Influence of megestrol acetate on nutrition, inflammation and quality of life in dialysis patients

AIM

Malnutrition is a common clinical problem in dialysis patients. The objective of this study was to evaluate the efficacy and safety of megestrol acetate in malnourished dialysis patients. Thirty-two hypoalbuminemic dialysis patients took 160 mg of megestrol acetate daily for up to 6 months.

METHODS

We measured height, dry weight, BMI, modified Subjective Global Assessment (SGA) score, and serum albumin, triglycerides, total cholesterol, hsCRP, IL-1β and IL-6 concentrations. We used validated questionnaires to evaluate selected dimensions of the quality of life.

RESULTS

Only 12 patients completed the study. All patients reported improved appetite, and there were concurrent statistically significant increases in weight, BMI, SGA and albumin concentration (P < 0.05). For the 12 patients who completed 6 months of treatment the increase in these parameters was from 63.26 ± 13.04 to 65.58 ± 12.53 kg, from 23.5 ± 3.8 to 24.66 ± 4.23 kg/m(2), from 5.16 ± 0.94 to 6.16 ± 0.72 points, and from 36.45 ± 1.82 to 40.33 ± 2.71 g/l, respectively. However, there were no significant changes in the levels of inflammatory markers and in quality of life. Side effects included overhydration, excessive weight gain and hyperglycaemia.

CONCLUSION

Megestrol acetate may be effective in reversing poor appetite in carefully selected maintenance dialysis patients, but it might not reduce inflammation or improve the quality of life. Because of the potential side effects, close monitoring is essential.

[Serum cystatin C: a practical alternative for renal function evaluation?]

Glomerular filtration rate is the main marker of renal function in healthy individuals and patients. Despite incontestable advances in medicine, it is still difficult to define precisely this test in clinical practice. Early markers of renal lesion are important, because glomerular filtration rate usually decreases before the first chronic renal failure symptoms or signs appear. Cystatin C has been pointed as an alternative, but it was not tested in many diseases. Advantages and disadvantages of this marker are discussed. Although serum cystatin C determination is increasingly being used in clinical practice worldwide, its limitations as well as the conditions its use is in fact indicated are not adequately established; on the other hand serum creatinine (and creatinine clearance) is an easily available and low cost laboratory marker with well-known limitations that can be used routinely in the assessment of renal function.

C-reactive protein and the risk of contrast-induced acute kidney injury in patients undergoing percutaneous coronary intervention

BACKGROUND

The relationship between preprocedural C-reactive protein (CRP) levels and the incidence of contrast-induced acute kidney injury (CI-AKI) is unknown.

METHODS

Documents of 7,310 consecutive patients undergoing percutaneous coronary intervention (PCI) were screened. Patients with acute myocardial infarction, cardiogenic shock, concomitant inflammatory conditions or undergoing CABG within 48 h were excluded due to potential confounding effects.

RESULTS

A total of 4,522 patients were valid for analysis. The median follow-up was 26 months (interquartile range 20-33 months). According to preprocedural CRP values, patients were divided into 3 groups: group 1: CRP <1.0 mg/l (n = 1,523); group 2: 1.0 mg/l ≤ CRP ≤ 3.0 mg/l (n = 1,626); group 3: CRP >3.0 mg/l (n = 1,373). Patients with higher preprocedural CRP levels were associated with a significantly increased rate of CI-AKI (10.6 vs. 14.9 vs. 23.5%, p < 0.0001). After adjustment for baseline covariates, CRP level was still an independent predictor for the incidence of CI-AKI, either as a continuous variable or a categorical variable. Patients with higher CRP values had a significantly higher rate of all-cause mortality and myocardial infarction during follow-up.

CONCLUSION

Elevated preprocedural CRP is associated with an increased risk for CI-AKI in patients undergoing PCI. Preprocedural risk stratification with CRP as an adjunct to established clinical risk factors might be useful.

Risk of acute kidney injury after exposure to gadolinium-based contrast in patients with renal impairment

OBJECTIVES

Gadolinium-based contrast media (Gd-CM) are reported to induce acute kidney injury (AKI) in a high-risk population group at the usual dose for magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) examinations. We assessed gadolinium-induced nephropathy in patients with renal impairment who underwent MRI or MRA examinations, and evaluated the risk factors.

MATERIALS AND METHODS

In this retrospective study, 238 patients with baseline renal impairment, who received MRI or MRA examinations with Gd-CM, were recruited. After all other AKI causes-liver decompensation, severe heart failure, all kinds of shock, and severe sepsis-and patients on dialysis were excluded, 158 patients were enrolled. AKI was defined as a decrease in glomerular filtration rate (GFR) >10% of baseline data within 3 days after administration of Gd-CM. Regression analysis was used to find independent risk factors for gadolinium-induced AKI (Gd-AKI).

RESULTS

Twenty-six of the 158 patients (16.5%) developed Gd-AKI. There were no significant differences in gender, age, or baseline GFR between those who did and who did not develop AKI. Comorbid coronary artery disease, liver cirrhosis, diabetes mellitus, and hypertension were not significantly associated with the development of Gd-AKI. However, sepsis was an independent risk factor for Gd-AKI after multivariate regression analysis (adjusted odds ratio: 4.417; 95% confidence interval: 1.671-11.676, p = 0.03).

CONCLUSIONS

It is potential AKI after administration of Gd-CM under sepsis condition at the dose for MRI and MRA examinations in patients with renal impairment. It is important to identify high-risk patients and closely monitor renal function after administration of Gd-CM.

In addition to malnutrition and renal function impairment, anemia is associated with hyponatremia in the elderly

Hyponatremia is the most common electrolyte abnormality among the elderly living in long-term care facilities. In this study, we investigate the associated factors of hyponatremia, and its association with anemia in the institutionalized elderly in Taiwan. A total of 414 participants aged 65 years and above were recruited from eight long-term care facilities in 2002-2003. Baseline characteristics, medical records, and biomarkers were obtained. Hyponatremia was defined as a serum Na-concentration<135 mmol/l. Relationships between hyponatremia and the demographic and laboratory characteristics were tested using multiple logistic and linear regression analyses. The prevalence of hyponatremia and anemia was 14.7% and 56.0%, respectively. Anemia, hypouricemia, and the placement of tubes (including nasogastric tube, tracheostomy tube, and Foley catheter) were significantly associated with hyponatremia after adjustment for potential confounders using multiple logistic regression analysis. The adjusted odds ratios (OR) and 95% confidence interval (95%CI) for these three factors were 3.28 (1.40-7.69), 4.98 (2.18-11.36), 9.15 (3.33-25.12), respectively. Multiple linear regression analyses also showed that serum Na concentration was significantly associated with hemoglobin, uric acid, and number of tubes. In conclusion, it was found that anemia, the placement of tubes, and hypouricemia were associated with hyponatremia in the institutionalized elderly. In those with the above conditions, serum Na concentration should be monitored.

Predictive role of multilocus genetic polymorphisms in cardiovascular disease and inflammation-related genes on chronic kidney disease in Type 2 diabetes--an 8-year prospective cohort analysis of 1163 patients

BACKGROUND

Chinese diabetic patients are at greater risk of developing chronic kidney disease (CKD) than Caucasian counterparts. In this hypothesis-generating study, we examined the independent and joint effects of multiple genetic variants on CKD in a prospective Chinese cohort of Type 2 diabetic patients.

METHODS

Seventy-seven single-nucleotide polymorphisms (SNPs) of 54 candidate genes for cardiorenal diseases and inflammation were genotyped in 1163 patients with no past history of CKD at baseline. CKD was defined as the first estimated glomerular filtration rate <60 mL/min/1.73 m(2) or the first hospitalization with a diagnosis of renal disease.

