Comparative performance of the CKD Epidemiology Collaboration (CKD-EPI) and the Modification of Diet in Renal Disease (MDRD) Study equations for estimating GFR levels above 60 mL/min/1.73 m2

Psychosocial correlates of apparent treatment-resistant hypertension in the Jackson Heart Study

Apparent treatment-resistant hypertension (aTRH) is associated with adverse cardiovascular outcomes. aTRH is common and disproportionately affects African Americans. The objective of this study is to explore psychosocial correlates of aTRH in a population-based cohort of African Americans with hypertension. The sample included 1392 participants in the Jackson Heart Study with treated hypertension who reported being adherent to their antihypertensive medications. aTRH was defined as uncontrolled clinic BP (⩾140/90 mm Hg) with ⩾3 classes of antihypertensive medication or treatment with ⩾4 classes of antihypertensive medication, including a diuretic. Self-reported medication adherence was defined as taking all prescribed antihypertensive medication in the 24 h before the study visit. The association of psychosocial factors (chronic stress, depressive symptoms, perceived social support and social network) with aTRH was evaluated using Poisson regression with progressive adjustment for demographic, clinical and behavioural factors. The prevalence of aTRH was 15.1% (n=210). Participants with aTRH had lower social network scores (that is, fewer sources of regular social contact) compared with participants without aTRH (P<0.01). No other psychosocial factors differed between groups. Social network was also the only psychosocial factor that was associated with aTRH prevalence in regression analyses. In age-, sex-adjusted and fully adjusted models, one additional unique source of social contact was associated with a 19% (PR=0.81; 95% confidence interval (CI): 0.68-0.94, P=0.001) and a 13% (PR=0.87; 95% CI 0.74-1.0, P=0.041) lower prevalence of aTRH, respectively. Social network was independently associated with aTRH and warrants further investigation as a potentially modifiable determinant of aTRH in African Americans.

International Collaboration for the Epidemiology of eGFR in Low and Middle Income Populations - Rationale and core protocol for the Disadvantaged Populations eGFR Epidemiology Study (DEGREE)

Background

There is an increasing recognition of epidemics of primarily tubular-interstitial chronic kidney disease (CKD) clustering in agricultural communities in low- and middle-income countries (LMICs). Although it is currently unclear whether there is a unified underlying aetiology, these conditions have been collectively termed CKD of undetermined cause (CKDu). CKDu is estimated to have led to the premature deaths of tens to hundreds of thousands of young men and women over the last 2 decades. Thus, there is an urgent need to understand the aetiology and pathophysiology of these condition (s). International comparisons have provided the first steps in understanding many chronic diseases, but such comparisons rely on the availability of standardised tools to estimate disease prevalence. This is a particular problem with CKD, since the disease is asymptomatic until the late stages, and the biases inherent in the methods used to estimate the glomerular filtration rate (GFR) in population studies are highly variable across populations.

Method

We therefore propose a simple standardised protocol to estimate the distribution of GFR in LMIC populations – The Disadvantaged Populations eGFR Epidemiology (DEGREE) Study. This involves the quantification of renal function in a representative adult population-based sample and a requirement for standardisation of serum creatinine measurements, along with storage of samples for future measurements of cystatin C and ascertainment of estimates of body composition, in order to obtain valid comparisons of estimated GFR (eGFR) within and between populations.

Discussion

The methodology we present is potentially applicable anywhere, but our particular focus is on disadvantaged populations in LMICs, since these appear to be most susceptible to CKDu. Although the protocol could also be used in specific groups (e.g. occupational groups, thought to be at excess risk of CKDu) the primary aim of the DEGREE project is characterise the population distribution of eGFR in multiple regions so that international comparisons can be performed. It is only with a standardised approach that it will be possible to estimate the scale of, and variation in, impaired kidney function between affected areas. These data should then provide insights into important social, demographic and environmental risk factors for this increasingly recognised disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0417-1) contains supplementary material, which is available to authorized users.

Risk Factors Associated with Decreased Renal Function after Hand-Assisted Laparoscopic Donor Nephrectomy: A Multivariate Analysis of a Single Surgeon Experience

Background: Hand-assisted laparoscopic donor nephrectomy is a minimally invasive procedure for living kidney donation. The surgeon operative volume is associated with postoperative morbidity and mortality. We evaluated the risk factors associated with decreased renal function after hand-assisted laparoscopic donor nephrectomy performed by a single experienced surgeon. Methods: We included living renal donors who underwent hand-assisted laparoscopic donor nephrectomy by a single experienced surgeon between 2006 and 2013. Decreased renal function was defined as an estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m² on postoperative day 4. The donors were categorized into groups with postoperative eGFR < 60 mL/min/1.73 m² or ≥ 60 mL/min/1.73 m². Univariate and multivariate logistic regression analyses were performed to evaluate the risk factors associated with decreased renal function after hand-assisted laparoscopic donor nephrectomy. The hospital stay duration, intensive care unit admission rate, and eGFR at postoperative year 1 were evaluated. Results: Of 643 patients, 166 (25.8%) exhibited a postoperative eGFR of < 60 mL/min/1.73 m². Multivariate logistic regression analysis demonstrated that the risk factors for decreased renal function were age [odds ratio (95% confidence interval), 1.062 (1.035-1.089), P < 0.001], male sex [odds ratio (95% confidence interval), 3.436 (2.123-5.561), P < 0.001], body mass index (BMI) [odds ratio (95% confidence interval), 1.093 (1.016-1.177), P = 0.018], and preoperative eGFR [odds ratio (95% confidence interval), 0.902 (0.881-0.924), P < 0.001]. There were no significant differences in postoperative hospital stay duration and intensive care unit admission rate between the two groups. In addition, 383 of 643 donors were analyzed at postoperative year 1. Sixty donors consisting of 14 (5.0%) from the group of 279 donors in eGFR ≥ 60 mL/min/1.73 m², and 46 (44.2%) from the group of 104 donors in eGFR < 60 mL/min/1.73 m² had eGFR < 60 mL/min/1.73 m² at postoperative year 1 (P < 0.001). Conclusions: Increased age, male sex, higher BMI, and decreased preoperative eGFR were risk factors for decreased renal function after hand-assisted laparoscopic donor nephrectomy by a single experienced surgeon. These results provide important evidence for the safe perioperative management of living renal donors.

Heart Failure and Kidney Disease

Kidney disease is commonly found in heart failure (HF) patients. They share many risk factors and common pathophysiological pathways which often lead to mutual dysfunction. Both haemodynamic and non-haemodynamic mechanisms are involved in the development of renal impairment in heart failure patients. Moreover, the presence of a chronic kidney disease is a significant independent predictor of worse outcome in chronic as well as in acute decompensated HF. As a consequence, an accurate evaluation of renal function plays a key role in the management of HF patients. Serum creatinine levels and glomerular filtration rate (GFR) estimates are the corner stones of renal function evaluation in clinical practice. However, to overcome their limits, several emerging glomerular and tubular biomarkers have been proposed over the last years. Alongside the renal biomarkers, imaging techniques could complement the laboratory data exploring different pathophysiological pathways. In particular, Doppler evaluation of renal circulation is a highly feasible technique that can effectively identify HF patients prone to develop renal dysfunction and with a worse outcome. Finally, some classes of drugs currently used in heart failure treatment can affect renal function and their use can be influenced by the presence of chronic kidney disease.

Thyroid hormones associate with risk of incident chronic kidney disease and rapid decline in renal function: a prospective investigation

Background

Thyroid hormones have been associated with renal dysfunction in cross-sectional studies. However, prospective studies exploring the effect of thyroid hormones on renal function decline were sparse and got contradictive results. We aimed to prospectively explore the associations of thyroid hormones with incident chronic kidney disease (CKD) and rapid decline in estimated glomerular filtration rate (eGFR) in Chinese adults.

Methods

The participants were from a community-based cohort including 2103 individuals aged 40 years or above without CKD at baseline. Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxin (FT4) were measured by radioimmunoassay at baseline. Serum creatinine, urinary creatinine and albumin were measured at baseline and follow-up. CKD was defined as eGFR <60 ml/min/1.73 m² or urinary albumin-to-creatinine ratio ≥30 mg/g. Rapid eGFR decline was defined as an annual eGFR decline >3 ml/min/1.73 m².

Results

During 4 years of follow-up, 198 participants developed CKD and 165 experienced rapid eGFR decline. Compared to tertile 1, tertile 3 of FT4 levels were associated with 1.88-folds (95% confidence interval [CI], 1.27–2.77) increased risk of incident CKD; and 1.64-folds (95% CI, 1.07–2.50) increased risk of rapid eGFR decline (both P for trend ≤0.02), after adjustment for confounders. Each 1-pmol/l of FT4 was associated with 12% increased risk of incident CKD and 10% of rapid eGFR decline. Among the incident CKD individuals, FT4 was significantly associated with higher risk of concurrent complications and further outcomes of CKD. We did not find associations of FT3 or TSH with CKD or rapid eGFR decline.

Conclusions

Higher FT4, but not TSH and FT3, was associated with increased risk of incident CKD and rapid eGFR decline in middle-aged and elderly Chinese.

