Evaluation of the Modification of Diet in Renal Disease equation (eGFR) against simultaneous, dual-marker multi-sample measurements of glomerular filtration rate

BACKGROUND

Estimation of glomerular filtration rate (GFR) using plasma creatinine remains controversial, especially when GFR approaches normal values. The aim was to re-examine estimated GFR (eGFR) using dual-reference GFR measurements.

METHODS

eGFR (simplified modified Modification of Diet in Renal Disease equation) was compared with GFR measured with iohexol for predicting GFR measured with (51)Cr-ethylenediaminetetraacetic acid (EDTA). Dual six-sample GFR (20-240 min postinjection) was measured in 60 patients and 20 normal volunteers with (51)Cr-EDTA (GFR(EDTA)) and iohexol (GFR(iohexol)) injected into separate arms and sampled contralaterally. This was repeated in the normal volunteers under fasting conditions (twice in nine). Percentage bias, imprecision (SD of bias) and disagreement (sign-less difference) between eGFR and GFR(EDTA) were compared with those between GFR(iohexol) and GFR(EDTA).

RESULTS

Changes between fasting and postprandial eGFR correlated significantly with corresponding changes in GFR(iohexol) and GFR(EDTA). eGFR predicted GFR(EDTA) less precisely (SD 19.9%) than GFR(iohexol) (10.5%; P < 0.01). Although eGFR showed a poorer correlation with GFR(EDTA) when GFR(EDTA) > 80 mL/min/1.73 m(2) compared with <80 mL/min/1.73 m(2), there was no significant difference with respect to imprecision or disagreement of >20 or 30%. However, eGFR was closer than GFR(iohexol) to GFR(EDTA) in a higher fraction of studies when GFR(EDTA) > 80 mL/min/1.73 m(2) (28/60) than when it was <80 mL/min/1.73 m(2) (9/37; P < 0.05).

CONCLUSION

eGFR is inferior to GFR(iohexol) for predicting GFR(EDTA). The disagreement between GFR(iohexol) and GFR(EDTA) illustrates the extent to which uncertainty in GFR(EDTA) contributes to the performance of eGFR. eGFR performs no better at lower, compared with higher levels of GFR.

Screening for kidney disease in vascular patients: SCreening for Occult REnal Disease (SCORED) experience

BACKGROUND

SCreening for Occult REnal Disease (SCORED) is a novel screening guideline recently developed to identify individuals with a high likelihood of having prevalent chronic kidney disease (CKD). This simple scoring system, developed from general US representative samples and independently validated, was shown to outperform current clinical practice guidelines. Recently, CKD screening in individuals with cardiovascular disease (CVD) has been emphasized. We therefore evaluated the SCORED model in CVD patients in order to better understand the implications of CKD screening in this population.

METHODS

Two clinical trials that enrolled patients with heart attack (N = 2481) or stroke (N = 3680) were combined to create our sample. The performance of the SCORED guideline was evaluated by standard diagnostic measures. Correlations among various risk scores and their predictive abilities for recurrent CVD were ascertained.

RESULTS

For heart attack and stroke patients, respectively, the SCORED guideline yielded sensitivity of 94 and 97%, specificity of 27 and 11%, positive predictive value of 32 and 30%, negative predictive value of 93 and 89%, with AUC of 0.75 and 0.68. SCORED was strongly correlated with other risk scores and exhibited a similar performance in the prediction of recurrent CVD.

CONCLUSIONS

The higher risk of CKD in CVD patients with high SCORED values is demonstrated. This simple education and screening tool may help promote awareness of CKD in CVD patients, in addition to general populations, and assess the CKD risk and its relationship with recurrent CVD.

Cystatin C: current position and future prospects

Cystatin C is a low-molecular-weight protein which has been proposed as a marker of renal function that could replace creatinine. Indeed, the concentration of cystatin C is mainly determined by glomerular filtration and is particularly of interest in clinical settings where the relationship between creatinine production and muscle mass impairs the clinical performance of creatinine. Since the last decade, numerous studies have evaluated its potential use in measuring renal function in various populations. More recently, other potential developments for its clinical use have emerged. This review summarises current knowledge about the physiology of cystatin C and about its use as a renal marker, either alone or in equations developed to estimate the glomerular filtration rate. This paper also reviews recent data about the other applications of cystatin C, particularly in cardiology, oncology and clinical pharmacology.

Report of the Asian Forum of Chronic Kidney Disease Initiative (AFCKDI) 2007. "Current status and perspective of CKD in Asia": diversity and specificity among Asian countries

The Japanese Society of Nephrology (JSN) sponsored the Asian Forum of CKD Initiative (AFCKDI) 2007 with the support of the International Society of Nephrology-Commission for Global Advancement in Nephrology (ISN-COMGAN), Asian Pacific Society of Nephrology (APSN), the Kidney Disease: Improving Global Outcome (KDIGO) and other national societies of nephrology in the Asian Pacific region on 27-28 May 2007 in Hamamatsu City, Japan. An international organising committee was established by leading experts of the CKD initiative. The main objective of this forum was to clarify the current status and perspectives of CKD and to promote coordination, collaboration and integration of initiatives in the Asian Pacific region. The forum received 56 papers from 16 countries; it began with the symposium "A Challenge to CKD in the world" and was followed by the ISN-COMGAN affiliated workshop "Current status and perspective of CKD in Asia". The second day was dedicated to discussion on the evaluation, surveillance and intervention in CKD in this area. At the end of the forum, we decided on the future plan as follows: (1) The AFCKDI will provide opportunities annually or biannually for every person who promotes CKD initiatives in the Asian Pacific region to join together and build consensus for action; (2) the second forum will be held in Kuala Lumpur on 4 May 2008 at the time of the 11th Asian Pacific Congress of Nephrology (APCN). Zaki Morad, President of the 11th APCN, will host the second forum; (3) the International Organising Committee (IOC) of the 1st AFCKDI will continue its function by adding other experts, including the organisers of the APCN; (4) the AFCKDI is not an organisation by itself, nor does it belong to any society, but is organised by each host national society of nephrology. The IOC will assist the domestic committee for the success of the forum and will assure the continuation of the mission; (5) in order to organise the forum and promote CKD initiatives in the Asia Pacific region, the AFCKDI will look for support by both national and international societies. The AFCKDI will keep an intimate and mutual relation with the ISN, APSN and KDIGO.

