Nrupen A. Bhavsar

Comparison of Measured GFR, Serum Creatinine, Cystatin C, and Beta-Trace Protein to Predict ESRD in African Americans With Hypertensive CKD

BACKGROUND Identification of persons with chronic kidney disease (CKD) who are at highest risk to progress to end-stage renal disease (ESRD) is necessary to reduce the burden of kidney failure. The relative utility of traditional markers of kidney function, including estimated glomerular filtration rate (eGFR) and serum creatinine level, and emerging markers of kidney function, including cystatin C and beta-trace protein (BTP) levels, to predict ESRD and mortality has yet to be established. STUDY DESIGN Randomized clinical trial followed by an observational cohort study. SETTING & PARTICIPANTS 865 African American individuals with hypertensive CKD enrolled in a clinical trial of 2 levels of blood pressure control and 3 different antihypertensive drugs as initial therapy and subsequently followed by an observational cohort study. PREDICTORS Quintile of measured GFR (mGFR) by iothalamate clearance, serum creatinine, serum creatinine-based eGFR, cystatin C, and BTP values. OUTCOMES & MEASUREMENTS Incidence of ESRD and mortality. RESULTS 246 participants reached ESRD during a median follow-up of 102 months. The incidence rate of ESRD was higher with higher quintiles of each marker. The association between higher BTP level and ESRD was stronger than those for the other markers, including mGFR. All markers remained significantly associated with ESRD after adjustment for mGFR and relevant covariates (all P < 0.05), with BTP level retaining the strongest association (HR for highest vs lowest quintile, 5.7; 95% CI, 2.2-14.9). Associations with the combined end point of ESRD or mortality (n = 390) were weaker, but remained significant for cystatin C (P = 0.05) and BTP levels (P = 0.004). LIMITATIONS The ability of these markers to predict ESRD and mortality in other racial and ethnic groups and in individuals with CKD due to other causes is unknown. CONCLUSIONS Plasma BTP and cystatin C levels may be useful adjuncts to serum creatinine level and mGFR in evaluating risk of progression of kidney disease.

Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Kidney Injury Molecule 1 (KIM-1) as Predictors of Incident CKD Stage 3: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND Identifying individuals at risk of chronic kidney disease (CKD) is critical for timely treatment initiation to slow progression of the disease. Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1) are known biomarkers of acute kidney injury, but it is unknown whether these markers are associated with incident CKD stage 3 in the general population. STUDY DESIGN Matched case-control study. SETTING & PARTICIPANTS African American and white participants from the Atherosclerosis Risk in Communities (ARIC) Study who at baseline had an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m(2) and urinary albumin-creatinine ratio ≤30 mg/g. 143 controls were matched for age, sex, and race to 143 cases of incident CKD stage 3 after 8.6 years of follow-up. PREDICTORS Quartile of NGAL and KIM-1. OUTCOMES & MEASUREMENTS Incident CKD stage 3 (eGFR <60 mL/min/1.73 m(2) at follow-up and a decrease in eGFR from baseline to follow-up ≥25%). RESULTS Both NGAL (P = 0.05) and KIM-1 levels (P < 0.001) were correlated positively with baseline urinary albumin-creatinine ratio; neither was associated with baseline eGFR. Participants with NGAL concentrations in the fourth quartile had more than 2-fold higher odds (adjusted OR, 2.11; 95% CI, 0.96-4.64) of incident CKD stage 3 compared with participants in the first quartile after multivariable adjustment (P-trend = 0.03). Adjustment for urinary creatinine and albumin levels resulted in a nonsignificant association (highest quartile adjusted OR, 1.52; 95% CI, 0.64-3.58; P = 0.2). No significant association between KIM-1 level and incident CKD was observed in crude or adjusted models. LIMITATIONS The relatively small sample size of the study limits precision and power to detect weak associations. CONCLUSIONS Higher NGAL, but not KIM-1, levels were associated with incident CKD stage 3. Adjustment for urinary creatinine and albumin concentration attenuated this association. Additional studies are needed to confirm these findings and assess the utility of urinary NGAL as a marker of CKD risk.

