Prevalence of chronic kidney disease in Kinshasa: results of a pilot study from the Democratic Republic of Congo

BACKGROUND

The burden of chronic kidney disease (CKD) in sub-Saharan Africa is unknown. The aim of this study was to investigate the prevalence and the risk factors associated with CKD in Kinshasa, the capital of the Democratic Republic of Congo (DRC).

METHODS

In a cross-sectional study, 503 adult residents in 10 of the 35 health zones of Kinshasa were studied in a randomly selected sample. Glomerular filtration rate was estimated using the simplified Modification of Diet in Renal Disease Study equation (eGFR) and compared with the Cockcroft-Gault equation for creatinine clearance. The associations between health characteristics, indicators of kidney damage (proteinuria) and kidney function (<60 ml/min/1.73 m(2)) were examined.

RESULTS

The prevalence of all stages of CKD according to K/DOQI guidelines was 12.4% [95% confidence interval (CI), 11.0-15.1%]. By stage, 2% had stage 1 (proteinuria with normal eGFR), 2.4% had stage 2 (proteinuria with an eGFR of 60-89 ml/min/1.73 m(2)), 7.8% had stage 3 (eGFR, 30-59 ml/min/1.73 m(2)) and 0.2% had stage 5 (eGFR < 15 ml/min/1.73 m(2)). Hypertension and age were independently associated with CKD stage 3. The prevalences of major non-communicable diseases considered in this study were 27.6% (95% CI, 25.7-31.3%) for hypertension, 11.7% (95% CI, 10.3-14.4%) for diabetes mellitus and 14.9% (95% CI, 13.3-17.9%) for obesity. Hypertension was also independently associated with proteinuria.

CONCLUSION

More than 10% of the Kinshasa population exhibits signs of CKD, which is affecting adults in their productive years. Risk factors for CKD, including hypertension, diabetes and obesity, are increasing. These alarming data must guide current and future healthcare policies to meet the challenge raised by CKD in this city and hopefully in the whole country.

Mortality risks for all causes and cardiovascular diseases and reduced GFR in a middle-aged working population in Taiwan

BACKGROUND

Effects of decreased estimated glomerular filtration rate (eGFR) on cardiovascular disease (CVD) mortality are uncertain in Chinese general populations.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

17,026 adults 50 years and older in Taiwan. A subset of 7,968 had repeated measurements.

PREDICTOR

Decreased eGFR and its progression. eGFR was calculated from serum creatinine level by using the Modification of Diet in Renal Disease Study equation.

OUTCOMES

Mortality from all causes and CVD, including coronary heart disease (CHD) and stroke, from the National Death Registry.

MEASUREMENTS

Hazard ratios (HRs) and Kaplan-Meier survival curves were calculated for participants with a moderate to severe decrease in eGFR (<60 mL/min/1.73 m(2)) compared with those with normal eGFR (> or =90 mL/min/1.73 m(2)). HR of a rapid decrease (> or =20%) in eGFR was also calculated.

RESULTS

Mean age of all participants was 57.2 +/- 5.2 (SD) years. We observed 1,682 deaths in 15 years of follow-up. Participants with a moderate to severe decrease in eGFR had increased HRs for mortality from all causes (1.44; 95% confidence interval [CI], 1.22 to 1.70), CVD (1.90; 95% CI, 1.36 to 2.65), CHD (2.07; 95% CI, 1.26 to 3.41), and stroke (2.16; 95% CI, 1.29 to 3.62) after adjusting for confounders. Decreased eGFR was associated with ischemic stroke, but not hemorrhagic stroke. No significant interaction between decreased eGFR and anemia, diabetes, or smoking was found. There were 660 participants with a 20% or greater decrease in eGFR from baseline during 18 months of follow-up. They had increased HRs for all causes (1.45; 95% CI, 1.13 to 1.86), CVD (2.48; 95% CI, 1.58 to 3.89), CHD (2.14; 95% CI, 1.07 to 4.29), and stroke (2.79; 95% CI, 1.45 to 5.36) compared with those with less than a 20% decrease in eGFR during the same period.

LIMITATIONS

Data for proteinuria were not available. Creatinine assay was not calibrated.

CONCLUSIONS

A moderate to severe or fast decrease in eGFR was associated with all-cause and CVD mortality in this ethnic Chinese cohort.

Cystatin C improves the diagnosis and stratification of chronic kidney disease, and the estimation of glomerular filtration rate in diabetes

AIMS

Estimation of glomerular filtration rate (GFR) is recommended to diagnose and stratify chronic kidney disease (CKD). Can cystatin-C (cysC) assay improve the results in diabetic patients?

METHODS

In 124 diabetic patients with a wide range of GFR, as determined by 51Cr-EDTA clearance (i-GFR), we estimated 'e-GFR' by: the recommended Cockcroft-Gault (CG) formula and Modification of Diet in Renal Disease (MDRD) study equation; the new Mayo Clinic quadratic (MCQ) equation; the recently proposed composite estimation including both serum creatinine and cysC; and a simplified approach dividing the MDRD by cysC if less than 1.10mg/L.

RESULTS

The highest diagnostic accuracy (receiver operating characteristic [ROC] curves) and the highest proportions of well-stratified patients were obtained by cysC and the MDRD which, however, underestimated i-GFR for patients without CKD (-17%, P<0.001). The CG overestimated GFR in KDOQI stages 1 and 2, ignored stage 5 and was the least accurate. The MCQ equation overrepresented stage 2, overestimating GFR at this stage (+23%, P<0.005). The composite estimation (54.7+/-27.0mL per minute 1.73m(2)) correlated best with i-GFR (56.1+/-35.3; r=0.90, P<0.001), and did not significantly differ from it across the entire population and within each Kidney Disease Outcome Quality Initiative (KDOQI) stage but was also biased (Bland-Altman procedure). Simply dividing the MDRD by cysC ifless than1.10mg/L produced a comparable performance and eliminated the bias.

CONCLUSION

The recommended creatinine-based estimations of GFR need to be improved. CysC assay helps in the diagnosis and stratification of CKD and leads to better estimates of GFR in diabetic patients without any substantial increase in complexity.

Association of kidney function with inflammatory and procoagulant markers in a diverse cohort: a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Prior studies using creatinine-based estimated glomerular filtration rate (eGFR) have found limited associations between kidney function and markers of inflammation. Using eGFR and cystatin C, a novel marker of kidney function, the authors investigated the association of kidney function with multiple biomarkers in a diverse cohort.

METHODS

The Multi-Ethnic Study of Atherosclerosis consists of 6,814 participants of white, African-American, Hispanic, and Chinese descent, enrolled from 2000-2002 from six U.S. communities. Measurements at the enrollment visit included serum creatinine, cystatin C, and six inflammatory and procoagulant biomarkers. Creatinine-based eGFR was estimated using the four-variable Modification of Diet in Renal Disease equation, and chronic kidney disease was defined by an eGFR < 60 mL/min/1.73 m2.

RESULTS

Adjusted partial correlations between cystatin C and all biomarkers were statistically significant: C-reactive protein (r = 0.08), interleukin-6 (r = 0.16), tumor necrosis factor-alpha soluble receptor 1 (TNF-alphaR1; r = 0.75), intercellular adhesion molecule-1 (r = 0.21), fibrinogen (r = 0.14), and factor VIII (r = 0.11; two-sided p < 0.01 for all). In participants without chronic kidney disease, higher creatinine-based eGFR was associated only with higher TNF-alphaR1 levels.

