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.

Progression of Chronic Kidney Disease Risk Categories and Risk of Cardiovascular Disease and Total Mortality: Coronary Artery Risk Development in Young Adults Cohort.

Background Previous studies of worsening chronic kidney disease (CKD) based on declining estimated glomerular filtration rate (eGFR) or increasing urine albumin-creatinine ratio (UACR) are limited to later middle-age and older adults. We examined associations of CKD progression and incident cardiovascular disease (CVD) and mortality in younger adults. Methods and Results We studied 4382 adults in CARDIA (Coronary Artery Risk Development in Young Adults) initially aged 27 to 41 years and prospectively over 20 years. Five-year transition probabilities across CKD risk categories were based on eGFR and UACR measured at each exam. Proportional hazards models predicted incident CVD and all-cause mortality by time-varying CKD risk category, adjusting for demographics and CVD risk factors. Progression of CKD risk categories over 20 years occurred in 28.7% (1256/4382) of participants, driven by increases in UACR, but including 5.8% (n=255) with eGFR<60 mL/min per 1.73 m2 or UACR ≥300 mg/g. Compared with eGFR ≥60 and UACR <10, demographic and smoking-adjusted hazard ratios for CVD were 1.62 (95% CI, 1.21-2.18) for low CKD risk (eGFR ≥60 with UACR 10-29) and 13.65 (95% CI, 7.52-24.79) for very high CKD risk (eGFR <30 or eGFR 30-44 with UACR 30-299; or eGFR 30-59 with UACR ≥300). Corresponding hazard ratios for all-cause mortality were 1.42 (95% CI, 1.08-1.88) and 14.75 (95% CI, 9.97-21.82). Although CVD associations were attenuated after adjustment for mediating CVD risk factors, all-cause mortality associations remained statistically significant. Conclusions Among young to middle-aged adults, progression to higher CKD risk category was common. Routine monitoring eGFR and UACR holds promise for prevention of CVD and total mortality.

Risk of chronic kidney disease in people living with HIV by tenofovir disoproxil fumarate (TDF) use and baseline D:A:D chronic kidney disease risk score.

OBJECTIVES: To assess the risk of chronic kidney disease (CKD) associated with tenofovir disoproxil fumarate (TDF) use by baseline D:A:D CKD risk score. METHODS: Adult antiretroviral therapy (ART)-naïve people living with HIV (PLWH) initiating treatment, with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2 , were identified in the OPERA cohort. CKD was defined as two or more consecutive eGFR < 60 mL/min/1.73 m2 , > 90 days apart. Associations between TDF use, baseline D:A:D CKD risk and incident CKD were assessed with incidence rates (IRs; Poisson regression) and adjusted pooled logistic regression. The impact of pharmacoenhancers on the observed association between TDF and CKD was also evaluated. RESULTS: Of 9802 PLWH included, 6222 initiated TDF and 3580 did not (76% and 79% low D:A:D CKD risk, respectively). Overall, 125 CKD events occurred over 24 382 person-years of follow-up. Within strata of D:A:D CKD risk score, IRs were similar across TDF exposure, with high baseline CKD risk associated with highest incidence. Compared with the low-risk group without TDF, there was no statistical difference in odds of incident CKD in the low-risk group with TDF (adjusted odds ratio = 0.55, 95% confidence interval: 0.19-1.54). Odds of incident CKD did not differ statistically significantly by pharmacoenhancer exposure, with or without TDF. CONCLUSIONS: In this large cohort of ART-naïve PLWH, incident CKD following ART initiation was infrequent and strongly associated with baseline CKD risk. TDF-containing regimens did not increase the odds of CKD in those with a low baseline D:A:D CKD risk, the largest group of ART-naïve PLWH, and may remain a viable treatment option in appropriate settings.

The Association Between Kidney Disease and Diabetes Remission in Bariatric Surgery Patients With Type 2 Diabetes.