Cystatin C is associated with the metabolic syndrome and other cardiovascular risk factors in a hypertensive population

Serum cystatin C has been associated with cardiovascular disease. We investigated whether cystatin C concentration is associated with the metabolic syndrome and with other cardiovascular risk factors in a hypertensive population. In this cross-sectional study, we prospectively included 611 essential hypertensive patients during a 12-month period. Cystatin C concentration was measured by nephelometry. The metabolic syndrome was present in 46% of the patients. Cystatin C was significantly higher in patients with the metabolic syndrome (0.94 +/- 0.27 mg/L) than in those without (0.87 +/- 0.23 mg/L) (P < .0001). Pearson partial correlation analysis showed a significant correlation between cystatin C and body mass index (r = 0.240; P = .001); waist circumference (r = 0.173; P = .012); microalbuminuria (r = 0.273; P < .0001); triglycerides (r = 0.138; P = .047); C-reactive protein (r = 0.190; P = .006); uric acid (r = 0.284; P < .0001); age (r = 0.409; P < .0001); and glomerular filtration rate (GFR) (r = -0.638; P < .0001). Multivariate analysis showed that GFR (B = -0.0061; 95% confidence interval [CI], -0.0073 to -0.0049; P < .0001), age (B = 0.0023; 95% CI, 0.0005-0.0041; P = .009), microalbuminuria (B = 0.0005; 95% CI, 0.0002-0.0007; P < .0001), uric acid (B = 0.0252; 95% CI, 0.0085-0.0418; P = .003), body mass index (B = 0.0051, 95% CI, 0.0012-0.0089; P = .011), and C-reactive protein (B = 0.0048; 95% CI, 0.0015-0.0082; P = .005) were independent determinants of cystatin C concentration. Measuring cystatin C concentration in hypertensive patients may be useful for evaluating their cardiovascular risk profile.

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

BACKGROUND

Chronic 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.

METHODS

A community based, cross-sectional study involving multistage random cluster sampling was done in Delhi and its surrounding regions. Adults > or = 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 (> or = 1+) was assessed using visually read dipsticks. Odds ratios, crude and adjusted, were calculated to ascertain associations between renal impairment, proteinuria and risk factors.

RESULTS

The 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.

CONCLUSION

The 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.

Is frequency of patient-physician clinic contact important in peritoneal dialysis patients?

OBJECTIVE

In a single-center retrospective cohort study, we investigated whether the frequency of clinic patient-physician contact (PPC) correlates with quality of care and can predict outcome in peritoneal dialysis (PD) patients.

PATIENTS AND METHODS

We enrolled 307 incident PD patients who started PD from July 2002 to February 2007. All patients who visited the clinic at least once every 6 months and who lived for at least 6 months were followed until death, transfer to hemodialysis, renal transplantation, or February 2008 (censor date). Throughout the study period, an integrative follow-up strategy was used, including PPC and three other modes of contact between patients and non-physicians. Patients' PPC frequency was divided into 3 categories: high frequency (monthly or more often), intermediate frequency (every 1-3 months), and low frequency (every 3-6 months). Baseline demographic and biochemical data were collected. Indices of diet, dialysis adequacy, biochemistry, and nutrition were measured at every visit and then calculated as mean values.

RESULTS

We followed the 307 patients for a mean of 31.45 +/- 13.62 months (range: 12-64 months). By PPC frequency, 127 patients (41.3%) were in the high-frequency group; 136 (44.3%), in the intermediate-frequency group; and 44 (14.3%), in the low-frequency group. We observed no difference of baseline demographic and biochemical data between the three groups (p > 0.05). Patients in the low-frequency group had lower mean hemoglobin and total urea clearance rates, but higher serum phosphate than did patients in the intermediate- or high-frequency groups (p < 0.05). Mean indices of nutrition, including serum albumin, daily protein and energy intake, and lean body mass were not different between the three groups (p > 0.05). Frequency of PPC did not show an effect on the survival of PD patients (p = 0.37 by Kaplan-Meier plot). Age (p = 0.002), Charlson comorbidity score (p = 0.001), and pre-dialysis albumin (p = 0.019) were independent negative risk factors for death in multivariate Cox proportional hazard models, which were adjusted for sex, PPC frequency, baseline hemoglobin, and glomerular filtration rate.

CONCLUSIONS

Frequency of PPC did not predict outcome in PD patients after an integrative care strategy was implemented. Control of anemia and hyperphosphatemia needs to be strengthened in patients with a low frequency of PPC.

High prevalence of chronic kidney disease in Iran: a large population-based study

Background

Chronic kidney disease (CKD) is a global public health threat, associated with an alarming increase in morbidity and mortality. The importance is the worldwide increase in its incidence and prevalence.

Methods

In this cross-sectional study, we estimate the prevalence and determine the associated factors of chronic kidney disease in a representative sample of 10063 participants aged over 20 years, in Tehran, Iran. Chronic kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m2. Glomerular filtration rate was estimated from abbreviated prediction equation provided by the Modification of Diet in Renal Disease study (MDRD).

Results

Overall prevalence of CKD with the abbreviated MDRD equation was 18.9% (95% confidence interval (CI) 18.2, 20.6). Age adjusted prevalence of CKD was 14.9% (95%CI 14.2, 15.6). Factors associated to CKD include age(years)(odds ratio(OR) 1.1, 95% CI 1.0 to 1.2), female gender (OR 3.1, 95% CI 2.6, 3.7), BMI (BMI 25 to <30 OR 1.5, 95% CI 1.3, 1.8 and BMI ≥ 30 OR 1.6, 95% CI 1.3, 2.0), high waist circumference (OR 1.2, 95% CI 1.1, 1.4), hypertension (OR 1.2, 95% CI 1.1, 1.4), and dyslipidemia (OR 1.3, 95% CI 1.1, 1.5).

Conclusion

CKD with its high prevalence poses a definite health threat in Iran.