The use of adjuvant radiotherapy in elderly patients with early-stage breast cancer: changes in practice patterns after publication of Cancer and Leukemia Group B 9343.

The Cancer and Leukemia Group B (CALGB) 9343 randomized phase 3 trial established lumpectomy and adjuvant therapy with tamoxifen alone, rather than both radiotherapy and tamoxifen, as a reasonable treatment course for women aged >70 years with clinical stage I (AJCC 7th edition), estrogen receptor‐positive breast cancer. An analysis of the Surveillance, Epidemiology, and End Results (SEER) registry was undertaken to assess practice patterns before and after the publication of this landmark study.

Trefoil Factor 3 Predicts Incident Chronic Kidney Disease: A Case-Control Study Nested within the Atherosclerosis Risk in Communities (ARIC) Study

Background: Early detection of individuals at high risk for chronic kidney disease (CKD) may aid prevention. Urinary levels of trefoil factor 3 (TFF3) are associated with acute kidney injury in animal models, but the association of TFF3 levels with incident CKD in humans is unknown. Methods: We conducted a case-control study nested within the Atherosclerosis Risk in Communities (ARIC) Study and the ARIC Carotid MRI Study to determine whether urinary TFF3 levels predict incident CKD over 8.6 years of follow-up. A total of 143 participants with incident CKD (eGFR decreasing by ≧25% to <60 ml/min/1.73 m2) were matched on age, sex and race to 143 non-cases. Results: Higher TFF3 levels at baseline were strongly associated with Black race, diabetes (both p = 0.002), and antihypertensive medication use (p = 0.02). Compared to participants with TFF3 levels in the lowest quartile, the odds ratio (OR) of incident CKD was 1.84 (95% confidence interval (CI): 0.80, 4.22) for individuals with TFF3 levels in the second quartile, 2.43 (95% CI: 1.06, 5.53) for the third quartile, and 2.77 (95% CI: 1.22, 6.28) for the fourth quartile (p trend = 0.02). Adjustment for covariates, including urinary albumin: creatinine ratio, did not markedly change the associations. Twofold higher TFF3 levels were strongly associated with incident CKD after adjustment for CKD risk factors (adjusted OR = 1.35; 95% CI: 1.11, 1.64). Conclusions: Higher urinary TFF3 levels may indicate ongoing repair of damage in the kidney. Additional studies are needed to confirm whether TFF3 can be useful as a marker of increased risk for CKD.

Primary Care Providers' Response to the US Preventive Services Task Force Draft Recommendations on Screening for Prostate Cancer

Editorial Comment: Will anyone listen to the recommendation of the task force? These authors queried 123 practitioners in the Johns Hopkins Community Physicians practice, which in 2010 evaluated approximately 40,000 men 40 years or older who were eligible for prostate cancer screening. When asked how they thought the draft recommendations would change their approach, 2% said they would no longer order prostate specific antigen (PSA) testing, 22% said they would be much less likely do so, 39% said they would be somewhat less likely do so and 37% said they would not change their screening practices. However, even among those clinicians who agreed with the draft recommendations fewer than half (41%) stated that they would no longer order routine PSA testing or would be less likely to do so. Reasons that physicians would not change their practice included patient expectation for them to continue screening (75%); lack of time to explain changes (67%); fear of malpractice litigation (54%); and discomfort with uncertainty (42.5%). Finally, the clinicians who were most likely to believe that the draft recommendations would change their practice were also the providers who were least likely to report routinely ordering PSA in the past year. At the same time another article demonstrated that despite the U.S. Preventive Services Task Force recommendations against prostate cancer screening in men 75 years or older, PSA screening rates did not change.

Lower urinary connective tissue growth factor levels and incident CKD stage 3 in the general population.

