKD prevalence have used single measurements. This longitudinal study assessed eGFR and albuminuria reproducibility, and impact on estimate of CKD prevalence, in factory workers. Methods: A total of 512 white workers in a Belarusian industrial factory were initially tested, identifying 206 with abnormal (eGFR <59 ml/min/1.73 m² or albuminuria) or near-abnormal (eGFR up to 1 SD above abnormal) renal function. At 3 months, 142 of the abnormal/near-abnormal cohort were re-tested. Results: Analysis of repeat samples revealed no significant change in eGFR in this population, however 21% individually changed CKD stage. Initial proteinuria was reproducible in only 48% at 3 months. This had a major impact on estimated CKD prevalence: a point prevalence of 8.2% halved with repeat testing. The predictive value of initially abnormal eGFR or albuminuria for repeat abnormality at 3 months was 0.5. Conclusion: Non-targeted screening for CKD is inaccurate and can overestimate prevalence. This study emphasises the importance of confirming abnormal eGFR and proteinuria on at least one further sample 3 months apart before categorising the individual as having CKD. This has wide implications for screening in European general populations.

Estimating glomerular filtration rate in a population-based study

Glomerular filtration rate (GFR)-estimating equations are used to determine the prevalence of chronic kidney disease (CKD) in population-based studies. However, it has been suggested that since the commonly used GFR equations were originally developed from samples of patients with CKD, they underestimate GFR in healthy populations. Few studies have made side-by-side comparisons of the effect of various estimating equations on the prevalence estimates of CKD in a general population sample. We examined a population-based sample comprising adults from Wisconsin (age, 43-86 years; 56% women). We compared the prevalence of CKD, defined as a GFR of <60 mL/min per 1.73 m(2) estimated from serum creatinine, by applying various commonly used equations including the modification of diet in renal disease (MDRD) equation, Cockcroft-Gault (CG) equation, and the Mayo equation. We compared the performance of these equations against the CKD definition of cystatin C >1.23 mg/L. We found that the prevalence of CKD varied widely among different GFR equations. Although the prevalence of CKD was 17.2% with the MDRD equation and 16.5% with the CG equation, it was only 4.8% with the Mayo equation. Only 24% of those identified to have GFR in the range of 50-59 mL/min per 1.73 m(2) by the MDRD equation had cystatin C levels >1.23 mg/L; their mean cystatin C level was only 1 mg/L (interquartile range, 0.9-1.2 mg/L). This finding was similar for the CG equation. For the Mayo equation, 62.8% of those patients with GFR in the range of 50-59 mL/min per 1.73 m(2) had cystatin C levels >1.23 mg/L; their mean cystatin C level was 1.3 mg/L (interquartile range, 1.2-1.5 mg/L). The MDRD and CG equations showed a false-positive rate of >10%. We found that the MDRD and CG equations, the current standard to estimate GFR, appeared to overestimate the prevalence of CKD in a general population sample.

Epidemiology of Chronic Kidney Disease Among Normotensives

Among adults in the United States, 1 in 4 has hypertension and 1 in 8 has chronic kidney disease (CKD). Although the relationship between hypertension and CKD has been recognized for several hundred years, the prevalence of CKD among patients with normal blood pressure has not been assessed in randomly sampled populations. Crews et al1 in this issue of Hypertension are the first to report such estimates: 13.4% of people who have normal blood pressure have CKD. Among those with prehypertension, the prevalence is 17.3%; among those with undiagnosed hypertension, the prevalence is 22.0%; and among those with diagnosed hypertension, the prevalence is 27.4%. The magnitude of these CKD prevalence estimates is astounding and may even be misleading unless placed in appropriate context. The awareness of CKD diagnosis was dismal: <10% of people were aware of CKD regardless of hypertension category. A thorough analysis of the definition of CKD is necessary to understand how the varying definitions of CKD may have influenced both the prevalence and awareness estimates. The prevalence estimates may be inflated because of CKD that is so mild that it may not be considered a disease at all. For example, examination of the Figure (derived from Table 3 of the article) shows that if one considers the prevalence of more severe CKD defined as macroalbuminuria or estimated glomerular filtration rate (GFR) <45 mL/min per 1.73 m2, then the prevalence estimates fall dramatically. These stricter definitions of CKD yield the following prevalence estimates of CKD: normal blood pressure 0.5%; prehypertension 1.0%; undiagnosed hypertension 2.0%; and <5.0% prevalence of CKD among those with diagnosed hypertension. These prevalence estimates are much lower than those obtained with the more sensitive definition that is typically used to define CKD. Thus, the prevalence estimates of CKD may be driven up …