RESULTS

In Cox-regression analysis, 15 SNPs of 13 genes were associated with incident CKD. After correction for multiple comparisons, 6 SNPs including PON1 55Met, PON2 311Cys CETP-629C, ITGA2 873A, LTA 26Asn and LTA 252Gly remained independently associated with CKD, with respective hazard ratios (95% confidence interval):2.6 (1.4-4.8, P = 0.002), 1.5 (1.2-1.9, P = 0.003), 1.4 (1.1-1.7, P = 0.001), 2.2 (1.3-3.7, P = 0.002), 1.6 (1.1-2.2, P = 0.008) and 1.5 (1.1-2.1, P = 0.019). Analysis of joint effect of the six SNPs showed stepwise increase in risk of CKD with the accumulation of risk alleles and weighted genetic risk score (P(trend) = 8.9 × 10(-7) and 4.0 × 10(-5), respectively).

CONCLUSIONS

In Type 2 diabetes, there are independent and joint effects of multiple genetic variants on risk of CKD. Risk associations with PON1, PON2, CETP, ITGA2 and LTA genetic polymorphisms underline the importance of lipid metabolism, haemostasis and inflammation in the development of CKD in patients with Type 2 diabetes.

Association of low glomerular filtration rate with the incidence of stroke in patients following complete coronary revascularization

BACKGROUND

Low glomerular filtration rate (GFR) is associated with a worse outcome after coronary revascularization. Recently, a new specific equation to calculate the estimated GFR (eGFR) in Japanese populations has been reported, and it might be more accurate than the previously used equations. However, the relationship between a low GFR defined using the new equation for the Japanese population and the incidence of stroke following complete coronary revascularization is not yet known.

METHODS AND RESULTS

Consecutive patients who underwent complete coronary revascularization (percutaneous coronary intervention and bypass surgery) between 1984 and 1992 were enrolled. Patients on dialysis were excluded. Enrolled patients were divided into 2 groups: the preserved GFR group and the low GFR group. Low GFR was defined as eGFR<60 ml·min⁻¹·1.73 m⁻². The incidence of fatal and non-fatal stroke was compared between the groups. Among the 1,809 patients that were enrolled, 321 were placed in the low GFR group. During follow up (mean, 11.4 [2.9] years), there were 127 (7.0%) stroke events. Multivariable analysis using a Cox proportional hazards regression model revealed that the incidence of stroke was significantly higher in the low GFR group than in the preserved GFR group (hazard ratio, 1.66; 95% confidence interval, 1.10-2.48; P = 0.008).

CONCLUSIONS

Low GFR, defined as eGFR <60 ml·min⁻¹·1.73 m⁻², using a new specific equation for the Japanese population was associated with an increased risk of fatal and non-fatal stroke over a 10-year period after complete coronary revascularization.

Time-dependent associations between total sodium removal and mortality in patients on peritoneal dialysis

PURPOSE

To determine if the time-dependent association between total sodium removal and mortality in patients on continuous ambulatory peritoneal dialysis (CAPD) is confounded by markers of diet and nutrition.

METHODS

The study enrolled 305 incident patients who started CAPD between July 2002 and February 2007. All patients were followed until death or censoring in February 2008. Demographics, blood pressure, and markers of volume and inflammation were collected at baseline. Biochemistry, fluid and solute removal, and diet and nutrition parameters were collected quarterly and thus calculated as time-averaged values.

RESULTS

Mean age of the study patients was 59.4 years, 42.3% were men, and 40.3% had diabetes. During the 31.4-month follow-up, 74 patients died. The time-averaged daily total sodium removal (TSR) in the overall cohort was 2.67 g (range: 2.02 g-3.47 g). Participants with a high time-averaged TSR tended to experience higher fluid, sodium, urea, and creatinine removal, mainly as a result of better residual renal function (RRF). They also had a higher nutrient intake and a higher lean body mass. Time-dependent TSR was an independent predictor of death, including when adjusted for age, Charlson index, time-dependent hemoglobin, RRF, and peritoneal transport rate (hazard ratio: 0.84; 95% confidence interval: 0.70 to 1.00; p=0.05), but the predictive effect disappeared in multivariate models after further individual adjustment for time-dependent total energy intake, total protein intake, serum albumin, and lean body mass. By contrast, the predictive effect did not disappear if the only adjustment was for time-dependent RRF.

CONCLUSIONS

The time-dependent association between TSR and mortality in patients on peritoneal dialysis can be largely explained by diet and nutrition parameters.

Pulsatile hemodynamics and clinical outcomes in acute heart failure

BACKGROUND

The role of pulsatile hemodynamics in the management of patients with acute heart failure syndrome (AHFS) remains to be elucidated. We investigated the changes of the pulsatile hemodynamics along the hospital course of AHFS in relation to short-term outcomes.

METHODS

A total of 80 AHFS patients (73.2 ± 14.1 years, 82.5% men) were enrolled and followed up for up to 6 months after discharge. Measures of the pulsatile hemodynamics including brachial and central systolic blood pressure (SBP) and pulse (PP) pressure, carotid-femoral pulse wave velocity (cf-PWV), carotid augmentation index (cAI and cAI(75)) and carotid augmented pressure (cAP) were obtained within 24 h of admission, before discharge, and 2 weeks after discharge.

RESULTS

During a follow-up of 174 ± 32 days (16-183 days), 29 patients experienced events including rehospitalization for heart failure, nonfatal myocardial infarction, nonfatal stroke, and mortality. Predischarge brachial and central PP, and cAP, and postdischarge brachial and central SBP and PP, cAP, and cf-PWV were significantly lower in patients without events than those with events. Predischarge central PP (hazard ratio per 1-s.d. and 95% confidence interval: 1.62 (1.12-2.34)) and cAP (1.47 (1.05-2.05)) predicted events independent of age and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. Similarly, postdischarge brachial and central SBP and PP, cAP, and cf-PWV were also significant independent predictors.

CONCLUSION

Suboptimal recovery of the perturbations of the pulsatile hemodynamics in patients hospitalized due to AHFS may relate to adverse short-term outcomes and warrant aggressive treatment.

Aristolochic acid nephropathy: variation in presentation and prognosis

BACKGROUND

Aristolochic acid nephropathy (AAN) is a worldwide problem and one of the common causes of chronic kidney disease (CKD) in China.

METHODS

Three hundred patients diagnosed as AAN from 1997 to 2006 were enrolled. Medical histories of Chinese herb ingestion, clinical-pathological features and risk factors for renal failure were recorded. Patients were followed up for 2-156 months. Factors involved in the prognosis of AAN were investigated.

RESULTS

The 300 patients with AAN manifested three clinical subtypes, including acute kidney injury (acute AAN) in 13 patients, abrupt tubular dysfunction with normal serum creatinine (Scr) levels in seven cases and chronic tubulointerstitial nephropathy with decreased estimated glomerular filtration rate (eGFR) (chronic AAN) in 280 cases. The acute AAN cases had the highest aristolochic acid (AA)-I intake per day and developed progressive kidney failure during 1-7 years follow-up. The tubular dysfunction AAN patients had the lowest cumulative AA-I intake and were able to keep normal Scr levels during 2-8 years follow-up. The chronic AAN patients took the lowest AA-I dose per day but with the longest period and the highest cumulative dosage and exhibited a very large range of eGFR changing rate (from -21.6 to 5.2, median -3.5 mL/min/year). The cumulative AA-I intake (r = 0.330, P = 0.045) and the time course from the termination of AA medication to the start of follow-up (r = -0.430, P = 0.009) were found to be independent factors correlated with the decrease rate of eGFR in the chronic AAN patients. AA and the metabolites could be detected in a high frequency in patients who had stopped herbal medication for 1 year, which indicates a rather long washout time for these chemicals.