CONCLUSION

In a cohort characterized by ethnic diversity, cystatin C was directly associated with multiple procoagulant and inflammatory markers. Creatinine-based eGFR had similar associations with these biomarkers among subjects with chronic kidney disease.

A comparison of change in measured and estimated glomerular filtration rate in patients with nondiabetic kidney disease

BACKGROUND AND OBJECTIVES

All glomerular filtration rate (GFR) estimating equations have been developed from cross-sectional data. The aims of this study were to examine the concordance between use of measured GFR (mGFR) and estimated GFR (eGFR) in tracking changes in kidney function over time among patients with moderately severe chronic kidney disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective cohort study of subjects who had been enrolled in the MDRD Study A and who had two or more contemporaneous assessments of mGFR and eGFR (n = 542; mGFR range, 25 to 55 ml/min per 1.73 m(2)) during the chronic phase (month 4 and afterwards). mGFR was based on urinary iothalamate clearance; eGFR was based on the 4-variable MDRD Study equation. Temporal changes in GFR were assessed by within-subject linear regression of time on GFR.

RESULTS

Median follow-up time for all subjects was 2.6 yr; median number of GFR measurements was six. The eGFR slope tended to underestimate measured decrements in GFR. The absolute value of the difference in mGFR and eGFR slopes was <or=2 ml/min per 1.73 m(2) per yr among 58.3% of subjects; the remainder of subjects had larger absolute differences. Among the 22 variables studied, none predicted a systematic difference between mGFR slope and eGFR slope.

CONCLUSIONS

Although eGFR and mGFR exhibited similar relationships to 22 baseline variables, the overall bias seen in the full cohort suggests that clinicians and researchers should exercise caution when interpreting eGFR slope as a marker of progression of kidney disease.

Natriuretic peptides in chronic kidney disease

BACKGROUND AND OBJECTIVES

B-type natriuretic peptide (BNP) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP) are biomarkers of cardiovascular disease that is common in patients with chronic kidney disease (CKD). Conflicting data on the influence of glomerular filtration rate (GFR) on BNP and NT-proBNP levels in CKD may stem from failure to account fully for the effects of coexistent cardiac disease, dysfunction, and volume overload.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Prospective head-to-head comparison of plasma BNP and NT-proBNP in ambulatory euvolemic CKD patients with normal LV ejection fraction and no manifest cardiac or vascular disease. GFR was estimated by the Modification of Diet in Renal Disease formula, BNP and NT-proBNP measured using Abbott AxSYM and Roche Elecsys assays, respectively, and cardiac morphology and function assessed by transthoracic echocardiography.

RESULTS

In 142 patients (42% female) of mean age 60 +/- 11 yr, mean left ventricular ejection fraction was 71% +/- 6%, GFR 38 +/- 14 ml/min per 1.73 m(2), and median BNP and NT-proBNP level 59 and 311 pg/ml, respectively. Multivariate predictors of NT-proBNP level were GFR, beta-blocker usage, LV mass index, and hemoglobin level. Plasma BNP was independently predicted by LV mass index and beta-blocker usage but not GFR. In the 74 patients without diastolic dysfunction, there was a significant rise in NT-proBNP but not BNP as GFR declined.

CONCLUSIONS

Unlike NT-proBNP, plasma BNP level is relatively independent of GFR. BNP may therefore be the more appropriate biomarker to screen for cardiac dysfunction in CKD.

Stepwise increase in the prevalence of isolated systolic hypertension with the stages of chronic kidney disease

BACKGROUND

Hypertension is common in patients with chronic kidney disease (CKD), and isolated systolic hypertension (ISH) accounts for most patients with inadequate blood pressure (BP) control. However, it remains unclear whether the prevalence of ISH would increase with the advancement of CKD.

METHODS

CKD patients of stages 3, 4 and 5 were recruited (n = 324). Based on office systolic BP (SBP) and diastolic BP (DBP), they were classified into any of the four hypertensive subtypes: normotension (SBP/DBP <140/90 mmHg), isolated diastolic hypertension (IDH, SBP <140 mmHg and DBP >or=90 mmHg), ISH (SBP >or=140 mmHg and DBP <90 mmHg) and systolic-diastolic hypertension (SDH, SBP/DBP >or=140/90 mmHg).

RESULTS

The control rate was 45.7% at stage 3, which decreased with the advancement of CKD (control rate was 51.9%, 40.4% and 38.6% in stage 3, 4 and 5, respectively; P < 0.05). The prevalence of IDH changed from 5.0% to 5.3% and 0% from stage 3 to 4 and 5, while there was no significant change in the prevalence of SDH (15.0%, 14.9% and 15.7% at stage 3, 4 and 5, respectively). There was a stepwise increase in the prevalence of ISH with the stages of CKD (it was 28.1%, 39.4% and 45.7% in stage 3, 4 and 5, respectively). Logistic regression showed that age and CKD stages [compared with stage 3, stage 4 and 5 had 2.57 (95% CI 1.04-6.33) and 3.68 (95% CI 1.09-12.47) folds higher risk to develop ISH, respectively] were independent predictors of ISH.

CONCLUSION

The prevalence of ISH increased correspondingly with advanced stages of CKD, which may partially contribute to the increased cardiovascular mortality during the progress of CKD.

The metabolic syndrome increases cardiovascular mortality in Taiwanese elderly

BACKGROUND

The prevalence of the metabolic syndrome (MetS) is high among the elderly. However, evidence that mortality increases with MetS is rare. In this study, we investigated the relationship between MetS, cardiovascular disease (CVD) and all cause mortality in the elderly.

MATERIALS AND METHODS

A total 10 547 participants, aged 65 years and older, of baseline cohort were recruited from four nationwide Health Screening Centres in Taiwan from 1998 to 1999. The metabolic syndrome was defined according to the America Heart Association/National Heart Lung Blood Institute definition. Cox proportional hazards regression analyses were used to estimate the relative risks (RRs) of CVD and all cause mortality for those with MetS for up to 8 years of follow-up.

RESULTS

The baseline prevalence of MetS was 50.1% (45.6% in men and 54.4% in women, respectively). A total of 1312 participants died; of these, 300 participants died from CVD. Adjusted for age, gender, smoking, total cholesterol and estimated glomerular filtration rate, the RRs for CVD and all cause mortality among participants with MetS were 1.48 (95% confidence interval = 1.16-1.90) and 1.16 (1.03-1.30), respectively, for participants compared to those without MetS. The mean RRs for CVD, however, ranged from 1.21 to 5.31 among different combinations of MetS components.

CONCLUSION

The elderly with MetS, compared to those without MetS, had a higher CVD and all cause mortality in Taiwan. Furthermore, different combinations of MetS components posed different risks to the mortality, which deserves further research in the future.

Reliability of the MDRD method for estimating glomerular filtration rate in relation to gender, body mass index and extracellular fluid volume

BACKGROUND

The accuracy of estimating glomerular filtration rate from plasma creatinine (eGFR) has been questioned but it is unclear how much covert error in several reference methods that have been used has contributed to this perceived inaccuracy. The aim of the study was to evaluate eGFR in comparison with a second 'gold standard' to test the performance of the primary gold standard and to examine the influence of patient demographics (age, body mass index (BMI), extracellular fluid volume (ECV) and gender).

