Association between prediabetes and risk of chronic kidney disease: a systematic review and meta-analysis.

AIMS: To assess the effect of prediabetes (impaired fasting glucose and/or impaired glucose tolerance) on the incidence of chronic kidney disease. METHODS: PubMed and EMBASE were searched (for studies published up to March 2015). Effects estimated from cohort studies reporting the relationship of prediabetes to incident chronic kidney disease [kidney damage (microalbuminuria, albuminuria or proteinuria) and/or decreased glomerular filtration rate] were pooled using a random-effects model meta-analysis. RESULTS: Nine cohort studies with a total of 185 452, mainly Asian and white, participants were followed for a total of 835 146 person-years. In eight cohort studies defining impaired fasting glucose as fasting glucose 6.1-6.9 mmol/l, the summary relative risk of chronic kidney disease after adjustment for established risk factors was 1.11 (95% CI 1.02-1.21). When a study defining impaired fasting glucose as fasting glucose 5.6-6.9 mmol/dl was added, the overall relative risk of chronic kidney disease was 1.12 (95% CI 1.02-1.21). Exclusion of the only study with information on impaired glucose tolerance did not change the relative risk (1.12; 95% CI 1.02-1.21). There was no evidence of publication bias (P value for Egger test = 0.12). CONCLUSION: Prediabetes is modestly associated with an increase in chronic kidney disease risk, but this remains to be robustly confirmed. Chronic kidney disease screening among people with prediabetes, and aggressive management of prediabetes in those with chronic kidney disease may be warranted.

Disparities in provision of transplant education by profit status of the dialysis center.

Kidney transplant education is associated with higher transplantation rates; however national policies regarding optimal timing and content of transplant education are lacking. We aimed to characterize nephrologists' attitudes regarding kidney transplant education, and to compare practices between nephrologists at for-profit and nonprofit centers. We surveyed 906 nephrologist practicing in the United States. Most respondents (81%) felt the ideal time to spend on transplant education was >20 min, but only 43% reported actually doing so. Spending >20 min was associated with covering more topics, having one-on-one and repeated conversations, involving families in discussions and initiating discussions at CKD-stage 4. Providers at for-profit centers were significantly less likely to spend >20 min (RR = 0.89, 95%CI: 0.80-0.99) or involve families (RR = 0.57, 95%CI: 0.38-0.87); they reported that fewer of their patients received transplant counseling (RR = 0.58, 95%CI: 0.37-0.96), initiated transplant discussions (RR = 0.58, 95%CI: 0.38-0.88), or were eligible for transplantation (RR = 0.45, 95%CI: 0.30-0.68). Of nephrologists who spent ≤20 min, those at for-profit centers more often cited lack of reimbursement as a reason (30.0% vs. 18.9%, p = 0.02). Disparities in quality of education at for-profit centers might partially explain previously documented disparities in access to transplantation for patients at these centers. National policies detailing the optimal timing and content of transplant education are needed to improve equity.

Disparities in provision of transplant information affect access to kidney transplantation.

Recently Centers for Medicare and Medicaid Services (CMS) began asking providers on Form-2728 whether they informed patients about transplantation, and if not, to select a reason. The goals of this study were to describe national transplant education practices and analyze associations between practices and access to transplantation (ATT), based on United States Renal Data System (USRDS) data from 2005 to 2007. Multinomial logistic regression was used to examine factors associated with not being informed about transplantation, and modified Poisson regression to examine associations between not being informed and ATT (all models adjusted for demographics/comorbidities). Of 236,079 incident end-stage renal disease (ESRD) patients, 30.1% were not informed at time of 2728 filing, for reasons reported by providers as follows: 42.1% unassessed, 30.4% medically unfit, 16.9% unsuitable due to age, 3.1% psychologically unfit and 1.5% declined counsel. Older, obese, uninsured, Medicaid-insured and patients at for-profit centers were more likely to be unassessed. Women were more likely to be reported as unsuitable due to age, medically unfit and declined, and African Americans as psychologically unfit. Uninformed patients had a 53% lower rate of ATT, a disparity persisting in the subgroup of uninformed patients who were unassessed. Disparities in ATT may be partially explained by disparities in provision of transplant information; dialysis centers should ensure this critical intervention is offered equitably.

Lead-related nephrotoxicity: a review of the epidemiologic evidence.

