Modification of the CKD epidemiology collaboration (CKD-EPI) equation for Japanese: accuracy and use for population estimates

Serum total bilirubin concentration is negatively associated with increasing severity of retinopathy in patients with type 2 diabetes mellitus

AIMS

Serum bilirubin concentration is associated with diabetic retinopathy in patients with type 2 diabetes. This study investigated the relationships between serum bilirubin concentration and the severity of diabetic retinopathy. In addition, the importance of bilirubin was compared with factors that were previously shown to be associated with the incidence of diabetic retinopathy.

METHODS

A total of 674 patients with type 2 diabetes were investigated in this cross-sectional study. Serum total bilirubin concentration was compared between patients with and without diabetic retinopathy, and according to the severity of retinopathy. Univariate and multivariate analyses were performed to evaluate the association of retinopathy with total bilirubin concentration, duration of diabetes, body mass index, systolic blood pressure, and haemoglobin A1c.

RESULTS

Serum total bilirubin concentration was significantly lower in patients with retinopathy than in those without. Patients with severer retinopathy showed lower total bilirubin concentration, longer diabetes duration, and higher systolic blood pressure. These three parameters were independent explanatory factors for diabetic retinopathy.

CONCLUSIONS

Total bilirubin concentration is lower in patients with type 2 diabetes complicated with severer retinopathy. Thus, bilirubin might protect against retinopathy in patients with type 2 diabetes.

Thyroid hormone levels and incident chronic kidney disease in euthyroid individuals: the Kangbuk Samsung Health Study

BACKGROUND

Overt and subclinical hypothyroidism are associated with higher levels of serum creatinine and with increased risk of chronic kidney disease (CKD). The prospective association between thyroid hormones and kidney function in euthyroid individuals,however, is largely unexplored.

METHODS

We conducted a prospective cohort study in 104 633 South Korean men and women who were free of CKD and proteinuria at baseline and had normal thyroid hormone levels and no history of thyroid disease or cancer. At each annual or biennial follow-up visit, thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxin (FT4) levels were measured by radioimmunoassay. The study outcome was incident CKD, defined as an estimated glomerular filtration rate (eGFR)<60 ml/min/1.73 m2 based on the Chronic Kidney Disease Epidemiology Collaboration creatinine equation.

RESULTS

After a median follow-up of 3.5 years, 1032 participants developed incident CKD.There was a positive association between high-normal levels of TSH and increased risk of incident CKD. In fully-adjusted models including baseline eGFR, the hazard ratio comparing the highest vs the lowest quintiles of TSH was 1.26 [95% confidence interval (CI) 1.02 to 1.55; P for linear trend=0.03]. In spline models, FT3 levels below 3 pg/ml were also associated with increased risk of incident CKD. There was no association between FT4 levels and CKD.

CONCLUSIONS

In a large cohort of euthyroid men and women, high levels of TSH and low levels of FT3, even within the normal range, were modestly associated with an increased risk of incident CKD.

Reduction in the incidence of acute kidney injury after aortic arch surgery with low-dose atrial natriuretic peptide: a randomised controlled trial

BACKGROUND

Acute kidney injury (AKI) after surgery is associated with an increased risk of adverse events and death. Atrial natriuretic peptide (ANP) dilates the preglomerular renal arteries and inhibits the renin-angiotensin axis. A low-dose ANP infusion increases glomerular filtration rate after cardiovascular surgery, but it is not known whether it reduces the incidence of AKI or the mortality rate.

OBJECTIVE

To evaluate whether an intravenous ANP infusion prevents AKI in patients undergoing aortic arch surgery requiring hypothermic circulatory arrest.

DESIGN

A randomised controlled study.

SETTING

Operating room and intensive care unit at Kawasaki Saiwai Hospital, Kanagawa, Japan.

PATIENTS

Forty-two patients with normal preoperative renal function undergoing elective repair of an aortic arch aneurysm.

INTERVENTION

Patients were assigned randomly to receive a fixed dose of ANP (0.0125 μg (-1) kg(-1)  min) or placebo. The infusion was started after induction of anaesthesia and continued for 24  h postoperatively.

MAIN OUTCOME MEASURES

The primary end-point was the incidence of AKI within 48 h after surgery.

RESULTS

AKI developed in 30% of patients who received ANP compared with 73% of patients who received placebo (P = 0.014). Intraoperative urine output was almost 1 l greater in patients who received ANP (1865 ± 1299 versus 991 ± 480  ml in the control group, P = 0.005). However, there were no differences in mean arterial pressure or number of episodes of hypotension between the groups. Length of hospital and intensive care stays were not significantly different, nor was there a difference in 30-day mortality. No patients required haemodialysis or continuous renal replacement therapy.

CONCLUSION

We found that an intravenous infusion of ANP at 0.0125  μg  kg(-1)  min(-1) is an effective intervention for reducing the incidence of postoperative AKI, and appears to afford a degree of renal protection during and after cardiovascular surgery.

TRIAL REGISTRATION

Kawasaki ANP trial, UMIN Clinical Trials Registry ID: UMIN000011650.

Biomarkers in chronic kidney disease, from kidney function to kidney damage

Chronic kidney disease (CKD) typically evolves over many years, with a long latent period when the disease is clinically silent and therefore diagnosis, evaluation and treatment is based mainly on biomarkers that assess kidney function. Glomerular filtration rate (GFR) remains the ideal marker of kidney function. Unfortunately measuring GFR is time consuming and therefore GFR is usually estimated from equations that take into account endogenous filtration markers like serum creatinine (SCr) and cystatin C (CysC). Other biomarkers such as albuminuria may precede kidney function decline and have demonstrated to have strong associations with disease progression and outcomes. New potential biomarkers have arisen with the promise of detecting kidney damage prior to the currently used markers. The aim of this review is to discuss the utility of the GFR estimating equations and biomarkers in CKD and the different clinical settings where these should be applied. The CKD-Epidemiology Collaboration equation performs better than the modification of diet in renal disease equation, especially at GFR above 60 mL/min per 1.73 m². Equations combining CysC and SCr perform better than the equations using either CysC or SCr alone and are recommended in situations where CKD needs to be confirmed. Combining creatinine, CysC and urine albumin to creatinine ratio improves risk stratification for kidney disease progression and mortality. Kidney injury molecule and neutrophil gelatinase-associated lipocalin are considered reasonable biomarkers in urine and plasma to determine severity and prognosis of CKD.

Association between Serum Bilirubin and Estimated Glomerular Filtration Rate among Diabetic Patients

The subjects comprised 230 men aged 77 ± 10 (range: 50-100) years and 279 women aged 81 ± 10 (50-101) years that visited the medical department. We examined the relationship between increased serum bilirubin and renal function evaluated by estimated glomerular filtration rate (eGFR) using CKD-EPI equations modified by a Japanese coefficient. Compared with the fourth quartile in serum bilirubin (1.01-1.97 mg/dL), the nonadjusted, age and gender-adjusted, and multivariate-adjusted odds ratios {95% confidence interval (CI)} of eGFR <60 mL/min/1.73 m(2) for the first quartile in serum bilirubin (0.13-0.50 mg/dL) were 2.08 (1.25-3.44), 1.82 (1.07-3.09), and 1.53 (0.83-2.81), respectively. Moreover, compared with the fourth quartile, nonadjusted, age and gender-adjusted, and multivariate-adjusted odds ratios (95% CI) of eGFR <45 mL/min/1.73 m(2) for the first quartile were 3.50 (1.95-6.23), 3.12 (1.72-5.65), and 3.53 (1.71-7.26), respectively. The data were further stratified by gender, age, medication (antihypertensive, antidyslipidemic, and antidiabetic agents), and prevalence of cardiovascular disease (CVD). The standardized coefficients for eGFR were significant in all the subgroups other than the prevalence of CVD, and there were significant interactions between the two groups regarding CVD. Our data demonstrated an independent positive association between serum bilirubin and eGFR among diabetic patients.