Epidemiology of chronic kidney disease in heart failure

Heart failure is common and is associated with a poor prognosis. Chronic kidney disease is common in heart failure and shares many risk factors with heart failure, such as age, hypertension, diabetes, and coronary artery disease. Over half of all patients who have heart failure may have moderate-to-severe chronic kidney disease. The presence of chronic kidney disease is associated with increased morbidity and mortality, yet it is also associated with underuse of evidence-based heart failure therapy that may reduce morbidity and mortality. Understanding the epidemiology and outcomes of chronic kidney disease in heart failure is essential to ensure proper management of these patients.

The prevalence of chronic kidney disease (CKD) and the associated factors to CKD in urban Korea: a population-based cross-sectional epidemiologic study

Chronic kidney disease (CKD) is a worldwide problem. This study was designed to survey the prevalence and risk factors for CKD in Korea. The 2,356 subjects were selected in proportion to age, gender, and city. Subjects 35 yr of age or older were selected from 7 cities. Estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) Study equation, with albuminuria defined as a urine albumin to creatinine ratio of 30 mg/g or more. The overall prevalence of CKD was 13.7%. The prevalences of CKD according to stage were 2.0% stage 1, 6.7% stage 2, 4.8% stage 3, 0.2% stage 4, and 0.0% stage 5. The prevalences of microalbuminuria and macroalbuminuria were 8.6% and 1.6%, respectively. The prevalence of eGFR less than 60 mL/min/1.73 m(2) was 5.0%. Age, body mass index (BMI), hypertension, diabetes mellitus, systolic blood pressure (SBP), diastolic blood pressure (DBP), and fasting blood glucose were independent factors related to the presence of CKD. In conclusions, Korea, in which the prevalence of CKD is increasing, should prepare a policy for early detection and appropriate treatment of CKD. The present data will be helpful in taking those actions.

Effect of repeated freeze-thaw cycles on urinary albumin-to-creatinine ratio

BACKGROUND

Urinary albumin-to-creatinine ratio (UACR) is widely used for diagnosis of chronic kidney disease in population investigation surveys. It is recommended that urinary albumin should be measured as soon as possible after urine is collected. It is not clear whether freezing and thawing affect the value of UACR and it is very inconvenient to measure UACR quickly in a population survey. The current study tries to determine the effect of repeated freezing and thawing on UACR to explore the possibility of freezing urine samples.

METHODS

Fifty-three urine samples with abnormal urinary albumin (ranging from 22.9 mg/L to 891.9 mg/L) were selected. The albumin and creatinine were measured before freezing, then all sample were stored at -30 degrees C. After being thawed at room temperature, the albumin and creatinine concentrations were measured again. The samples were frozen and thawed for five times, and albumin and creatinine were measured after each thawing. The measurements of albumin, creatinine, and UACR after each thawing were calculated and compared with its initial values using multiple comparisons of one-way ANOVA.

RESULTS

Compared with its initial value, urine albumin, creatinine and UACR all did not show any significant differences (p > 0.05).

CONCLUSIONS

It is feasible to freeze urine samples for future measurement of UACR. Urine samples can be safely frozen and thawed at least five times.

Asian leadership in chronic kidney disease

Asian Pacific countries include those with the highest incidence of renal failure in the world, the richest and poorest economies and unparalleled diversity of economy, culture and geography. From this come many challenges, but also a strong basis for the introduction of strategies to combat renal diseases. With a rapidly developing scientific community, Asia needs to accept the challenge of becoming a global leader in nephrology in the near future.

Additive interaction of hyperglycemia and albuminuria on risk of ischemic stroke in type 2 diabetes: Hong Kong Diabetes Registry

OBJECTIVE

The study aims to test whether biological interaction between hyperglycemia and albuminuria can explain the inconsistent findings from epidemiological studies and clinical trials about effects of hyperglycemia on stroke in type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 6,445 Hong Kong Chinese patients with type 2 diabetes and free of stroke at enrollment were followed up for a median of 5.37 years. Spline Cox proportional hazard regression was used to obtain hazard ratio curves, which were used to identify cutoff points of A1C and spot urinary albumin-to-creatinine ratio for increased ischemic stroke risk. The identified cutoff point of A1C was used to check biological interaction between A1C and albuminuria (micro- and macroalbuminuria). The biological interaction was estimated using relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index.

RESULTS

During the follow-up period, 4.45% (n = 287) of patients developed ischemic stroke. A1C was associated with increased hazard ratios of ischemic stroke in a near-linear manner except for two points-6.2 and 8.0%-where the slope between these two points accelerated. For A1C values <6.2%, the presence of micro/macroalbuminuria did not confer additional risk, while significant biological interaction between A1C and micro/macroalbuminuria for values >or=6.2% was observed (RERI 0.92, 95% CI 0.16-1.68, and AP 0.40, 0.01-0.78).

CONCLUSIONS

A1C >or=6.2% and micro/macroalbuminuria interact to markedly increase the ischemic stroke risk, which explains a large proportion of risk in patients with type 2 diabetes harboring both risk factors.

Gender-specific reference value of urine albumin-creatinine ratio in healthy Chinese adults: results of the Beijing CKD survey

BACKGROUND

The reference value of urine albumin-creatinine ratio (ACR) has racial disparities. The ACR reference value in a healthy Beijing population is reported.

METHODS

A reference Beijing population was sampled via a multistage, clustered complex sampling method. By excluding subjects with self-reported kidney disease, hypertension, diabetes, dyslipidemia, cardiovascular disease, obesity or underweight condition, overt proteinuria, hematuria, or pyuria, as well as those with an estimated glomerular filtration rate (eGFR) > 200ml/min/1.73m2 or < 60ml/min/1.73m2, apparently healthy subjects (1260 males, 2305 females, aged 18-84y) were selected to be included in the current analysis. Urine albumin was measured using the immunoturbidimetic method, creatinine was measured using Jaffe's kinetic method on a morning spot-urine sample, and ACR was calculated. The 95th percentile of ACR was used as the normal upper limit. The association between ACR and each of gender, age, systolic blood pressure, body mass index, serum glucose, lipids, and eGFR was examined.

RESULTS

The normal upper limit of ACR was 14mg/g (1.58mg/mmol) for males and 20mg/g (2.26mg/mmol) for females. Females had higher ACR values than males, and age, systolic blood pressure, and eGFR were positively correlated with ACR.