Chronic kidney disease (CKD) represents a major global public health concern. Efforts to prevent and/or slow progression of CKD are essential. Lead nephropathy, characterized by chronic tubulointerstitial nephritis, is a well-known risk of chronic, high-level lead exposure. However, in recent years, lead exposure has declined sharply, particularly in developed countries. We reviewed epidemiologic research in general, occupational, and patient populations to assess whether lead, at current exposure levels, still contributes to nephrotoxicity. Other pertinent topics, such as risk in children, genetic susceptibility, and co-exposure to cadmium, are also considered. The data reviewed indicate that lead contributes to nephrotoxicity, even at blood lead levels below 5 microg/dl. This is particularly true in susceptible populations, such as those with hypertension (HTN), diabetes, and/or CKD. Low socioeconomic status is a risk factor for both lead exposure and diseases that increase susceptibility. Future public health risk for lead-related nephrotoxicity may be most significant in those rapidly developing countries where risk factors for CKD, including obesity and secondary HTN and diabetes mellitus, are increasing more rapidly than lead exposure is declining. Global efforts to reduce lead exposure remain important. Research is also needed to determine whether specific therapies, such as chelation, are beneficial in susceptible populations.

Changes in serum calcium, phosphate, and PTH and the risk of death in incident dialysis patients: a longitudinal study.

Elevated bone mineral parameters have been associated with mortality in dialysis patients. There are conflicting data about calcium, parathyroid hormone (PTH), and mortality and few data about changes in bone mineral parameters over time. We conducted a prospective cohort study of 1007 incident hemodialysis and peritoneal dialysis patients. We examined longitudinal changes in bone mineral parameters and whether their associations with mortality were independent of time on dialysis, inflammation, and comorbidity. Serum calcium, phosphate, and calcium-phosphate product (CaP) increased in these patients between baseline and 6 months (P<0.001) and then remained stable. Serum PTH decreased over the first year (P<0.001). In Cox proportional hazards models adjusting for inflammation, comorbidity, and other confounders, the highest quartile of phosphate was associated with a hazard ratio (HR) of 1.57 (1.07-2.30) using both baseline and time-dependent values. The highest quartiles of calcium, CaP, and PTH were associated with mortality in time-dependent models but not in those using baseline values. The lowest quartile of PTH was associated with an HR of 0.65 (0.44-0.98) in the time-dependent model with 6-month lag analysis. We conclude that high levels of phosphate both at baseline and over follow-up are associated with mortality in incident dialysis patients. High levels of calcium, CaP, and PTH are associated with mortality immediately preceding an event. Promising new interventions need to be rigorously tested in clinical trials for their ability to achieve normalization of bone mineral parameters and reduce deaths of dialysis patients.

Septicemia in diabetic hemodialysis patients: comparison of incidence, risk factors, and mortality with nondiabetic hemodialysis patients.

Diabetes mellitus is the most common cause of treated end-stage renal disease (ESRD), and diabetic hemodialysis patients have a high mortality rate. To identify differences in risk of septicemia among diabetic and nondiabetic hemodialysis patients, we examined the incidence, risk factors, and mortality for septicemia in a large sample of the US hemodialysis population. We performed a longitudinal cohort study of the incidence and risk factors for hospitalized cases of septicemia in diabetic and nondiabetic hemodialysis patients using baseline data from the US Renal Data System case-mix severity study with 7-year follow-up from hospitalization and death records. Independent risk factors for septicemia were assessed using Poisson regression. Independent effect of septicemia on mortality was assessed using Cox proportional hazards analysis. Over 7 years, 11.1% of nondiabetic patients and 12.5% of diabetic patients experienced at least one episode of septicemia. Older age and low serum albumin were independent risk factors for septicemia in all patients. In diabetics, white race, peripheral vascular disease, and hemodialyzer reuse, particularly in type 1, were independent risk factors. In nondiabetics, coronary artery disease, cerebrovascular disease, and temporary and permanent catheters were associated with an increased risk. In both groups, patients who experienced an episode of septicemia had twice the risk of death from any cause and an eightfold risk of death from septicemia. Septicemia occurs equally frequently and carries a marked increased risk of death in both nondiabetic and diabetic hemodialysis patients. Improving nutritional status and minimizing the use of catheters might help ameliorate the risk of septicemia. In diabetics, aggressive treatment of peripheral vascular disease might help reduce the risk of septicemia. Further research to elucidate potential mechanisms for variations in risk for septicemia according to race and hemodialyzer reuse practices are warranted in diabetic patients.