DESIGN

Non-fasting multisample GFR and ECV were measured in 80 subjects simultaneously and independently with Cr-51-EDTA (GFR(EDTA)) and iohexol (GFR(iohexol)). Percentage bias and imprecision in the prediction of, and disagreement with, GFR(EDTA) were compared between eGFR and GFR(iohexol). Another simplified method for measuring GFR, the slope-only method ((SO)GFR), was also evaluated against multisample GFR (measured with the opposing indicator). Accuracies were assessed in all subjects and across age, BMI and ECV boundaries of 65 y, 29 kg m(-2) and 14 L.

RESULTS

eGFR was less precise than GFR(iohexol) (imprecisions of 22.3% and 12.9%; P < 0.01). The precision of (SO)GFR was intermediate between eGFR and GFR(iohexol). Both GFR(iohexol) and eGFR were less precise in the elderly, the obese and men, but minimally influenced by ECV. (SO)GFR was minimally influenced by subject demographics.

CONCLUSION

Although eGFR does not predict GFR (based on a primary gold standard) as accurately as a second gold standard, a significant component of its poor performance is the result of inaccuracy in the primary gold standard. (SO)GFR measured with Cr-51-EDTA is superior to eGFR.

Antineutrophil cytoplasmic autoantibody-associated vasculitis in older patients

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is increasingly recognized in older patients. The differences in disease presentation and outcome between older and younger patients remain controversial. We conducted the current study to analyze the characteristics of patients aged over 65 years with AAV and to compare the younger and older cohorts. We recruited 234 consecutive Chinese patients with AAV. We compared clinical and pathologic characteristics as well as outcomes between younger and older patients. Among the 234 patients with AAV, 99 were older than 65 years. Compared with the 135 younger patients, the older patients had a significantly higher proportion of positive myeloperoxidase-ANCA (94.9% vs. 80.0%, p < 0.01) and a higher proportion of microscopic polyangiitis (79.8% vs. 50.4%, chi = 11.8, p < 0.001), but had a lower proportion of Wegener granulomatosis (18.2% vs. 37.8%, p < 0.01) and renal-limited vasculitis (0% vs. 11.1%, p < 0.001).Older patients had more prevalent and severe pulmonary involvement than younger patients, including pulmonary infiltration, interstitial fibrosis, and mechanical ventilation dependence at presentation (47.5% vs. 31.9%, p < 0.05; 37.4% vs. 18.5%, p < 0.01; and 9.1% vs. 1.5%, p < 0.05, respectively). Older patients were less likely to respond to treatment (p < 0.01) and had worse survival than younger patients (p = 0.000). During follow-up, older patients had a higher risk of secondary pulmonary infection (p < 0.001), and those with pulmonary interstitial fibrosis were more likely to develop secondary pulmonary infections (p < 0.05). In conclusion, compared with younger patients, older patients with AAV had more severe and more prevalent pulmonary lesions, which might contribute to subsequent pulmonary infections after the initiation of immunosuppressive therapy. Age and pulmonary infection were independent predictors of death.

Chronic kidney disease prevalence estimates among racial/ethnic groups: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND OBJECTIVES

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.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

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.

RESULTS

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).

CONCLUSIONS

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.

Thresholds of risk factors for ischemic stroke in type 2 diabetic patients with and without albuminuria: a non-linear approach

OBJECTIVES

Multiple risk factors in type 2 diabetes may explain their high risk for ischemic stroke (IS). However, it remains unknown whether these risk factors exhibit threshold characteristics and whether these relationships are influenced by albuminuria. The study aims to investigate whether risk factors exhibit any albuminuria specific threshold for IS.

PATIENTS AND METHODS

This is a prospective cohort study with 6969 Chinese type 2 diabetic patients without history of stroke after a median follow-up of 5.36 years. We identified thresholds of risk factors for IS using hazard ratio plots followed by confirmation using traditional Cox regression analysis.

RESULTS

In the non-albuminuric group (n=4008), IS risk started to increase rapidly at a body mass index threshold of 24 kg/m(2). The risk of IS declined with increasing blood hemoglobin reaching a threshold value of 14 g/dl. Using these threshold values as cutoff point, body mass index > or =24 kg/m(2) and hemoglobin <14 g/dl were associated with 2-fold increased risk of IS in these subjects. In the albuminuric group (n=2961). IS risk started to increase rapidly from a systolic blood pressure threshold of 135 mmHg and declined with increasing estimated glomerular filtration rate (eGFR) reaching a trough of 115 ml/min per 1.73 m(2). Using these values as cutoff points, patients with systolic blood pressure > or =135 mmHg and eGFR <115 ml/min per 1.73 m(2) had 2-fold increased risk of IS.

CONCLUSION

In type 2 diabetic patients, body mass index, hemoglobin, systolic blood pressure and eGFR exhibit different risk relationships and thresholds for IS contingent upon presence or absence of albuminuria.

Socioeconomic disadvantage and kidney disease in the United States, Australia, and Thailand

OBJECTIVES

We sought to determine whether an elevated burden of chronic kidney disease is found among disadvantaged groups living in the United States, Australia, and Thailand.

METHODS

We used data on participants 35 years or older for whom a valid serum creatinine measurement was available from studies in the United States, Thailand, and Australia. We used logistic regression to analyze the association of income, education, and employment with the prevalence of chronic kidney disease (estimated glomerular filtration rate<60 mL/min/1.73 m(2)).

RESULTS

Age- and gender-adjusted odds of having chronic kidney disease were increased 86% for US Whites in the lowest income quartile versus the highest quartile (odds ratio [OR] = 1.86; 95% confidence interval [CI] = 1.27, 2.72). Odds were increased 2 times and 6 times, respectively, among unemployed (not retired) versus employed non-Hispanic Black and Mexican American participants (OR=2.89; 95% CI=1.53, 5.46; OR=6.62; 95% CI=1.94, 22.64. respectively). Similar associations were not evident for the Australian or Thai populations.

CONCLUSIONS

Higher kidney disease prevalence among financially disadvantaged groups in the United States should be considered when chronic kidney disease prevention and management strategies are created. This approach is less likely to be of benefit to the Australian and Thai populations.

Gender differences in predictors of the decline of renal function in the general population

We sought to identify predictors of the decline in renal function, especially those that are modifiable, in the 5488 participants of the prospective, community-based cohort study PREVEND who completed three visits during a mean follow-up of 6.5 years. The change in renal function was used as the outcome and this was calculated as the linear regression of three estimated GFR measurements obtained during follow-up. Risk factors, known to influence renal outcome in patients with primary renal diseases, were used as potential predictors in multivariate regression analyses. High systolic blood pressure and plasma glucose were found to be independent predictors for an accelerated decline in function for both genders. In males, albuminuria was the strongest independent predictor for renal function decline, whereas in females albuminuria was univariately associated only after adjustment for age. The direction of the association between cholesterol/HDL ratio and decline of renal function differed by gender. Surprisingly, in males, waist circumference was an independent predictor and positively associated with renal function outcome. These studies show that there are gender differences in the standard predictors of the decline in renal function.

Development and validation of a risk score for hospitalization for heart failure in patients with Type 2 diabetes mellitus

Background

There are no risk scores available for predicting heart failure in Type 2 diabetes mellitus (T2DM). Based on the Hong Kong Diabetes Registry, this study aimed to develop and validate a risk score for predicting heart failure that needs hospitalisation in T2DM.