Adefovir dipivoxil-induced Fanconi syndrome and its predictive factors: A study of 28 cases

The aim of the present study was to identify monitoring and prevention measures as well as predictive factors for early detection of renal toxicity associated with long-term administration of adefovir dipivoxil in order to avoid progression to Fanconi syndrome. Clinical data of 28 patients with Fanconi syndrome caused by long-term administration of adefovir dipivoxil for the treatment of chronic hepatitis B virus (HBV) infection were collected pre-and post-administration for analysis. Patients presented with fatigue, progressive systemic pain in multiple bones and joints, as well as difficulty in walking and pathological fractures in a number of severe cases. Laboratory examinations revealed hypophosphatemia, elevated serum cystatin C (Cys-C), elevated serum creatinine (SCr), reduced glomerular filtration rate (GFR), positive urinary protein, erythrocytes and glucose, as well as osteoporosis. In consequence, adefovir dipivoxil administration was stopped, and patients received concentrated divitamins, sodium phosphate syrup and calcitriol. Symptoms and abnormalities in laboratory examinations were significantly improved in all patients after 2-6 months. Therefore, serum phosphate, SCr, routine urine parameters, Cys-C and GFR should be monitored regularly in chronic HBV patients treated with adefovir dipivoxil. The following factors were identified as predictive of kidney damage and Fanconi syndrome: Age ≥40 years, living in rural areas, previous renal toxicity, estimated GFR (eGFR) <90 ml/min/1.73 m², hypertension, diabetes, cirrhosis and duration of adefovir dipivoxil treatment exceeding 24 months. The present results indicate that timely termination of adefovir dipivoxil treatment and replacement with other antiviral agents is critical once renal impairment appears, and that it is necessary to change to other antiviral agents and prolong the interval of administration according to the eGFR level.

Long-term versus short-term dual antiplatelet therapy was similarly associated with a lower risk of death, stroke, or infarction in patients with acute coronary syndrome regardless of underlying kidney disease

Scarce and conflicting evidence exists on whether clopidogrel is effective and whether dual antiplatelet treatment (DAPT) is safe in patients with acute coronary syndrome and chronic kidney disease (CKD). To study this, we performed an observational, prospective, multicenter cohort study of 36,001 patients of the SWEDEHEART registry. The exposure was DAPT prolonged after 3 months versus DAPT stopped at 3 months in consecutive patients with acute coronary syndrome and known serum creatinine. DAPT duration with clopidogrel and aspirin was assessed by dispensed tablets. CKD stages were classified according to estimated glomerular filtration rate (eGFR). Study outcomes were 1) the composite of death, myocardial infarction, or ischemic stroke; 2) bleeding; or 3) the aggregate of these two outcomes within day 111 and 365 from discharge. A longer DAPT duration, as compared with 3-month DAPT, was associated with lower hazard ratios for outcome one in each CKD stratum (eGFR over 60, adjusted hazard ratio [95% confidence interval] 0.76 [0.67-0.85]; eGFR 60 and less, 0.84 [0.73-0.96], of which eGFR between 45 and 60, 0.85 [0.70-1.05], eGFR between 30 and 45, 0.78 [0.62-0.97]; eGFR 30 and less ml/min/1.73 m², 0.93 [0.70-1.24]. Bleeding (outcome 2) was in general more common in the longer DAPT group of each aforementioned CKD stratum. Aggregated outcome analysis (outcome 3) similarly favored longer DAPT in each stratum. There was no interaction between DAPT duration and CKD strata for any of the study outcomes. Thus, a prolonged as compared with three-month DAPT was similarly associated with a lower risk of death, stroke, or reinfarction regardless of underlying CKD.

LEADER-6: Baseline renal function and associated factors in a high cardiovascular risk type 2 diabetes population

AIMS

To examine the prevalence of chronic kidney disease (CKD) and its associated factors in a multinational population with type 2 diabetes mellitus (T2DM) and prior cardiovascular disease (CVD).

METHODS

The LEADER trial randomized 9340 participants-81.3% with prior CVD at baseline. CKD was defined as estimated GFR <60ml/min/1.73m² and/or an albumin-to-creatinine ratio ≥3.0mg/mmol.

RESULTS

At baseline, 51.9% of participants with prior CVD had CKD. CKD prevalence was highest in Asia (75.8%) and lowest in Europe (43.7%) and the Middle East (43.4%). Baseline factors associated with increased CKD prevalence included increased age, HbA_1c, diabetes duration, systolic blood pressure or triglyceride levels; greater number of antihypertensive medications; living in Asia, the Americas or Africa versus Europe; being male; and not receiving oral antidiabetic drugs (most receiving insulin), beta-blockers or ACE inhibitors. Factors associated with decreased CKD prevalence included increased diastolic blood pressure, no diuretic treatment and prior myocardial infarction, angina or stroke.

CONCLUSIONS

CKD prevalence is high among patients with T2DM and prior CVD. Advanced age, long diabetes duration, poor glycemic control, comorbidities and medications used are associated with CKD. Our results strengthen the rationale for early screening and interventions for CKD in patients with T2DM and prior CVD.

Role of ultrasonographic chronic kidney disease score in the assessment of chronic kidney disease

PURPOSE

Ultrasonography (US) is an inexpensive, noninvasive and easy imaging procedure to comment on the kidney disease. Data are limited about the relation between estimated glomerular filtration rate (e-GFR) and all 3 renal US parameters, including kidney length, parenchymal thickness and parenchymal echogenicity, in chronic kidney disease (CKD). In this study, we aimed to investigate the association between e-GFR and ultrasonographic CKD score calculated via these ultrasonographic parameters.

METHODS

One hundred and twenty patients with stage 1-5 CKD were enrolled in this study. The glomerular filtration rate was estimated by the Chronic Kidney Disease Epidemiology Collaboration equation. US was performed by the same radiologist who was blinded to patients' histories and laboratory results. US parameters including kidney length, parenchymal thickness and parenchymal echogenicity were obtained from both kidneys. All 3 parameters were scored for each kidney, separately. The sum of the average scores of these parameters was used to calculate ultrasonographic CKD score.

RESULTS

The mean age of patients was 63.34 ± 14.19 years. Mean kidney length, parenchymal thickness, ultrasonographic CKD score and median parenchymal echogenicity were found as 96.2 ± 12.3, 10.97 ± 2.59 mm, 6.28 ± 2.52 and 1.0 (0-3.5), respectively. e-GFR was positively correlated with kidney length (r = 0.343, p < 0.001), parenchymal thickness (r = 0.37, p < 0.001) and negatively correlated with CKD score (r = -0.587, p < 0.001) and parenchymal echogenicity (r = -0.683, p < 0.001). Receiver operating characteristic curve analysis for distinction of e-GFR lower than 60 mL/min showed that the ultrasonographic CKD score higher than 4.75 was the best parameter with the sensitivity of 81% and positive predictivity of 92% (AUC, 0.829; 95% CI, 0.74-0.92; p < 0.001).

CONCLUSION

We found correlation between e-GFR and ultrasonographic CKD score via using all ultrasonographic parameters. Also, our study showed that ultrasonographic CKD score can be useful for distinction of CKD stage 3-5 from stage 1 and 2. We suggested that the ultrasonographic CKD score provided more objective data in the assessment of CKD.

A phase I pharmacokinetic and safety study of cabazitaxel in adult cancer patients with normal and impaired renal function

PURPOSE

Limited data are available on cabazitaxel pharmacokinetics in patients with renal impairment. This open-label, multicenter study assessed cabazitaxel in patients with advanced solid tumors and normal or impaired renal function.

METHODS

Cohorts A (normal renal function: creatinine clearance [CrCL] >80 mL/min/1.73 m²), B (moderate renal impairment: CrCL 30 to <50 mL/min/1.73 m²) and C (severe impairment: CrCL <30 mL/min/1.73 m²) received cabazitaxel 25 mg/m² (A, B) or 20 mg/m² (C, could be escalated to 25 mg/m²), once every 3 weeks. Pharmacokinetic parameters and cabazitaxel unbound fraction (F _U) were assessed using linear regression and mixed models. Geometric mean (GM) and GM ratios (GMRs) were determined using mean CrCL intervals (moderate and severe renal impairment: 40 and 15 mL/min/1.73 m²) versus a control (90 mL/min/1.73 m²).

RESULTS

Overall, 25 patients received cabazitaxel (median cycles: 3 [range 1-20]; Cohort A: 5 [2-13]; Cohort B: 3 [1-15]; and Cohort C: 5 [1-20]), of which 24 were eligible for pharmacokinetic analysis (eight in each cohort). For moderate and severe renal impairment versus normal renal function, GMR estimates were: clearance normalized to body surface area (CL/BSA) 0.95 (90% CI 0.80-1.13) and 0.89 (0.61-1.32); area under the curve normalized to dose (AUC/dose) 1.06 (0.88-1.27) and 1.14 (0.76-1.71); and F _U 0.99 (0.94-1.04) and 0.97 (0.87-1.09), respectively. Estimated slopes of linear regression of log parameters versus log CrCL (renal impairment) were: CL/BSA 0.06 (-0.15 to 0.28); AUC/dose -0.07 (-0.30 to 0.16); and F _U 0.02 (-0.05 to 0.08). Cabazitaxel safety profile was consistent with previous reports.