Chronic kidney disease screening methods and its implication for Malaysia: an in depth review

Chronic Kidney Disease has become a public health problem, imposing heath, social and human cost on societies worldwide. Chronic Kidney Disease remains asymptomatic till late stage when intervention cannot stop the progression of the disease. Therefore, there is an urgent need to detect the disease early. Despite the high prevalence of Chronic Kidney Disease in Malaysia, screening is still lacking behind. This review discusses the strengths and limitations of current screening methods for Chronic Kidney Disease from a Malaysian point of view. Diabetic Kidney Disease was chosen as focal point as Diabetes is the leading cause of Chronic Kidney Disease in Malaysia. Screening for Chronic Kidney Disease in Malaysia includes a urine test for albuminuria and a blood test for serum creatinine. Recent literature indicates that albuminuria is not always present in Diabetic Kidney Disease patients and serum creatinine is only raised after substantial kidney damage has occurred.  Recently, cystatin C was proposed as a potential marker for kidney disease but this has not been studied thoroughly in Malaysia.  Glomerular Filtration Rate is the best method for measuring kidney function and is widely estimated using the Modification of Diet for Renal Disease equation. Another equation, the Chronic Kidney Disease Epidemiology Collaboration Creatinine equation was introduced in 2009. The new equation retained the precision and accuracy of the Modification of Diet for Renal Disease equation at GFR < 60ml/min/1.73m2, showed less bias and improved precision at GFR>60ml/min/1.73m2. In Asian countries, adding an ethnic coefficient to the equation enhanced its performance. In Malaysia, a multi-ethnic Asian population, the Chronic Kidney Disease Epidemiology Collaboration equation should be validated and the Glomerular Filtration Rate should be reported whenever serum creatinine is ordered. Reporting estimated Glomerular Filtration Rate will help diagnose patients who would have been otherwise missed if only albuminuria and serum creatinine are measured.

Association between serum bilirubin and estimated glomerular filtration rate among elderly persons

Chronic kidney disease (CKD) is a major public health problem. However, few studies have examined the significance of serum bilirubin as a risk factor for the development of CKD in the general Japanese population. The subjects comprised 413 men (mean age: 79±9 years; (range, 60-100 years) and 637 women (mean age: 81±8 years; range, 60-106 years) who visited the medical department of Seiyo Municipal Nomura Hospital. We examined the relationship between increased serum bilirubin and renal function that was evaluated by estimated glomerular filtration rate (eGFR) using CKD-EPI equations modified by a Japanese coefficient. Stepwise multiple regression analysis with eGFR as the objective variable, and adjusted risk factors as the explanatory variables, showed that serum bilirubin (β = 0.11, P<0.001) was significantly and independently associated with eGFR, in addition to gender, age, prevalence of antihypertensive medication, triglycerides, prevalence of antidiabetic medication, and serum uric acid. Compared with stages 1+2 (eGFR ≥60.0 ml/min/1.73 m2), mean multivariate-adjusted odds ratio {95% (confidence interval (CI)} for hypobilirubinemia (first quartile, <0.52 mg/dL) was 3.52 (range: 1.88-6.59). Next, to control potential confounding factors, data were further stratified by gender, age, medication (antihypertensive, antidyslipidemic, and antidiabetic agents), and prevalence of cardiovascular disease. The standardized coefficient for eGFR was significant in both groups, and there was no interaction between the groups. Our data demonstrated an independent positive association between serum bilirubin and eGFR in both genders. Low serum bilirubin level would be useful as a potential risk factor for renal function.

Performance of the Japanese glomerular filtration rate equation based on standardized serum cystatin C in potential kidney donors

BACKGROUND

It was reported that the glomerula filtration rate (GFR) equation based on serum creatinine underestimated the GFR in potential kidney donors. Recently, the Japanese GFR equation based on standardized serum cystatin C was reported. Therefore, we assessed the performance of the equation in potential kidney donors.

METHODS

Forty-five potential kidney donors from 2 hospitals were included. GFR was measured (mGFR) using inulin renal clearance. Serum creatinine was measured using the enzymatic method. Serum cystatin C was measured using a nephelometric immunoassay (Siemens) and calibrated to the standardized value traceable to ERM-DA471/IFCC using an equation reported previously. The estimated GFR (eGFR) was calculated using the Japanese GFR equation based on serum creatinine (eGFRcreat) and the Japanese GFR equation based on serum cystatin C (eGFRcys). Bias (mGFR - eGFR) and accuracy (P30) of the equations were evaluated.

RESULTS

Inulin clearance, eGFRcreat, and eGFRcys were 91.0 ± 18.2, 78.5 ± 18.8, and 93.3 ± 16.3 mL/min/1.73 m(2), respectively. Bias of eGFRcreat was 12.4 ± 15.8 mL/min/1.73 m(2) and significantly different from zero, indicating underestimation of GFR. Bias of eGFRcys was -2.3 ± 16.3 mL/min/1.73 m(2) and was not significantly different from zero, suggesting better performance. But, the precision (standard deviation [SD] of bias) and accuracy (P30: Percentage of participants with eGFR within 30% of mGFR) of eGFRcys were not better compared with eGFRcreat. Accuracies (P30) of eGFRcreat and eGFRcys were 87% (95% confidence interval [CI], 74-94) and 82% (95% CI, 69-91), respectively.

CONCLUSION

Bias of eGFRcys was better compared with eGFRcreat. But, the precision (SD of bias) and accuracy of eGFRcys were not superior compared with eGFRcreat in potential kidney donors.

Clinical implications of linear immunofluorescent staining for immunoglobulin G in patients with diabetic nephropathy

AIMS

The kidneys of patients with diabetes mellitus usually exhibit a characteristic pattern of linear immunofluorescent staining for immunoglobulin G (IgG) along the glomerular and tubular basement membranes. However, the association between linear IgG staining and the renal prognosis remains unclear.

METHODS

Among 223 patients with diabetes who underwent renal biopsy from 1985 to 2010 and were confirmed to have pure diabetic nephropathy according to the classification of Tervaert et al., 165 patients (glomerular classes I to III) were enrolled in this study. Immunofluorescent staining was classified into three categories according to its intensity (0=none, 1=weakly positive, and 2=positive). Cox proportional hazards regression analysis was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for death-censored renal death, with each regression analysis employing four levels of multivariate adjustment.

RESULTS

After adjustment for important clinical factors at the time of renal biopsy, the HR for death-censored renal death in patients with an IgG staining score of 1 or 2 was, respectively, 3.01 (95% CI: 1.05-8.68) and 4.68 (1.67-13.1) compared with patients who had a staining score of 0. Even after adjustment for clinical variables and pathological findings, the HR for IgG score of 1 or 2 was higher than that for an IgG score of 0, and it was, respectively, 2.22 (0.71-7.00) and 3.76 (1.27-11.2).

CONCLUSIONS

More intense linear IgG staining is associated with a higher HR for renal death, which suggests that linear immunofluorescent staining for IgG may be a prognostic indicator in patients with diabetic nephropathy.

A new modified CKD-EPI equation for Chinese patients with type 2 diabetes

Objective

To improve the performance of glomerular filtration rate (GFR) estimating equation in Chinese type 2 diabetic patients by modification of the CKD-EPI equation.

Design and patients

A total of 1196 subjects were enrolled. Measured GFR was calibrated to the dual plasma sample ^99mTc-DTPA-GFR. GFRs estimated by the re-expressed 4-variable MDRD equation, the CKD-EPI equation and the Asian modified CKD-EPI equation were compared in 351 diabetic/non-diabetic pairs. And a new modified CKD-EPI equation was reconstructed in a total of 589 type 2 diabetic patients.

Results

In terms of both precision and accuracy, GFR estimating equations all achieved better results in the non-diabetic cohort comparing with those in the type 2 diabetic cohort (30% accuracy, P≤0.01 for all comparisons). In the validation data set, the new modified equation showed less bias (median difference, 2.3 ml/min/1.73 m² for the new modified equation vs. ranged from −3.8 to −7.9 ml/min/1.73 m² for the other 3 equations [P<0.001 for all comparisons]), as was precision (IQR of the difference, 24.5 ml/min/1.73 m² vs. ranged from 27.3 to 30.7 ml/min/1.73 m²), leading to a greater accuracy (30% accuracy, 71.4% vs. 55.2% for the re-expressed 4 variable MDRD equation and 61.0% for the Asian modified CKD-EPI equation [P = 0.001 and P = 0.02]).