CONCLUSIONS

AAN has variant phenotypes with distinct prognosis, which is determined by the variable AA medications. With better understanding of toxic and environmental causes for kidney injury, there would be a better chance to uncover the causal factors of cases of 'CKD without known causes' which is crucial for improving the disease outcomes.

Metabolic syndrome, cardiovascular disease, and risk for chronic kidney disease in an Italian cohort: analysis of the INCIPE study

BACKGROUND

Metabolic syndrome is a frequent condition that has been linked to cardiovascular disease (CVD) and mortality. Metabolic syndrome has been extensively shown to increase the risk of chronic nephropathies in Americans and Asians, but not in European populations. Renal disease increases the risk of CVD and mortality. However, the chronic nephropathy-CVD liaison has not been analyzed in the framework of the possible role of metabolic syndrome in both.

METHODS

We analyzed data from 3,757 subjects participating in the INCIPE survey (Initiative on Nephropathy, of relevance to public health, which is Chronic, possibly in its Initial stages, and carries a Potential risk of major clinical End-points), a cross-sectional study enrolling subjects from the general population in the Veneto region in Italy, and calculated the odds ratio (OR) and 95% confidence interval (CI) of the association between metabolic syndrome, and/or chronic kidney disease (CKD) and albuminuria, and/or previous CVD after adjustment for confounding factors.

RESULTS

Metabolic syndrome is associated with CKD (OR 2.17; P<0.001) and albuminuria (OR 2.28; P<0.001) and CVD (OR 1.58; P=0.002). There is a direct correlation between number of metabolic syndrome traits and nephropathy and CVD. CVD and nephropathies are associated even after adjustment for metabolic syndrome (OR 2.30; P<0.001).

CONCLUSIONS

In a homogeneous Caucasian European population, metabolic syndrome is associated with CKD and albuminuria, and CVD. Although metabolic syndrome is a risk factor for both CVD and nephropathy, it does not entirely explain the dangerous CVD-nephropathy liaison.

CKD in Hispanics: Baseline characteristics from the CRIC (Chronic Renal Insufficiency Cohort) and Hispanic-CRIC Studies

BACKGROUND

Little is known regarding chronic kidney disease (CKD) in Hispanics. We compared baseline characteristics of Hispanic participants in the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC (H-CRIC) Studies with non-Hispanic CRIC participants.

STUDY DESIGN

Cross-sectional analysis.

SETTING & PARTICIPANTS

Participants were aged 21-74 years with CKD using age-based estimated glomerular filtration rate (eGFR) at enrollment into the CRIC/H-CRIC Studies. H-CRIC included Hispanics recruited at the University of Illinois in 2005-2008, whereas CRIC included Hispanics and non-Hispanics recruited at 7 clinical centers in 2003-2007.

FACTOR

Race/ethnicity.

OUTCOMES

Blood pressure, angiotensin-converting enzyme (ACE)-inhibitor/angiotensin receptor blocker (ARB) use, and CKD-associated complications.

MEASUREMENTS

Demographic characteristics, laboratory data, blood pressure, and medications were assessed using standard techniques and protocols.

RESULTS

Of H-CRIC/CRIC participants, 497 were Hispanic, 1,650 were non-Hispanic black, and 1,638 were non-Hispanic white. Low income and educational attainment were nearly twice as prevalent in Hispanics compared with non-Hispanics (P < 0.01). Hispanics had self-reported diabetes (67%) more frequently than non-Hispanic blacks (51%) and whites (40%; P < 0.01). Blood pressure >130/80 mm Hg was more common in Hispanics (62%) than blacks (57%) and whites (35%; P < 0.05), and abnormalities in hematologic, metabolic, and bone metabolism parameters were more prevalent in Hispanics (P < 0.05), even after stratifying by entry eGFR. Hispanics had the lowest use of ACE inhibitors/ARBs among the high-risk subgroups, including participants with diabetes, proteinuria, and blood pressure >130/80 mm Hg. Mean eGFR was lower in Hispanics (39.6 mL/min/1.73 m(2)) than in blacks (43.7 mL/min/1.73 m(2)) and whites (46.2 mL/min/1.73 m(2)), whereas median proteinuria was higher in Hispanics (protein excretion, 0.72 g/d) than in blacks (0.24 g/d) and whites (0.12 g/d; P < 0.01).

LIMITATIONS

Generalizability; observed associations limited by residual bias and confounding.

CONCLUSIONS

Hispanics with CKD in the CRIC/H-CRIC Studies are disproportionately burdened with lower socioeconomic status, more frequent diabetes mellitus, less ACE-inhibitor/ARB use, worse blood pressure control, and more severe CKD and associated complications than their non-Hispanic counterparts.

Simplified estimation of aminoglycoside pharmacokinetics in underweight and obese adult patients

Aminoglycosides are an important class of agents that are used in combination antimicrobial regimens to treat bacterial pathogens. Dosing of aminoglycosides is typically based on total body weight. However, the most appropriate alternative body size descriptor for dosing aminoglycosides at the extremes of weight (underweight and obese) is not known. Also, the predictive performance of newer formulas to assess kidney function, such as the modification of diet in renal disease (MDRD) and chronic kidney disease-epidemiology (CKD-EPI) equations compared to the Cockcroft-Gault equation to predict aminoglycoside clearance, is not known. We sought to examine dosing of aminoglycosides across the extremes of weight using a variety of formulas to assess kidney function. Pharmacokinetic data were obtained from a set of prospectively collected data (1982 to 2003) of 2,073 (53.5% male) adult patients that included 497 tobramycin- and 1,576 gentamicin-treated cases. The median (minimum, maximum) age, weight, and body mass index were 66 (18, 98) years, 70.0 (29.7, 206.7) kg, and 24.4 (11.3, 73.8) kg/m(2), respectively. The percentage of underweight, normal-weight, overweight, and obese cases based on the World Health Organization classification were 8.8%, 45.5%, 26.5%, and 19.2%, respectively. The aminoglycoside volume of distribution was normalized to several alternative body size descriptors. Only lean body weight estimated by the method of S. Janmahasatian et al. (Clin. Pharmacokinet. 44:1051-1065, 2005) normalized the volume of distribution for both tobramycin and gentamicin across all weight strata, with the estimate being approximately 0.45 liter/kg. Aminoglycoside dosing can be simplified across all weight strata with the use of lean body weight. The CKD-EPI equation best predicts aminoglycoside clearance.

Reference intervals for serum creatinine with enzymatic assay and evaluation of four equations to estimate glomerular filtration rate in a healthy Chinese adult population

BACKGROUND

With the wide usage of enzymatic assays to determine serum creatinine (Scr) in China, reference interval (RI) needs to be established. At the same time, the performance of Scr based equations to calculate estimated glomerular filtration rate (eGFR) in healthy Chinese adults has not been extensively investigated.

METHODS

This study has strictly followed the International Federation of Clinical Chemistry (IFCC) recommendations and the Clinical Laboratory Standards Institute (CLSI) C28-A2 document. A total number of 778 healthy Chinese adults (male 433, female 345) were enrolled in this study.