CONCLUSIONS

Renal impairment had no clinically meaningful effect on cabazitaxel pharmacokinetics.

Evaluation of Vancomycin Prediction Methods Based on Estimated Creatinine Clearance or Trough Levels

BACKGROUND

The aim of this study was to investigate whether vancomycin clearance (CLva) can be adequately predicted with CLva prediction methods. Additionally, other covariates influencing the CLva were investigated and predictivity of monitoring of only trough levels to 24-hour area under the curve (AUC24) was evaluated.

METHODS

Routine vancomycin plasma levels were measured with a fluorescence polarization immunoassay. Pharmacokinetic (PK) parameters of individual patients, that is, CLva and volume of distribution, were determined with maximum a posteriori Bayesian estimation. CLva was calculated with the 3 prediction methods, which are solely based on creatinine clearance (CLcr) estimated with Cockcroft and Gault formula and was compared with the calculated CLva with maximum a posteriori Bayesian estimation. Prediction errors were calculated. Correlations between CLva and CLcr, creatinine, age, weight, sex, and neutropenia were made. Furthermore, correlations between trough levels and AUC24 were evaluated.

RESULTS

A total of 171 patients were included. Prediction errors and absolute prediction errors of the 3 methods ranged from 28% to 80% and 39% to 83%, respectively. In the multivariate analysis, CLva was significantly associated with CLcr, creatinine, age, weight, sex, and neutropenia. Linear correlation between AUC24 and trough levels was R(2) 0.38.

CONCLUSIONS

Large prediction errors make the CLva algorithms based on estimated plasma CLcr unsuitable for use in patient care. Additionally, other factors, which are not accounted for in the current algorithms, influence the CLva individually. Owing to low association of AUC24 and trough levels, the AUC24 cannot be predicted with through levels. For a reliable AUC24 guided vancomycin dosing, therapeutic drug monitoring is necessary.

The relationship between three eGFR formulas and hospitalization for heart failure in 54 486 individuals with type 2 diabetes

OBJECTIVE

This study aims to study the association between renal function and hospitalization for heart failure (HF) in individuals with type 2 diabetes.

METHODS

Renal function was determined according to three formulas used to estimate glomerular filtration rate (eGFR): Cockcroft-Gault, modified diet in renal disease (MDRD) and chronic kidney disease epidemiology (CKD-EPI). Proportional hazards regression models adjusted for age, sex, HbA_1c , blood pressure, smoking and cardiovascular comorbidities were constructed for each eGFR formula to estimate risk of hospitalization for heart failure. Systematic pairwise likelihood ratio tests of nested models were used to compare the predictive power of each eGFR formula.

RESULTS

In 54 486 patients, evaluated over a median follow-up of 7.0 years, a total of 5936 (10.9%) developed heart failure, with an excess risk in all eGFR categories below 60 mL/min/1.73 m² (reference: eGFR >90 mL/min/1.73 m² ). Hazard ratios ranged from 1.25 to 1.35 for eGFR 45-60 mL/min/1.73 m² , 1.62 to 1.66 for eGFR 30-45 mL/min/1.73 m² and 2.18 to 2.52 for eGFR <30 mL/min/1.73 m² in the three eGFR formulas. In pairwise comparisons, the model with the MDRD variable added significantly more information than the Cockcroft-Gault variable. For the model with the CKD-EPI variable, no clear differences in predictive power for HF hospitalization existed in relation to the other eGFR formulas.

CONCLUSION

Patients with type 2 diabetes, with eGFR 45 to 60 mL/min/1.73 m² , have approximately 25-35% increased risk of hospitalization for HF, increasing with lower eGFR, to 2-2.5 times in those with eGFR <30 mL/min/1.73 m² . The MDRD formula for calculating eGFR is more predictive of hospitalization for heart failure than the Cockcroft-Gault formula. Copyright © 2016 John Wiley & Sons, Ltd.

Evaluation of mortality and readmissions following hospitalization with heart failure

OBJECTIVE

To examine the association of patient/clinical characteristics with mortality and readmission following a heart failure (HF)-related hospitalization.

RESEARCH DESIGN AND METHODS

Claims data, linked to laboratory, race/ethnicity, and mortality data, from a large US health plan were utilized to identify individuals with ≥1 inpatient claim with a diagnosis code for HF (1 January 2008-30 September 2012). Study variables were analyzed using descriptive and multivariable approaches to identify patient/clinical characteristics associated with post-discharge outcomes.

MAIN OUTCOME MEASURES

Primary outcomes included post-discharge mortality and readmission.

RESULTS

A total of 126,214 individuals were identified with a HF-related hospitalization; 19.1% with data to calculate chronic kidney disease (CKD) stage. For the overall sample, mortality probability was 4.9% and 13.4% at 1 and 6 months post-discharge, respectively (4.5% and 12.4% for subset with calculated CKD stage), while readmission (all-cause) probability was 14.8% and 39.6% at 1 and 6 months post-discharge, respectively (18.4% and 44.5% for subset with calculated CKD stage). Within the subset with calculated CKD stage, mortality and readmission probabilities differed by CKD stage (p < 0.001), with decreased renal function corresponding with increased risk of mortality and readmission. After multivariable adjustment, increasing age was associated with increased risk of mortality, while advancing CKD stage, various index hospitalization variables (i.e., pre-admission emergency room visit, intensive care unit during hospitalization), and baseline all-cause hospitalization were associated with both increased risk of mortality and all-cause 1 month readmission.

CONCLUSIONS

Calculated CKD, various index hospitalization variables, and baseline all-cause hospitalization were associated with increased risk of mortality and all-cause 1 month readmission among patients hospitalized with HF. Risk of post-discharge readmission and mortality increased with worse renal function, suggesting that improved management of this subset may reduce the burden and cost of this disease. Key study limitations include those related to retrospective claims-based studies and that renal function data were available for a subset of study patients.

Innovative non-invasive model for screening reduced estimated glomerular filtration rate in a working population

AIM

Most of the existing risk scores for identifying people with reduced estimated glomerular filtration rate (eGFR) involve laboratory-based factors, which are not convenient and cost-effective to use in a large population-based screening programme. We aimed at using non-invasive variables to identify subjects with reduced eGFR in a Chinese working population.

METHODS

Two study populations were recruited in 2012 and 2015, respectively. The 2012 study population (n = 14 374) was randomly separated as the training dataset (n = 9621) or the internal testing dataset (n = 4753) at a ratio of 2:1, and the 2015 study population (n = 4371) was used as the external testing dataset. Stepwise logistic regression analysis with age, gender, hypertension and body mass index (BMI) status were first performed in the training dataset and then validated in both internal and external testing dataset. A nomogram was further developed based on the final model.

RESULTS

Results showed that older females with higher BMI status were more likely to have reduced eGFR. The model had excellent discrimination (AUC: 0.887 [95%CI: 0.865, 0.909] in the internal validation and 0.880 [95%CI: 0.829, 0.931] in the external validation) and calibration (Hosmer-Lemeshow test, P = 0.798 and 0.397 for internal and external dataset, respectively). The probability of having reduced eGFR increased gradually from <0.1% at a total score of 0 to 26% at a total score of 58 shown in the nomogram.

CONCLUSION

Non-invasive variables could help identify individuals at high risk of reduced eGFR for further kidney function testing or intervention, aiding in decision-making and resource allocation in large population screening.

Association of Urinary Biomarkers of Inflammation, Injury, and Fibrosis with Renal Function Decline: The ACCORD Trial

BACKGROUND AND OBJECTIVES

Current measures for predicting renal functional decline in patients with type 2 diabetes with preserved renal function are unsatisfactory, and multiple markers assessing various biologic axes may improve prediction. We examined the association of four biomarker-to-creatinine ratio levels (monocyte chemotactic protein-1, IL-18, kidney injury molecule-1, and YKL-40) with renal outcome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used a nested case-control design in the Action to Control Cardiovascular Disease Trial by matching 190 participants with ≥40% sustained eGFR decline over the 5-year follow-up period to 190 participants with ≤10% eGFR decline in a 1:1 fashion on key characteristics (age within 5 years, sex, race, baseline albumin-to-creatinine ratio within 20 μg/mg, and baseline eGFR within 10 ml/min per 1.73 m(2)), with ≤10% decline. We used a Mesoscale Multiplex Platform and measured biomarkers in baseline and 24-month specimens, and we examined biomarker associations with outcome using conditional logistic regression.

RESULTS

Baseline and 24-month levels of monocyte chemotactic protein-1-to-creatinine ratio levels were higher for cases versus controls. The highest quartile of baseline monocyte chemotactic protein-1-to-creatinine ratio had fivefold greater odds, and each log increment had 2.27-fold higher odds for outcome (odds ratio, 5.27; 95% confidence interval, 2.19 to 12.71 and odds ratio, 2.27; 95% confidence interval, 1.44 to 3.58, respectively). IL-18-to-creatinine ratio, kidney injury molecule-1-to-creatinine ratio, and YKL-40-to-creatinine ratio were not consistently associated with outcome. C statistic for traditional predictors of eGFR decline was 0.70, which improved significantly to 0.74 with monocyte chemotactic protein-1-to-creatinine ratio.