CONCLUSIONS

The ACR reference value in the healthy Beijing population is lower than that of the Western population. Age, systolic blood pressure, and eGFR were found to correlate with ACR.

The NCEP-ATPIII but not the IDF criteria for the metabolic syndrome identify Type 2 diabetic patients at increased risk of chronic kidney disease

AIM

To examine the association between chronic kidney disease (CKD) and the metabolic syndrome (MetS) using both International Diabetes Federation (IDF) and National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATPIII) definitions in Chinese subjects with Type 2 diabetes.

METHODS

Subjects with Type 2 diabetes were categorized according to the presence or absence of MetS by IDF or NCEP-ATPIII criteria. CKD was considered present if glomerular filtration rate, calculated using the abbreviated equation developed by the Modification of Diet in Renal Disease study with Chinese modification, was < 60 ml/min per 1.73 m2. Multivariate logistic regression analysis of the association between CKD and MetS by either definition was performed.

RESULTS

Of 6350 subjects (mean age 55.1 +/- 13.3 years), 3439 (54.2%) and 3204 (50.5%) had MetS by IDF and NCEP-ATPIII definitions, respectively. Using the IDF definition, the presence of MetS was not associated with CKD [odds ratio (OR) 0.96, 95% confidence interval (CI) 0.71, 1.29, P = 0.784]. In contrast, the association with CKD was significant when MetS was defined by the NCEP-ATPIII definition (OR 1.75, 95% CI 1.37, 2.24, P < 0.001). In subjects who did not have MetS (n = 2911) as defined by IDF criteria, 997 fulfilled the MetS criteria of NCEP-ATP III. The association with CKD was stronger, after adjustment for covariates, in these subjects (OR 1.42, 95% CI 1.03, 1.97, P = 0.032) compared with subjects who met IDF criteria of MetS.

CONCLUSION

In Type 2 diabetes, NCEP-ATPIII, but not the IDF definition of MetS, identifies a subgroup of patients who have a higher risk of CKD.

Metabolic syndrome predicts new onset of chronic kidney disease in 5,829 patients with type 2 diabetes: a 5-year prospective analysis of the Hong Kong Diabetes Registry

OBJECTIVE

Type 2 diabetes is the leading cause of end-stage renal disease worldwide. Aside from hyperglycemia and hypertension, other metabolic factors may determine renal outcome. We examined risk associations of metabolic syndrome with new onset of chronic kidney disease (CKD) in 5,829 Chinese patients with type 2 diabetes enrolled between 1995 and 2005.

RESEARCH DESIGN AND METHODS

Metabolic syndrome was defined by National Cholesterol Education Program Adult Treatment Panel III criteria with the Asian definition of obesity. Estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Modification of Diet in Renal Disease formula modified for the Chinese population. New onset of CKD was defined as eGFR <60 ml/min per 1.73 m(2) at the time of censor. Subjects with CKD at baseline were excluded from the analysis.

RESULTS

After a median follow-up duration of 4.6 years (interquartile range: 1.9-7.3 years), 741 patients developed CKD. The multivariable-adjusted hazard ratio (HR) of CKD was 1.31 (95% CI 1.12-1.54, P = 0.001) for subjects with metabolic syndrome compared with those without metabolic syndrome. Relative to subjects with no other components of metabolic syndrome except for diabetes, those with two, three, four, and five metabolic syndrome components had HRs of an increased risk of CKD of 1.15 (0.83-1.60, P = 0.407) 1.32 (0.94-1.86, P = 0.112), 1.64 (1.17-2.32, P = 0.004), and 2.34 (1.54-3.54, P < 0.001), respectively. The metabolic syndrome traits of central obesity, hypertriglyceridemia, hypertension, and low BMI were independent predictors for CKD.

CONCLUSIONS

The presence of metabolic syndrome independently predicts the development of CKD in subjects with type 2 diabetes.

Aldose reductase genotypes and cardiorenal complications: an 8-year prospective analysis of 1,074 type 2 diabetic patients

OBJECTIVE

We report the independent risk association of type 2 diabetic nephropathy with the z-2 allele of the 5'-(CA)(n) microsatellite and C-106T promoter polymorphisms of the aldose reductase gene (ALR2) using a case-control design. In this expanded cohort, we examined their predictive roles on new onset of cardiorenal complications using a prospective design.

RESEARCH DESIGN AND METHODS

In this 8-year prospective cohort of 1,074 type 2 diabetic patients (59% male, median age 61 years; disease duration 7 years) with an observation period of 8,592 person-years, none had clinical evidence of coronary heart disease (CHD) or chronic kidney disease at recruitment. The renal end point was defined as new onset of estimated glomerular filtration rate <60 ml/min per 1.72 m(2) or hospitalizations with dialysis or death due to renal disease, and CHD was defined as hospitalizations with myocardial infarction, ischemic heart disease, or related deaths.

RESULTS

After controlling for baseline risk factors and use of medications, we found that the ALR2 z-2 allele of (CA)(n) microsatellite carriers had increased risk of renal (hazard ratio 1.53 [95% CI 1.14-2.05], P = 0.005) or combined cardiorenal (1.31 [1.01-1.72], P = 0.047) end points. Carriers of the ALR2 C-106T polymorphism also had increased risk of renal (1.54 [1.15-2.07], P = 0.004) and cardiorenal (1.49 [1.14-1.95], P = 0.004) end points. Compared with noncarriers, patients with two risk-conferring genotypes had a twofold increased risk of renal (2.41 [1.57-3.70], P < 0.001) and cardiorenal (1.94 [1.29-2.91], P = 0.002) end points.

CONCLUSIONS

In Chinese type 2 diabetic patients, genetic polymorphisms of ALR2 independently predicted new onset of renal and cardiorenal end points, with the latter being largely mediated through renal disease.

Prevalence and risk factors associated with chronic kidney disease in an adult population from southern China

BACKGROUND

Population-based studies evaluating the prevalence of kidney damage in different communities have been limited in developing countries. We conducted a population-based screening study in the southern Chinese city of Guangzhou that aimed to identify the prevalence and associated risk factors of chronic kidney disease (CKD) in southern Chinese populations.