RESULTS

By nonparametric method, RIs for males were: <60 years, 58-93 μmol/l and >60 years, 54-109 μmol/l; RIs for females were: <60 years, 42-69 μmol/l and >60 years, 43-83 μmol/l. Modification of Diet in Renal Disease (MDRD) equation and MDRD for Japanese made the percentage of eGFR >90 ml/min/1.73 m(2) 31.7% and 4.9%; percentage of eGFR 60-89 ml/min/1.73 m(2) 65.2% and 64.0%, respectively. Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and CKD-EPI for Asian made the percentage of eGFR >90 ml/min/1.73 m(2) 89.2% and 94.0%; percentage of eGFR 60-89 ml/min/1.73 m(2) 10.3% and 5.7%, respectively.

CONCLUSION

Scr RIs of healthy Chinese adults were found to be lower than those of Caucasians. Two MDRD equations underestimated GFR, while two CKD-EPI equations seemed to estimate a reasonable distribution of eGFR in healthy Chinese adult populations.

Asymmetric dimethylarginine and clinical outcomes in chronic kidney disease

BACKGROUND AND OBJECTIVES

Elevated plasma level of asymmetric dimethylarginine (ADMA) have been reported to be associated with endothelial dysfunction and atherosclerosis risk factors, and may predict cardiovascular events in patients with ESRD. In this study, we aimed to assess the association between plasma ADMA and long-term outcome in a cohort of patients with stage 3 to 4 chronic kidney disease (CKD).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From July 2006 to June 2009, 298 consecutive patients with stage 3 to 4 CKD scheduled to undergo coronary angiography were recruited. Plasma ADMA levels were determined using HPLC.

RESULTS

The mean age was 73 ± 10 years. Approximately half of the patients had diabetes and 88 patients had proteinuria. The baseline estimated GFR (eGFR) was 44 ± 13 ml/min per 1.73 m². The plasma ADMA levels of the patients with proteinuria were significantly higher than those without. The plasma ADMA levels correlated significantly with eGFR. During the median follow-up period of 2.7 years, we observed 26 all-cause deaths, 12 nonfatal myocardial infarctions, and 2 strokes. Multivariate Cox analysis revealed that an increase of 0.1 μmol/L in plasma ADMA level was associated with a 37% increased risk of the composite outcomes of all-cause deaths, nonfatal myocardial infarctions, and strokes.

CONCLUSIONS

In this elder and high-risk population with stage 3 to 4 CKD, high plasma ADMA level was associated with low eGFR and macroalbuminuria. Furthermore, high plasma ADMA level appeared to be an independent predictor of long-term outcome.

Regular use of nephrotoxic medications is an independent risk factor for chronic kidney disease--results from a Chinese population study

BACKGROUND

Prescription drug abuse is an important global health concern. Our previous survey in Beijing indicates that nephrotoxic medication use is independently associated with chronic kidney disease (CKD).

METHODS

In the present study, the study population consisted of participants from our previous survey with a confirmed history of nephrotoxic medication use. Nephrotoxic mediations included three antipyretic analgesics (58.2%) and three Chinese traditional medicines containing aristolochic acids (CTM-AAs, 47.3%). Prevalence of CKD (defined by presence of albuminuria and/or reduced estimated glomerular filtration rate) as well as markers of tubular injury was analysed, and compared with 109 age- and sex-matched controls.

RESULTS

The prevalence of CKD was higher among medication users compared with controls, which was 18.3% and 8.5%, respectively. Among participants with medication use without CKD, markers of tubular injury including N-acetyl-β-d-glucosaminidase, transferrin and α(1)-microglobulin, were present in 26.6%. CKD was associated with CTM-AA use (cumulative AA-I dose > 0.5 g, OR = 5.625, P < 0.05) and antipyretic analgesic use (cumulative dose > 2.0 kg, OR = 3.848, P = 0.063) in a dose-dependent manner. Albuminuria and tubular injury persisted among CTM-AA users, but not among analgesic users after cessation of drug.

CONCLUSIONS

Our study suggests that education about rational analgesic use and CTM-AA banning may constitute an effective CKD prevention strategy.

Simple cystatin C formula compared to sophisticated CKD-EPI formulas for estimation of glomerular filtration rate in the elderly

Despite the fact that the serum creatinine level is notoriously unreliable for the estimation of glomerular filtration rate (GFR) in the elderly, the serum creatinine concentration and serum creatinine-based formulas, such as the Modification of Diet in Renal Disease study equation (MDRD) are the most commonly used markers to estimate GFR. Recently, serum cystatin C-based formulas, the newer creatinine formula (the Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI creatinine formula), and an equation that uses both serum creatinine and cystatin C (CKD-EPI creatinine and cystatin formula) were proposed as new GFR markers. The aim of our study was to compare the MDRD formula, CKD-EPI creatinine formula, CKD-EPI creatinine and cystatin formula, and simple cystatin C formula (100/serum cystatin C) against (51) Cr-EDTA clearance in the elderly. A total of 317 adult Caucasian patients aged >65 years were enrolled. In each patient, (51) Cr-EDTA clearance, serum creatinine, and serum cystatin C were determined, and the GFR was calculated using the MDRD formula, CKD-EPI formulas, and simple cystatin C formula. Statistically significant correlations between (51) Cr-EDTA clearance and all formulas were found. In the receiver operating characteristic (ROC) curve analysis with a cut-off of GFR 45 mL/min/1.73 m(2), a higher diagnostic accuracy was achieved with the equation that uses both serum creatinine and cystatin C (CKD-EPI creatinine and cystatin formula) than the MDRD formula (P < 0.013) or CKD-EPI creatinine formula (P < 0.01), but it was not higher than that achieved for the simple cystatin C formula (P = 0.335). Bland and Altman analysis for the same cut-off value showed that the creatinine formulas underestimated and the simple cystatin C formula overestimated measured GFR. All equations lacked precision. The accuracy within 30% of estimated (51) Cr-EDTA clearance values differ according to the stage of CKD. Analysis of the ability to correctly predict GFR below and above 45 mL/min/1.73 m(2) showed a high prediction for all formulas. Our results indicate that the simple cystatin C formula, which requires just one variable (serum cystatin C concentration), is a reliable marker of GFR in the elderly and comparable to the creatinine formulas, including the CKD-EPI formulas.

Urinary podocyte-associated mRNA profile in various stages of diabetic nephropathy

Background

Podocyte injury and subsequent excretion in urine play a crucial role in the pathogenesis and progression of diabetic nephropathy (DN). Quantification of messenger RNA (mRNA) expression in urinary sediment by real-time PCR is emerging as a noninvasive method of screening DN-associated biomarkers. We hypothesized that the urinary mRNA profile of podocyte-associated molecules may provide important clinical insight into the different stages of diabetic nephropathy.

Methods

DN patients (N = 51) and healthy controls (N = 13) were enrolled in this study. DN patients were divided into a normoalbuminuria group (UAE<30 mg/g, n = 17), a microalbuminuria group (UAE 30∼300 mg/g, n = 15), and a macroalbuminuria group (UAE>300 mg/g, n = 19), according to their urinary albumin excretion (UAE). Relative mRNA abundance of synaptopodin, podocalyxin, CD2-AP, α-actin4, and podocin were quantified, and correlations between target mRNAs and clinical parameters were examined.

Results

The urinary mRNA levels of all genes studied were significantly higher in the DN group compared with controls (p<0.05), and mRNA levels increased with DN progression. Urinary mRNA levels of all target genes positively correlated with both UAE and BUN. The expression of podocalyxin, CD2-AP, α-actin4, and podocin mRNA correlated with serum creatinine (r = 0.457, p = 0.001; r = 0.329, p = 0.01; r = 0.286, p = 0.021; r = 0.357, p = 0.006, respectively). Furthermore, podocalyxin mRNA was found to negatively correlate with eGFR (r = −0.349, p = 0.01).