CONCLUSIONS

Urinary monocyte chemotactic protein-1-to-creatinine ratio concentrations were strongly associated with sustained renal decline in patients with type 2 diabetes with preserved renal function.

The new Asian modified CKD-EPI equation leads to more accurate GFR estimation in Chinese patients with CKD

OBJECTIVE

To verify whether the new Asian modified CKD-EPI equation improved the performance of original one in determining GFR in Chinese patients with CKD.

METHOD

A well-designed paired cohort was set up. Measured GFR (mGFR) was the result of ^99mTc-diethylene triamine pentaacetic acid (^99mTc-DTPA) dual plasma sample clearance method. The estimated GFR (eGFR) was the result of the CKD-EPI equation (eGFR1) and the new Asian modified CKD-EPI equation (eGFR2). The comparisons were performed to evaluate the superiority of the eGFR2 in bias, accuracy, precision, concordance correlation coefficient and the slope of regression equation and measure agreement.

RESULTS

A total of 195 patients were enrolled and analyzed. The new Asian modified CKD-EPI equation improved the performance of the original one in bias and accuracy. However, nearly identical performance was observed in the respect of precision, concordance correlation coefficient, slope of eGFR against mGFR and 95 % limit of agreement. In the subgroup of GFR < 60 mL min^-1/1.73 m², the bias of eGFR1 was less than eGFR2 but they have comparable precision and accuracy. In the subgroup of GFR > 60 mL min^-1/1.73 m², eGFR2 performed better than eGFR1 in terms of bias and accuracy.

CONCLUSION

The new Asian modified CKD-EPI equation can lead to more accurate GFR estimation in Chinese patients with CKD in general practice, especially in the higher GFR group.

The new Asian modified CKD-EPI equation leads to more accurate GFR estimation in Chinese patients with CKD

OBJECTIVE

To verify whether the new Asian modified CKD-EPI equation improved the performance of original one in determining GFR in Chinese patients with CKD.

METHOD

A well-designed paired cohort was set up. Measured GFR (mGFR) was the result of ^99mTc-diethylene triamine pentaacetic acid (^99mTc-DTPA) dual plasma sample clearance method. The estimated GFR (eGFR) was the result of the CKD-EPI equation (eGFR1) and the new Asian modified CKD-EPI equation (eGFR2). The comparisons were performed to evaluate the superiority of the eGFR2 in bias, accuracy, precision, concordance correlation coefficient and the slope of regression equation and measure agreement.

RESULTS

A total of 195 patients were enrolled and analyzed. The new Asian modified CKD-EPI equation improved the performance of the original one in bias and accuracy. However, nearly identical performance was observed in the respect of precision, concordance correlation coefficient, slope of eGFR against mGFR and 95 % limit of agreement. In the subgroup of GFR < 60 mL min^-1/1.73 m², the bias of eGFR1 was less than eGFR2 but they have comparable precision and accuracy. In the subgroup of GFR > 60 mL min^-1/1.73 m², eGFR2 performed better than eGFR1 in terms of bias and accuracy.

CONCLUSION

The new Asian modified CKD-EPI equation can lead to more accurate GFR estimation in Chinese patients with CKD in general practice, especially in the higher GFR group.

Differential associations between glomerular filtration rate and duration of obesity depending on the presence or absence of left ventricular diastolic dysfunction

BACKGROUND

A robust and consistent association between increasing body mass index (BMI) and chronic kidney disease (CKD) has been reported in several observational studies. Obesity remains the main preventable risk factor for CKD because it largely mediates diabetes and hypertension, the 2 most common etiologies for end-stage kidney disease (ESKD). Obesity is associated weakly with early stages of kidney disease but strongly with kidney progression to ESKD, even after adjustment for hypertension and diabetes.

AIM

To assess the relationship between estimated glomerular filtration rate (eGFR) and trans-thoracic echocardiography left ventricular function parameters in a cohort of patients with obesity.

MATERIALS & METHODS

Cross-sectional study involving 324 obese (BMI=44.0±2.2Kg/m(2)) apparently healthy asymptomatic patients with an eGFR >60ml/min/1.73m(2). Each patient underwent transthoracic echocardiography and a blood testing. The eGFR was addressed by the CKD-EPI formula.

RESULTS

All patients had a normal systolic function whereas 24.5% disclosed diastolic dysfunction (DD). Hypertension and type 2 diabetes mellitus prevalence were 34.5% and 4.5% (respectively). All patients disclosed an eGFR >60ml/min while none of them disclosed hyperfiltration (eGFR >120ml/min). eGFR correlated inversely with BMI and the duration of obesity and positively with diastolic function parameters (P<0.001 for all, respectively). Patients with diastolic dysfunction displayed lower eGFR (P<0.0005) and longer duration of obesity (P<0.0005).

CONCLUSIONS

Obesity and its duration are likely to impose hemodynamic changes affecting simultaneously both heart (diastolic dysfunction) and kidney (decreased glomerular filtration rate). Larger prospective studies are warranted.

Preoperative renal dysfunction and mortality after non-cardiac surgery

BACKGROUND

Chronic kidney disease is an important preoperative risk factor. However, the association between renal dysfunction and risk of death has not been well explored in non-cardiac surgery.

METHODS

Two prospective observational studies in non-cardiac surgery were analysed: the European Surgical Outcomes Study (EuSOS) and the UK National Confidential Enquiry into Patient Outcome and Death (NCEPOD). The relationship between preoperative estimated glomerular filtration rate (eGFR) and postoperative mortality was examined using multivariable Cox proportional hazards models.

RESULTS

In EuSOS, 1580 (4·3 per cent) of 36 779 patients died in hospital; in NCEPOD, 298 (2·8 per cent) of 10 466 patients had died by 60 days after surgery. Chronic kidney disease (eGFR below 60·0 ml per min per 1·73 m(2) ) was present in 6415 patients (17·4 per cent) in EuSOS and 2262 (21·6 per cent) in NCEPOD. Preoperative chronic kidney disease was associated with older age, men, diagnosis of diabetes, cardiovascular or respiratory disease, and non-elective surgery. Preoperative eGFR categories below 60·0 ml per min per 1·73 m(2) were associated with increasing adjusted hazard ratios (HRs) for death compared with a value of 90·0 ml per min per 1·73 m(2) and above. In EuSOS, the risk of death increased with lower eGFR category, to a maximum with eGFR 15·0-29·9 ml per min per 1·73 m(2) (HR 3·37, 95 per cent c.i. 2·70 to 4·22). In NCEPOD, the risk of death also increased with declining eGFR and was maximal for eGFR below 15·0 ml per min per 1·73 m(2) (HR 3·40, 1·78 to 6·50).

CONCLUSION

Renal dysfunction is an important risk factor for death after non-cardiac surgery and the risk increases steeply for patients with moderate to severe kidney dysfunction.

Imaging patients with renal impairment

Imaging with intravascular contrast media is generally considered safe, particularly in patients without renal failure. However, as renal function deteriorates, the potential risk of nonallergic-type adverse events increases. This presents a unique challenge, particularly when the use of intravenous contrast media is deemed essential for diagnostic purposes. Following a discussion regarding the definition and epidemiology of kidney injury, this review focuses on the evolving understanding of both contrast-induced nephropathy and nephrogenic systemic fibrosis and discusses preventative strategies aimed at minimizing the risk of developing these entities. Alternative non-contrast imaging techniques are also discussed.

Use of the Modification of Diet in Renal Disease Equation for Estimating Glomerular Filtration Rate in the Urologic Literature

PURPOSE

To evaluate the use of the modification of diet in renal disease (MDRD) equation in the urologic literature and the degree to which it is used appropriately.

METHODS

Medline was queried searching the title, keywords, or abstract of seven urology journals for the exact phrases "MDRD" or "modification of diet in renal disease." Forty-seven articles published between 2004 and 2013 met the inclusion criteria and were reviewed. Each article was reviewed in its entirety and graded on the appropriateness of its use of MDRD to estimate glomerular filtration rate (GFR). Inappropriate use was defined as using the MDRD equation to make comparisons or conclusions about true renal function with the majority of estimated glomerular filtration rate (eGFR) values >60 mL/min per 1.73 m(2).

RESULTS

Of the 47 articles reviewed, 17 (36%) were Grade 1 (appropriate use of MDRD), 20 (43%) were Grade 2 (inappropriate use of MDRD but not critical to claims of article), and 10 (21%) were Grade 3 (inappropriate use of MDRD). Of the Grade 3 articles, only 40% (4 of 10) acknowledged the limitations of this equation for estimating GFR.

CONCLUSIONS

The majority of articles using the MDRD equation to estimate GFR did so using values where the estimate is quite unstable (eGFR >60 mL/min per 1.73 m(2)), thereby limiting the validity of the claims. Urologists should reconsider the use of MDRD for comparing estimates of GFR in patients with normal renal function in published articles.