Conclusion

A new modified CKD-EPI equation for type 2 diabetic patients was developed and validated. The new modified equation improves the performance of GFR estimation.

Relative risks of chronic kidney disease for mortality and end-stage renal disease across races are similar

Some suggest race-specific cutpoints for kidney measures to define and stage chronic kidney disease (CKD), but evidence for race-specific clinical impact is limited. To address this issue, we compared hazard ratios of estimated glomerular filtration rates (eGFR) and albuminuria across races using meta-regression in 1.1 million adults (75% Asians, 21% Whites, and 4% Blacks) from 45 cohorts. Results came mainly from 25 general population cohorts comprising 0.9 million individuals. The associations of lower eGFR and higher albuminuria with mortality and end-stage renal disease (ESRD) were largely similar across races. For example, in Asians, Whites, and Blacks, the adjusted hazard ratios (95% confidence interval) for eGFR 45-59 versus 90-104 ml/min per 1.73 m(2) were 1.3 (1.2-1.3), 1.1 (1.0-1.2), and 1.3 (1.1-1.7) for all-cause mortality, 1.6 (1.5-1.7), 1.4 (1.2-1.7), and 1.4 (0.7-2.9) for cardiovascular mortality, and 27.6 (11.1-68.7), 11.2 (6.0-20.9), and 4.1 (2.2-7.5) for ESRD, respectively. The corresponding hazard ratios for urine albumin-to-creatinine ratio 30-299 mg/g or dipstick 1+ versus an albumin-to-creatinine ratio under 10 or dipstick negative were 1.6 (1.4-1.8), 1.7 (1.5-1.9), and 1.8 (1.7-2.1) for all-cause mortality, 1.7 (1.4-2.0), 1.8 (1.5-2.1), and 2.8 (2.2-3.6) for cardiovascular mortality, and 7.4 (2.0-27.6), 4.0 (2.8-5.9), and 5.6 (3.4-9.2) for ESRD, respectively. Thus, the relative mortality or ESRD risks of lower eGFR and higher albuminuria were largely similar among three major races, supporting similar clinical approach to CKD definition and staging, across races.

Long-term exposure to tenofovir continuously decrease renal function in HIV-1-infected patients with low body weight: results from 10 years of follow-up

OBJECTIVES

To investigate the effect of long-term tenofovir disoproxil fumarate (TDF) use on renal function, especially in patients with low body weight who are vulnerable to TDF nephrotoxicity.

DESIGN

A single-center, observational study in Tokyo, Japan.

METHODS

We performed a 10 years cohort study of 792 HIV-1-infected patients. The effect of long-term TDF use on estimated glomerular filtration rate (eGFR) was investigated on treatment-naive patients who started TDF-containing antiretroviral therapy (n = 422) and those who started abacavir-containing antiretroviral therapy as control (n = 370). Three renal endpoints were examined by the logistic regression model: decrement in eGFR of higher than 10 ml/min per 1.73 m relative to the baseline, more than 25% decrement in eGFR, and eGFR lower than 60 ml/min per 1.73 m at least 3 months apart. The loss in eGFR was estimated using linear mixed models for repeated measures.

RESULTS

The median weight at baseline was 63 kg. TDF use increased the risk of all three renal outcomes compared with the control group: higher than 10 ml/min per 1.73 m decrement in eGFR [adjusted odds ratio (OR) = 2.1, 95% confidence interval (CI) 1.45-3.14, P < 0.001], more than 25% decrement (adjusted OR = 2.1, 95% CI 1.50-2.90, P < 0.001), and eGFR lower than 60 ml/min per 1.73 m at least 3 months apart (adjusted OR = 3.9, 95% CI 1.62-9.36, P = 0.002). The cumulative mean loss relative to the control after 1, 2, 3, 4, and 5 years of TDF exposure was -3.8, -3.6, -5.5, -6.6, and -10.3 ml/min per 1.73 m, respectively, indicating that the loss in eGFR increased over time (P < 0.001).

CONCLUSION

In this cohort of patients with low body weight, TDF exposure increased the risk of renal dysfunction. Furthermore, the loss in eGFR relative to the control increased continuously up to 5 years.

Pharmacokinetic of antiepileptic drugs in patients with hepatic or renal impairment

Many factors influence choice of antiepileptic drugs (AEDs), including efficacy of the drug for the indication (epilepsy, neuropathic pain, affective disorder, migraine), tolerability, and toxicity. The first-generation AEDs and some newer AEDs are predominately eliminated by hepatic metabolism. Other recent AEDs are eliminated by renal excretion of unchanged drug or a combination of hepatic metabolism and renal excretion. The effect of renal and hepatic disease on the dosing will depend on the fraction of the AED eliminated by hepatic and/or renal excretion, the metabolic isozymes involved, as well as the extent of protein binding, if therapeutic drug monitoring is used. For drugs that are eliminated by renal excretion, methods of estimating creatinine clearance can be used to determine dose adjustments. For drugs eliminated by hepatic metabolism, there are no specific markers of liver function that can be used to provide guidance in dosage adjustments. Based on studies with probe drugs, the hepatic metabolic enzymes are differentially affected depending on the cause and severity of hepatic disease, which can aid in predicting dose adjustment when clinical data are not available. Several AEDs are also associated with laboratory markers of mild hepatic dysfunction and, rarely, more severe hepatic injury. In contrast, the risk of renal injury from AEDs is generally low. In general, co-morbid hepatic or renal diseases influence the decision for the selection of an AED. For some patients dosing changes to their existing AEDs may be appropriate. For others, a change to another AED may be a better option.

Comparison of predictive value for first cardiovascular event between Japanese GFR equation and coefficient-modified CKD-EPI equation

BACKGROUND

The most superior GFR-estimating equation from the viewpoint of cardiovascular disease (CVD) prediction remains unclear. Thus, we performed cross-sectional comparison between two GFR-estimating equations (Japanese GFR equation and coefficient-modified CKD-EPI equation) and CVD incidence using Japanese nationwide "specific health checkup" data.

METHODS

We recruited Japanese residents (241,159 individuals; mean 63 years; male, 38.6 %) who had not experienced CVD event (cardiac disease or stroke, or both). We calculated estimated GFR using two equations, and compared their predictive value for first symptomatic CVD event within 1 year.

RESULTS

Of all subjects, the mean GFR estimated by the Japanese GFR equation (JPN-eGFR) modified for Japanese was 75.83 ± 16.18 mL/min/1.73 m(2), and that by the coefficient-modified CKD-EPI equation (mCKDEPI-eGFR) was 76.39 ± 9.61 mL/min/1.73 m(2). Area under the receiver operating characteristics curves (95 % confidence intervals) for predicting CVD event by mCKDEPI-eGFR vs. JPN-eGFR were 0.596 (0.589-0.603) vs. 0.562 (0.554-0.569). Using mCKDEPI-eGFR, the crude odds ratio (OR) for CVD incident in the 4th quartile group was far more than double (OR 2.46, 95 % CI 2.29-2.66) that in the 1st quartile group. Using JPN-eGFR, the crude OR in the 4th quartile group was less than double (OR 1.61, 95 % CI 1.51-1.73) that in the 1st quartile group. However, such superior predictive value of mCKDEPI-eGFR disappeared after adjustment for confounding factors (age, gender, BMI, presence of proteinuria, hypertension, diabetes, dyslipidemia and current smoking).

CONCLUSION

GFR estimated by the coefficient-modified CKD-EPI equation was more closely related to CVD incidence than that estimated by the Japanese GFR equation. However, it is possible that low mCKDEPI-eGFR also reflects some cardiovascular risk(s) other than kidney dysfunction.

Night-time blood pressure is associated with the development of chronic kidney disease in a general population: the Ohasama Study

OBJECTIVE

Ambulatory blood pressure (BP) is reportedly associated with target organ damage. However, whether ambulatory BP carries prognostic significance for the development of chronic kidney disease (CKD) has not been confirmed.