METHODS

We interviewed 6311 residents (>20 years) from six districts of Guangzhou from July 2006 to June 2007 and tested for haematuria, albuminuria and reduced renal function. Associations between age, gender, smoking, diabetes mellitus, hypertension, hyperuricaemia and kidney damage were examined.

RESULTS

There were 6311 subjects enrolled in this study. After adjustment for age and gender, the prevalence of albuminuria, haematuria and reduced estimated glomerular filtration rate (eGFR) was 6.6% [95% confidence interval (CI): 5.5-7.6%], 3.8% (95% CI: 3.4%, 4.3%) and 3.2% (95% CI: 2.4%, 3.3%), respectively. Approximately 12.1% (95% CI: 11.3%, 12.9%) of the sample population had at least one indicator of kidney damage. Age, diabetes mellitus, hypertension, central obesity, hyperlipidaemia and use of nephrotoxic medications were independently associated with albuminuria; hyperuricaemia, age, gender, hypertension and use of nephrotoxic medications were independently associated with reduced eGFR, and female gender was independently associated with haematuria.

CONCLUSIONS

In the general adult population from southern China, 12.1% has either proteinuria, haematuria and/or reduced eGFR, indicating the presence of kidney damage, with an awareness of only 9.6%. The high prevalence and low awareness of CKD in this population suggest an urgent need for CKD prevention programmes in China.

Complement deposition in renal histopathology of patients with ANCA-associated pauci-immune glomerulonephritis

BACKGROUND

The pathogenesis of ANCA-associated pauci-immune glomerulonephritis has not been fully elucidated. Several studies had suggested that complement deposition could be detected in renal histopathology. The current study investigated the clinical and pathological significance of complement deposition in renal histopathology of patients with ANCA-associated pauci-immune glomerulonephritis.

METHODS

Renal biopsy specimens from 112 patients with ANCA-associated pauci-immune glomerulonephritis were investigated using direct immunofluorescence, light and electron microscopy. For direct immunofluorescence, IgG, IgA, IgM, C3c and C1q staining on fresh frozen renal tissue were routinely performed immediately after a renal biopsy. Complement deposition was defined as the presence of C3c or C1q for at least 1+ in a 0-4+ scale. Clinical and histopathological data between patients with and without complement deposition were compared.

RESULTS

In direct immunofluorescence microscopy, C3c and C1q could be detected in glomerular capillary wall and/or mesangium in the specimens of 37/112 (33.0%), 7/112 (6.3%) patients, respectively. Compared with patients without C3c deposition, patients with C3c deposition had a higher level of urinary protein (P < 0.01) and poorer initial renal function (P < 0.05).

CONCLUSION

Complement deposition was not rare in renal histopathology of human ANCA-associated pauci-immune glomerulonephritis, which was associated with more severe renal injury.

The changing spectrum of primary glomerular diseases within 15 years: a survey of 3331 patients in a single Chinese centre

BACKGROUND

Primary glomerular disease (PGD) is the leading cause of end-stage renal disease (ESRD) in China. With the development of socioeconomic status of Chinese people in the last two decades, PGD in ESRD is intent to decrease. However, whether this affects the spectrum of PGD is not clear. The aim of the current study is to investigate the changing spectrum of PGD in China.

METHODS

The records of 5398 consecutive native renal biopsies performed in adults (>or=14 years of age) in our centre between 1993 and 2007 were retrospectively analysed. The criteria for renal biopsy and pathologic diagnosis were kept unchanged. The patients were grouped according to a 5-year interval, 1993-97 (period 1), 1998-2002 (period 2) and 2003-07 (period 3). Then they were divided into four groups according to age for stratified analysis: 14-24 years, 25-44 years, 45-59 years and the elderly (>or=60 years).

RESULTS

Three thousand, three hundred and thirty-one patients were diagnosed with PGD. PGD remained the most common renal disease, accounting for 65.9%, 57.7% and 63.2% in period 1, 2 and 3, respectively, without any significant difference. The proportion of elder patients increased significantly from 0% in 1993 to 9.1% in 2007 (P < 0.001). Within 1993-97, the leading PGD was IgA nephropathy (50.7%), followed by non-IgA MsPGN (19.9%), membranous nephropathy (MN) (13.3%) and minimal change disease (MCD) (6.3%), while within 2003-07, the most common PGD was still IgAN (58.2%), but followed by MN (14.3%), MCD (13.4%) and non-IgA MsPGN (7.0%). The age-adjusted frequency of IgAN and MCD increased significantly from period 1 to period 3 (P < 0.01 and P < 0.001, respectively), while that of non-IgA MsPGN, EnPGN and MPGN decreased significantly (P < 0.001, P < 0.01 and P < 0.05, respectively). There was no significant change in the age-adjusted frequency of FSGS, MN and CreGN during the study period. However, when patients were stratified by age, a sixfold increase in frequency of FSGS was identified in the 14- to 24-year group (P < 0.01).

CONCLUSIONS

The spectrum of primary glomerulonephritis has changed within the last 15 years. The relative frequency of non-IgA MsPGN, EnPGN and MPGN decreased significantly, while that of MCD and IgA nephropathy increased significantly. The relative frequency of FSGS increased significantly in younger patients.

Combination therapy of prednisone and ACE inhibitor versus ACE-inhibitor therapy alone in patients with IgA nephropathy: a randomized controlled trial

BACKGROUND

Recent studies have shown that both steroids and angiotensin-converting enzyme (ACE) inhibitors improve kidney survival and decrease proteinuria in patients with immunoglobulin A nephropathy. In this study, we aim to investigate whether the addition of steroids to ACE-inhibitor therapy produces a more potent antiproteinuric effect and better protection of kidney function than an ACE inhibitor alone.

STUDY DESIGN

Randomized controlled trial.

SETTING & PARTICIPANTS

Patients with biopsy-proven immunoglobulin A nephropathy with proteinuria of 1 to 5 g/d of protein.

INTERVENTION

63 patients were randomly assigned to either cilazapril alone (ACE-inhibitor group; n = 30) or steroid plus cilazapril (combination group; n = 33).