Comparison of the heart failure risk stratification performance of the CKD-EPI equation and the MDRD equation for estimated glomerular filtration rate in patients with Type 2 diabetes

AIMS

To investigate the risk prediction and the risk stratification performances of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the Modification of Diet in Renal Disease (MDRD) equation for estimated glomerular filtration rate (eGFRCKD - EPI vs. eGFRMDRD ) on heart failure in patients with Type 2 diabetes.

METHODS

The study cohort included 12 258 White and 16 886 African American low-income patients with Type 2 diabetes who were 30-90 years old at baseline. Heart failure risk according to different eGFRCKD - EPI and eGFRMDRD categories was prospectively assessed.

RESULTS

During a mean follow-up of 6.5 years, 5043 incident heart failure cases were identified. Multivariable-adjusted hazard ratios (HRs) of heart failure associated with the eGFRCKD - EPI categories [≥ 90 (reference group), 75-89, 60-74, 30-59 and < 30 ml/min/1.73 m(2) ] were 1.00, 1.11, 1.31, 1.75 and 2.93 (Ptrend < 0.001) for African American patients, and 1.00, 1.11, 1.08, 1.59 and 2.92 (Ptrend < 0.001) for White patients, respectively. The model with eGFRCKD - EPI and the other risk factors had significantly higher Harrell's C than the model with eGFRMDRD and other risk factors. Patients reclassified downward from eGFRMDRD 60-74 to eGFRCKD - EPI 30-59 and from eGFRMDRD 30-59 to eGFRCKD - EPI < 30 ml/min/1.73 m(2) showed higher heart failure risk than those who were not reclassified.

CONCLUSIONS

Impaired kidney function (i.e. GFR < 60 ml/min/1.73 m(2) ), and even mildly decreased GFR (60-74 ml/min/1.73 m(2) ) estimated by both equations is associated with an increased risk of heart failure. Compared with GFR estimated using the MDRD equation, GFR estimated using the CKD-EPI equation added more predictive power to the model with the other risk factors. Also, eGFRCKD - EPI provided more accurate heart failure risk stratification than eGFRMDRD .

The correct renal function evaluation in patients with thyroid dysfunction

Thyroid dysfunction induces several renal derangements involving all nephron portions. Furthermore, dysthyroidism is a recognized risk factor associated with the development of chronic kidney disease. Current data, in fact, demonstrate that either subclinical or overt thyroid disease is associated with significant changes in creatinine, estimated glomerular filtration rate, measured glomerular filtration rate and Cystatin C. Herein, we systematically reviewed several relevant studies aiming at the identification of the most sensitive and specific parameter for the correct renal function evaluation in patients with thyroid dysfunction, that are usually treated as outpatients. Our systematic review indicates that estimated glomerular filtration rate, preferably with CKD-EPI equation, appears to be the most reliable and wieldy renal function parameter. Instead, Cystatin C should be better used in the grading of thyroid dysfunction severity.

Renal evaluation in patients with type 2 diabetes mellitus and its association with diastolic blood pressure

Background: HbA1c is correlated with the estimated glomerular filtration rate (eGFR) and diastolic blood pressure (DBP). Our main objective was to evaluate the trend of biochemical and clinical variables, in relation to the eGFR in patients with type 2 diabetes mellitus (T2DM). Methods: This was a retrospective, longitudinal, and descriptive study, including patients with T2DM, who were cared for from January 2014 until December 2014, at the Clínica de Diabetes, Hospital Regional “Gral. Ignacio Zaragoza", ISSSTE, Mexico City, Mexico. eGFR was calculated using three formulas: the chronic kidney disease – epidemiology collaboration (CKD-EPI), Cockcroft-Gault, and modification of diet in renal disease (MDRD), during two periods of observation, 3 and 6 months. The results were compared by Student t tests or Wilcoxon-Mann-Whitney test depending on the variable distribution. Pearson correlation was employed to determine the relation between the eGFR determined with each formula and the analyzed variables. Results: The mean age was 56.5±11.3 years in the group of 3 months’ follow-up (n=110) and 57.1±13.8 years in the group of 6 months’ follow-up (n=47). In both groups, the formula with the lowest percentages of cases of CKD was CKD-EPI and the difference of this formula had a basal and final significant positive correlation with the DBP. Conclusion: The CKD-EPI formula showed the lowest percentages of cases of CKD in a short follow-up period, and its difference is consistently associated with the DBP, confirming the importance of controlling the later to mitigate the evolution to CKD.

Cost to government and society of chronic kidney disease stage 1-5: a national cohort study

BACKGROUND

Costs associated with chronic kidney disease (CKD) are not well documented. Understanding such costs is important to inform economic evaluations of prevention strategies and treatment options.

AIM

To estimate the costs associated with CKD in Australia.

METHODS

We used data from the 2004/2005 AusDiab study, a national longitudinal population-based study of non-institutionalised Australian adults aged ≥25 years. We included 6138 participants with CKD, diabetes and healthcare cost data. The annual age and sex-adjusted costs per person were estimated using a generalised linear model. Costs were inflated from 2005 to 2012 Australian dollars using best practice methods.

RESULTS

Among 6138 study participants, there was a significant difference in the per-person annual direct healthcare costs by CKD status, increasing from $1829 (95% confidence interval (CI): $1740-1943) for those without CKD to $14 545 (95% CI: $5680-44 842) for those with stage 4 or 5 CKD (P < 0.01). Similarly, there was a significant difference in the per-person annual direct non-healthcare costs by CKD status from $524 (95% CI: $413-641) for those without CKD to $2349 (95% CI: $386-5156) for those with stage 4 or 5 CKD (P < 0.01). Diabetes is a common cause of CKD and is associated with increased health costs. Costs per person were higher for those with diabetes than those without diabetes in all CKD groups; however, this was significant only for those without CKD and those with early stage (stage 1 or 2) CKD.

CONCLUSION

Individuals with CKD incur 85% higher healthcare costs and 50% higher government subsidies than individuals without CKD, and costs increase by CKD stage. Primary and secondary prevention strategies may reduce costs and warrant further consideration.

Association of interleukin 18-607A/C and -137C/G polymorphisms with oxidative stress in renal transplant recipients

Objectives IL-18 mediates various inflammatory and oxidative responses including renal injury, fibrosis, and graft rejection. It has been reported that the promoter -607 and -137 polymorphisms of IL-18 influence the level of IL-18. This prospective observational study investigated the association between oxidative stress with IL-18-607 and -137 polymorphisms in renal transplant recipients. Patients and methods This study included 75 renal transplant recipients (28 female, 47 male) from living-related donors. Blood samples were collected immediately before and after transplantation at day 7 and month 1. Serum IL-18, creatinine, cystatin C, CRP, and oxidative stress markers (TOS, TAC) were measured. The Oxidative Stress Index (OSI) was calculated. Polymorphisms of the promoter region of the IL-18 gene, IL18-607A/C, and -137C/G were determined by analysis of a "real-time PCR/Melting curve". Results Serum creatinine, cystatin C, CRP, IL-18, TOS, and OSI levels significantly decreased after transplantation. Post-transplant levels of serum TAC and estimated GFR demonstrated consistent significant increases. Serum IL-18 levels were significantly higher in patients with IL-18-137 GG and IL-18-607 CC genotypes before transplantation. Conclusion Our results indicate that the IL-18-137 GG and -607 CC genotypes contribute to higher IL-18 levels; however, the influence of these polymorphisms on oxidative stress has not been observed.

Comparison of the Schwartz and CKD-EPI Equations for Estimating Glomerular Filtration Rate in Children, Adolescents, and Adults: A Retrospective Cross-Sectional Study

BACKGROUND

Estimating kidney glomerular filtration rate (GFR) is of utmost importance in many clinical conditions. However, very few studies have evaluated the performance of GFR estimating equations over all ages and degrees of kidney impairment. We evaluated the reliability of two major equations for GFR estimation, the CKD-EPI and Schwartz equations, with urinary clearance of inulin as gold standard.

