Risk of CKD Following Detection of Microscopic Hematuria: A Retrospective Cohort Study.

RATIONALE & OBJECTIVE: Microscopic hematuria is an uncertain risk factor for chronic kidney disease (CKD). We investigated the association between persistent or single episodes of microscopic hematuria and the development of incident CKD, overall and separately among men and women. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: A total of 232,220 Korean adults without CKD at baseline who underwent repeated regular health examinations at Kangbuk Samsung Health Study formed the study cohort. EXPOSURE: Microscopic hematuria was defined by≥5 red blood cells per high-power field. Participants were categorized into 1 of 4 groups according to the presence of hematuria at 2 consecutive examinations: (1) no hematuria at both examinations (reference group); (2) hematuria followed by no hematuria (regressed hematuria group); (3) no hematuria followed by hematuria (developed hematuria group); and (4) hematuria at both examinations (persistent hematuria group). OUTCOME: CKD was defined as an estimated glomerular filtration rate<60mL/min/1.73m2 or proteinuria (1+or more on dipstick examination). ANALYTICAL APPROACH: Semiparametric proportional hazards models were used to estimate hazard ratios. RESULTS: During a 4.8-year median follow-up period, 2,392 participants developed CKD. Multivariable-adjusted hazard ratios for incident CKD, comparing the regressed, developed, and persistent hematuria groups to the no-hematuria group were 1.85 (95% CI, 1.35-2.53), 3.18 (95% CI, 2.54-3.98), and 5.23 (95% CI, 4.15-6.59), respectively. The association between persistent hematuria and incident CKD was stronger in men than women (P for interaction<0.001), although a statistically significant association was observed in both sexes. LIMITATIONS: Lack of albuminuria and inability to consider specific glomerular diseases. CONCLUSIONS: Men and women with microscopic hematuria, especially persistent hematuria, may be at increased risk of CKD.

Association Between Gestational Diabetes and Incident Maternal CKD: The Coronary Artery Risk Development in Young Adults (CARDIA) Study.

BACKGROUND: Gestational diabetes mellitus (GDM) is associated with increased risk for diabetes mellitus, metabolic syndrome, and cardiovascular disease. We evaluated whether GDM is associated with incident chronic kidney disease (CKD), controlling for prepregnancy risk factors for both conditions. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: Of 2,747 women (aged 18-30 years) enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) Study in 1985 to 86, we studied 820 who were nulliparous at enrollment, delivered at least 1 pregnancy longer than 20 weeks' gestation, and had kidney function measurements during 25 years of follow-up. PREDICTOR: GDM was self-reported by women for each pregnancy. OUTCOMES: CKD was defined as the development of estimated glomerular filtration rate (eGFR)<60mL/min/1.73m2 or urine albumin-creatinine ratio ≥ 25mg/g at any one CARDIA examination in years 10, 15, 20, or 25. MEASUREMENTS: HRs for developing CKD were estimated for women who developed GDM versus women without GDM using complementary log-log models, adjusting for prepregnancy age, systolic blood pressure, dyslipidemia, body mass index, smoking, education, eGFR, fasting glucose concentration, physical activity level (all measured at the CARDIA examination before the first pregnancy), race, and family history of diabetes. We explored for an interaction between race and GDM. RESULTS: During a mean follow-up of 20.8 years, 105 of 820 (12.8%) women developed CKD, predominantly increased urine albumin excretion (98 albuminuria only, 4 decreased eGFR only, and 3 both). There was evidence of a GDM-race interaction on CKD risk (P=0.06). Among black women, the adjusted HR for CKD was 1.96 (95% CI, 1.04-3.67) in GDM compared with those without GDM. Among white women, the HR was 0.65 (95% CI, 0.23-1.83). LIMITATIONS: Albuminuria was assessed by single untimed measurements of urine albumin and creatinine. CONCLUSIONS: GDM is associated with the subsequent development of albuminuria among black women in CARDIA.

Recovery From Acute Kidney Injury and CKD Following Heart Transplantation in Children, Adolescents, and Young Adults: A Retrospective Cohort Study.