Methods

7067 Hong Kong Chinese diabetes patients without history of heart failure, and without history and clinical evidence of coronary heart disease at baseline were analyzed. The subjects have been followed up for a median period of 5.5 years. Data were randomly and evenly assigned to a training dataset and a test dataset. Sex-stratified Cox proportional hazard regression was used to obtain predictors of HF-related hospitalization in the training dataset. Calibration was assessed using Hosmer-Lemeshow test and discrimination was examined using the area under receiver's operating characteristic curve (aROC) in the test dataset.

Results

During the follow-up, 274 patients developed heart failure event/s that needed hospitalisation. Age, body mass index (BMI), spot urinary albumin to creatinine ratio (ACR), HbA_1c, blood haemoglobin (Hb) at baseline and coronary heart disease during follow-up were predictors of HF-related hospitalization in the training dataset. HF-related hospitalization risk score = 0.0709 × age (year) + 0.0627 × BMI (kg/m²) + 0.1363 × HbA_1c(%) + 0.9915 × Log₁₀(1+ACR) (mg/mmol) - 0.3606 × Blood Hb(g/dL) + 0.8161 × CHD during follow-up (1 if yes). The 5-year probability of heart failure = 1-S₀(5)^{EXP{0.9744 × (Risk Score - 2.3961)}}. Where S₀(5) = 0.9888 if male and 0.9809 if female. The predicted and observed 5-year probabilities of HF-related hospitalization were similar (p > 0.20) and the adjusted aROC was 0.920 for 5 years of follow-up.

Conclusion

The risk score had adequate performance. Further validations in other cohorts of patients with T2DM are needed before clinical use.

Prevalence of chronic kidney disease in population-based studies: systematic review

BACKGROUND

Chronic kidney disease (CKD) is becoming a major public health problem worldwide. This article reviews the published evidence of prevalence of CKD in population-based study samples that used the standardized definition from the Kidney Disease Outcomes Quality Initiative of the National Kidney Foundation (K/DOQI) practice guideline, and particularly focus on performance of serum-creatinine based equations for GFR estimation. We provide a summary of available data about the burden of CKD in various populations.

METHODS

We performed a systematic review of available published data in MEDLINE. A combination of various keywords relevant to CKD was used in this research. Related data of included studies were extracted in a systematic way.

RESULTS

A total of 26 studies were included in this review. The studies were conducted in different populations, and the number of study participants ranged from 237 to 65181. The median prevalence of CKD was 7.2% in persons aged 30 years or older. In persons aged 64 years or older prevalence of CKD varied from 23.4% to 35.8%. Importantly, the prevalence of CKD strongly depended on which estimating equations were used. The Modification of Diet in Renal Disease Study (MDRD) equation was likely to be preferred in recent epidemiological studies compared to the adjusted Cockcroft-Gault (CG) equation.

CONCLUSION

Worldwide, CKD is becoming a common disease in the general population. Accurately detecting CKD in special groups remains inadequate, particularly among elderly persons, females or other ethnic groups such as Asians.

Nonalcoholic fatty liver disease predicts chronic kidney disease in nonhypertensive and nondiabetic Korean men

In the absence of significant research, we performed a prospective study to examine the association between nonalcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). The study cohort comprised a total of 8329 healthy men, with normal baseline kidney functions and no proteinuria, working in a semiconductor manufacturing company and its 13 affiliates. Alcohol intake was assessed with a self-reported questionnaire. Biochemical tests for liver and metabolic function and abdominal ultrasonography were done. Chronic kidney disease was defined as either the presence of proteinuria or a glomerular filtration rate (GFR) of <60 mL/min per 1.73 m(2). Cox proportional hazards model was used to estimate hazard ratios in the model for CKD. During 26717.1 person-years of follow-up, 324 men developed CKD. Nonalcoholic fatty liver disease was associated with the development of CKD (crude relative risk, 2.18; 95% confidence interval [CI], 1.75-2.71); and this relationship remained significant even after adjustment for age, GFR, triglyceride, and high-density lipoprotein cholesterol (adjusted relative risk [aRR], 1.55; 95% CI, 1.23-1.95). The association between NAFLD and incident CKD was evident in the NAFLD group with elevated serum gamma-glutamyltransferase (GGT) (aRR, 2.31; 95% CI, 1.53-3.50), even after adjustment for age, GFR, triglyceride, and high-density lipoprotein cholesterol, but not in the NAFLD group without elevated GGT (aRR, 1.09; 95% CI, 0.79-1.50) (P = .008 for interaction). To summarize, NAFLD with elevated GGT concentration was associated with an increased CKD risk among nondiabetic, nonhypertensive Korean men, irrespective of metabolic syndrome.

Comparison of glomerular filtration rate measurements with the two plasma sample and single plasma sample, gamma camera Gates, creatinine clearance, and prediction equation methods in potential kidney donors with normal renal function

OBJECTIVE

To compare measured glomerular filtration rate (GFR) by single plasma sample methods (SPSMs), gamma camera Gates, 24-h endogenous creatinine clearance, and prediction equations (Cockcroft-Gault and modification of renal disease (MDRD)) with the two plasma sample method (TPSM) considered as the reference in potential kidney donors with normal renal function.

METHODS

One hundred and fifteen subjects (50 male, 65 female; mean age 41.9+/-12.2 years) with normal renal function were prospectively included in this study. GFR was calculated by TPSM (120-min and 240-min samples) and SPSM (180-min sample).

RESULTS

While there was strong statistically significant correlation between the TPSM and all SPSMs, low correlation was found in Gates, creatinine clearance, Cockcroft-Gault and MDRD. In all SPSMs, 95% limits of agreements were consistent with each other and within clinically acceptable limits. The lowest bias, median absolute difference, mean percentage error, and the best precision were found for Christensen and Groth's method as modified by Watson (CGmW).

CONCLUSIONS

Among the SPSMs, CGmW can reflect GFR more accurately than the other methods. Neither the gamma camera Gates method nor the creatinine clearance method nor the prediction equations (Cockcroft-Gault and MDRD) could calculate GFR accurately. All these techniques could result in mistakes in the management of potential kidney donors.

Effects of albuminuria and renal dysfunction on development of dyslipidaemia in type 2 diabetes--the Hong Kong Diabetes Registry

BACKGROUND

It is uncertain whether albuminuria precedes the future development of high total cholesterol (TC > 6.2 mmol/l) and high LDL-C (>4.1 mmol/l) while renal dysfunction precedes the future development of low HDL-C (<0.9 mmol/l) in type 2 diabetes.

METHODS

A prospective cohort of 2761 type 2 diabetic patients without significant dyslipidaemia and having at least one measurement of TC, LDL-C and HDL-C during 2.8 years of follow-up was analysed. The spline Cox regression model was used to derive hazard ratio (HR) curves of the spot urinary albumin:creatinine ratio (ACR) and the estimated glomerular filtration rate (eGFR) for dyslipidaemia, followed by standard Cox models to confirm the findings from the HR curves.

RESULTS

Seven percent of the cohort developed high TC, 4.6% developed high LDL-C and 5.7% developed low HDL-C during follow-up. In multivariate analysis, the HR of ACR for high TC and high LDL-C increased rapidly and linearly from zero with no apparent threshold. Patients with macroalbuminuria (ACR >/=25 mg/mmol) were, respectively, 1.6- and 2.4 folds more likely to develop high TC and high LDL-C than those with normoalbuminuria at baseline. The HR of eGFR for low HDL-C increased rapidly with declining eGFR at <110 ml/min/ 1.73 m(2). Subjects with eGFR <60 ml/min/1.73 m(2) and >/=60-<110 ml/min/1.73 m(2), respectively, had 3.0-fold and 1.8-fold risks of low HDL-C compared to those with eGFR >/=110-<140 ml/min/1.73 m(2).