METHODS AND FINDINGS

The study included 10,610 participants referred to the Renal and Metabolic Function Exploration Unit of Edouard Herriot Hospital (Lyon, France). GFR was measured by urinary inulin clearance (only first measurement kept for analysis) then estimated with isotope dilution mass spectrometry (IDMS)-traceable CKD-EPI and Schwartz equations. The participants' ages ranged from 3 to 90 y, and the measured GFRs from 3 to 160 ml/min/1.73 m2. A linear mixed-effects model was used to model the bias (mean ratio of estimated GFR to measured GFR). Equation reliability was also assessed using precision (interquartile range [IQR] of the ratio) and accuracy (percentage of estimated GFRs within the 10% [P10] and 30% [P30] limits above and below the measured GFR). In the whole sample, the mean ratio with the CKD-EPI equation was significantly higher than that with the Schwartz equation (1.17 [95% CI 1.16; 1.18] versus 1.08 [95% CI 1.07; 1.09], p < 0.001, t-test). At GFR values of 60-89 ml/min/1.73 m2, the mean ratios with the Schwartz equation were closer to 1 than the mean ratios with the CKD-EPI equation whatever the age class (1.02 [95% CI 1.01; 1.03] versus 1.15 [95% CI 1.13; 1.16], p < 0.001, t-test). In young adults (18-40 y), the Schwartz equation had a better precision and was also more accurate than the CKD-EPI equation at GFR values under 60 ml/min/1.73 m2 (IQR: 0.32 [95% CI 0.28; 0.33] versus 0.40 [95% CI 0.36; 0.44]; P30: 81.4 [95% CI 78.1; 84.7] versus 63.8 [95% CI 59.7; 68.0]) and also at GFR values of 60-89 ml/min/1.73 m2. In all patients aged ≥65 y, the CKD-EPI equation performed better than the Schwartz equation (IQR: 0.33 [95% CI 0.31; 0.34] versus 0.40 [95% CI 0.38; 0.41]; P30: 77.6 [95% CI 75.7; 79.5] versus 67.5 [95% CI 65.4; 69.7], respectively). In children and adolescents (2-17 y), the Schwartz equation was superior to the CKD-EPI equation (IQR: 0.23 [95% CI 0.21; 0.24] versus 0.33 [95% CI 0.31; 0.34]; P30: 88.6 [95% CI 86.7; 90.4] versus 29.4 [95% CI 26.8; 32.0]). This study is limited by its retrospective design, single-center setting with few non-white patients, and small number of patients with severe chronic kidney disease.

CONCLUSIONS

The results from this study suggest that the Schwartz equation may be more reliable than the CKD-EPI equation for estimating GFR in children and adolescents and in adults with mild to moderate kidney impairment up to age 40 y.

Moderate Increase of Indoxyl Sulfate Promotes Monocyte Transition into Profibrotic Macrophages

OBJECTIVE

The uremic toxin Indoxyl-3-sulphate (IS), a ligand of Aryl hydrocarbon Receptor (AhR), raises in blood during early renal dysfunction as a consequence of tubular damage, which may be present even when eGFR is normal or only moderately reduced, and promotes cardiovascular damage and monocyte-macrophage activation. We previously found that patients with abdominal aortic aneurysms (AAAs) have higher CD14+CD16+ monocyte frequency and prevalence of moderate chronic kidney disease (CKD) than age-matched control subjects. Here we aimed to evaluate the IS levels in plasma from AAA patients and to investigate in vitro the effects of IS concentrations corresponding to mild-to-moderate CKD on monocyte polarization and macrophage differentiation.

METHODS

Free IS plasma levels, monocyte subsets and laboratory parameters were evaluated on blood from AAA patients and eGFR-matched controls. THP-1 monocytes, treated with IS 1, 10, 20 μM were evaluated for CD163 expression, AhR signaling and then induced to differentiate into macrophages by PMA. Their phenotype was evaluated both at the stage of semi-differentiated and fully differentiated macrophages. AAA and control sera were similarly used to treat THP-1 monocytes and the resulting macrophage phenotype was analyzed.

RESULTS

IS plasma concentration correlated positively with CD14+CD16+ monocytes and was increased in AAA patients. In THP-1 cells, IS promoted CD163 expression and transition to macrophages with hallmarks of classical (IL-6, CCL2, COX2) and alternative phenotype (IL-10, PPARγ, TGF-β, TIMP-1), via AhR/Nrf2 activation. Analogously, AAA sera induced differentiation of macrophages with enhanced IL-6, MCP1, TGF-β, PPARγ and TIMP-1 expression.

CONCLUSION

IS skews monocyte differentiation toward low-inflammatory, profibrotic macrophages and may contribute to sustain chronic inflammation and maladaptive vascular remodeling.

The association of renal artery calcification with hypertension in community-living individuals: the multiethnic study of atherosclerosis

Hypertension (HTN) is a modifiable risk factor for cardiovascular disease (CVD). Renal artery calcium (RAC) may signal the presence of flow-limiting atherosclerotic disease that may contribute to changes in the kidney's regulation of blood pressure. We hypothesized that RAC is independently associated with HTN. We examined a multiethnic cohort of 1285 participants who underwent abdominal computed tomography scans in five US communities. After adjustment for age, gender, race/ethnicity, CVD risk factors, abdominal aortic calcium score, and kidney function, the presence of RAC was associated with a 50% higher odds of HTN (odds ratio: 1.54; 95% confidence interval 1.11-2.13). Similarly, the presence of RAC was associated with a 8.5 mm Hg higher systolic blood pressure, a 2.1 mm Hg higher diastolic blood pressure, and a 7.4-mm Hg higher pulse pressure. In conclusion, independent of CVD risk factors, abdominal aortic calcium, and kidney function, the presence of RAC is associated with HTN prevalence.

Kidney Function and Cardiovascular Events in Postmenopausal Women: The Impact of Race and Ethnicity in the Women's Health Initiative

BACKGROUND

Kidney disease disproportionately affects minority populations, including African Americans and Hispanics; therefore, understanding the relationship of kidney function to cardiovascular (CV) outcomes within different racial/ethnic groups is of considerable interest. We investigated the relationship between kidney function and CV events and assessed effect modification by race/ethnicity in the Women's Health Initiative.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Baseline serum creatinine concentrations (assay traceable to isotope-dilution mass spectrometry standard) of 19,411 postmenopausal women aged 50 to 79 years who self-identified as either non-Hispanic white (n=8,921), African American (n=7,436), or Hispanic (n=3,054) were used to calculate estimated glomerular filtration rates (eGFRs).

PREDICTORS

Categories of eGFR (exposure); race/ethnicity (effect modifier).

OUTCOMES

The primary outcome was the composite of 3 physician-adjudicated CV events: myocardial infarction, stroke, or CV-related death.

MEASUREMENTS

We evaluated the multivariable-adjusted associations between categories of eGFR and CV events using proportional hazards regression and formally tested for effect modification by race/ethnicity.

RESULTS

During a mean follow-up of 7.6 years, 1,424 CV events (653 myocardial infarctions, 627 strokes, and 297 CV-related deaths) were observed. The association between eGFR and CV events was curvilinear; however, the association of eGFR with CV outcomes differed by race (P=0.006). In stratified analyses, we observed that the U-shaped association was present in non-Hispanic whites, whereas African American participants had a rather curvilinear relationship, with lower eGFR being associated with higher CV risk, and higher eGFR, with reduced CV risk. Analyses among Hispanic women were inconclusive owing to few Hispanic women having very low or high eGFRs and very few events occurring in these categories.

LIMITATIONS

Lack of urinary albumin measurements; residual confounding by unmeasured or imprecisely measured characteristics.

CONCLUSIONS

In postmenopausal women, the patterns of association between eGFR and CV risk differed between non-Hispanic whites and African American women.

Nocturnal and Circadian Rhythm of Blood Pressure Is Associated with Renal Structure Damage and Function in Patients with IgAN

BACKGROUND AND AIMS

Abnormal circadian rhythm of blood pressure (BP) is closely related to target organ damage in hypertension. However, the association between abnormal circadian rhythm of BP and renal injury is not clear. We investigated whether renal injury is associated with nocturnal BP and circadian rhythm of BP in Chinese IgAN patients.

METHODS

Clinic and 24 h ambulatory BP monitoring data were obtained from 330 Chinese IgAN patients with mean 24 h BP < 130/80 and mean daytime BP < 135/85 mmHg. Renal histopathological injury was determined according to the Oxford classification of IgAN.

RESULTS

Among the 330 IgAN subjects, 35.8% suffered from nocturnal hypertension, 61.5% had abnormal circadian BP, and 27% had nocturnal hypertension with a nondipping pattern. Compared with nocturnal normotensive patients, patients with nocturnal hypertension had significantly higher levels of blood cystatin C, blood uric acid, and lower estimated glomerular filtration rate (eGFR), and significantly a higher mean renal tissue injury score. The nondipping hypertensive group had significantly higher nocturnal diastolic and systolic BP, blood uric acid, and glomerulosclerosis rates, whereas eGFR was lower. In nondipping hypertensive patients, urinary sodium excretion and renal tissue injury scores were significantly higher than dipping patients. Nocturnal hypertension and abnormal circadian BP correlated with renal tissue injury, renal interstitial fibrosis, and aortic arch atherosclerosis.

CONCLUSION

Abnormal circadian rhythm of BP and nocturnal hypertension are common clinical manifestations in Chinese IgAN patients with normal mean 24 h BP. Abnormal circadian BP and nocturnal hypertension may accelerate IgAN progression by inducing renal dysfunction and histopathological damage.

The 2014 Atrial Fibrillation Guidelines Companion: A Practical Approach to the Use of the Canadian Cardiovascular Society Guidelines

The Canadian Cardiovascular Society (CCS) Atrial Fibrillation Guidelines Program has generated a comprehensive series of documents regarding the management of atrial fibrillation (AF) between 2010 and 2014. The guidelines provide evidence-based consensus management recommendations in a broad range of areas. These guidelines have proven useful in informing clinical practice, but often lack detail in specifications related to practical application, particularly for areas in which the evidence base is limited or conflicting. Based on feedback from the community, the CCS Atrial Fibrillation Guidelines Committee has identified a number of areas that require clarification to address commonly asked practical questions related to guidelines application. In the present article a number of such questions are presented and suggestions about how they can be answered are suggested. Among the issues considered are: (1) What duration of AF is clinically significant? (2) How are the risk factors in the CCS Algorithm for selecting anticoagulation therapy derived and defined? (3) How is valvular heart disease defined and how do different forms of valve disease affect the choice of anticoagulant therapy for AF patients? (4) How should we quantify renal dysfunction and how does it affect therapeutic choices? The response to these questions and the underlying logic are provided, along with an indication of future research needed where no specific approach can presently be recommended based on the literature.