METHOD

We measured ambulatory BP in 843 participants without CKD at baseline from a general Japanese population and examined the incidence of CKD defined as positive proteinuria or an estimated glomerular filtration rate (eGFR) less than 60 ml/min per 1.73 m at health checks. The association between baseline ambulatory BP and CKD incidence was examined using the Cox proportional hazard regression model adjusted for sex, age, BMI, habitual smoking, habitual alcohol consumption, diabetes mellitus, hypercholesterolemia, a history of cardiovascular disease, antihypertensive medication, eGFR at baseline, the number of follow-up examinations, and the year of the baseline examination.

RESULTS

The mean age of the participants averaged 62.9 ± 8.1 years, 71.3% were women and 23.7% were under antihypertensive medication. During a median follow-up of 8.3 years, 220 participants developed CKD events. The adjusted hazard ratios for CKD in a 1-standard deviation increase in daytime and night-time SBP were 1.13 [95% confidence interval (CI) 0.97-1.30] and 1.21 (95% CI 1.04-1.39), respectively. When night-time and daytime BP was mutually adjusted into the same model, only night-time BP persisted as an independent predictor of CKD.

CONCLUSION

Night-time BP is a better predictor of CKD development than daytime BP in the general population. Ambulatory BP measurement is considered useful for evaluating the risk of progression to CKD.

Modification of diet in renal disease (MDRD) study and CKD epidemiology collaboration (CKD-EPI) equations for Taiwanese adults

Background

Estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) study or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations may not be accurate for Asians; thus, we developed modified eGFR equations for Taiwanese adults.

Methods

This cross-sectional study compared the Taiwanese eGFR equations, the MDRD study, and the CKD-EPI equations with inulin clearance (C_in). A total of 695 adults including 259 healthy volunteers and 436 CKD patients were recruited. Participants from the Kaohsiung Medical University Hospital were used as the development set (N = 556) to develop the Taiwanese eGFR equations, whereas participants from the National Taiwan University Hospital were used as the validation set (N = 139) for external validation.

Results

The Taiwanese eGFR equations were developed by using the extended Bland-Altman plot in the development set. The Taiwanese MDRD equation was 1.309×MDRD^0.912, Taiwanese CKD-EPI was 1.262×CKD-EPI^0.914 and Taiwanese four-level CKD-EPI was 1.205×four-level CKD-EPI^0.914. In the validation set, the Taiwanese equations had the lowest bias, the Taiwanese equations and the Japanese CKD-EPI equation had the lowest RMSE, whereas the Taiwanese and the Japanese equations had the best precision and the highest P₃₀ among all equations. However, the Taiwanese MDRD equation had higher concordance correlation than did the Taiwanese CKD-EPI, the Taiwanese four-level CKD-EPI and the Japanese equations. Moreover, only the Taiwanese equations had no proportional bias among all of the equations. Finally, the Taiwanese MDRD equation had the best diagnostic performance in terms of ordinal logistic regression among all of the equations.

Conclusion

The Taiwanese MDRD equation is better than the MDRD, CKD-EPI, Japanese, Asian, Thai, Taiwanese CKD-EPI, and Taiwanese four-level CKD-EPI equations for Taiwanese adults.

Urinary and plasma levels of vasohibin-1 can predict renal functional deterioration in patients with renal disorders

Vasohibin-1 (VASH-1) is a negative feedback regulator of angiogenesis, and a small vasohibin-binding protein (SVBP) serves as its secretory chaperone and contributes to its antiangiogenic effects. In the present study, we aimed to define the clinical significance of VASH-1 and SVBP in patients with chronic kidney disease (CKD). We recruited 67 Japanese hospitalized patients with renal disorders with (n = 45) or without (n = 22) renal biopsy samples and 10 Japanese healthy controls. We evaluated the correlations between the plasma and urinary levels of VASH-1/VASH-1-SVBP complex/SVBP and the clinicopathological parameters. The plasma levels of VASH-1 were inversely correlated with age and systolic and diastolic blood pressure and positively correlated with crescent formation. Increased plasma and urinary levels of VASH-1 and VASH-1-SVBP complex were significantly correlated with worse renal outcomes. These results demonstrate an association between elevated urinary and plasma levels of VASH-1 and progressive decline of the renal function, thus suggesting a potential role for VASH-1 in predicting a worse renal prognosis in patients with renal disease, including CKD.

Serum albumin, but not glycated albumin was a potent factor affecting the performance of GFR equation based on serum creatinine

BACKGROUND

Recently, Tsuda et al. reported that high HbA1C or high glycated albumin (GA) level is a major factor in overestimation of GFR by Japanese GFR equation based on serum creatinine (Eq-cr). They developed a modified equation of Eq-cr (M-Eq-cr) using GA or HbA1c. Therefore, effect of GA levels on the estimated GFR (eGFR) by Eq-cr was evaluated in Japanese subjects. We validated the accuracy of the modified equation using GA by Tsuda et al. (M-Eq-cr) and new equations that we developed in the present study.

METHODS

Seven hundred and fifteen Japanese subjects were included. GFR was measured by inulin renal clearance (Cin). The subjects were divided into two groups by upper limit of the GA reference range (GA-1: GA < 16.3 % and GA-2: GA > 16.4 %). Factors affecting the ratio of eGFR to Cin (eGFR/Cin) were evaluated using multivariate analysis. New equations based on creatinine and albumin (Eq-cr-alb) and based on creatinine, albumin and GA were developed from development dataset (382 subjects). Performances of the equations were validated in validation dataset (333 subjects).

RESULTS

Correlation coefficients between eGFR by Eq-cr and Cin were 0.839 and 0.914 in GA-1 and GA-2, respectively. Slopes (95 % confidential interval) of the regression lines with zero intercepts were 1.013 (0.991 to 1.036) and 0.997 (0.951 to 1.043), respectively. Both slopes were not significantly different from 1.0. Biases were -2.3 ± 19.0 and 0.2 ± 11.7 ml/min/1.73 m(2), respectively. Accuracy (p30; percentage of subjects within 30 % of Cin) (95 % CI) were 78 % (75, 81) and 71 % (62, 78), respectively. There was no significant difference in bias and accuracy between the two groups, indicating a reasonable accuracy of Eq-cr in GA-1 and GA-2. Multiple regression analysis showed that lower serum albumin and higher GA were associated with higher eGFR/Cin. Albumin was a more potent factor affecting eGFR/Cin than GA. M-Eq-cr significantly underestimated GFR and had significantly larger bias compared with Eq-cr in subjects with GA > 20 %, suggesting that the modification of Eq-cr using GA by Tsuda et al. was too much compensation in our subjects. Precisions of Eq-cr-alb were significantly better compared with Eq-cr.

CONCLUSION

Eq-cr has a reasonable accuracy in GA-1 and GA-2. Lower serum albumin and higher GA were significantly associated with higher eGFR/Cin. The former was a more potent factor affecting eGFR/Cin. Eq-cr-alb showed better performance compared with Eq-cr. M-Eq-cr using GA showed too much compensation and did not improve the accuracy of the equation in our subjects.

Multidetector-row computed tomography is useful to evaluate the therapeutic effects of bisphosphonates in glucocorticoid-induced osteoporosis

Osteoporosis is one of the major complications of glucocorticoid therapy. Osteoporosis is usually defined by the levels of bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DEXA); however, glucocorticoids often induce fractures in patients with normal BMD. Thus, novel diagnostic approaches are required. In this study, we examined whether multidetector-row computed tomography (MDCT) is useful to assess the bone status in glucocorticoid-induced osteoporosis (GIO). Because bisphosphonates have been proven to prevent bone fracture in GIO, we tried to detect the therapeutic effects of bisphosphonates in GIO by MDCT. Fifteen Japanese patients with immunoglobulin A nephropathy who had normal renal function were enrolled in this open-label randomized trial. Patients were randomly divided into three groups-calcitriol (VD), menatetrenone (VK), or bisphosphonate (Bis). Bone conditions were analyzed twice by three different methods-bone turnover markers, DEXA, and MDCT-at the start and 6 months after the start of therapy. Both bone markers and DEXA could not detect significant differences among the therapeutic groups; however, MDCT-based analyses detected the preventive effects of bisphosphonates in GIO. Compared to VD, Bis improved structural indices, such as bone volume fraction, trabecular separation, marrow star volume, and structure model index whereas the difference between VD and VK was not significant. Finite element analysis revealed that simulated fracture load in the Bis group was significantly improved. These findings suggested that MDCT-based assessment is superior to bone markers and/or DEXA in assessing the therapeutic effect of bisphosphonates on GIO.