CONCLUSIONS

In type 2 diabetes, macroalbumninuria predicts high TC and high LDL-C, while reduced renal function, even within normal range, predicts low HDL-C.

Prevalence and factors associated with CKD: a population study from Beijing

BACKGROUND

Chronic kidney disease (CKD) is considered a serious worldwide public health problem, but data from developing countries are extremely limited.

STUDY DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

A representative sample of 13,925 adults in Beijing, China.

PREDICTORS

Age (18 to 39, 40 to 59, 60 to 69, and >70 years), sex, urban or rural area, history of chronic respiratory infection and cardiovascular disease, hepatitis B virus infection, smoking, family history (diabetes, hypertension, and CKD), nephrotoxic medications, central obesity, diabetic and hypertension status, and dyslipidemia.

OUTCOMES AND MEASUREMENTS

CKD was defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) or markers of kidney damage. Glomerular filtration rate was estimated by using calibrated serum creatinine level and a formula specific for China. Persistent albuminuria and hematuria were considered markers of kidney damage.

RESULTS

The prevalence of CKD in adults in Beijing was 13.0% (95% confidence interval [CI], 11.9 to 14.2). It therefore was estimated that the number of adults in Beijing with CKD was 1.43 million. In subjects aged 18 to 39, 40 to 59, 60 to 69, and older than 70 years, prevalences of CKD were 10.0% (95% CI, 8.9 to 11.3), 14.2% (95% CI, 13.0 to 15.4), 20.8% (95% CI, 18.1 to 23.9), and 30.5% (95% CI, 26.6 to 34.7), respectively. Factors independently associated with decreased kidney function included older age (odds ratio [OR], 1.83; 95% CI, 1.51 to 2.22 per 10-year increase), nephrotoxic medications (OR, 2.19; 95% CI, 1.21 to 3.97), rural area (versus urban area; OR, 0.47; 95% CI, 0.28 to 0.78), history of cardiovascular disease (OR, 2.04; 95% CI, 1.24 to 3.38), high-density lipoprotein cholesterol level less than 40 mg/dL (OR, 3.00; 95% CI, 1.39 to 6.51), and hypertension status (with duration > 10 years; OR, 1.85; 95% CI, 1.19 to 2.88).

LIMITATIONS

Kidney function and indicators of kidney damage were based on single measurements.

CONCLUSIONS

CKD is a public health burden in Beijing.

Inadequate energy and excess protein intakes may be associated with worsening renal function in chronic kidney disease

OBJECTIVES

Dietary energy and protein play important roles in chronic kidney disease (CKD). This study investigates the relationship between energy/protein intake status and renal function in CKD.

DESIGN AND STUDY POPULATION

This cross-sectional study included 599 adult patients diagnosed with stage 3 to 5 CKD in nephrology and nutrition outpatient clinics in Taiwan.

MAIN OUTCOME MEASURE

Energy and protein intakes were assessed using 24-h dietary recall. We recorded recommended calorie/protein amounts and renal function indices, glomerular filtration rate (GFR), creatinine, and blood urea nitrogen (BUN). Patients were categorized into three intake calorie/protein groups by a ratio of actual intake vs. recommended intake. High intake was defined as a ratio of actual intake/recommended intake > or = 110%, moderate intake as > or = 90% to <110%, and low intake as <90%. Data were analyzed by paired t test, one-way analysis of variance, least significant differences, and multiple linear regression.

RESULTS

The energy and protein intakes in CKD patients were significantly higher and lower than recommended levels (P < .001). Low energy intake was significantly related to worsening GFR at increments of -4.41 mL/min/1.73 m(2), compared with moderate and high energy intake (P = .008); high protein intake was also associated with worsening GFR at increments of -3.50 mL/min/1.73m(2), compared with moderate and low protein intake (P < .001). Low energy intake and high protein intake were significantly positively correlated with elevations in creatinine and BUN.

CONCLUSION

Lower energy and higher protein intakes than recommended may be associated with deteriorating renal function.

Association between waist-to-hip ratio and chronic kidney disease in the elderly

BACKGROUND

To compare the anthropometric indices of obesity and identify which index serves as a better discriminator in the chronic kidney disease (CKD) for the elderly.

METHODS

Participants of a 1-day health check, older than 60 years, in our hospital from 2003 to 2005 were enrolled. CKD was defined as estimated glomerular filtration rate by modification of diet in renal disease formula less than 60 mL/min per 1.73 m(2). Indices of obesity include body mass index, waist circumference, waist-to-hip ratio (WHR) and waist-to-height ratio. Traditional risk factors including diabetes, hypertension and metabolic syndrome were also taken into consideration. The accuracy of indices of obesity in predicting CKD was measured by area under the receiver operating characteristic curve (AUC). Association between risk factors was estimated by multivariate logistic regression.

RESULTS

We studied 984 participants (537 men and 447 women) with a mean age of 66.7 +/- 5.3 years. A total of 161 (16.4%) participants was found having CKD. In the indices of obesity, WHR showed best diagnostic accuracy in predicting CKD (AUC: 0.58). A WHR cut-off value of 0.88 had a sensitivity of 68.9% and a specificity of 45.4%. The odds ratios were significant for WHR, hypertension and diabetes (P = 0.025, P < 0.001 and P = 0.033).

CONCLUSION

In indices of obesity, WHR is better than body mass index, bodyweight and waist circumferences in predicting CKD in elder Taiwanese. Furthermore, the association of WHR and CKD is independent of hypertension and diabetes.

Development and validation of a total coronary heart disease risk score in type 2 diabetes mellitus

There are no validated risk scores for predicting coronary heart disease (CHD) in Chinese patients with type 2 diabetes mellitus. This study aimed to validate the UKPDS risk engine and, if indicated, develop CHD risk scores. A total of 7,067 patients without CHD at baseline were analyzed. Data were randomly assigned to a training data set and a test data set. Cox models were used to develop risk scores to predict total CHD in the training data set. Calibration was assessed using the Hosmer-Lemeshow test, and discrimination was examined using the area under the receiver-operating characteristic curve in the test data set. During a median follow-up of 5.40 years, 4.97% of patients (n = 351) developed incident CHD. The UKPDS CHD risk engine overestimated the risk of CHD with suboptimal discrimination, and a new total CHD risk score was developed. The developed total CHD risk score was 0.0267 x age (years) - 0.3536 x sex (1 if female) + 0.4373 x current smoking status (1 if yes) + 0.0403 x duration of diabetes (years) - 0.4808 x Log(10) (estimated glomerular filtration rate [ml/min/1.73 m(2)]) + 0.1232 x Log(10) (1 + spot urinary albumin-creatinine ratio [mg/mmol]) + 0.2644 x non-high-density lipoprotein cholesterol (mmol/L). The 5-year probability of CHD = 1 - 0.9616(EXP(0.9440 x [RISK SCORE - 0.7082])). Predicted CHD probability was not significantly different from observed total CHD probability, and the adjusted area under the receiver-operating characteristic curve was 0.74 during 5 years of follow-up. In conclusion, the UKPDS CHD risk engine overestimated the risk of Chinese patients with type 2 diabetes mellitus and the newly developed total CHD risk score performed well in the test data set. External validations are required in other Chinese populations.