RATIONALE & OBJECTIVE: The association between bariatric surgery, type 2 diabetes, and chronic kidney disease (CKD) is poorly understood. We studied whether remission of type 2 diabetes induced by bariatric surgery influences markers of kidney disease, if CKD is associated with remission of diabetes after bariatric surgery, and if baseline levels of gut hormones and peptides modify these associations. STUDY DESIGN: Prospective observational study. STUDY PARTICIPANTS: 737 bariatric surgery patients with type 2 diabetes who participated in a multicenter cohort study for up to 5 years. PREDICTORS: Demographics, blood pressure, medications, type of bariatric surgery, anthropometrics, markers of kidney disease, and circulating levels of gut hormones and peptides. OUTCOMES: Estimated glomerular filtration rate (eGFR), urinary albumin excretion, prognostic risk for CKD, and remission of diabetes. ANALYTICAL APPROACH: Linear mixed models for eGFR; generalized linear mixed models with logit link for albuminuria, prognostic risk for CKD, and diabetes remission. RESULTS: Remission of diabetes at 5 years post-bariatric surgery was not independently associated with eGFR but was associated with lower risk for moderate/severe increase in albuminuria (risk ratio, 0.66; 95% CI, 0.48-0.90) and stabilization in prognostic risk for CKD. These findings were modified by baseline ghrelin level. Lower preoperative eGFR and greater prognostic risk for CKD were independently associated with reduced likelihood of diabetes remission. The association with preoperative GFR was modified by C-peptide level. Higher baseline circulating ghrelin level was independently associated with a lower prognostic risk for CKD. LIMITATIONS: A minority of participants had baseline CKD; lack of comparison group; no information on duration of diabetes, other clinical end points, or kidney biopsy results. CONCLUSIONS: Remission of type 2 diabetes 5 years after bariatric surgery was associated with improvements in albuminuria and stabilized prognostic risk for CKD, but not with eGFR. Lower kidney function and greater prognostic risk at the time of bariatric surgery was linked to a lower likelihood of diabetes remission. These results highlight the need to identify the mechanisms through which bariatric surgery may delay the long-term progression of CKD in type 2 diabetes.

Association Between Hypertension and Kidney Function Decline: The Atherosclerosis Risk in Communities (ARIC) Study.

RATIONALE & OBJECTIVE: The relationship between hypertension, antihypertension medication use, and change in glomerular filtration rate (GFR) over time among individuals with preserved GFR requires investigation. STUDY DESIGN: Observational study. SETTING & PARTICIPANTS: 14,854 participants from the Atherosclerosis Risk in Communities (ARIC) Study. PREDICTORS: Baseline hypertension status (1987-1989) was categorized according to the 2017 American College of Cardiology/American Heart Association Clinical Practice Guideline as normal blood pressure, elevated blood pressure, stage 1 hypertension, stage 2 hypertension without medication, or stage 2 hypertension with medication. OUTCOMES: Slope of estimated GFR (eGFR) at 5 study visits over 30 years. ANALYTICAL APPROACH: Mixed models with random intercepts and random slopes were fit to evaluate the association between baseline hypertension status and slope of eGFR. RESULTS: At baseline, 13.2%, 7.3%, and 19.4% of whites and 15.8%, 14.9%, and 39.9% of African Americans had stage 1 hypertension, stage 2 hypertension without medication, and stage 2 hypertension with medication. Compared with those with normal blood pressure, the annual eGFR decline was greater in people with higher blood pressure (whites: elevated blood pressure, -0.11mL/min/1.73m2; stage 1 hypertension, -0.15mL/min/1.73m2; stage 2 hypertension without medication, -0.36mL/min/1.73m2; stage 2 hypertension with medication, -0.17mL/min/1.73m2; African Americans: elevated blood pressure, -0.21mL/min/1.73m2; stage 1 hypertension, -0.16mL/min/1.73m2; stage 2 hypertension without medication, -0.50mL/min/1.73m2; stage 2 hypertension with medication, -0.16mL/min/1.73m2). The 30-year predicted probabilities of developing chronic kidney disease stage G3a+with normal blood pressure, elevated blood pressure, stage 1 hypertension, stage 2 hypertension without medication, or stage 2 hypertension with medication among whites were 54.4%, 61.6%, 64.7%, 78.1%, and 70.9%, respectively, and 55.4%, 62.8%, 60.9%, 76.1%, and 66.6% among African Americans. LIMITATIONS: Slope estimated using a maximum of 5 eGFR assessments; differential loss to follow-up. CONCLUSIONS: Compared to normotension, baseline hypertension status was associated with faster kidney function decline over 30-year follow-up in a general population cohort. This difference was attenuated among people using antihypertensive medications.

Predictive Value of Cortical Thickness Measured by Ultrasonography for Renal Impairment: A Longitudinal Study in Chronic Kidney Disease.