OUTCOMES & MEASUREMENTS

The primary end point was kidney survival, defined as a 50% increase in baseline serum creatinine level.

RESULTS

After follow-up for up to 48 months, 7 patients in the ACE-inhibitor group (24.1%) reached the primary end point compared with 1 patient (3%) in the combination group. Kaplan-Meier kidney survival was significantly better in the combination group than the ACE-inhibitor group after 24 and 36 months (96.6% versus 75.7%, 96.6% versus 66.2%; P = 0.001). Urine protein excretion significantly decreased in patients in the combination group compared with the ACE-inhibitor group (time-average proteinuria, 1.04 +/- 0.54 versus 1.57 +/- 0.86 g/d of protein; P = 0.01). Multivariate analysis showed that combination treatment (hazard ratio, 0.1; 95% confidence interval, 0.014 to 0.946) and time-average proteinuria (hazard ratio, 14.3; 95% confidence interval, 2.86 to 71.92) were independent predictors of kidney survival.

LIMITATIONS

Small sample size, a single center, and slight imbalances at baseline.

CONCLUSIONS

Our results suggest that the addition of steroid to ACE-inhibitor therapy provided additional benefit compared with an ACE inhibitor alone. However, this was a pilot study with a small number of participants achieving the end points, and thus further validation is necessary.

Geographic difference in the prevalence of chronic kidney disease among Japanese screened subjects: Ibaraki versus Okinawa

BACKGROUND

In Japan, there is a geographic difference in the prevalence of end-stage renal disease (ESRD). Few epidemiologic studies, however, have compared the prevalence of chronic kidney disease (CKD) among different geographic areas. Other than genetic factors, socioeconomic conditions and lifestyle are targets for modification.

METHODS

We examined the prevalence of CKD among two large community-based screened populations, 40 years of age and older, in Japan: Ibaraki (N = 187,863) and Okinawa (N = 83,150). Prevalence of CKD was defined as an estimated glomerular filtration rate (eGFR) of less than 60 ml/min/1.73 m(2) using the coefficient modified abbreviated Modification of Diet in Renal Disease (aMDRD) study equation using a standardized serum creatinine value. CKD prevalence was compared among screenees with (+) or without (-) hypertension (systolic blood pressure > or =140 mmHg, diastolic blood pressure > or =90 mmHg) and hyperglycemia (plasma glucose > or = 126 mg/dl).

RESULTS

Both male and female participants in Okinawa had a significantly lower prevalence of hypertension (-)/hyperglycemia (-) than did patients in Ibaraki. The prevalence of CKD in Okinawa was higher than that in Ibaraki among screenees with hypertension (-)/hyperglycemia (-), and highest among screenees with hypertension (+)/hyperglycemia (-).

CONCLUSION

The regional difference in CKD prevalence may underlie the variation in ESRD prevalence observed in Japan.

Variability and risk factors for kidney disease progression and death following attainment of stage 4 CKD in a referred cohort

BACKGROUND

The outcomes of patients referred to nephrologists are not well described in large cohorts. The objectives of this analysis are to describe the predictors of rapid progression of kidney disease and death in patients followed up by nephrologists.

STUDY DESIGN

Retrospective study.

SETTING & PARTICIPANTS

A cohort derived from all patients registered in the provincial database was formed that included all patients with index estimated glomerular filtration rate (eGFR) less than 30 mL/min/1.73 m(2), at least 3 subsequent eGFR values, and 4 months of follow-up between January 2000 and January 2004.

PREDICTORS

Variables used to predict outcomes included baseline eGFR, duration of follow-up before eGFR less than 30 mL/min/1.73 m(2), age, sex, ethnicity, presence of diabetes, blood pressure, level of proteinuria, hemoglobin level, phosphate level, calcium level, parathyroid hormone level, and use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, erythropoiesis-stimulating agents, and vitamin D.

OUTCOMES

Key outcomes of interest were death, dialysis therapy start, or loss of GFR greater than 5 mL/min/1.73 m(2)/y.

RESULTS

4,231 patients met inclusion criteria. Mean age was 67 years. Median follow-up was 31 months. During the first 2 years of follow-up, 24% started dialysis therapy, 1% received a transplant, 7% died, and 1% was lost to follow-up. Statistically significant variables associated with more rapid kidney disease progression differ from those that predict death. Younger age, male sex, higher eGFR, higher systolic and diastolic blood pressure, lower hemoglobin level, higher phosphorus and parathyroid hormone levels, and greater proteinuria are associated with more rapid kidney disease progression, and use of angiotensin-converting enzymes/angiotensin receptor blockers are protective. Older age, lower diastolic blood pressure, lower hemoglobin level, and higher phosphorous and parathyroid hormone levels are associated with death, whereas vitamin D use is protective.

LIMITATIONS

Results cannot be generalized to unreferred patients with eGFR less than 30 mL/min/1.73 m(2).

CONCLUSION

The clinical course of patients with chronic kidney disease stage 4 is variable. Targeted therapy aimed at modifiable risk factors needs to be evaluated to determine benefits of this approach.

Progression-related bias in the monitoring of kidney function in patients with diabetes and chronic kidney disease

The Cockcroft and Gault (CG) and Modification of Diet in Renal Disease (MDRD) equations underestimate the glomerular filtration rate (GFR) decline in diabetes. Do this decline and the albumin excretion rate (AER) influence their validity? In 161 diabetic patients, isotopically determined GFR (i-GFR) (51Cr-EDTA) was compared with estimated GFR (e-GFR) by the CG, MDRD, and the new Mayo Clinic Quadratic (MCQ) equations. We searched for a relation between the error in e-GFR and the AER. An influence of the AER outcome on the e-GFR decline was evaluated in 63 subjects followed up over 3 years. The MDRD and the MCQ were more precise and accurate than the CG, but they were biased. The error increased with AER for the CG (r = 0.25, P = .001) and the MDRD (r = 0.20, P = .009), but not for the MCQ. For the 63 patients followed up, the e-GFR declines by the 3 estimations were related to the initial AER, whereas no relation with arterial blood pressure, hemoglobin A(1C), hemoglobin, and blood lipids emerged. The MCQ declines were more pronounced: -10.5% +/- 8.9% in the macroalbuminuric group (P < .05 vs both microalbuminuric [-2.6% +/- 10.1%] and normoalbuminuric [-0.1% +/- 6.6%] groups), and were related to the outcome of the AER (r = 0.33, P < .05). As chronic kidney disease progresses in diabetes, the declining GFR and rising AER influence the estimation of GFR by the CG and MDRD equations, underestimating the GFR decline and the benefit of reducing the AER. The less affected MCQ evidences a slower e-GFR decline with AER control.