Risk factors in V-shaped risk associations with all-cause mortality in type 2 diabetes-The Hong Kong Diabetes Registry

BACKGROUND

Body mass index (BMI) is associated with death in a V-shaped manner in general populations but it is unknown whether BMI or other risk factors also exhibit V-shaped relationships with death in type 2 diabetic patients.

METHODS

A prospective cohort of 7534 Chinese, type 2 diabetic patients enrolled since 1995 were censored on 30 July 2005. Spline Cox regression analysis with a stepwise algorithm (p < 0.05) was used to select predictors. Hazard ratio (HR) curves were used to explore the relationships, which were confirmed by standard Cox models.

RESULTS

763 patients died during the 5.5 years of follow-up. BMI, high-density lipoprotein cholesterol (HDL-C) and white blood cell (WBC) count were related to all-cause mortality in a V-shaped manner. The nadirs of the risk curves were at 26 kg/m(2) for BMI, 1.15 mmol/L for HDL-C and 6.25 x 10(9) counts/L for WBC. The multivariate hazard ratio of BMI away from 26.0 kg/m(2) was 1.08; HDL-C, 1.06 per mmol/L for values less than the nadir and 6.97 per mmol/L for greater than the nadir; and WBC, 1.16 per 10(9) count/L for less than 6.25 x 10(9) and 1.47 for greater than the nadir. Respiratory and neoplastic deaths were the major contributors to the increased death in patients with low or high BMI. Neoplastic death was the major contributor to the increased death in those with low WBC. Genitourinary death was the major contributor to the increased death in those with low and high HDL-C.

CONCLUSION

BMI, HDL-C and WBC are associated with death in a V-shaped manner in type 2 diabetic patients.

Genome-wide linkage scans for renal function and albuminuria in Type 2 diabetes mellitus: the Diabetes Heart Study

AIMS/HYPOTHESIS

Glomerular filtration rate (GFR), end-stage renal disease and albuminuria are highly heritable. We performed a genome-wide linkage scan in 416 Diabetes Heart Study (DHS) families to detect loci that contributed to renal function and albuminuria.

MATERIALS AND METHODS

A total of 1067 individuals (900 with Type 2 diabetes mellitus) from 348 European American and 68 African American DHS families had measures of urine albumin : creatinine ratio (ACR), serum creatinine concentration and Modification of Diet in Renal Disease estimated GFR (eGFR). Variance components quantitative trait linkage analysis (using SOLAR) was computed.

RESULTS

Participants had mean +/- sd age 61.4 +/- 9.4 years; diabetes duration 10.5 +/- 7.4 years; eGFR 1.15 +/- 0.32 ml/sec; and urine ACR 15.8 +/- 67.2 mmol/l (median 1.4). In all families, significant evidence for linkage of GFR was observed on chromosome 2p16 (log of the odds; LOD = 4.31 at 72.0 cM, ATA47C04P/D2S1352) and 1p36 (LOD = 3.81 at 45.0 cM, D1S3669/D1S3720), with suggestive evidence on 7q21 (LOD = 2.42 at 99.0 cM, D7S820/D7S821) and 13q13 (LOD = 2.28 at 28.0 cM, D13S1493/D13S894). The evidence for linkage to ACR was far weaker, on 13q21-q22 (LOD = 1.84 at 50 cM, D13S1807/D13S800), 3p24-p23 (LOD = 1.81 at 58 cM, D3S3038/D3S2432) and 10p11 (LOD = 1.78 at 71.0 cM, D10S1208/D10S1221).

CONCLUSIONS/INTERPRETATIONS

The eGFR linkage peaks on 2p16, 7q21 and 13q13 closely overlap with nephropathy peaks identified in family studies enriched for severe kidney disease. These diabetes-enriched families provide an opportunity to map genes regulating renal function, potentially leading to the identification of genes producing nephropathy susceptibility in subjects with Type 2 diabetes.

Urinary IL-18 and NGAL as early predictive biomarkers in contrast-induced nephropathy after coronary angiography

BACKGROUND/AIMS

Contrast-induced nephropathy (CIN) is at present the third leading cause of hospital-acquired acute kidney injury (AKI). Traditionally, it is diagnosed by measuring the increase of the serum creatinine concentration. However, in patients with acute changes in their glomerular filtration rate, serum creatinine is an insensitive marker. This clinical study was designed to investigate whether human urinary interleukin-18 (IL-18) and neutrophil gelatinase-associated lipocalin (NGAL) are early predictive markers for AKI after coronary angiography and their correlation with later cardiac events.

METHODS

Patients undergoing coronary angiography using low-osmolar contrast medium were enrolled and then followed up for at least 17 months. Urine samples were collected before and 24 h after coronary angiography and IL-18 and NGAL levels measured by using an ELISA kit.

RESULTS

CIN was diagnosed in 13 of 150 (8.7%) patients (CIN group); 27 patients without CIN served as control group. At 24 h after the procedure, the urinary IL-18 and NGAL levels were significantly increased in the CIN group, but not in the control group (p < 0.05). The predictable time of AKI onset determined by IL-18 was 24 h earlier than determined by serum creatinine (p < 0.01). Receiver operating characteristic curve analysis showed that both IL-18 and NGAL showed a good performance in early diagnosis of CIN as compared with serum creatinine (p < 0.05). We also found that IL-18 is an independent predictive marker for later major cardiac events: relative risk = 2.09 (p < 0.01).

CONCLUSIONS

We conclude that urinary IL-18 or NGAL could be early biomarkers of CIN and that urinary IL-18 is well associated with the later cardiac outcomes in patients after coronary angiography.

Monitoring renal function and limitations of renal function tests

Chronic kidney disease (CKD) is a world-wide public health problem, with adverse outcomes of kidney failure, cardiovascular disease, and premature death. The National Kidney Foundation, through its Kidney Disease Quality Outcome Initiative (K/DOQI) and other National institutions, recommend glomerular filtration rate (GFR) estimates for the definition, classification, screening, and monitoring of CKD. Prediction equations based on serum creatinine values were chosen both for adults (Cockcroft-Gault [C-G] and Modification of Diet in Renal Disease [MDRD] study equations) and for children (Schwartz and Counahan-Barratt equations). This review aims to evaluate from recent literature the clinical efficiency and relevance of these equations in terms of bias, precision, and reproducibility in different specific indications (eg, screening CKD, assessment of disease progression, or therapy efficacy) in different populations. Because these prediction equations based on serum creatinine have limitations, especially in the normal or near-normal GFR range, kidney transplant recipients, and pediatric populations, other prediction equations based on serum cystatin C value were also considered as possibly more sensitive GFR surrogate markers. Recent guidelines state that the cystatin C-based prediction equation cannot be recommended for use in clinical practice. With prediction equations based on serum creatinine, the National Kidney Disease Education Program (NKDEP) recommendations are to report a numerical estimate in round numbers only for GFR values <60 mL/min per 1.73 m(2). The MDRD equation generally outperforms the C-G equation but may still have a high level of bias, depending on creatinine assay calibration, and low precision with, at best, approximately 80% of estimated GFR in the "accuracy range" of 70-130% of the measured GFR value, even in patients with known CKD. According to Kidney Disease Improving Global Outcomes (KDIGO) recommendations, many indications remain for GFR measurements using a clearance method. In that context, it should be recalled that radiolabeled-tracer plasma or urinary clearance methods, are safe, simple, accurate and reproducible.