Conclusion

The urinary mRNA profiles of synaptopodin, podocalyxin, CD2-AP, α-actin4, and podocin were found to increase with the progression of DN, which suggested that quantification of podocyte-associated molecules will be useful biomarkers of DN.

GFR estimating equations in a multiethnic Asian population

BACKGROUND

Clinical practice guidelines recommend using equations for estimating glomerular filtration rate (GFR) in chronic kidney disease (CKD) management and research. The MDRD (Modification of Diet in Renal Disease) Study and CKD-EPI (CKD Epidemiology Collaboration) equations originally were derived from a North American population and had an ethnic coefficient adjustment for African Americans. A Chinese coefficient for the MDRD Study equation subsequently was determined, but this has not been externally validated. We compared the accuracy of the equations, evaluated the ethnic coefficients, and assessed the equations for disease staging in a multiethnic Asian population with CKD.

STUDY DESIGN

A diagnostic test study comparing the Asian coefficient (and subgroups)-modified MDRD Study and CKD-EPI equations and a cross-sectional study assessing disease staging.

SETTING & PARTICIPANTS

232 outpatients (52% men; 40.5% Chinese, 32% Malay, and 27.5% Indian/other) with stable CKD.

INDEX TEST

Asian and ethnicity-based modifications of the MDRD Study and CKD-EPI equations.

REFERENCE TEST

Measured GFR using 3-sample plasma clearance of technetium-99m diethylenetriaminepentaacetic acid ((99m)Tc-DTPA), calculated using the slope-intercept method, with body surface area normalization (du Bois) and Brochner-Mortensen correction.

RESULTS

Overall, the CKD-EPI equation is more accurate than the MDRD Study equation throughout the GFR range, with improved bias (median difference of estimated GFR - measured GFR) and root mean square error (P <0.001). CKD-EPI versus MDRD Study equation: bias, 1.1 ± 13.8 vs -1.0 ± 15.2 mL/min/1.73 m(2); precision, 12.1 vs 12.2 mL/min/1.73 m(2). Ethnic coefficients did not improve estimates of GFR significantly. The correctness of staging was improved using the CKD-EPI equation.

LIMITATIONS

All participants had CKD, but few were of European descent. The reference GFR technique was different from the original studies.

CONCLUSIONS

The CKD-EPI is more accurate than the MDRD Study equation, particularly at higher GFRs. Therefore, we recommend adopting the CKD-EPI equation without ethnic adjustment for estimating GFR in multiethnic Asian patients with CKD.

High rates of albuminuria but not of low eGFR in urban indigenous Australians: the DRUID study

BACKGROUND

Indigenous Australians have an incidence of end stage kidney disease 8-10 times higher than non-Indigenous Australians. The majority of research studies concerning Indigenous Australians have been performed in rural or remote regions, whilst the majority of Indigenous Australians actually live in urban settings. We studied prevalence and factors associated with markers of kidney disease in an urban Indigenous Australian cohort, and compared results with those for the general Australian population.

METHODS

860 Indigenous adult participants of the Darwin Region Urban Indigenous Diabetes (DRUID) Study were assessed for albuminuria (urine albumin-creatinine ratio≥2.5 mg/mmol males, ≥3.5 mg/mmol females) and low eGFR (estimated glomular filtration rate < 60 mls/min/1.73 m(2)). Associations between risk factors and kidney disease markers were explored. Comparison was made with the AusDiab cohort (n = 8,936 aged 25-64 years), representative of the general Australian adult population.

RESULTS

A high prevalence of albuminuria (14.8%) was found in DRUID, whilst prevalence of low eGFR was 2.4%. Older age, higher HbA1c, hypertension, higher C-reactive protein and current smoking were independently associated with albuminuria on multiple regression. Low eGFR was independently associated with older age, hypertension, albuminuria and higher triglycerides. Compared to AusDiab participants, DRUID participants had a 3-fold higher adjusted risk of albuminuria but not of low eGFR.

CONCLUSIONS

Given the significant excess of ESKD observed in Indigenous versus non-Indigenous Australians, these findings could suggest either: albuminuria may be a better prognostic marker of kidney disease than low eGFR; that eGFR equations may be inaccurate in the Indigenous population; a less marked differential between Indigenous and non-Indigenous Australians for ESKD rates in urban compared to remote regions; or that differences in the pathophysiology of chronic kidney disease exist between Indigenous and non-Indigenous populations.

Associations of intra-renal arterial resistance index with chronic kidney disease and carotid intima-media thickness in type 2 diabetes mellitus

Renal dysfunction can be evaluated by increased intra-renal arterial resistance index (RI). We evaluated 113 Chinese men with type 2 diabetes on their RI. Results suggest that RI is associated with chronic kidney disease and subclinical arteriosclerosis. RI may help monitoring the deterioration of intra-renal hemodynamics.

Serum fetuin-A associates with type 2 diabetes and insulin resistance in Chinese adults

Background

Previous studies have demonstrated that fetuin-A is related to insulin resistance among subjects with normal glucose tolerance but not patients with type 2 diabetes. There are limited data available concerning fetuin-A and insulin resistance in Chinese. We aimed to study the association of feuin-A with insulin resistance among participants with or without type 2 diabetes in a large sample size of adults aged 40 and older.

Methodology and Principal Findings

A community-based cross-sectional study was performed among 5,227 Chinese adults. The average age of our study was 61.5±9.9 years. Serum fetuin-A concentrations were not significantly different between male and female (296.9 vs. 292.9 mg/l, p = 0.11). Compared with the lowest quartile, the highest quartile of serum fetuin-A revealed a significant higher proportion of type 2 diabetic patients (34.8% vs. 27.3%, p<0.0001). In the multinomial logit models, the risk of type 2 diabetes was associated with each one quartile increase of serum fetuin-A concentrations when referenced not only to normal glucose tolerance (OR 1.24, 95% CI 1.07–1.43, p = 0.004) but also to impaired glucose regulation (OR 1.25, 95% CI 1.08–1.44, p = 0.003, respectively), after adjustment for age, sex, community, current smoking, and current drinking. The logistic regression analysis showed that fetuin-A were associated with elevated HOMA-IR and fasting serum insulin both among the participants with or without type 2 diabetes in the full adjusted analysis. There was no significant association between elevated serum fetuin-A concentrations and impaired glucose regulation (all p≥0.12).

Conclusions and Significance

Higher fetuin-A concentrations were associated with type 2 diabetes and insulin resistance in middle aged and elderly Chinese.

Cancer-specific mortality in chronic kidney disease: longitudinal follow-up of a large cohort

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is known to be associated with increased all-cause and cardiovascular mortality, but no large studies examined the cancer-specific mortality in non-dialysis-dependent CKD patients. Such outcome data are needed for proper allocation of resources and would help to develop better preventive services.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between 1998 and 1999, 123,717 adults were recruited from four health screening centers in Taiwan. The estimated glomerular filtration rate was calculated using the four-variable Modification of Diet in Renal Disease Study equation for the Chinese. Mortality was ascertained by computer linkage to the national death registry after a median follow-up of 7.06 years. Cox proportional hazards regression models were used to estimate the impact of CKD on cancer-specific mortality.

