No abstract

Obesity is associated with less access to transplantation among adults with ESRD. To examine the association between body mass index at ESRD onset and survival and transplantation in children, we performed a retrospective analysis of children ages 2-19 years old beginning RRT from 1995 to 2011 using the US Renal Data System. Among 13,172 children, prevalence of obesity increased from 14% to 18%, whereas prevalence of underweight decreased from 12% to 9% during this period. Over a median follow-up of 7.0 years, 10,004 children had at least one kidney transplant, and 1675 deaths occurred. Risk of death was higher in obese (hazard ratio [HR], 1.17; 95% confidence interval [95% CI], 1.03 to 1.32) and underweight (HR, 1.26; 95% CI, 1.09 to 1.47) children than children with normal body mass indices. Obese and underweight children were less likely to receive a kidney transplant (HR, 0.92; 95% CI, 0.87 to 0.97; HR, 0.83; 95% CI, 0.78 to 0.89, respectively). Obese children had lower odds of receiving a living donor transplant (odds ratio, 0.85; 95% CI, 0.74 to 0.98) if the transplant occurred within 18 months of ESRD onset. Adjustment for transplant in a timedependent Cox model attenuated the higher risk of death in obese but not underweight children (HR, 1.09; 95% CI, 0.96 to 1.24). Lower rates of kidney transplantation may, therefore, mediate the higher risk of death in obese children with ESRD. The increasing prevalence of obesity among children starting RRT may impede kidney transplantation, especially from living donors.

ABSTRACT. The recommended albumin (μg)/creatinine (mg) ratio (ACR) (30 μg/mg) to detect microalbuminuria does not account for sex or racial differences in creatinine excretion. In a nationally representative sample of subjects, the distribution of urine albumin and creatinine concentrations was examined by using one ACR value (≥30 μg/mg) and sex-specific cutpoints (≥17 μg/mg in men and ≥25 μg/mg in women) measured in spot urine specimens. Mean urine albumin concentrations were not significantly different between men and women, but urine creatinine concentrations were significantly higher (P < 0.0001). Compared with non-Hispanic whites, urine creatinine concentrations were significantly higher in non-Hispanic blacks (NHB) and Mexican Americans, whereas urine albumin concentrations were significantly higher in NHB (P < 0.0001) but not Mexican Americans. When a single ACR is used, the prevalence of microalbuminuria was significantly lower among the men compared with women (6.0 versus 9.2%; P < 0.0001) and among non-Hispanic whites compared with NHB (7.2 versus 10.2%; P < 0.0001). No significant difference in the prevalence of microalbuminuria between men and women was noted when sex-specific ACR cutpoints were used. In the multivariate adjusted model, female sex (odds ratio, 1.62; 95% confidence interval, 1.29 to 2.05) and NHB race/ethnicity (odds ratio, 1.34; 95% confidence interval, 1.12 to 1.61) were independently associated with microalbuminuria when a single ACR threshold was used. When a sex-specific ACR was used, NHB race/ethnicity remained significantly associated with microalbuminuria but sex did not. The use of one ACR value to define microalbuminuria may underestimate microalbuminuria in subjects with higher muscle mass (men) and possibly members of certain racial/ethnic groups.

Background and objectives Poor linear growth is common in children with CKD and has been associated with higher mortality. However, recent data in adult dialysis patients have suggested a higher risk of death in persons of tall stature. In this study, we aimed to examine the risk of all-cause and cause-specific mortality in children at both extremes of height at the time of first RRT.Design, setting, participants, & measurements Using the US Renal Data System, we performed a retrospective analysis of 13,218 children aged 2-19 years, who received their first RRT (dialysis or transplant) during 1995-2011. We used adjusted Cox models to examine the association between short (,3rd percentile) and tall (.3rd percentile) stature and risk of death, compared with less extreme heights.Results Over a median follow-up of 7.1 years, there were 1721 deaths. Risk of death was higher in children with short (hazard ratio, 1.49; 95% confidence interval, 1.33 to 1.66) and tall stature (hazard ratio, 1.32; 95% confidence interval, 1.03 to 1.69) in adjusted analysis. In secondary analyses, there was a statistically significant interaction between height and body mass index categories (P=0.04), such that the association of tall stature with higher mortality was limited to children with elevated body mass index (defined as $95th percentile for age and sex). Children with short stature had a higher risk of cardiac-and infection-related death, whereas children with tall stature had a higher risk of cancer-related death.Conclusions Children with short and tall stature are at higher mortality risk, although this association was modified by body mass index at time of first RRT. Studies to further explore the reasons behind the higher risk of mortality in children with extremes of height at the time of first RRT are warranted.