Additive interaction of oral health disorders on risk of hypertension in a Japanese urban population: the Suita Study

BACKGROUND

This study assessed the relationship between different oral health markers-periodontitis, gingival bleeding, tooth number, and occlusal status-and hypertension in a Japanese urban population.

METHODS

A total of 1,643 participants with no prior cardiovascular disease (mean age = 66.6 years; 43.4% women) underwent comprehensive health checkups, including a lifestyle questionnaire and dental examination in the Suita Study.

RESULTS

In the multivariable-adjusted logistic model, none of the individual oral health markers, namely severe periodontitis, gingival bleeding, lowest quartile of tooth number, and malocclusion, were significantly associated with increased odds of hypertension. The additive effects of oral health markers on hypertension were examined and showed that, compared with subjects with no component of the oral health markers, the multivariale-adjusted odds ratio of hypertension in those with ≥3 components was 1.82 (95% confidence interval (CI) = 1.23-2.72; P = 0.003). In the subpopulation without antihypertensive medication (n = 1,148; 59.8% women), a significant graded relationship between multivariable-adjusted systolic blood pressure and the number of components was found (P trend = 0.03), and, compared with subjects with no component of the oral health markers, having ≥3 components was related to a higher systolic blood pressure (β = 5.41; 95% CI = 1.16-9.66; P = 0.01).

CONCLUSIONS

There is an additive relationship between oral health disorders and risk of hypertension. Our results suggest that the existence of moderate or severe oral health disorders-that is, several concomitant oral health disorders-is associated with risk of hypertension.

Comparison between Three Different Equations for the Estimation of Glomerular Filtration Rate in Omani Patients with Type 2 Diabetes Mellitus

OBJECTIVES

Estimated glomerular filtration rate (eGFR) is an important component of a patient's renal function profile. The Modification of Diet in Renal Disease (MDRD) equation and the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation are both commonly used. The aim of this study was to compare the performance of the original MDRD186, revised MDRD175 and CKD-EPI equations in calculating eGFR in type 2 diabetes mellitus (T2DM) patients in Oman.

METHODS

The study included 607 T2DM patients (275 males and 332 females, mean age ± standard deviation 56 ± 12 years) who visited primary health centres in Muscat, Oman, during 2011 and whose renal function was assessed based on serum creatinine measurements. The eGFR was calculated using the three equations and the patients were classified based on chronic kidney disease (CKD) stages according to the National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines. A performance comparison was undertaken using the weighted kappa test.

RESULTS

The median eGFR (mL/min/1.73 m(2)) was 92.9 for MDRD186, 87.4 for MDRD175 and 93.7 for CKD-EPI. The prevalence of CKD stage 1 was 55.4%, 44.7% and 57% while for stages 2 and 3 it was 43.2%, 54% and 41.8%, based on MDRD186, MDRD175 and CKD-EPI, respectively. The agreement between MDRD186 and CKD-EPI (к 0.868) was stronger than MDRD186 and MDRD175 (к 0.753) and MDRD175 and CKD-EPI (к 0.730).

CONCLUSION

The performances of MDRD186 and CKD-EPI were comparable. Considering that CKD-EPI-based eGFR is known to be close to isotopically measured GFR, the use of MDRD186 rather than MDRD175 may be recommended.

Variation in genes that regulate blood pressure are associated with glomerular filtration rate in Chinese

Chronic kidney disease (CKD) can be a consequence of diabetes, hypertension, immunologic disorders, and other exposures, as well as genetic factors that are still largely unknown. Glomerular filtration rate (GFR), which is widely used to measure kidney function, has a heritability ranging from 25% to 75%, but only 1.5% of this heritability is explained by genetic loci that have been identified to date. In this study we tested for associations between GFR and 234 SNPs in 26 genes from pathways of blood pressure regulation in 3,025 rural Chinese participants of the "Genetic Epidemiology Network of Salt Sensitivity" (GenSalt) study. We estimated GFR (eGFR) using baseline serum creatinine measurements obtained prior to dietary intervention. We identified significant associations between eGFR and 12 SNPs in 6 genes (ACE, ADD1, AGT, GRK4, HSD11B1, and SCNN1G). The cumulative effect of the protective alleles was an increase in mean eGFR of 4 mL/min per 1.73 m2, while the cumulative effect of the risk alleles was a decrease in mean eGFR of 3 mL/min per 1.73 m2. In addition, we identified a significant interaction between SNPs in CYP11B1 and ADRB2. We have identified common variants in genes from pathways that regulate blood pressure and influence kidney function as measured by eGFR, providing new insights into the genetic determinants of kidney function. Complex genetic effects on kidney function likely involve interactions among genes as we observed for CYP11B1 and ADRB2.

Thoracic aortic aneurysms in octogenarians: the results of open surgical repair using hypothermic circulatory arrest with antegrade selective cerebral perfusion

OBJECTIVE

Although recent progress has expanded the indications for thoracic aortic surgery to include elderly patients, the procedure remains extremely invasive. We performed a chart review to determine the early and late outcomes of thoracic aortic surgery using hypothermic circulatory arrest (HCA) and antegrade selective cerebral perfusion (ASCP) in octogenarians.

MATERIALS AND METHODS

Of 79 patients who underwent surgery for thoracic aortic aneurysms from April 2007 through December 2012, 8 patients 80 years or older were selected for analysis. Mean age at the time of surgery was 84.3±1.39 years. The diagnoses were aortic dissection in 5 patients and degenerative thoracic aneurysm in 3 patients. All patients underwent surgery with HCA. The lowest body temperature was 25℃ ASCP was used as an additional brain-protection technique. Emergency operations were performed in 5 patients (62.5%).

RESULTS

The mean duration of HCA was 60.4±19.7 minutes, that of aortic cross-clamping time was 143.0±30.4 minutes, and mean pump time was 207.8±44.4 minutes. The hospital mortality rate was 0%. Major postoperative complications occurred in 3 (37.5%) patients: stroke, temporary neurologic dysfunction, and paraparesis in 1 patient each. No patients required temporary dialysis for new-onset renal dysfunction. There were no deaths during the 65-month follow-up period.

CONCLUSION

The early and late outcomes after thoracic aortic surgery at our hospital using HCA with ASCP in octogenarians are acceptable. The operations are performed with an acceptable operative risk, even under emergency situations, including acute aortic dissection.

Low levels of urinary liver-type fatty acid-binding protein may indicate a lack of kidney protection during aortic arch surgery requiring hypothermic circulatory arrest

STUDY OBJECTIVE

To examine the change in liver-type fatty acid-binding protein (L-FABP) levels in patients undergoing aortic arch surgery and the correlation between L-FABP and postoperative acute kidney injury.

DESIGN

Prospective observational study.

SETTING

Operating room of a general hospital.

PATIENTS

36 adult patients.

INTERVENTIONS AND MEASUREMENTS

Urine samples were obtained to measure urinary L-FABP at initiation of cardiopulmonary bypass (CPB) and 5 minutes after termination of hypothermic circulatory arrest.

MAIN RESULTS

22 (61.1%) patients developed acute kidney injury within a 48-hour period. L-FABP increases more than a thousand-fold were found. In patients who subsequently developed acute kidney injury, significant increases in L-FABP were noted from 2.9 (3.6) ng/mg of creatinine before CPB to 62.1 (995.6) ng/mg of creatinine 5 minutes after termination of circulatory arrest. Values in patients who did not develop acute kidney injury increased from 1.1 (5.7) ng/mg before CPB to 1133.0 (6358.8) ng/mg of creatinine showing a significant mean difference (P = 0.011). The area under the L-FABP receiver operating characteristic curve at 5 minutes after termination of circulatory arrest was 0.758. A cutoff value of 75.13 ng/mg of creatinine yielded both good sensitivity (1.000) and specificity (0.546) for detecting non-acute kidney injury. Patients who developed acute kidney injury after aortic arch surgery demonstrated lower levels of urinary L-FABP.