RESULTS

A higher risk for overall cancer mortality was found in CKD patients compared with non-CKD patients (adjusted hazard ratio, 1.2). CKD was associated with increased mortality from liver cancer, kidney cancer, and urinary tract cancer, with an adjusted hazard ratio of 1.74, 3.3, and 7.3, respectively. A graded relationship between the severity of renal impairment and cancer mortality was also found.

CONCLUSIONS

Patients with CKD had a higher mortality risk of liver cancer, kidney cancer, and urinary tract cancer. This is the first large study that showed an inverse association between renal function and liver cancer mortality. The increased mortality could be caused by higher cancer incidence or worse response to cancer treatment. Future research is warranted to clarify the mechanism.

Obesity and chronic kidney disease in patients with chronic heart failure: an insight from the China Heart Survey

BACKGROUND

Obesity and decreased kidney function have been shown to be prevalent in Western patients with heart failure; however, whether this phenomenon exists in Chinese patients with chronic heart failure (CHF) is not known.

METHODS AND RESULTS

One thousand and nine patients with CHF from the China Heart Survey were assessed. The prevalence of chronic kidney disease (CKD) was 34.2%, and there was a stepwise increase in the prevalence of CKD with New York Heart Association (NYHA) classes (P < 0.001). Moreover, patients with CKD had a significantly elevated risk for developing severe extent of CHF (OR = 1.69, 95% CI: 1.27-2.24, P < 0.001). The prevalence of obesity and central obesity was 35.7% and 62.5%, respectively. Notably, there was a downward trend in the prevalence of obesity with advanced NYHA classes (trend test, P = 0.003). Multivariate analysis further supported the finding that obesity, but not central obesity, was inversely associated with the extent of CHF (OR = 0.72, 95% CI: 0.55-0.94, P = 0.017).

CONCLUSIONS

Renal dysfunction is common in Chinese patients with CHF and is independently associated with advanced NYHA classes. Obesity was inversely associated with the extent of CHF, which further supports the notion that obesity confers improved prognosis in patients with heart failure.

Brachial-ankle pulse wave velocity and rate of renal function decline and mortality in chronic kidney disease

BACKGROUND AND OBJECTIVES

Increased arterial stiffness was reported to be associated with decreased estimated GFR (eGFR). Previous studies suggested that arterial stiffness might play a role in renal function progression in patients with chronic kidney disease (CKD). The aim of this study was to investigate whether there was an independent association between brachial-ankle pulse wave velocity (baPWV), a marker of arterial stiffness, and renal function progression in CKD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This longitudinal study enrolled 145 patients with CKD stages 3 to 5. The baPWV was measured by using an ABI-form device. The change in renal function was estimated by eGFR slope. The study endpoints were defined as commencement of dialysis or death.

RESULTS

After a stepwise multivariate analysis, the eGFR slope was positively associated with baseline eGFR and negatively associated with hypertension and baPWV (β=-0.165, P=0.033). Seventeen patients entering dialysis, and eight deaths were recorded. Multivariate forward Cox regression analysis identified that higher baPWV (hazard ratio, 1.001; P=0.001), lower baseline eGFR, and higher serum phosphate level were independently associated with progression to commencement of dialysis or death.

CONCLUSIONS

Our results show an independent association between baPWV and renal function decline and progression to commencement of dialysis or death in patients with CKD. Screening CKD patients by means of baPWV may help identify a high-risk group of rapid renal function decline and progression to commencing dialysis or death.

Trends in the prevalence of chronic kidney disease, other chronic diseases and health-related behaviors in an adult Korean population: data from the Korean National Health and Nutrition Examination Survey (KNHANES)

BACKGROUND

Chronic kidney disease (CKD) is an increasing public health problem. However, there have been limited data on the trend of CKD prevalence, along with the changes of health-related behaviors and other chronic diseases in an adult Korean population.

METHODS

Data from the Korean National Health and Nutrition Examination Survey in 2005 and 2007 were analyzed. The study subjects comprised 8400 participants aged ≥ 20 years with creatinine data. CKD was defined as estimated glomerular filtration rate (GFR) <60 mL/min/1.73m(2). GFR was estimated by the abbreviated Modification of Diet in Renal Disease equation.

RESULTS

The CKD prevalence was significantly decreased from 2005 to 2007 (8.8 versus 7.2%; P = 0.010). The prevalence of hypertension was stable but that of diabetes was increased. The proportion of blood pressure (BP) <130/80 mmHg in the whole population, and HbA1c <7% in the diabetic participants was increased from 2005 to 2007. Participants in 2007 walked more than those in 2005. The proportion of current smoking and sodium/energy/protein excess was decreased from 2005 to 2007. In subgroup analysis, only hypertensive participants without diabetes revealed a decreasing trend of CKD.

CONCLUSIONS

The CKD prevalence was decreased from 2005 to 2007. Since increased diabetes and improved diabetic control neutralized their impact on CKD, improved BP was the fundamental reason for the decrease. Various health-related behaviors may have indirectly affected the decrease of CKD through their effect in controlling BP and diabetes.

Are the creatinine-based equations accurate to estimate glomerular filtration rate in African American populations?

Regarding the high prevalence of African American patients with ESRD, it is important to estimate the prevalence of early stages of chronic kidney disease in this specific population. Because serum creatinine concentration is dependent on muscular mass, an ethnic factor has to be applied to creatinine-based equations. Such ethnic factors have been proposed in the Modification of Diet in Renal Disease (MDRD) study equation and in the more recent Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. This review analyzes how these correction factors have been developed and how they have, or have not, been validated in external populations. It will be demonstrated that the African American factor in the MDRD study equation is accurate in African American chronic kidney disease (CKD) patients. However, it will be shown that this factor is probably too high for subjects with a GFR of ≥60 ml/min per 1.73 m(2), leading to an underestimation of the prevalence of CKD in the global African American population. It will also be confirmed that this ethnic factor is not accurate in African (non-American) subjects. Lastly, the lack of true external validation of the new CKD-EPI equations will be discussed. Additional trials seem necessary in American African and African populations to better estimate GFR and apprehend the true prevalence of CKD in this population with a high renal risk.

Daily protein intake and survival in patients on peritoneal dialysis

BACKGROUND

The decreased protein intake may lead to protein-energy wasting and poor survival. It is unknown what the appropriate protein intake in patients on peritoneal dialysis (PD) is. We aimed to explore the appropriate levels of daily protein intake (DPI) in favor of outcome in a large PD cohort.

METHODS

Our study enrolled 305 incident patients, who could be followed regularly. Demographic data were collected at baseline. Biochemical, dietary and nutritional data and dialysis adequacy were measured at the baseline and thereafter at regular intervals. Outcome events included all-cause death, cardiovascular disease (CVD) death and first-episode peritonitis.

RESULTS

A total of 127 patients died during the 44.5-month follow-up, 41.7% of whom died from CVD. A total of 129 cases first-episode peritonitis were observed. Patients with a high tertile of baseline DPI (≥ 0.94 g/kg/day) had significantly higher serum albumin, prealbumin, hemoglobin, lean body mass and handgrip strength compared to the low tertile group (≤ 0.73 g/kg/day) (P < 0.05-0.001). They also had significantly lower risk for all-cause, CVD death and first-episode peritonitis than the low tertile group adjusted for commonly recognized confounders. Although patients in the middle tertile of DPI (0.74-0.93 g/kg/day) did not show significant differences in the majority of nutritional markers, all-cause and CVD mortality compared to high tertile group, they had a trend to a negative nitrogen balance and similar risk for first-episode peritonitis to the low tertile group. The DPI included as a time-dependent variable could not predict any outcome events in multivariate Cox models.