Implementation of the routine reporting of eGFR in Australia and New Zealand

The reporting of an eGFR (estimated glomerular filtration rate) with every requested serum creatinine concentration measurement has been successfully introduced as routine practice in Australia and New Zealand. This change in laboratory practice has been linked with a major educational initiative in the diagnosis and management of chronic kidney disease as well as standardization of a range of laboratory measurement and reporting issues. The process has been collaborative between renal physicians, chemical pathologists and laboratory scientists and their respective professional bodies, and the relevant decisions have been made collectively on the best available evidence. The initial guidelines were released in August 2005 and these have been followed up in 2007 with further recommendations to address issues arising since that time.

Independent associations between low-density lipoprotein cholesterol and cancer among patients with type 2 diabetes mellitus

BACKGROUND

The risk association between low-density lipoprotein (LDL) cholesterol and cancer remains controversial and largely unexplored for people not receiving statin therapy.

METHODS

We examined the risk association between LDL cholesterol and cancer among patients with type 2 diabetes mellitus who were free of cancer at enrolment and whose statin use was known. We considered a variety of nonlinear relationships in our analysis.

RESULTS

During a median follow-up period of 4.90 years, cancer developed in 270 (4.4%) of 6107 patients. Among the 3800 patients who did not receive statin therapy, the risk association between LDL cholesterol and cancer was represented by a V-shaped curve. Compared with patients whose LDL cholesterol was at least 2.80 mmol/L but less than 3.80 mmol/L, the risk of cancer, death from any cause or the composite outcome of cancer or death was greater among those with an LDL cholesterol level of less than 2.80 mmol/L (hazard ratio for cancer 1.74, 95% confidence interval [CI] 1.20-2.52) and those with an LDL cholesterol level of 3.80 mmol/L or greater (hazard ratio for cancer 1.87, 95% CI 1.29-2.71). Using 3.8 mmol/L as a reference point, we found that the hazard ratio for cancer for every millimole per litre absolute change in LDL cholesterol was 1.54 (95% CI 1.19-1.99) among patients not using statins; the hazard ratio was reduced to 1.24 (1.01-1.53) for the entire sample (statin users and those not using statins). These associations persisted after adjustment for covariates and exclusion of patients with less than 2.5 years of follow-up.

INTERPRETATION

Among patients with type 2 diabetes, the association between LDL cholesterol and cancer was V-shaped, whereby both low and high levels of LDL cholesterol were associated with elevated risk of cancer.

Establishing a renal management clinic in China: initiative, challenges, and opportunities

BACKGROUND

Chronic kidney disease (CKD) has been identified as a growing global burden and traditional health care systems are inadequate for the management of CKD patients. This paper describes an initiative to establish a renal management clinic (RMC) in China and discusses the challenges and opportunities in the management of CKD patients.

SUBJECTS AND METHODS

We collected and analyzed the data for the first 1,000 CKD patients treated since the establishment of the RMC (from April 2006 to April 2007). They had CKD stages 1-4 and stage 5 (before dialysis), as described by the Kidney Outcome Quality Initiatives (KDOQI). They were managed at the RMC established at the Peking University Third Hospital, by a multidisciplinary team (nephrologists, nurses, and dietitians) who developed care plans, clinical pathways, and a multidimensional patient-education program.

RESULTS

The most frequent causes of CKD among these 1,000 patient were glomerulonephritis (35%), hypertensive nephrosclerosis (19%), chronic interstitial nephritis (13%), and diabetic nephropathy (11%). Six percent of the patients had stage 1 CKD, 27% stage 2, 33% stage 3, 20% stage 4, and 13% had stage 5. Five hundred and fifty-four were male and 446 were female; mean age was 55 +/- 18.9 years (range 18-92 years). Seven hundred and seventy patients (77%) had hypertension; 400 patients (40%) had body mass index (BMI) equal to or higher than 25 kg/m(2); 180 (18%) had overt cardiovascular disease; 726 (72.6%) had low-density lipoprotein (LDL)-cholesterol higher than 2.6 mmol/l; 440 patients (44%) had hyperuriemia; and 274 patients (27.4%) had anemia (hemoglobin <110 g/l). Although the team is multidisciplinary, management of the patients in the RMC is undertaken mainly by nephrologists, whereas nurses and dietitians still do not play an important role. There are no family doctors in China and nephrologists are responsible for management of these patients' kidney disease and related complications.

CONCLUSIONS

Our findings show that the prevalence of hypertension, diabetes mellitus, overweight. and hyperuricemia is high among Chinese CKD population. Nurses and dietitians do not yet play an important role in the present pattern of RMC. We believe that the present medical care model should be revised because it does not address the concerns of CKD patients and their need for lifestyle changes that would help them to cope with their chronic condition.

Type 2 diabetes mellitus and its renal complications in relation to apolipoprotein E gene polymorphism

The apolipoprotein E (APOE) epsilon2 allele is reported to be associated with greater risk of renal impairment in type 2 diabetes. Relationships among APOE polymorphisms, renal impairment, and biochemical parameters were explored. A prospective study of 405 consenting Chinese type 2 diabetic patients [mean age +/- standard deviation (SD): 59.2 +/- 10.3 years] without advanced complications at entry was conducted. APOE genotyping and measurement of plasma biomarkers of oxidative stress and antioxidants were performed at entry. HbA1C, plasma glucose, lipids, creatinine, urine albumin/creatinine, and blood pressure were measured at entry and at up to 4 years of follow-up. APOE allelic frequencies were in Hardy-Weinberg equilibrium. Odds ratios of albuminuria at entry and/or during follow-up for different APOE groups were not significantly different. The non-epsilon2 (epsilon3/3, epsilon3/4, epsilon4/4) group had significantly greater plasma ascorbate (51.6 +/- 20.1 mumol/L) than the epsilon2 (epsilon2/2, epsilon2/3) group (44.5 +/- 16.2 mumol/L, P = 0.021), but higher plasma ascorbate levels did not seem to decrease the risk of renal impairment in the non-epsilon2 group. Baseline plasma lipid-standardized alpha-tocopherol levels were least in epsilon2 subjects with persistent albuminuria (3.6 +/- 1.1 mumol/mmol of total cholesterol plus triglycerides, P = 0.008) compared with epsilon2 subjects who had no albuminuria at entry or during follow-up (4.5 +/- 0.8 mumol/mmol of total cholesterol plus triglycerides). The APOE epsilon2 allele does not seem to be associated with increased risk of renal impairment in Chinese type 2 diabetic patients. Plasma lipid-standardized alpha-tocopherol may play a role in determining risk of renal dysfunction in type 2 diabetes.