BACKGROUND: Acute kidney injury (AKI) is common in children following surgery for congenital heart disease and has been associated with poor long-term kidney outcomes. Children undergoing heart transplantation may be at increased risk for the development of both AKI and chronic kidney disease (CKD). This study examines AKI rates in children, adolescents, and young adults after heart transplantation and analyzes the relationship between AKI and CKD in this population. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 88 young patients who underwent heart transplantation at Lucile Packard Children's Hospital, Stanford, CA, September 1, 2007, to November 30, 2013. PREDICTOR: The primary independent variable was AKI within the first 7 postoperative days, ascertained according to the KDIGO (Kidney Disease: Improving Global Outcomes) creatinine criteria (increase in serum creatinine ≥ 1.5 times baseline within 7 days). OUTCOMES: Recovery from AKI at 3 months, ascertained as serum creatinine level < 1.5 times baseline; and development of CKD at 6 and 12 months, ascertained as estimated glomerular filtration rate < 60mL/min/1.73m(2) for more than 3 months. RESULTS: 63 (72%) patients developed AKI; 57% had moderate (stage 2 or severe stage 3) disease. Recovery occurred in 39 of 63 (62%), 50% for stage 2 or 3 versus 78% for stage 1 (P=0.04). At 6 and 12 months, 3 of 82 (4%) and 4 of 76 (5%) developed CKD, respectively. At both time points, CKD was more common in those without recovery (3/22 [14%] vs 0/38 (0%); P=0.04, and 3/17 (18%) vs (0/34) 0%; P=0.03, respectively). LIMITATIONS: Retrospective design, small sample size, and single-center nature of the study. CONCLUSIONS: AKI is common after heart transplantation in children, adolescents, and young adults. Nonrecovery from AKI is more common in patients with more severe AKI and is associated with the development of CKD during the first year.

Detection and Clinical Patterns of Nephron Hypertrophy and Nephrosclerosis Among Apparently Healthy Adults.

BACKGROUND: Even among ostensibly healthy adults, there is often mild pathology in the kidney. The detection of kidney microstructural variation and pathology by imaging and the clinical pattern associated with these structural findings is unclear. STUDY DESIGN: Cross-sectional (clinical-pathologic correlation). SETTING & PARTICIPANTS: Living kidney donors at Mayo Clinic (Minnesota and Arizona sites) and Cleveland Clinic 2000 to 2011. PREDICTORS: Predonation kidney function, risk factors, and contrast computed tomographic scan of the kidneys. These scans were segmented for cortical volume and medullary volume, reviewed for parenchymal cysts, and scored for kidney surface roughness. OUTCOMES: Nephrosclerosis (glomerulosclerosis, interstitial fibrosis/tubular atrophy, and arteriosclerosis) and nephron size (glomerular volume, mean profile tubular area, and cortical volume per glomerulus) determined from an implantation biopsy of the kidney cortex at donation. RESULTS: Among 1,520 living kidney donors, nephrosclerosis associated with increased kidney surface roughness, cysts, and smaller cortical to medullary volume ratio. Larger nephron size (nephron hypertrophy) associated with larger cortical volume. Nephron hypertrophy and larger cortical volume associated with higher systolic blood pressure, glomerular filtration rate, and urine albumin excretion; larger body mass index; higher serum uric acid level; and family history of end-stage renal disease. Both nephron hypertrophy and nephrosclerosis associated with older age and mild hypertension. The net effect of both nephron hypertrophy and nephrosclerosis associating with cortical volume was that nephron hypertrophy diminished volume loss with age-related nephrosclerosis and fully negated volume loss with mild hypertension-related nephrosclerosis. LIMITATIONS: Kidney donors are selected on health, restricting the spectrum of pathologic findings. Kidney biopsies in living donors are a small tissue sample leading to imprecise estimates of structural findings. CONCLUSIONS: Among apparently healthy adults, the microstructural findings of nephron hypertrophy and nephrosclerosis differ in their associations with kidney function, macrostructure, and risk factors.