GFR estimating equations, CKD prevalence and the public health

GFR estimating equations, CKD prevalence and the public health

A Health Policy Model of CKD: 1. Model Construction, Assumptions, and Validation of Health Consequences

A cost-effectiveness model that accurately represents disease progression, outcomes, and associated costs is necessary to evaluate the cost-effectiveness of interventions for chronic kidney disease (CKD). We developed a microsimulation model of the incidence, progression, and treatment of CKD. The model was validated by comparing its predictions with survey and epidemiologic data sources. US patients. The model follows up disease progression in a cohort of simulated patients aged 30 until age 90 years or death. The model consists of 7 mutually exclusive states representing no CKD, 5 stages of CKD, and death. Progression through the stages is governed by a person's glomerular filtration rate and albuminuria status. Diabetes, hypertension, and other risk factors influence CKD and the development of CKD complications in the model. Costs are evaluated from the health care system perspective. Usual care, including incidental screening for persons with diabetes or hypertension. Progression to CKD stages, complications, and mortality. The model provides reasonably accurate estimates of CKD prevalence by stage. The model predicts that 47.1% of 30-year-olds will develop CKD during their lifetime, with 1.7%, 6.9%, 27.3%, 6.9%, and 4.4% ending at stages 1-5, respectively. Approximately 11% of persons who reach stage 3 will eventually progress to stage 5. The model also predicts that 3.7% of persons will develop end-stage renal disease compared with an estimate of 3.0% based on current end-stage renal disease lifetime incidence. The model synthesizes data from multiple sources rather than a single source and relies on explicit assumptions about progression. The model does not include acute kidney failure. The model is well validated and can be used to evaluate the cost-effectiveness of CKD interventions. The model also can be updated as better data for CKD progression become available.

Referral patterns to renal services: what has changed in the past 4 years?

Awareness of chronic kidney disease (CKD) has been prompted by the publication of several large epidemiological studies since 2002. This has led to various initiatives for the early identification and management of CKD, including the introduction of automated glomerular filtration rate (GFR) reporting and renal indicators in the primary care quality and outcomes framework (QOF) since April 2006. These initiatives were intended to promote identification of CKD and have had an impact on referral patterns to renal services. The aim of this study was to understand the nature of this impact in a catchment population of 1.2 million people. Data were collected and recorded from all written referrals from primary care between 1 April 2004 and 31 March 2008. Referral patterns for each postcode sector were mapped using Microsoft MapPoint 2004. The effect of chance on referral patterns was modelled by using small area analysis techniques. The association between the CKD prevalence reported from QOF data and the estimated CKD prevalence was examined at post-code district level. There were 1461 referrals in 2 years prior to the introduction of the initiatives and 2890 referrals in the 2 years post-introduction. The main reason for referral in both groups was impaired renal function or previously established renal disease. Reported comorbidity was similar between the groups. Mapping showed that there was wide heterogeneity in referral behaviour in the first 2 years of the study, which was less in the second period. Small area analysis suggested that the variation that led to the extremal quotients observed in both of the study periods was not due to random variation in referral pattern alone. There was no correlation between the reported CKD prevalence and the referral rates. Referral patterns have changed between 1 April 2004 and 31 March 2008. The main findings were an increase in referral rate and in the age at referral without a significant change in reported comorbidity of the people referred. The main increase in referral rates was seen in more advanced CKD suggesting more targeted referral of patients with CKD to renal services.

Differential Estimation of CKD Using Creatinine- Versus Cystatin C–Based Estimating Equations by Category of Body Mass Index