Coincidence of obesity associated with cardio-renal abnormalities in Thais obese population

AIM

To investigate the patterns and relationship among the metabolic syndrome (MS), coronary heart disease (CHD) and kidney function.

METHODS

A cross-sectional secondary data set of 9359 individuals, age 30-74 years, receiving annual health check-up in 2012 were used in this studied. Identification of MS and CHD development was determined by International Diabetes Federation criteria and Framingham risk score, respectively, while kidney function was assessed by using the estimate glomerulus filtration rate (eGFR) and chronic kidney disease epidemiology (CKD-EPI) formula.

RESULTS

The prevalence of MS was 16.1%. The majority pattern of MS in male displayed abnormalities of body mass index (BMI) plus triglyceride and blood pressure (BP). Most of them had high risk of CHD, and kidney function in stage 1 and 2. Furthermore, abnormalities of BMI plus BP and blood glucose were the main components related to high risk of CHD, and stage 1 of kidney function in female.

CONCLUSION

This finding showed the cleared pattern of the sequential abnormality factors which potentially use for setting the activity and empowerment team to prevention, promotion, and treatment strategy in MS patients. Particularly, BMI is the first assessment and then follow by blood pressure and blood sugar which could be used as the guideline for reducing MS associated with CHD and kidney disorder in Thai population.

Estimating glomerular filtration rate: Performance of the CKD-EPI equation over time in patients with type 2 diabetes

AIMS

To assess the performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation at baseline and longitudinally in people with type 2 diabetes.

METHODS

Adults with type 2 diabetes attending Austin Health, Melbourne, with≥3 prospective GFR measurements were included in this retrospective study. Plasma disappearance rate of DTPA (diethylene-triamine-penta-acetic acid) was used to calculate measured GFR (mGFR) and compared to estimated GFR (eGFR). The agreement between mGFR and eGFR was estimated using Intraclass Correlation Coefficient (ICC).

RESULTS

152 patients had a median of 4 (IQR: 3, 5) mGFR measurements over a period of 11years (IQR: 9, 12). The difference between mGFR and eGFR increased proportionally to the magnitude of the GFR, increasing by 0.2ml/min/1.73m(2) for every 1ml/min/1.73m(2) increase in mGFR, indicative of proportional bias. At lower mGFR levels, eGFR overestimated mGFR, and at higher mGFR levels, eGFR underestimated mGFR. There was a significant association between LDL cholesterol, triglycerides, HbA1c, diastolic blood pressure and the difference between mGFR and eGFR.

CONCLUSIONS

The CKD-EPI formula underestimates mGFR and the rate of decline of mGFR in patients with type 2 diabetes with an mGFR greater than 60ml/min/1.73m(2). The association between LDL cholesterol, triglycerides, HbA1c, diastolic blood pressure and the difference between mGFR and eGFR warrants further study.

Usefulness of serum cystatin C to determine the dose of vancomycin in neonate

Purpose

The vancomycin dosage regimen is regularly modified according to the patient's glomerular filtration rate (GFR). In the present study, we aimed to assess the usefulness of serum cystatin C (Cys-C) concentration, compared with serum creatinine (SCr) concentration, for predicting vancomycin clearance (CLvcm) in neonates.

Methods

We retrospectively analyzed the laboratory data of 50 term neonates who were admitted to the neonatal intensive care unit and received intravenous vancomycin, and assessed the pharmacokinetic profiles. Creatinine clearance (CLcr) and GFR based on Cys-C (GFRcys-c) were estimated using the Schwartz and Larsson formulas, respectively.

Results

The mean CLvcm (±standard deviation) was 74.52±31.17 L/hr, the volume of distribution of vancomycin was 0.67±0.14 L, and vancomycin half-life was 9.16±17.42 hours. The SCr was 0.46±0.25 mg/dL and serum Cys-C was 1.43±0.34 mg/L. The peak and trough concentrations of vancomycin were 24.65±14.84 and 8.10±5.35 mcg/mL, respectively. The calculated GFR based on serum creatinine concentration (GFR-Cr) and GFRcys-c were 70.2±9.45 and 63.6±30.18 mL/min, respectively. The correlation constant for CLvcm and the reciprocal of Cys-C (0.479, P=0.001) was significantly higher than that for CLvcm and the reciprocal of SCr (0.286, P=0.044). GFRcys-c was strongly correlated with CLvcm (P=0.001), and the correlation constant was significantly higher than that for CLvcm and CLcr (0.496, P=0.001). Linear regression analysis showed that only GFRcys-c was independently and positively correlated with CLvcm (F=41.9, P<0.001).

Conclusion

The use of serum Cys-C as a marker of CLvcm could be beneficial for more reliable predictions of serum vancomycin concentrations, particularly in neonates.

Clinical Correlates of Mass Effect in Autosomal Dominant Polycystic Kidney Disease

Mass effect from polycystic kidney and liver enlargement can result in significant clinical complications and symptoms in autosomal dominant polycystic kidney disease (ADPKD). In this single-center study, we examined the correlation of height-adjusted total liver volume (htTLV) and total kidney volume (htTKV) by CT imaging with hepatic complications (n = 461) and abdominal symptoms (n = 253) in patients with ADPKD. “Mass-effect” complications were assessed by review of medical records and abdominal symptoms, by a standardized research questionnaire. Overall, 91.8% of patients had 4 or more liver cysts on CT scans. Polycystic liver disease (PLD) was classified as none or mild (htTLV < 1,600 mL/m); moderate (1,600 ≤ htTLV <3,200 mL/m); and severe (htTLV ≥ 3,200 mL/m). The prevalence of moderate and severe PLD in our patient cohort was 11.7% (n = 54/461) and 4.8% (n = 22/461), respectively, with a female predominance in both the moderate (61.1%) and severe (95.5%) PLD groups. Pressure-related complications such as leg edema (20.4%), ascites (16.6%), and hernia (3.6%) were common, and patients with moderate to severe PLD exhibited a 6-fold increased risk (compared to no or mild PLD) for these complications in multivariate analysis. Similarly, abdominal symptoms including back pain (58.8%), flank pain (53.1%), abdominal fullness (46.5%), and dyspnea/chest-discomfort (44.3%) were very common, and patients with moderate to severe PLD exhibited a 5-fold increased risk for these symptoms. Moderate to severe PLD is a common and clinically important problem in ~16% of patients with ADPKD who may benefit from referral to specialized centers for further management.

The Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation does not improve the underestimation of Glomerular Filtration Rate (GFR) in people with diabetes and preserved renal function

BACKGROUND

Our hypothesis was that both the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations would underestimate directly measured GFR (mGFR) to a similar extent in people with diabetes and preserved renal function.

METHODS

In a cross-sectional study, bias (eGFR - mGFR) was compared for the CKD-EPI and MDRD equations, after stratification for mGFR levels. We also examined the ability of the CKD-EPI compared with the MDRD equation to correctly classify subjects to various CKD stages. In a longitudinal study of subjects with an early decline in GFR i.e., initial mGFR > 60 ml/min/1.73 m(2) and rate of decline in GFR (ΔmGFR) > 3.3 ml/min/1.73 m(2) per year, ΔmGFR (based on initial and final values) was compared with ΔeGFR by the CKD-EPI and MDRD equations over a mean of 9 years.

RESULTS

In the cross-sectional study, mGFR for the whole group was 80 ± 2.2 ml/min/1.73 m(2) (n = 199, 75 % type 2 diabetes). For subjects with mGFR >90 ml/min/1.73 m(2) (mGFR: 112 ± 2.0, n = 76), both equations significantly underestimated mGFR to a similar extent: bias for CKD-EPI: -12 ± 1.4 ml/min/1.73 m(2) (p < 0.001) and for MDRD: -11 ± 2.1 ml/min/1.73 m(2) (p < 0.001). Using the CKD-EPI compared with the MDRD equation did not improve the number of subjects that were correctly classified to a CKD-stage. No biochemical or clinical patient characteristics were identified to account for the under estimation of mGFR values in the normal to high range by the CKD-EPI equation. In the longitudinal study (n = 30, 66 % type 1 diabetes), initial and final mGFR values were 102.8 ± 6 and 54.6 ± 6.0 ml/min/1.73 m(2), respectively. Mean ΔGFR (ml/min/1.73 m(2) per year) was 6.0 by mGFR compared with only 3.0 by MDRD and 3.2 by CKD-EPI (both p < 0.05 vs mGFR) CONCLUSIONS: Both the CKD-EPI and MDRD equations underestimate reference GFR values > 90 ml/min/1.73 m(2) as well as an early decline in GFR to a similar extent in people with diabetes. There is scope to improve methods for estimating an early decline in GFR.

The Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation does not improve the underestimation of Glomerular Filtration Rate (GFR) in people with diabetes and preserved renal function

Background

Our hypothesis was that both the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations would underestimate directly measured GFR (mGFR) to a similar extent in people with diabetes and preserved renal function.

Methods

In a cross-sectional study, bias (eGFR – mGFR) was compared for the CKD-EPI and MDRD equations, after stratification for mGFR levels. We also examined the ability of the CKD-EPI compared with the MDRD equation to correctly classify subjects to various CKD stages. In a longitudinal study of subjects with an early decline in GFR i.e., initial mGFR >60 ml/min/1.73 m² and rate of decline in GFR (ΔmGFR) > 3.3 ml/min/1.73 m² per year, ΔmGFR (based on initial and final values) was compared with ΔeGFR by the CKD-EPI and MDRD equations over a mean of 9 years.

Results

In the cross-sectional study, mGFR for the whole group was 80 ± 2.2 ml/min/1.73 m² (n = 199, 75 % type 2 diabetes). For subjects with mGFR >90 ml/min/1.73 m² (mGFR: 112 ± 2.0, n = 76), both equations significantly underestimated mGFR to a similar extent: bias for CKD-EPI: -12 ± 1.4 ml/min/1.73 m² (p < 0.001) and for MDRD: -11 ± 2.1 ml/min/1.73 m² (p < 0.001). Using the CKD-EPI compared with the MDRD equation did not improve the number of subjects that were correctly classified to a CKD-stage. No biochemical or clinical patient characteristics were identified to account for the under estimation of mGFR values in the normal to high range by the CKD-EPI equation. In the longitudinal study (n = 30, 66 % type 1 diabetes), initial and final mGFR values were 102.8 ± 6 and 54.6 ± 6.0 ml/min/1.73 m², respectively. Mean ΔGFR (ml/min/1.73 m² per year) was 6.0 by mGFR compared with only 3.0 by MDRD and 3.2 by CKD-EPI (both p < 0.05 vs mGFR)

Conclusions

Both the CKD-EPI and MDRD equations underestimate reference GFR values >90 ml/min/1.73 m² as well as an early decline in GFR to a similar extent in people with diabetes. There is scope to improve methods for estimating an early decline in GFR.

Long-term effect of lithium maintenance therapy on estimated glomerular filtration rate in patients with affective disorders: a population-based cohort study

BACKGROUND

For more than 40 years, the long-term effect of lithium maintenance therapy on renal function has been debated. We aimed to assess the effect of lithium maintenance therapy on estimated glomerular filtration rate (eFGR) in patients with affective disorders, and explore predictors for a decrease in eGFR.

METHODS

This population-based cohort study included adult patients (18-65 years of age at baseline) in Tayside (Scotland, UK) who had recently started on lithium maintenance treatment between Jan 1, 2000, and Dec 31, 2011 (retrospectively assigned to the lithium group) or those with exposure to other first-line drugs used in the treatment of affective disorders (quetiapine, olanzapine, and semisodium valproate) during the same period (retrospectively assigned to the comparator group). Patients had to have at least 6 months of (incidence) exposure to lithium or any of the comparator drugs, at least two eGFR values available in the observation period (one at baseline and at least one after ≥6 months post baseline). We excluded patients with previous exposure to lithium or one of the comparator drugs, those with a previous diagnosis of schizophrenia or other psychotic disorder, those with glomerular disease, tubulo-interstitial disease, or chronic kidney disease stages 4-5 at baseline, and those who had undergone renal transplant before exposure. Maximum follow-up was 12 years. Data were provided by the University of Dundee Health Informatics Centre, who have access to health-related population-based datasets containing data for every patient registered with a regional family doctor. Each patient has a unique ten-digit identifier, the Community Health Index, enabling us to link laboratory tests, dispensed community prescriptions, Scottish Morbidity Records, and mortality records to the patient. All data were anonymised according to Health Informatics Centre standard operating procedures. The primary outcome was the change per year in the eGFR, adjusted for age, sex, and baseline eGFR, and analysed by random coefficient models.

FINDINGS

1120 patients (305 exposed to lithium and 815 to comparator drugs) qualified for inclusion, providing 13 963 eGFR values over 12 years. The mean duration of exposure to lithium was 55 months (SD 42; range 6-144). Mean annual decline in eGFR (adjusted for age, sex, and baseline eGFR) was 1·3 mL/min per 1·73 m(2) (SE 0·2) in the lithium group, which did not differ significantly to that in the comparator group (0·9 mL/min/1·73 m(2) [SE 0·15]). After adjustment for additional confounders, the monthly decline in eGFR attributable to lithium exposure amounted to 0·02 mL/min per 1·73 m(2) (SE 0·02, p=0·30). As a post-hoc secondary outcome, we estimated the annual decline in eGFR for the lithium group to be 1·0 mL/min per 1·73 m(2) (SE 0·2), which again did not differ significantly to that in the comparator group (0·4 mL/min/1·73 m(2) [SE 0·2]. Modelling identified significant predictors for eGFR decline as age, baseline eGFR, comorbidities, co-prescriptions of nephrotoxic drugs, and episodes of lithium toxicity; however, duration of exposure to lithium and mean serum lithium level were not significant predictors for eGFR decline.

INTERPRETATION

Our analysis suggests no effect of stable lithium maintenance therapy (lithium levels in therapeutic range) on the rate of change in eGFR over time. Our results therefore contradict the idea that long-term lithium therapy is associated with nephrotoxicity in the absence of episodes of acute intoxication and that duration of therapy and cumulative dose are the major determinants of toxicity.

FUNDING

None.

Phosphate excretion is decreased in older cardiac patients with normal kidney function: an emerging dietary risk factor?

Serum phosphate independently predicts cardiovascular events and mortality. Sixteen healthy adults and 9 adults with cardiovascular disease (CVD) ingested 500 mg of sodium phosphate after an over-night fast. In control subjects, the urine phosphate/creatinine ratio was significantly higher at 2 h (3.12 ± 1.02) than at baseline (1.98 ± 0.58, p < 0.001) but no change was observed in CVD patients. Decreased postprandial urinary excretion of phosphate could accelerate vascular calcification and may be an under-recognized risk factor for CVD.

Effect of Low-Osmolar Intravenous Contrast on Renal Length

OBJECTIVE

The purpose was to study the effect of low-osmolar nonionic contrast on renal length.

MATERIAL AND METHODS

This study included 56 patients (4-phase renal computed tomography [CT] and 4-phase CT urogram [CTU], 19 patients each; split-phase CTU, 18 patients). Three radiologists created the best off-axis plane and renal lengths measured on a postprocessing workstation. Two-way analysis of variance with Bonferroni corrections was performed along with single-sample t tests.

RESULTS

Four-phase renal CT and CTU average differences from unenhanced phases were 0.30/0.16 mm (corticomedullary), 0.88/1.33 mm (nephrographic), and 2.17/2.22 mm (delayed). The nephrographic and delayed phases were significantly different from their unenhanced phase (P < 0.01). Nonsignificant differences between the corticomedullary phase and the unenhanced phase were observed (P = 0.217, 4-phase renal CT; P = 0.232, 4-phase CTU). The split-phase CTU average difference in the enhanced phase was 1.36 mm (P < 0.001).

CONCLUSION

Renal length increases 1 to 2 mm with low-osmolar nonionic contrast.

Kaiser Permanente Creatinine Safety Program: A Mechanism to Ensure Widespread Detection and Care for Chronic Kidney Disease

BACKGROUND

Chronic kidney disease is highly prevalent but is challenging to diagnose because of the need to establish chronicity. Within the current healthcare environment, a single abnormal creatinine measurement often can go without a follow-up, which can lead to missed diagnoses or diagnostic errors. The Kaiser Permanente Southern California creatinine safety program (the Creatinine SureNet) was created to help ensure that all single abnormal creatinine results had a follow-up evaluation.

METHODS

In the period February 1, 2010, to March 1, 2014, the electronic health records were used to capture individuals with single abnormal creatinine results that went >90 days without a repeat measurement. A coordinated effort among a centralized regional nurse and providers was used to communicate with patients and order a repeat creatinine measurement.

RESULTS

A total of 12,396 individuals were identified (84% ambulatory care encounters). A total of 6981 individuals (52%) followed up with a repeat measurement. Female patients, non-Hispanic whites, and older individuals were more likely to obtain a repeat measurement. Subsequently, 3668 individuals had chronic kidney disease confirmed. Within 6 months, 1550 patients had chart documentation of their chronic kidney disease and 336 patients had a nephrology consultation.

CONCLUSIONS

The ambulatory care environment, given its high volume and various prioritizations, is an under-recognized area where diagnostic errors are not uncommon and failure to follow up on abnormal test results can occur routinely. The Kaiser Permanente Southern California Creatinine SureNet program leverages the electronic health records and its multidisciplinary resources in an effort to ensure that patients with potential chronic kidney disease are identified and managed properly.