Investigation of the prevalence of CKD in 13,383 Chinese hospitalised adult patients

BACKGROUND

There is an increase prevalence of chronic kidney disease (CKD)worldwide. However, the exact incidence of CKD in China is still uncertain. In this cross-sectional study, we retrospectively investigated the prevalence and distribution of CKD in Chinese hospitalised adult patients.

METHODS

Totally, 13,383 adults patients who were hospitalised at our hospital were included in this study. They included 6215 males and 7168 females. Patients' gender, age, blood pressure, serum creatinine, blood urea nitrogen, uric acid, triglyceride, total cholesterol, albumin, hemoglobin, hemotocrit, urine protein, and history of hypertension, diabetes, and smoking were investigated. CKD was defined as eGFR<60 ML/ MIN PER 1.73 m(2) and/or proteinuria, GFR was estimated by using of the simplified MDRD equation.

RESULTS

The prevalence rate of CKD was 14.82% in our group, which was respectively distributed from 1 to stage 5 at the following percentage, 3.33% (stage 1), 2.49% ( stage 2), 7.07% (stage 3), 1.08% (stage 4), and 0.86% (stage 5). Elderly patients (age >65 y) accounted for 53.07%, which had a higher CKD prevalence (29.47%) than middle and young-aged patients (9.49%). It was noted that 39.06% patients at stage 1-3 were undiagnosed with CKD during their hospitalization. The common etiology for CKD was hypertension (29.49%), diabetes (11.64%) and primary glomerulonephritis (4.39%). Hypertension, diabetes and ages were main associated factors for CKD.

CONCLUSIONS

CKD is a very common disease among the hospitalised patients in China. With the increasing of aging population, elderly people will be the highest risk group for CKD. More strategies have to be made for its early detection and prevention.

An association between the estimated glomerular filtration rate and carotid atherosclerosis

OBJECTIVE

Chronic kidney disease (CKD) is a major public health problem. There is conflicting evidence concerning whether CKD is an independent risk factor for carotid intima-media thickness (IMT).

PATIENTS AND METHODS

The study subjects were 428 men aged 70+/-15 (mean+/-standard deviation) years and 582 women aged 75+/-12 years enrolled consecutively from patients in the Medical Department of Seiyo Municipal Nomura Hospital. Carotid IMT was derived via B-mode ultrasonography and CKD was evaluated by the estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease Study equation.

RESULTS

In men, age (p<0.001), systolic blood pressure (p<0.001), antihypertensive drug use (p<0.001), HDL-C (p=0.006), LDL-C (p=0.004), prevalence of diabetes (p=0.035) and eGFR (p<0.001) were significantly correlated with carotid IMT. In women, age (p<0.001), systolic blood pressure (p<0.001), antihypertensive drug use (p<0.001), HDL-C (p=0.035), LDL-C (p=0.017) and eGFR (p<0.001) were significantly correlated with carotid IMT. Stepwise multiple linear regression analysis using IMT as an objective variable, adjusted by various factors as explanatory variables, showed that eGFR was a significant independent contributing factor along with known risk factors in men (beta, -0.096; p=0.018) and women (beta, -0.080; p=0.035).

CONCLUSIONS

Our data suggested that eGFR was associated with an increased prevalence of carotid atherosclerosis independent of common cardiovascular risk factors in both men and women.

An association between metabolic syndrome and the estimated glomerular filtration rate

OBJECTIVE

Metabolic syndrome (MetS) is a major public health problem. However, few studies have examined the significance of MetS as a risk factor for the development of chronic kidney disease (CKD) in the general Japanese population.

METHODS

Study participants without a clinical history of stroke, transient ischemic attack, myocardial infarction, angina, or renal failure (1,158 men, aged 61+/-15 years and 1,606 women, aged 63+/-12 years) were recruited from a single community. We examined the cross-sectional relationship between MetS and renal function as evaluated by estimated glomerular filtration rate (eGFR).

RESULTS

The presence of MetS was consistently associated with reduced eGFR, with the level of reduction proportional to the number of MetS components present. Multiple linear regression analysis using eGFR as an objective variable showed that BMI, DBP, antihypertensive drug use, high-density lipoprotein cholesterol, antilipidemic drug use and fasting blood glucose, which were components of MetS, were significantly and independently associated with eGFR, in addition to age and low-density lipoprotein cholesterol. Individuals with MetS showed a multivariate-adjusted odds ratio of 1.53 (95% confidence interval, 1.10-2.13) for CKD compared to those without MetS.

CONCLUSIONS

MetS was significantly associated with decreased eGFR in the general population.

Modification of the Modification of Diet in Renal Disease (MDRD) Study equation for Japan

BACKGROUND

Glomerular filtration rate (GFR)-estimating equations based on serum creatinine level may not be accurate across racial groups because of differences among races in creatinine generation. The Modification of Diet in Renal Disease (MDRD) Study equation was developed in whites and African Americans, but performance was not evaluated in Japanese.

STUDY DESIGN

Diagnostic test accuracy. Cross-sectional retrospective study of 3 patient groups. Equation development in 2 groups (n = 247 in 2002 to 2004; n = 214 in 2003 to 2004 with measured GFR <90 mL/min/1.73 m(2)); external validation in a separate group (n = 153 from 1988 to 1994).

SETTING & PARTICIPANTS

Hospitalized Japanese patients with chronic kidney disease in 3 medical centers.

REFERENCE TEST

Measured GFR (mGFR) computed from renal clearance of inulin.

INDEX TEST

Estimated GFR (eGFR) using the isotope dilution mass spectrometry (IDMS)-traceable 4-variable MDRD Study equation, a modified IDMS MDRD Study equation with a Japanese Society of Nephrology-Chronic Kidney Disease Initiatives (JSN-CKDI) coefficient derived in the development data set, and a new equation derived by refitting coefficients in the MDRD Study equation in the development data set.

MEASUREMENTS

Current creatinine assays were calibrated to standardized creatinine. Performance of equations was assessed as bias, accuracy, root-mean-squared error, and correlation coefficient of eGFR versus mGFR.

RESULTS

In the development data set, eGFR using the IDMS MDRD Study equation overestimated mGFR throughout the entire range. In the validation data set, the IDMS MDRD Study equation with the JSN-CKDI coefficient 0.741 and the new equation (JSN-CKDI) performed with significantly less bias and greater accuracy than the IDMS MDRD Study equation, but were similar to each other in accuracy and bias in patients with eGFR less than 60 mL/min/1.73 m(2). In the combined development and validation data sets, the JSN-CKDI coefficient was 0.763 (95% confidence interval, 0.743 to 0.783).

LIMITATIONS

Possible drift in creatinine assays over time, possible lower creatinine generation in hospitalized patients, exclusion of patients with higher GFR from the development data set.

CONCLUSION

GFR estimates using the IDMS MDRD Study equation with the JSN-CKDI coefficient or the new JSN-CKDI equation are more accurate than the IDMS MDRD Study equation in hospitalized Japanese patients with eGFR less than 60 mL/min/1.73 m(2). More studies are necessary to verify the accuracy of the JSN-CKDI coefficient and JSN-CKDI equation in other settings in Japan and elsewhere in Asia.