CONCLUSIONS

Low levels of urinary L-FABP may indicate kidney injury and lack of renal protection.

Comparison of efficacy of intensive versus mild pitavastatin therapy on lipid and inflammation biomarkers in hypertensive patients with dyslipidemia

Objective

Intensive as compared to mild statin therapy has been proven to be superior in improving cardiovascular outcome, whereas the effects of intensive statin therapy on inflammation and lipoprotein biomarkers are not well defined.

Methods

This study assigned essential hypertensive patients with dyslipidemia to 6 months administration of mild (1 mg/day, n = 34) or intensive pitavastatin therapy (4 mg/day, n = 29), and various lipid and inflammation biomarkers were measured at baseline, and 3 and 6 months after the start of treatment.

Results

Both pitavastatin doses were well tolerated, and there were no serious treatment-related adverse events. After 6 months, significant improvements in total cholesterol, triglycerides, low-density lipoprotein (LDL-) cholesterol, LDL/high-density lipoprotein cholesterol (LDL/HDL), apolipoproteins B, C-II, and E, apolipoprotein-B/apolipoprotein-A-I (Apo B/Apo A-I), and malondialdehyde (MDA-) LDL were observed in both groups. Compared with the mild pitavastatin group, the intensive pitavastatin therapy showed significantly greater decreases in C reactive protein (F = 3.76, p<0.05), total cholesterol (F = 10.65), LDL-cholesterol (F = 23.37), LDL/HDL (F = 12.34), apolipoproteins B (F = 19.07) and E (F = 6.49), Apo B/Apo A-I (F = 13.26), and MDA-LDL (F = 5.76) (p<0.01, respectively).

Conclusion

Intensive pitavastatin therapy may have a more favorable effect not only in decreasing LDL-cholesterol but also in pleiotropic benefits in terms of improvement of apolipoproteins, inflammation, or oxidation.

Vitamin D deficiency predicts decline in kidney allograft function: a prospective cohort study

CONTEXT

Vitamin D, often deficient in kidney transplant (KTx) recipients, has potential immunomodulatory effects.

OBJECTIVE

This study aimed to evaluate whether vitamin D status affects the rate of decline in kidney allograft function.

DESIGN, SETTING, AND PATIENTS

The study included a prospective cohort of 264 ambulatory KTx recipients at a single Japanese center.

MAIN OUTCOME MEASURES

We measured the baseline 25-hydroxyvitamin D (25D) concentration and examined its association with annual decline in estimated glomerular filtration rate (eGFR). Secondary outcome was rescue treatment with iv methylprednisolone (IV-MP) as an index of rejection episodes.

RESULTS

The mean serum 25D concentration was 17.1 (SD 6.5) ng/mL, and 68.4% patients had vitamin D inadequacy or deficiency. Time after KTx was a significant effect modifier for the association of serum 25D concentration with annual eGFR change and need for IV-MP (P for interaction < .1). We divided patients according to the median time after KTx (10 y) and found that low vitamin D was significantly associated with a rapid eGFR decline at less than 10 years after KTx but not at 10 or more years after KTx. The same was true for rescue treatment with IV-MP. Overall, propensity score matching showed independent associations of low vitamin D with both outcomes. Stratified matching confirmed pronounced associations at less than 10 years after KTx.

CONCLUSIONS

Vitamin D deficiency predicts a rapid decline in eGFR and need for IV-MP at less than 10 years after KTx. Future studies are warranted to evaluate the clinical efficacy of vitamin D supplementation.

The eGFR-C study: accuracy of glomerular filtration rate (GFR) estimation using creatinine and cystatin C and albuminuria for monitoring disease progression in patients with stage 3 chronic kidney disease--prospective longitudinal study in a multiethnic population

BACKGROUND

Uncertainty exists regarding the optimal method to estimate glomerular filtration rate (GFR) for disease detection and monitoring. Widely used GFR estimates have not been validated in British ethnic minority populations.

METHODS/DESIGN

Iohexol measured GFR will be the reference against which each estimating equation will be compared. The estimating equations will be based upon serum creatinine and/or cystatin C. The eGFR-C study has 5 components: 1) A prospective longitudinal cohort study of 1300 adults with stage 3 chronic kidney disease followed for 3 years with reference (measured) GFR and test (estimated GFR [eGFR] and urinary albumin-to-creatinine ratio) measurements at baseline and 3 years. Test measurements will also be undertaken every 6 months. The study population will include a representative sample of South-Asians and African-Caribbeans. People with diabetes and proteinuria (ACR ≥30 mg/mmol) will comprise 20-30% of the study cohort.2) A sub-study of patterns of disease progression of 375 people (125 each of Caucasian, Asian and African-Caribbean origin; in each case containing subjects at high and low risk of renal progression). Additional reference GFR measurements will be undertaken after 1 and 2 years to enable a model of disease progression and error to be built.3) A biological variability study to establish reference change values for reference and test measures.4) A modelling study of the performance of monitoring strategies on detecting progression, utilising estimates of accuracy, patterns of disease progression and estimates of measurement error from studies 1), 2) and 3).5) A comprehensive cost database for each diagnostic approach will be developed to enable cost-effectiveness modelling of the optimal strategy.The performance of the estimating equations will be evaluated by assessing bias, precision and accuracy. Data will be modelled as a linear function of time utilising all available (maximum 7) time points compared with the difference between baseline and final reference values. The percentage of participants demonstrating large error with the respective estimating equations will be compared. Predictive value of GFR estimates and albumin-to-creatinine ratio will be compared amongst subjects that do or do not show progressive kidney function decline.

DISCUSSION

The eGFR-C study will provide evidence to inform the optimal GFR estimate to be used in clinical practice.

TRIAL REGISTRATION

ISRCTN42955626.

Comparative efficacy and adverse effects of the addition of ezetimibe to statin versus statin titration in chronic kidney disease patients

BACKGROUND AND OBJECTIVES

The recent SHARP trial clearly demonstrated that a reduction in low-density lipoprotein (LDL) cholesterol with a daily regimen of simvastatin plus ezetimibe safely reduced the incidence of major atherosclerotic events in patients with chronic kidney disease (CKD). We aimed to compare the efficacy of and adverse effects from statin uptitration versus statin in combination with ezetimibe since only a few studies have addressed this question.

METHODS

This was a randomized, open-label, multicenter trial that included 286 patients with CKD whose LDL cholesterol levels were not reduced below 120 mg/dl despite a minimum dose of statin therapy. Patients received double doses of statin or usual statin dose with the addition of ezetimibe 10 mg daily. The observation period was 1 year during which time patients were checked regularly in clinic for adverse effects as well as for usual laboratory examinations. The key prespecified outcome was the incidence of adverse effects, which included skeletal muscle complaints, myalgia, muscle weakness, and muscle cramps with and without elevated CK levels. Increases in alanine transaminase (ALT) or aspartate transaminase (AST) levels >2 times the upper limit of normal (ULN) were considered clinically significant adverse effects.

RESULTS

Adverse events occurred in 9/145 in the combination group and in 24/141 in the statin uptitration group (p < 0.01). Moreover, in patients with CKD of stages 3-5, rates were 6/58 in the combination group versus 20/52 in the statin uptitration group (p < 0.01). No serious adverse effects such as rhabdomyolysis were noted in either group. Serum creatinine levels remained essentially unchanged in both groups except in CKD stages 4 and 5. Reductions in LDL cholesterol were similar between the two groups at the start of and at the end of the study. During the study, no atherosclerotic events were reported in either group.

CONCLUSION

When statin uptitration produces adverse effects such as myopathy, combination therapy with ezetimibe is recommended instead of statin alone.