Backgound Adiposity is associated with cystatin C. Cystatin C–based glomerular filtration rate (GFR) equations may result in overestimation of chronic kidney disease (CKD) prevalence at greater body mass index (BMI) levels. Study Design Cross-sectional. Setting & Participants 6,709 US adult Third National Health and Nutrition Examination Survey participants. Factor BMI. Outcome Absolute percentage of difference in prevalence of stage 3 or 4 CKD between creatinine- and cystatin C–based estimating equations by level of BMI. Measurements Normal weight, overweight, and obesity were defined as BMI of 18.5 to less than 25.0, 25 to less than 30.0, and 30 kg/m2 or greater, respectively. Stage 3 or 4 CKD (estimated glomerular filtration rate [eGFR], 15 to 59 mL/min/1.73 m2) was defined using the 4-variable creatinine-based Modification of Diet in Renal Disease Study equation (eGFRMDRD); cystatin C level, age, sex, and race equation (eGFRCysC,age,sex,race); cystatin C–only equation (eGFRCysC); cystatin C level of 1.12 mg/L or greater (increased cystatin C); and an equation incorporating serum creatinine level, cystatin C level, age, sex, and race (eGFRCr,CysC,age,sex,race). Results Differences in stage 3 or 4 CKD prevalence estimates between eGFRCysC,age,sex,race, eGFRCysC, and increased cystatin C, separately, and eGFRMDRD were greater at higher BMI levels. Specifically, compared with estimates derived using eGFRMDRD for normal-weight, overweight, and obese participants, estimated prevalences of stage 3 or 4 CKD were 2.1%, 3.0%, and 6.5% greater when estimated by using eGFRCysC,age,sex,race (P trend = 0.005); 0.1%, 0.6%, and 2.2% greater for eGFRCysC (P trend = 0.03); 2.9%, 5.2%, and 9.5% greater for increased cystatin C (P trend < 0.001); and −0.1%, −0.4%, and 0.0% greater for eGFRCr,CysC,age,sex,race, respectively (P trend = 0.7). Limitations No gold-standard measure of GFR was available. Conclusions BMI may influence the estimated prevalence of stage 3 or 4 CKD when cystatin C–based equations are used. Adiposity is associated with cystatin C. Cystatin C–based glomerular filtration rate (GFR) equations may result in overestimation of chronic kidney disease (CKD) prevalence at greater body mass index (BMI) levels. Cross-sectional. 6,709 US adult Third National Health and Nutrition Examination Survey participants. BMI. Absolute percentage of difference in prevalence of stage 3 or 4 CKD between creatinine- and cystatin C–based estimating equations by level of BMI. Normal weight, overweight, and obesity were defined as BMI of 18.5 to less than 25.0, 25 to less than 30.0, and 30 kg/m2 or greater, respectively. Stage 3 or 4 CKD (estimated glomerular filtration rate [eGFR], 15 to 59 mL/min/1.73 m2) was defined using the 4-variable creatinine-based Modification of Diet in Renal Disease Study equation (eGFRMDRD); cystatin C level, age, sex, and race equation (eGFRCysC,age,sex,race); cystatin C–only equation (eGFRCysC); cystatin C level of 1.12 mg/L or greater (increased cystatin C); and an equation incorporating serum creatinine level, cystatin C level, age, sex, and race (eGFRCr,CysC,age,sex,race). Differences in stage 3 or 4 CKD prevalence estimates between eGFRCysC,age,sex,race, eGFRCysC, and increased cystatin C, separately, and eGFRMDRD were greater at higher BMI levels. Specifically, compared with estimates derived using eGFRMDRD for normal-weight, overweight, and obese participants, estimated prevalences of stage 3 or 4 CKD were 2.1%, 3.0%, and 6.5% greater when estimated by using eGFRCysC,age,sex,race (P trend = 0.005); 0.1%, 0.6%, and 2.2% greater for eGFRCysC (P trend = 0.03); 2.9%, 5.2%, and 9.5% greater for increased cystatin C (P trend < 0.001); and −0.1%, −0.4%, and 0.0% greater for eGFRCr,CysC,age,sex,race, respectively (P trend = 0.7). No gold-standard measure of GFR was available. BMI may influence the estimated prevalence of stage 3 or 4 CKD when cystatin C–based equations are used.

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

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.

Chronic Kidney Disease Prevalence Estimates among Racial/Ethnic Groups

Muscle mass is not a major determinant of serum cystatin C levels, and its use to estimate GFR may lead to more congruent estimates of chronic kidney disease (CKD) across gender and racial/ethnic groups. The Multi-Ethnic Study of Atherosclerosis is a population-based study of 6814 men and women who are aged 45 to 85 yr and do not have clinical cardiovascular disease. Estimated CKD prevalence, defined as an estimated GFR <60 ml/min per 1.73 m(2) body surface area, was compared using three different GFR prediction equations: The abbreviated Modification of Diet in Renal Disease (MDRD) equation and two equations based on serum cystatin C. Among women, CKD prevalence estimates across the four racial/ethnic groups using the MDRD- or the cystatin C-based GFR equations, which include gender and race coefficients, varied by approximately two-fold (P < 0.0001) but were more congruent with use of a serum cystatin C-based equation without the use of coefficients (P = 0.3). CKD prevalence estimates did not differ significantly across racial/ethnic groups among men with the MDRD (P = 0.07) or cystatin C formula without coefficients (P = 0.05) but did differ significantly with the cystatin C formula, which incorporates gender and race coefficients (P = 0.006). CKD prevalence estimates vary across racial/ethnic groups, and the degree of variability depends on the method used to estimate GFR, especially among women. Further research is needed to determine the accuracy and precision of GFR prediction equations in racially diverse populations.