BACKGROUND: Kidney size is associated with renal function, however it is not elucidated whether kidney size is a risk for the progression of chronic kidney disease. The aim of this study was to investigate the predictive value of morphological evaluation of kidney size by ultrasonography for the progression of renal dysfunction. METHODS: Morphological parameters including kidney length, volume, cortical thickness, and medullary thickness were measured by ultrasonography in 87 patients with chronic kidney disease, and adjusted by body size. Renal functions at baseline and after 2 years were measured and the associations of morphological parameters to decline in renal function over 2 years were analyzed. RESULTS: Height-adjusted cortical thickness was correlated to decline in renal function (r = 0.426, p < 0.001). Height-adjusted cortical thickness could predict renal dysfunction with the area under the curve of 0.786, and height-adjusted cortical thickness of 4.0 mm/cm was a cut off value with a sensitivity of 72.5% and a specificity of 80.0% for the risk of a more than 30% decline in renal function or initiation of dialysis. CONCLUSIONS: We provide new insights into the utility of measuring cortical thickness by ultrasonography for predict future renal impairment.

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.

Nonalcoholic fatty liver disease increases risk of incident chronic kidney disease: A systematic review and meta-analysis.

BACKGROUND: Recent studies examined the prognostic impact of nonalcoholic fatty liver disease (NAFLD) on the risk of incident chronic kidney disease (CKD). However, the extent to which NAFLD may confer risk of incident CKD is uncertain. We performed a meta-analysis of relevant studies to quantify the magnitude of the association between NAFLD and risk of incident CKD. METHODS: We searched PubMed, Scopus and Web of Science from January 1, 2000 to August 31, 2017 using pre-defined keywords to identify large observational cohort studies with a follow-up duration of at least 1year, in which NAFLD was diagnosed by biochemistry, fatty liver index or ultrasonography. No studies with biopsy-proven NAFLD were available for the analysis. Data from selected studies were extracted, and meta-analysis was performed using random-effects modeling. RESULTS: A total of 9 observational studies with 96,595 adult individuals (34.1% with NAFLD) of predominantly Asian descent, and 4653 cases of incident CKD stage ≥3 (i.e., defined as occurrence of estimated glomerular filtration rate<60ml/min/1.73m2, with or without accompanying overt proteinuria) over a median period of 5.2years were included in the final analysis. Patients with NAFLD had a significantly higher risk of incident CKD than those without NAFLD (random-effects hazard ratio [HR] 1.37, 95% CI 1.20-1.53; I2=33.5%). Patients with more 'severe' NAFLD (according to ultrasonography and non-invasive fibrosis markers) were also more likely to develop incident CKD (n=2 studies; random-effects HR 1.50, 95% CI 1.25-1.74; I2=0%); this risk appeared to be even greater among those with ultrasound-diagnosed NAFLD and a high-intermediate NAFLD fibrosis score (n=1 study; random-effects HR 1.59, 95% CI 1.31-1.93). Sensitivity analyses did not alter these findings. Funnel plot and Egger's test did not reveal significant publication bias. CONCLUSIONS: This largest and most updated meta-analysis to date shows that NAFLD (detected by biochemistry, fatty liver index or ultrasonography) is associated with a nearly 40% increase in the long-term risk of incident CKD. However, the observational nature of the eligible studies does not allow for proving causality. Our findings pave the way for future large, prospective, histologically-based studies.

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.

Evaluation of the Scored Questionnaire to Identify Individuals with Chronic Kidney Disease in a Community-based Screening Program in Rural North Carolina.

BACKGROUND: Just over 10 percent of US adults over twenty years of age have chronic kidney disease (CKD). Early detection is essential to delay or halt CKD's progression, but screening and early detection of CKD in high risk populations is inconsistent, especially in rural and underserved communities. OBJECTIVE: The objective of this study was to evaluate the effectiveness of the Screening for Occult Renal Disease questionnaire as a simple, self-report tool to identify individuals with increased likelihood of prevalent CKD in a rural North Carolina setting. METHODS: Over an eight month period, in the context of the Kidney Education Outreach Program (KEOP), sixteen CKD screenings were conducted in two underserved, rural NC communities. For this study, the SCORED questionnaire was administered prior to the execution of the regular KEOP screening protocol. RESULTS: For 172 participants for whom both blood and urine specimens were collected, there were fifteen (8.7%) who demonstrated less than normal kidney function. The SCORED sensitivity and specificity were 100% and 42%, respectively. The positive predictive value was 14% and the negative predictive value was 100%. The positive likelihood ratio for low eGFR was 1.7 and conversely, the negative likelihood ratio for low eGFR was zero. CONCLUSION: In this study, the SCORED performed comparably to previous settings in established datasets and cohort studies, with high sensitivity and negative predictive values that allow for ruling out the presence of disease. SCORED appears to provides a practical alternative to the administration of regular CKD screening protocols that can be difficult to organize and administer in rural settings. The need for further evaluation of SCORED in underserved, high-risk communities is recommended.