Estimated glomerular filtration rate and proteinuria are separately and independently associated with the prevalence of atrial fibrillation in general population

BACKGROUND

Both, proteinuria and a decline in glomerular filtration rate (GFR) are associated with greater cardiovascular mortality. However, few studies have explored that proteinuria and lower GFR are related with prevalent atrial fibrillation (AF).

METHODS

This cross-sectional study was based on annual health check-up program of community-based population in Gunma, Japan from April 2011 to March 2012. A total of 20,019 adult participants were included. AF was ascertained by a standard 12-lead electrocardiogram. Cross-sectional association and correlates with prevalent AF were examined using multivariable logistic regression analysis.

RESULTS

The overall prevalence of AF was 0.6% (2.2 % in participants with eGFR < 60 mL▪min(-1)･1.73m(-2), 0.4% and 0.2% in those with eGFR 60 to 89 and ≧90 mL▪min(-1)･1.73m(-2), p for trend <0.001). The multivariable odds ratio (OR) for AF was 2.86 (95 % CI 1.16 - 7.08, p<0.001) for eGFR< 60 mL▪min(-1)▪1.73m(-2) versus eGFR≧ 90 mL▪min(-1)▪1.73m(-2). This association remained significant with further adjustment for proteinuria. In addition, proteinuria was also strongly associated with increased prevalence of AF (OR 2.96, 95 % CI 1.55-5.68, p<0.001), an association that remained significant after adjustment for eGFR.

CONCLUSIONS

Proteinuria and lower eGFR are separately and significantly associated with prevalence of AF independent of well-established risk factors for AF in general population.

High risks of all-cause and cardiovascular deaths in apparently healthy middle-aged people with preserved glomerular filtration rate and albuminuria: A prospective cohort study

BACKGROUND

The reason why coexistence of preserved estimated glomerular filtration rate (eGFR) and albuminuria contributes to a high risk of death and which cause of death increases all-cause mortality have not been elucidated.

METHODS

A total of 16,759 participants aged 40 to 69 years with normal or mildly reduced eGFR (45-119 ml/min/1.73 m(2)) were enrolled and divided into six groups (group 1, eGFR: 90-119 without albuminuria; group 2, eGFR: 90-119 with albuminuria; group 3, eGFR: 60-89 without albuminuria (reference); group 4, eGFR: 60-89 with albuminuria; group 5, eGFR: 45-59 without albuminuria; group 6, eGFR: 45-59 with albuminuria) based on GFR estimated by using the CKD-EPI study equation modified by a Japanese coefficient and albuminuria (urine albumin-creatinine ratio ≥ 30 mg/g). Outcomes included all-cause death (ACD), cardiovascular death (CVD) and neoplasm-related death (NPD). Multivariable-adjusted mortality rate ratios (RR) and their 95% confidence intervals (CIs) in the groups were estimated by Poisson's regression analysis.

RESULTS

The highest risk of ACD (RR (95% CIs): 3.95 (2.08-7.52)), CVD (7.15 (2.25-22.7)) and NPB (3.25 (1.26-8.38)) was observed in group 2. Subjects in group 2 were relatively young and had the highest levels of body mass index, blood pressure and HbA1c and the highest prevalence of diabetes and metabolic syndrome.

CONCLUSION

Coexistence of preserved eGFR and albuminuria increases risks for ACD, CVD and NPD. Relatively young metabolic persons having both preserved eGFR and albuminuria should be considered as a very high-risk population.

Comparison of the MDRD study and CKD-EPI equations for the estimation of the glomerular filtration rate in the Korean general population: the fifth Korea National Health and Nutrition Examination Survey (KNHANES V-1), 2010

BACKGROUND

We compared the accuracy of the Modification of Diet in Renal Disease (MDRD) study and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in Korean patients and evaluated the difference in CKD prevalence determined using the two equations in the Korean general population.

METHODS

The accuracy of the two equations was evaluated in 607 patients who underwent a chromium-51-ethylenediaminetetraacetic acid GFR measurement. Additionally, we compared the difference in CKD prevalence determined by the two equations among 5,822 participants in the fifth Korea National Health and Nutrition Examination Survey, 2010.

RESULTS

Among the 607 subjects, the median bias of the CKD-EPI equation was significantly lower than that of the MDRD study equation (0.9 vs. 2.2, p=0.020). The accuracy of the two equations was not significantly different in patients with mGFR <60 mL/min/1.73m(2); however, the accuracy of the CKD-EPI equation was significantly higher than that of the MDRD study equation in patients with GFR ≥60 mL/min/1.73m(2). The prevalences of the CKD stages 1, 2 and 3 in the Korean general population were 47.56, 49.23, and 3.07%, respectively, for the MDRD study equation; and were 68.48, 28.89, and 2.49%, respectively, for the CKD-EPI equation.

CONCLUSIONS

These data suggest that the CKD-EPI equation might be more useful in clinical practice than the MDRD study equation in Koreans.

Sex and age differences in the effect of obesity on incidence of hypertension in the Japanese population: A large historical cohort study

Elevated risk of death from any cause and stroke associated with high body mass index (BMI) values decline with aging. However, it is not clear whether the effect of obesity on the incidence of hypertension varies by sex or age. Cox regression analyses were performed using a large historical cohort composed of 6803 men and 22,800 women. In the final model, which included the main effect (sex, age, and BMI), all two-way interactions (sex*age, sex*BMI, and age*BMI), a three-way interaction (sex*age*BMI), and adjusted variables determined by backward elimination, the three-way interaction and two of the two-way interactions (age*sex and age*BMI) were not significant; the remaining two-way interaction between sex and BMI was significant (P = .016). In the next step, the effect of BMI on the incidence of hypertension stratified by sex was evaluated. Hazard ratios (HRs) were significantly higher for BMI 27.0 to <29.0 and ≥29.0 kg/m(2) than for the HR for BMI 21.0 to <23.0 kg/m(2) in women (HR, 1.45; 95% confidence interval [CI], 1.32-1.59 and HR, 1.46; 95% CI, 1.29-1.65, respectively), but not in men (HR, 1.14; 95% CI, 0.98-1.33 and HR, 1.01; 95% CI, 0.77-1.32, respectively). The effect of obesity on the incidence of hypertension is stronger in women than in men.

Estimation of GFR in South Asians: a study from the general population in Pakistan

BACKGROUND

South Asians are at high risk for chronic kidney disease. However, unlike those in the United States and United Kingdom, laboratories in South Asian countries do not routinely report estimated glomerular filtration rate (eGFR) when serum creatinine is measured. The objectives of the study were to: (1) evaluate the performance of existing GFR estimating equations in South Asians, and (2) modify the existing equations or develop a new equation for use in this population.

STUDY DESIGN

Cross-sectional population-based study.

SETTING & PARTICIPANTS

581 participants 40 years or older were enrolled from 10 randomly selected communities and renal clinics in Karachi.

PREDICTORS

eGFR, age, sex, serum creatinine level.

OUTCOMES

Bias (the median difference between measured GFR [mGFR] and eGFR), precision (the IQR of the difference), accuracy (P30; percentage of participants with eGFR within 30% of mGFR), and the root mean squared error reported as cross-validated estimates along with bootstrapped 95% CIs based on 1,000 replications.

RESULTS

The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation performed better than the MDRD (Modification of Diet in Renal Disease) Study equation in terms of greater accuracy at P30 (76.1% [95% CI, 72.7%-79.5%] vs 68.0% [95% CI, 64.3%-71.7%]; P < 0.001) and improved precision (IQR, 22.6 [95% CI, 19.9-25.3] vs 28.6 [95% CI, 25.8-31.5] mL/min/1.73 m(2); P < 0.001). However, both equations overestimated mGFR. Applying modification factors for slope and intercept to the CKD-EPI equation to create a CKD-EPI Pakistan equation (such that eGFRCKD-EPI(PK) = 0.686 × eGFRCKD-EPI(1.059)) in order to eliminate bias improved accuracy (P30, 81.6% [95% CI, 78.4%-84.8%]; P < 0.001) comparably to new estimating equations developed using creatinine level and additional variables.

LIMITATIONS

Lack of external validation data set and few participants with low GFR.