High prevalence of chronic kidney disease in Thailand

We describe the prevalence of stage III and IV chronic kidney disease in Thailand from a representative sample of individuals aged 35 years and above using a stratified, multistage, cluster-sampling method. Population estimates were calculated by applying sampling weights from the 2000 Thai census. Glomerular filtration rates were estimated from serum creatinine using the Cockroft-Gault and the simplified Modification of Diet in Renal Disease (MDRD) formulae. The prevalence of stage III disease among individuals aged 35 years and above was estimated to be about 20% using the Cockroft-Gault formula and about 13% from the MDRD formula. Stage IV disease was present in about 0.9 and 0.6% of this population using the respective formulae. The highest prevalence rates were observed in less well-developed rural areas and the lowest in developed urban areas. The prevalence of chronic kidney disease was significantly higher than that reported in individuals over 40 years old from the United States for both stage III and IV disease and higher than the reported incidence in Taiwan and Australia. This high prevalence of chronic kidney disease in Thailand has obvious implications for the health of its citizens and for the allocation of health-care resources.

Impacts of chronic kidney disease and albuminuria on associations between coronary heart disease and its traditional risk factors in type 2 diabetic patients - the Hong Kong diabetes registry

Background

Glycated haemoglobin (HbA_1c), blood pressure and body mass index (BMI) are risk factors for albuminuria, the latter in turn can lead to hyperlipidaemia. We used novel statistical analyses to examine how albuminuria and chronic kidney disease (CKD) may influence the effects of other risk factors on coronary heart disease (CHD).

Methods

A prospective cohort of 7067 Chinese type 2 diabetic patients without history of CHD enrolled since 1995 were censored on July 30^th, 2005. Cox proportional hazard regression with restricted cubic spline was used to auto-select predictors. Hazard ratio plots were used to examine the risk of CHD. Based on these plots, non-linear risk factors were categorised and the categorised variables were refitted into various Cox models in a stepwise manner to confirm the findings.

Results

Age, male gender, duration of diabetes, spot urinary albumin: creatinine ratio, estimated glomerular filtration rate, total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and current smoking status were risk factors of CHD. Linear association between TC and CHD was observed only in patients with albuminuria. Although in general, increased HDL-C was associated with decreased risk of CHD, full-range HDL-C was associated with CHD in an A-shaped manner with a zenith at 1.1 mmol/L. Albuminuria and CKD were the main contributors for the paradoxically positive association between HDL-C and CHD for HDL-C values less than 1.1 mmol/L.

Conclusion

In type 2 diabetes, albuminuria plays a linking role between conventional risk factors and CHD. The onset of CKD changes risk associations between lipids and CHD.

Performance and comparison of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease formulae in estimating glomerular filtration rate in a Chinese Type 2 diabetic population

AIMS

Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks.

METHODS

A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared.

RESULTS

The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks.

CONCLUSIONS

These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks.

Chronic kidney disease as a risk factor for coronary artery disease in Chinese with type 2 diabetes

BACKGROUND

Chronic kidney disease (CKD) is associated with cardiovascular disease (CVD) in the general population. We investigated the effects of renal function on coronary artery disease (CAD) in Chinese with type 2 diabetes who have a high risk of developing diabetic nephropathy but who may have a low risk of developing CAD.

METHODS

We recruited a total of 2,434 Chinese with type 2 diabetes (1,078 men and 1,356 women) and diagnosed CAD by history or with an abnormal electrocardiogram (coronary probable or possible by Minnesota codes). Renal function was evaluated by serum creatinine (SCr) levels, estimated glomerular filtration rate (eGFR) (calculated by the abbreviated Modification of Diet in Renal Disease Study Croup formula) and urinary albumin/creatinine ratio (ACR).

RESULTS

We found that patients with CAD were older, had higher SCr levels and body mass index (BMI), and had lower serum high-density lipoprotein cholesterol (HDL-c) levels. After adjusting for age, BMI, blood pressure, glycosylated hemoglobin, cholesterol, LDL-c, HDL-c, and triglycerides, we found that SCr levels >1.5 mg/dl, eGFR <60 ml/min, and urinary ACR >30 mg/g were independent risk factors for CAD in diabetic men, and that SCr levels >1.4 mg/dl and eGFR <60 ml/min were independently associated with CAD in women.

CONCLUSION

Our findings indicate that Chinese with type 2 diabetes and CKD are likely to have had CAD previously and CKD is 'CVD risk state' in diabetic Chinese.

Lactate levels in Asian patients with type 2 diabetes mellitus on metformin and its association with dose of metformin and renal function

AIM

Our aims are to discover the average fasting plasma lactate level (FPL) in Asian patients with type 2 diabetes mellitus on metformin, with or without renal impairment and whether FPL is associated with the total daily dose of metformin (Tmet) and the degree of renal impairment in these patients.

METHODS

We conducted an observational cross-sectional study of Asian patients with type 2 diabetes, using measurements of FPL levels and glomerular filtration rate (GFR) calculated, using the abbreviated modification of diet in renal disease (MDRD) formula. The association between FPL, Tmet, GFR and other potential predictors was analysed.

RESULTS

A total of 97 subjects were recruited from our diabetes centre between July 2005 and February 2006. Sixty (61.9%) of the subjects were males; 69 (71.1%) Chinese, 21 (21.6%) Malays and 6 (6.2%) Indians. The mean (SD) age was 58.8 years (10.7) and the mean body mass index was 27.1 kg/m(2) (5.3). The mean FPL was 1.8 mmol/l (0.9) with 20 (20.6%) of subjects having an FPL beyond the upper limit of our reference range of 2.2 mmol/l. The mean FPL (two SE) of subjects with Tmet of < or = 1000, 1001-2000 and > 2000 mg were 1.7 mmol/l (0.2), 1.6 mmol/l (0.2) and 2.1 mmol/l (0.5) respectively, (p = 0.119). The mean FPL of subjects with GFR of < 60, 60-90 and > 90 ml/min/1.73 m(2) was 1.7 mmol/l (0.3), 1.8 mmol/l (0.3) and 1.8 mmol/l (0.4) respectively, p = 0.757. Among the potential predictors analysed, aspartate transaminase (p = 0.001) was found to be significantly associated with FPL.

CONCLUSIONS

Our study shows no correlation between Tmet and GFR with FPL in Asian type 2 diabetic patients on metformin.

Improved GFR estimation by combined creatinine and cystatin C measurements

Plasma creatinine may not reflect glomerular filtration rate (GFR) especially in the early stages of chronic kidney disease (CKD). Plasma cystatin C (cysC), however, has the potential to more accurately determine early GFR reduction. We sought to improve the creatinine-based GFR estimation by including cysC measurements. We derived a reference GFR from standard dual plasma sampling (99m)Tc-DTPA clearance in a training cohort of 376 randomly selected adult Chinese patients with CKD. We compared reference values to estimated GFR and applied multiple regression models to one equation based solely on cysC, and to another combining plasma creatinine (Pcr) and cysC measurements of the training cohort. The results were validated by testing an additional 191 patients. The difference, precision, and accuracy of the two estimates were compared with the modified Modification of Diet in Renal Disease (MDRD) equation for Chinese patients, and another estimate combining cysC and modified MDRD calculations. The estimated GFR combining Pcr and cysC measurements more accurately matched the reference GFR at all stages of CKD than the other equations, particularly in patients with near-normal kidney function.