CONCLUSIONS

Our study revealed that DPI <0.73 g/kg/day was associated with protein-energy wasting and worst outcome for PD patients. The DPI >0.94 g/kg/day was in favor of nutrition status and long-term outcome in this population.

Metabolic syndrome and renal injury

Both metabolic syndrome (MetS) and chronic kidney disease (CKD) are major global health issues. Current clinical markers used to reflect renal injury include albuminuria and estimated glomerular filtration rate (eGFR). Given the same eGFR level, urine albumin might be a better risk marker to predict progression of CKD and future development of cardiovascular diseases (CVDs). Serum Cystatin C is emerging as a new biomarker for early detection of renal injury associated with MetS and cardiovascular risk. In addition to each component, MetS per se influences the incidence and prognosis of renal injury and the odds ratios increased with the increase in the number of metabolic abnormalities. Hyperinsulinemia, activation of rennin-angiotensin-aldosterone system, increase of oxidative stress, and inflammatory cytokines are proposed to be the plausible biological link between MetS and CKD. Weight control, stick control of blood pressure, glucose, and lipids disorders may lead to lessening renal injury and even the subsequent CVD.

Evaluation of the Chronic Kidney Disease Epidemiology Collaboration equation for estimating the glomerular filtration rate in multiple ethnicities

An equation from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) provides more accurate estimates of the glomerular filtration rate (eGFR) than that from the modification of diet in renal disease (MDRD) Study, although both include a two-level variable for race (Black and White and other). Since creatinine generation differs among ethnic groups, it is possible that a multilevel ethnic variable would allow more accurate estimates across all groups. To evaluate this, we developed an equation to calculate eGFR that includes a four-level race variable (Black, Asian, Native American and Hispanic, and White and other) using a database of 8254 patients pooled from 10 studies. This equation was then validated in 4014 patients using 17 additional studies from the United States and Europe (validation database), and in 1022 patients from China (675), Japan (248), and South Africa (99). Coefficients for the Black, Asian, and Native American and Hispanic groups resulted in 15, 5, and 1% higher levels of eGFR, respectively, compared with the White and other group. In the validation database, the two-level race equation had minimal bias in Black, Native American and Hispanic, and White and other cohorts. The four-level ethnicity equation significantly improved bias in Asians of the validation data set and in Chinese. Both equations had a large bias in Japanese and South African patients. Thus, heterogeneity in performance among the ethnic and geographic groups precludes use of the four-level race equation. The CKD-EPI two-level race equation can be used in the United States and Europe across a wide range of ethnicity.

Prognostic significance of glomerular filtration rate estimated by the Japanese equation among patients who underwent complete coronary revascularization

An equation that accurately estimates the glomerular filtration rate (GFR) in the Japanese population has been proposed; however, the prognostic significance of estimated GFR (eGFR) defined according to this equation has not been reported. In addition, the prognostic significance of eGFR during long-term follow-up after complete coronary revascularization remains unclear. We assessed the prognostic significance of eGFR values, estimated by the new Japanese equation, in a cohort of patients following complete coronary revascularization. We studied consecutive patients with complete revascularization from 1984 to 1992. Patients on dialysis were excluded. A novel Japanese equation was used to estimate the GFR: eGFR=194×(serum creatinine)(-1.094)×(age)(-0.287)(×0.739 if female). Multivariate Cox proportional hazards regression analyses were performed to determine all-cause and cardiac mortality. We analyzed data of 1809 patients, of whom 571 (31.6%) had an eGFR of ≥90 mlmin(-1) per 1.73 m(2), 917 (50.7%) had an eGFR of 60-89 mlmin(-1) per 1.73 m(2), 298 (16.5%) had an eGFR of 30-59 mlmin(-1) per 1.73 m(2) and 23 (1.3%) had an eGFR of <30 mlmin(-1) per 1.73 m(2). During follow-up (11.4±2.9 years), there were 397 (22.0%) all-cause and 123 (6.8%) cardiac deaths overall. Patients with an eGFR of 30-59 mlmin(-1) per 1.73 m(2), and <30 mlmin(-1) per 1.73 m(2) revealed significantly greater risk of all-cause mortality than those with eGFR of ≥90 mlmin(-1) per 1.73 m(2) (hazard ratio (HR) 1.91, P<0.001, HR 3.35, P<0.001, respectively). Furthermore, incidence of cardiac death was higher in patients with an eGFR of 30-59 mlmin(-1) per 1.73 m(2) than those with an eGFR of ≥90 mlmin(-1) per 1.73 m(2) (HR 2.89, P<0.001). GFR as estimated using the new Japanese equation had a prognostic significance among patients with complete coronary revascularization.

The need for robust validation for MDRD-based glomerular filtration rate estimation in various CKD populations

BACKGROUND

Currently, estimated glomerular filtration rate (eGFR) equations have been validated only in Caucasians and African-Americans and is not applicable to people of other races/ethnicities as shown in studies conducted in two Asian populations: Chinese and Japanese. Because of this, it is important that eGFR equations are validated in its prospective population before applying it in the clinical setting and in epidemiologic studies. Therefore, we examined all eGFR equations available: reexpressed isotope dilution mass spectroscopy (IDMS)-traceable Modification of Diet in Renal Disease (MDRD) equation, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, Chinese equation and Japanese equation.

METHODS

A total of 350 adult Thai CKD patients were studied. The (99m)Tc-DTPA plasma clearance was used as a reference for glomerular filtration rate (GFR). The serum creatinine was determined by IDMS reference enzymatic methods (Cr(Enz)) and Jaffe's kinetic assay (Cr(Jaffe)) as indicated in each equation.

RESULTS

The disagreement between the reference GFR and eGFR (reference GFR minus eGFR) was 9.6 mL/min/1.73 m(2) for the reexpressed IDMS-traceable MDRD equation, 8.0 mL/min/1.73 m(2) for CKD-EPI equation, 1.9 mL/min/1.73 m(2) for eGFR equation from the Chinese study and 20.9 mL/min/1.73 m(2) for the eGFR equation from the Japanese study. The Thai coefficient for the reexpressed MDRD was 1.129. The reexpressed MDRD equation for Thais is as follows: 175 × Cr(Enz) ((-1.154)) × Age ((-0.203)) × 0.742 (if female) × 1.129 (if Thai). When stepwise multiple regression analysis was used, the Thai eGFR formula is: 375.5 × Cr(Enz) ((-0.848)) × Age ((-0.364)) × 0.712 (if female).

CONCLUSIONS

Differences in race/ethnicity can significantly affect the results obtained from MDRD-based eGFR equation. It is highly recommended that each population should validate eGFR equations before applying the equation in epidemiologic studies or clinical use.