CONCLUSIONS

The CKD-EPI creatinine equation is more accurate and precise than the MDRD Study equation in estimating GFR in a South Asian population in Karachi. The CKD-EPI Pakistan equation further improves the performance of the CKD-EPI equation in South Asians and could be used for eGFR reporting.

Association of renal biomarkers with 3-month and 1-year outcomes among critically ill acute stroke patients

Background

The comparative relationships of widely recognized biomarkers of renal injury with short-term and long-term outcomes among critically ill acute stroke patients are unknown. We evaluated the impact of baseline albuminuria [urine albumin-creatinine ratio (UACR)≥30 mg/g] or low estimated glomerular filtration rate (eGFR<60 ml/min per 1.73 m²) on stroke patients admitted to the intensive care unit (ICU).

Methods

We reviewed data on consecutive stroke patients admitted to a hospital ICU in Taiwan from September 2007 to August 2010 and followed-up for 1 year. Baseline UACR was categorized into <30 mg/g (normal), 30–299 mg/g (microalbuminuria), and ≥300 mg/g (macroalbuminuria), while eGFR was divided into ≥60, 45–59, and <45 ml/min per 1.73 m². The outcome measure was death or disability at 3-month and 1-year after stroke onset, assessed by dichotomizing the modified Rankin Scale at 3–6 versus 0–2.

Results

Of 184 consecutive patients, 153 (83%) met study entry criteria. Mean age was 67.9 years and median admission NIHSS score was 16. Among the renal biomarkers, only macroalbuminuria was associated with poorer 3-month outcome (OR 8.44, 95% CI 1.38 to 51.74, P = 0.021) and 1-year outcome (OR 18.06, 95% CI 2.59 to 125.94, P = 0.003) after adjustment of relevant covariates. When ischemic and hemorrhagic stroke were analyzed separately, macroalbuminuria was associated with poorer 1-year outcome among ischemic (OR 17.10, 95% CI 1.04 to 280.07, P = 0.047) and hemorrhagic stroke patients (OR 1951.57, 95% CI 1.07 to 3561662.85, P = 0.048), respectively, after adjustment of relevant covariates and hematoma volume.

Conclusions

Presence of macroalbuminuria indicates poor 3-month and 1-year outcomes among critically ill acute stroke patients.

Switching tenofovir/emtricitabine plus lopinavir/r to raltegravir plus Darunavir/r in patients with suppressed viral load did not result in improvement of renal function but could sustain viral suppression: a randomized multicenter trial

Background

Whether tenofovir nephrotoxicity is reversible after its withdrawal is unknown. Furthermore, there are no data on the viral efficacy of raltegravir (RAL) plus ritonavir-boosted Darunavir (DRV/r) in patients with suppressed viral load.

Methods

This multicenter, randomized trial compared renal function and viral efficacy in patients with suppressed viral load treated with RAL+DRV/r and ritonavir-boosted lopinavir (LPV/r) plus tenofovir/emtricitabine (TVD), who had been previously on LPV/r+TVD. The primary endpoint was the proportion of patients with >10% improvement in estimated glomerular filtration rate (eGFR) at 48 weeks calculated with Cockcroft-Gault equation.

Results

58 randomized and treatment-exposed patients were analyzed (28 on RAL+DRV/r and 30 on LPV/r+TVD). Greater than 10% improvement in eGFR was noted in 6 (25%) out of 24 with RAL+DRV/r and 3 (11%) of 28 with LPV/r+TVD, and the difference was not statistically significant (p=0.272, 95% CI -0.067 to 0.354). Sensitivity analyses using three other equations for eGFR showed the same results. Urinary β2 microglobulin, a sensitive marker of tenofovir tubulopathy, significantly improved with RAL+DRV/r than with LPV/r+TVD (-271 versus -64 µg/gCr, p=0.026). Per protocol analysis showed that the HIV-RNA was <50 copies/mL at week 48 in all patients of both arms (24 in RAL+DRV and 29 in LPV/r+TVD).

Conclusions

Switching LPV/r+TVD to RAL+DRV/r did not significantly increase the proportion of patients who showed >10% improvement in renal function among those with relatively preserved eGFR. However, the switch improved urinary β2 microglobulin, suggesting that discontinuation of TDF might be beneficial in the long-term. RAL+DRV/r showed favorable viral efficacy in patients with suppressed viral load.

Trial Registration

ClinicalTrials.gov NCT01294761 http://clinicaltrials.gov/ct2/show/NCT01294761?term=SPARE&rank=2, Umin Clinical Trials Registry UMIN000005116 http://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000006083&language=J)

Prediction of cardiovascular disease mortality by proteinuria and reduced kidney function: pooled analysis of 39,000 individuals from 7 cohort studies in Japan

There are limited studies addressing whether proteinuria and estimated glomerular filtration rate (eGFR) are independently associated with cardiovascular disease in Asia. Using data from 7 prospective cohorts recruited between 1980 and 1994 in Japan, we assessed the influence of proteinuria (≥1+ on dipstick) and reduced eGFR on the risk of cardiovascular disease mortality in 39,405 participants (40-89 years) without kidney failure. During a 10.1-year follow-up, 1,927 subjects died from cardiovascular disease. Proteinuria was associated with a 1.75-fold (95% confidence interval (CI): 1.44, 2.11) increased risk of cardiovascular disease mortality after adjustment for potential confounding factors. Additionally, the multivariate-adjusted hazard ratio of cardiovascular disease mortality increased linearly with lower eGFR levels (P(trend) < 0.001): Subjects with eGFR of <45 mL/minute/1.73 m² had a 2.22-fold (95% CI: 1.60, 3.07) greater risk of cardiovascular disease mortality than those with eGFR of ≥90 mL/minute/1.73 m². Subjects with both proteinuria and eGFR of <45 mL/minute/1.73 m² had a 4.05-fold (95% CI: 2.55, 6.43) higher risk of cardiovascular disease mortality compared with those with neither of these risk factors. There was no evidence of interaction in the relationship between proteinuria and lower eGFR (P(interaction) = 0.77). The present results suggest that proteinuria and lower eGFR are independent risk factors for cardiovascular disease mortality in the Japanese population.

T/L-type calcium channel blocker reduces the composite ranking of relative risk according to new KDIGO guidelines in patients with chronic kidney disease

BACKGROUND

Recently, the Kidney Disease: Improving Global Outcomes (KDIGO) group recommended that patients with chronic kidney disease (CKD) be assigned according to stage and composite relative risk on the basis of glomerular filtration rate (GFR) and albuminuria criteria. The aim of this post-hoc analysis was to investigate the effects of add-on therapy with calcium channel blockers (CCBs) on changes in the composite ranking of relative risk according to KDIGO guidelines. Benidipine, an L- and T-type CCB, and amlodipine, an L-type CCB to angiotensin II receptor blocker (ARB), were examined.

METHODS

Patients with blood pressure (BP) > 130/80 mmHg, an estimated GFR (eGFR) of 30-90 mL/min/1.73 m2, and albuminuria > 30 mg/gCr, despite treatment with the maximum recommended dose of ARB, were randomly assigned to two groups. Each group received one of two treatments: 2 mg benidipine daily, increased to 8 mg daily (n = 52), or 2.5 mg amlodipine daily, increased to 10 mg daily (n = 52).

RESULTS

After 6 months of treatment, a significant and comparable reduction in systolic and diastolic BP was observed in both groups. The eGFR was significantly decreased in the amlodipine group, but there was no significant change in the benidipine group. The decrease in albuminuria in the benidipine group was significantly lower than in the amlodipine group. The composite ranking of relative risk according to the new KDIGO guidelines was significantly improved in the benidipine group; however, no significant change was noted in the amlodipine group. Moreover, significantly fewer cases in the benidipine group than the amlodipine group showed a reduced risk category score.

CONCLUSION

The present post-hoc analysis showed that compared to amlodipine benidipine results in a greater reduction in albuminuria accompanied by an improved composite ranking of relative risk according to the KDIGO CKD severity classification.

TRIAL REGISTRATION

TRIAL REGISTRATION NUMBER

UMIN000002644.