Screening for CKD with eGFR: doubts and dangers

The early identification of chronic kidney disease (CKD) is a legitimate enterprise if it provides meaningful opportunities for effective and safe interventions that reduce the risk of death, end-stage renal disease, or complications of renal dysfunction. The screening of unselected populations not already known to be at risk of CKD has the potential of harm and has not been shown to be cost-effective. The application of formulas for the estimation of GFR (eGFR) to the guidelines for staging of chronic kidney disease (Kidney Disease Outcomes Quality Initiative, K/DOQI) as universal screening tools is of dubious value and has inherent dangers. This conclusion is based both on the unreliability of current formulas for determining eGFR and flaws in the K/DOQI schema for staging of CKD. The failure to take into account the normal age- and gender- associated decline in GFR and the lack of a requirement for other evidence of kidney disease in CKD stage 3 leads to an erroneous categorization of large numbers of mostly elderly and female subjects as having an intermediate stage of a lethal disease. Criteria for CKD staging should take into account the percentile distribution of eGFR by age and gender. Targeted screening for CKD is likely to be more cost-effective than universal screening. Whether early identification and treatment of subjects with "reduced" levels of GFR within the normal range for their age/gender, but without any other manifestations of kidney disease, will reduce the subsequent risk of cardiovascular events or progression to end-stage-renal disease is currently unproven.

Longitudinal analysis of performance of estimated glomerular filtration rate as renal function declines in chronic kidney disease

BACKGROUND

Numerous studies have assessed the accuracy of equations estimating glomerular filtration rate (eGFR) from serum creatinine in individuals with chronic kidney disease (CKD) in cross-sectional studies. Limited literature exists, however, on the consistency of performance of these equations in longitudinal studies as renal function declines.

METHODS

Radionucleotide-measured GFR from 155 predialysis patients with stage 3-5 CKD was compared with eGFR derived from four equations [6-variable Modification of Diet in Renal Disease (6-MDRD), 4-variable MDRD (4-MDRD), Cockcroft-Gault (CG) and Cockcroft-Gault equations corrected for body surface area (CGC)] at baseline, 12 and 24 months. Bias (difference between eGFR and measured GFR) was used as a measure of performance. Restricted Maximum Likelihood (REML) models were used to identify variables potentially affecting the performance of estimating equations across time.

RESULTS

Mean measured GFR (+/-SD) at baseline, 12 and 24 months was 25.9 +/- 10.7, 23.1 +/- 10.6 and 20.3 +/- 10.1 mL/min/1.73 m(2), respectively. There was a statistically significant negative association between bias and GFR for all four estimates (range: -0.76 to -0.71, P < 0.001 for all), indicating worsening underestimation and overestimation at higher and lower GFR, respectively. This negative association significantly reduced over the 24 months (P < 0.001); however, this was largely due to persistent underestimation of eGFR from individuals with GFR >50 mL/min/1.73 m(2). For those with a baseline GFR <50 mL/min/1.73 m(2), the change in bias for any of the four equations over 24 months was <or=1.1 mL/min/1.73 m(2), suggesting relatively preserved performance with time. The MDRD equations showed a sustained advantage in estimating renal function that was more evident as GFR declined.

CONCLUSION

GFR estimates are inexpensive and show an acceptable longitudinal performance for monitoring CKD patients with GFR <50 mL/min/1.73 m(2). Inaccuracies appear more substantial above this level of GFR, and care with interpretation is required.

Tacrolimus for the treatment of systemic lupus erythematosus with pure class V nephritis

OBJECTIVES

The treatment of pure membranous (class V) lupus nephropathy remains unsatisfactory. We studied the efficacy and safety of tacrolimus in the treatment of membranous nephritis secondary to SLE.

METHODS

We recruited 18 consecutive SLE patients (tacrolimus group) with recently confirmed biopsy-proven class V lupus nephritis. They were treated with a tailing dose of oral prednisolone and tacrolimus 0.1-0.2 mg/kg/day for 6 months, followed by maintenance prednisolone and AZA. The rate of resolution of proteinuria and SLEDAI were compared with 19 historical controls treated with oral cyclophosphamide or AZA (control group). All patients were followed for 12 months.

RESULTS

Baseline clinical characteristics were comparable between the groups. For the tacrolimus group, the complete and partial remission rates were 27.8 and 50.0%, respectively at 12 weeks; for the control group, they were 15.8 and 47.4%, respectively (overall chi-square test, P = 0.5). However, tacrolimus group had faster resolution of proteinuria than the control group by the general linear model with repeated measures (P = 0.032). At 12 weeks, proteinuria was reduced by 76.2 +/- 17.0% for the tacrolimus group and 47.1 +/- 51.1% for the control group (P = 0.028). Serial change in renal function and SLEDAI score did not differ between the groups. During the study period, four patients of the tacrolimus group, and 11 of the control group, developed lupus flare (P = 0.027). There was no serious adverse effect in the tacrolimus group.

CONCLUSIONS

A 6-month course of tacrolimus is a safe and effective treatment of pure class V (membranous) lupus nephritis. As compared with conventional cytotoxic treatment, tacrolimus possibly results in a faster resolution of proteinuria, and a lower risk of lupus flare within 1 yr. The long-term effect and optimal regimen of tacrolimus require further study.

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.