Evaluation of erectile dysfunction and associated cardiovascular risk using structured questionnaires in Chinese type 2 diabetic men

Erectile dysfunction (ED) is not uncommon, but frequently underdiagnosed in type 2 diabetic men. In this study, we aimed to explore the frequency and severity of ED in Chinese type 2 diabetic men using a structured questionnaire. We furthermore sought to investigate the associations of ED with diabetes-related complications and metabolic indices. A consecutive cohort of 313 Chinese type 2 diabetic men aged between 25 and 76 years attending a diabetic centre were recruited between October 2006 and June 2007. Of the study population, the frequency of ED was 39.3% according to the National Institutes of Health (NIH) Consensus Conference criteria, compared with 84.3% (41.7% of them having moderate to severe ED) as diagnosed by International Index of Erectile Function (IIEF-5) questionnaire. After adjusting for potential confounding factors by multivariable logistic regression, ED defined by NIH criterion was associated with advanced age [OR = 1.05 (95% CI 1.01-1.09), p = 0.012], the presence of diabetic retinopathy [OR = 2.43 (95% CI 1.27-4.66), p = 0.008] and coronary heart disease [OR = 2.63 (95% CI 1.21-5.70), p = 0.015]. ED defined by IIEF-5 was associated with advanced age [OR = 1.12 (95% CI 1.06-1.17), p < 0.0001], use of insulin therapy [OR = 2.94 (95% CI 1.12-7.73), p = 0.029] and urinary albumin-creatinine ratio [OR = 2.29 (95% CI 1.05-5.01), p = 0.037]. In conclusion, ED was highly prevalent in Chinese type 2 diabetic men and was associated with multiple cardiovascular risk factors and complications. Advanced age, use of insulin therapy, the existence of microvascular complications such as retinopathy, albuminuria and coronary heart disease were associated with ED. NIH criteria diagnosed a much lower rate of ED compared with IIEF-5. Overall, structured questionnaires are useful and objective tools to detect ED, which should prompt a comprehensive risk assessment in these subjects.

Metabolic syndrome, chronic kidney disease, and cardiovascular disease: a dynamic and life-threatening triad

The metabolic syndrome (MS) and chronic kidney disease (CKD) have both become global public health problems, with increasing social and economic impact due to their high prevalence and remarkable impact on morbidity and mortality. The causality between MS and CKD, and its clinical implications, still does remain not completely understood. Moreover, prophylactic and therapeutic interventions do need to be properly investigated in this field. Herein, we critically review the existing clinical evidence that associates MS with renal disease and cardiovascular disease, as well as the associated pathophysiologic mechanisms and actual treatment options.

The association of dimethylarginine dimethylaminohydrolase 1 gene polymorphism with type 2 diabetes: a cohort study

BACKGROUND

Elevated plasma levels of asymmetric dimethylarginine (ADMA) has been reported to be associated with insulin resistance and micro/macrovascular diabetic complications, and may predict cardiovascular events in type 2 diabetic patients. Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is the major enzyme eliminating ADMA in humans, but the effect of genetic variations in DDAH1 on type 2 diabetes and its long-term outcome are unknown.

METHODS

From July 2006 to June 2009, we assessed the association between polymorphisms in DDAH1 and type 2 diabetes in 814 consecutive unrelated subjects, including 309 type 2 diabetic patients and 505 non-diabetic individuals. Six single nucleotide polymorphisms (SNPs) in DDAH1, rs233112, rs1498373, rs1498374, rs587843, rs1403956, and rs1241321 were analyzed. Plasma ADMA levels were determined by high performance liquid chromatography. Insulin sensitivity was assessed by the homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

Among the 6 SNPs, only rs1241321 was significantly associated with a decreased risk of type 2 diabetes (AA vs GG+AG, OR = 0.64, 95% CI 0.47-0.86, p = 0.004). The association remained unchanged after adjustment for plasma ADMA level. The fasting plasma glucose and log HOMA-IR tended to be lower in subjects carrying the homozygous AA genotype of rs1241321 compared with the GG+AG genotypes. Over a median follow-up period of 28.2 months, there were 44 all-cause mortality and 50 major adverse cardiovascular events (MACE, including cardiovascular death, non-fatal myocardial infarction and stroke). Compared with the GG and AG genotypes, the AA genotype of rs1241321 was associated with reduced risk of MACE (HR = 0.31, 95% CI: 0.11-0.90, p = 0.03) and all-cause mortality (HR = 0.18, 95% CI: 0.04-0.80, p = 0.02) only in subgroup with type 2 diabetes. One common haplotype (GGCAGC) was found to be significantly associated with a decreased risk of type 2 diabetes (OR = 0.67, 95% CI = 0.46-0.98, p = 0.04).

CONCLUSIONS

Our results provide the first evidence that SNP rs1241321 in DDAH1 is associated with type 2 diabetes and its long-term outcome.

Low HDL cholesterol, metformin use, and cancer risk in type 2 diabetes: the Hong Kong Diabetes Registry

OBJECTIVE

The AMP-activated protein kinase (AMPK) pathway is a master regulator in energy metabolism and may be related to cancer. In type 2 diabetes, low HDL cholesterol predicts cancer, whereas metformin usage is associated with reduced cancer risk. Both metformin and apolipoprotein A1 activate the AMPK signaling pathway. We hypothesize that the anticancer effects of metformin may be particularly evident in type 2 diabetic patients with low HDL cholesterol.

RESEARCH DESIGN AND METHODS

In a consecutive cohort of 2,658 Chinese type 2 diabetic patients enrolled in the study between 1996 and 2005, who were free of cancer and not using metformin at enrollment or during 2.5 years before enrollment and who were followed until 2005, we measured biological interactions for cancer risk using relative excess risk as a result of interaction (RERI) and attributable proportion (AP) as a result of interaction. A statistically significant RERI >0 or AP >0 indicates biological interaction.

RESULTS

During 13,808 person-years of follow-up (median 5.51 years), 129 patients developed cancer. HDL cholesterol <1.0 mmol/L was associated with increased cancer risk among those who did not use metformin, but the association was not significant among those who did. Use of metformin was associated with reduced cancer risk in patients with HDL cholesterol <1.0 mmol/L and, to a lesser extent, in patients with HDL cholesterol ≥ 1.0 mmol/L. HDL cholesterol <1.0 mmol/L plus nonuse of metformin was associated with an adjusted hazard ratio of 5.75 (95% CI 3.03-10.90) compared with HDL cholesterol ≥ 1.0 mmol/L plus use of metformin, with a significant interaction (AP 0.44 [95% CI 0.11-0.78]).

CONCLUSIONS

The anticancer effect of metformin was most evident in type 2 diabetic patients with low HDL cholesterol.

Fully automatic region of interest selection in glomerular filtration rate estimation from 99mTc-DTPA renogram

Glomerular filtration rate (GFR) is a common accepted standard estimation of renal function. Gamma camera-based methods for estimating renal uptake of (99m)Tc-diethylenetriaminepentaacetic acid (DTPA) without blood or urine sampling have been widely used. Of these, the method introduced by Gates has been the most common method. Currently, most of gamma cameras are equipped with a commercial program for GFR determination, a semi-quantitative analysis by manually drawing region of interest (ROI) over each kidney. Then, the GFR value can be computed from the scintigraphic determination of (99m)Tc-DTPA uptake within the kidney automatically. Delineating the kidney area is difficult when applying a fixed threshold value. Moreover, hand-drawn ROIs are tedious, time consuming, and dependent highly on operator skill. Thus, we developed a fully automatic renal ROI estimation system based on the temporal changes in intensity counts, intensity-pair distribution image contrast enhancement method, adaptive thresholding, and morphological operations that can locate the kidney area and obtain the GFR value from a (99m)Tc-DTPA renogram. To evaluate the performance of the proposed approach, 30 clinical dynamic renograms were introduced. The fully automatic approach failed in one patient with very poor renal function. Four patients had a unilateral kidney, and the others had bilateral kidneys. The automatic contours from the remaining 54 kidneys were compared with the contours of manual drawing. The 54 kidneys were included for area error and boundary error analyses. There was high correlation between two physicians' manual contours and the contours obtained by our approach. For area error analysis, the mean true positive area overlap is 91%, the mean false negative is 13.4%, and the mean false positive is 9.3%. The boundary error is 1.6 pixels. The GFR calculated using this automatic computer-aided approach is reproducible and may be applied to help nuclear medicine physicians in clinical practice.