BACKGROUND Connective tissue growth factor (CTGF) is involved in the development and progression of kidney diseases, including diabetic nephropathy and kidney fibrosis, but also may have a role in mesangial repair after injury. It is unknown whether, in the general population, urinary CTGF levels are associated with a decrease in estimated glomerular filtration rate (eGFR) to <60 mL/min/1.73 m(2) (ie, development of chronic kidney disease [CKD] stage 3). STUDY DESIGN Nested case-control. SETTING & PARTICIPANTS 100 cases of incident CKD stage 3 and 100 age-and sex-matched controls in the Framingham Heart Study; 141 cases and 135 age-, sex-, and race-matched controls in the Atherosclerosis Risk in Communities (ARIC) Study. Controls had eGFR ≥60 mL/min/1.73 m(2) at follow-up in both studies. PREDICTORS Urinary CTGF concentrations. OUTCOMES Incident CKD stage 3, defined as eGFR <60 mL/min/1.73 m(2). MEASUREMENTS Stored urine samples from Framingham Heart Study and ARIC were measured for CTGF. Covariates were obtained from Framingham Heart Study and ARIC participant examinations. RESULTS In the Framingham Heart Study, the median baseline urinary CTGF concentration was lower in cases (1.35 ng/mL) than controls (2.35 ng/mL; paired t test, P < 0.0001). The multivariable-adjusted OR for incident CKD stage 3 was 0.33 (95% CI, 0.17-0.64; P < 0.001) per 1-standard deviation in log urinary CTGF level after adjustment for CKD risk factors, baseline eGFR, and baseline log urinary albumin-creatinine ratio, with similar results in participants without diabetes (n = 184). Results were not materially different when urinary CTGF level was indexed to urinary creatinine level (multivariable-adjusted OR, 0.34; 95% CI, 0.21-0.56; P < 0.001). A similar, but nonsignificant, trend of risk of incident CKD stage 3 with lower baseline urinary CTGF concentration was observed in an independent case-control study conducted in the ARIC Study, with the strongest results observed in participants free of diabetes. This inverse relationship was robust in meta-analysis of both the overall and diabetes-free groups. LIMITATIONS Observational study; causality cannot be inferred. CONCLUSIONS Lower urinary CTGF concentrations precede the onset of CKD stage 3 in the general population. Further work is required to fully characterize how CTGF level influences risk of CKD.

Serum prostate-specific antigen (PSA) concentration is positively associated with rate of disease reclassification on subsequent active surveillance prostate biopsy in men with low PSA density.

To investigate the association between serum prostate‐specific antigen (PSA) concentration at active surveillance (AS) entry and disease reclassification on subsequent AS biopsy (‘biopsy reclassification’) in men with low PSA density (PSAD). To investigate whether a clinically meaningful PSA threshold for AS eligibility/ineligibility for men with low PSAD can be identified based on risk of subsequent biopsy reclassification.

A peripheral circulating TH1 cytokine profile is inversely associated with prostate cancer risk in CLUE II

Background: TH1 cytokines, such as IFNγ and TNFα, and potentially innate cytokines, such as IL6, can potentiate the immune response to tumor. Cytokines, such as IL1β, IL8, and IL10, may suppress anticancer immunity. Thus, we prospectively evaluated the association between peripheral-cytokine concentrations and prostate cancer. Methods: We conducted an age-race matched case–control study (268 pairs) of incident prostate cancer in CLUE-II. We measured plasma IFNγ, IL10, IL12p70, IL1β, IL6, IL8, and TNFα concentrations using an ultrasensitive multiplex kit. ORs and 95% confidence intervals (CI) were calculated using conditional logistic regression. Results: The OR of prostate cancer decreased across quartiles of IFNγ (highest vs. lowest quartiles: OR, 0.49; 95% CI, 0.30–0.81; Ptrend = 0.006), TNFα (OR, 0.56; 95% CI, 0.33–0.96; Ptrend = 0.01), and IL6 (OR, 0.46; 95% CI, 0.26–0.79; Ptrend = 0.007). Higher TNFα (OR, 0.28; 95% CI, 0.09–0.85; Ptrend = 0.01) and IL6 (OR, 0.20; 95% CI, 0.06–0.67; Ptrend = 0.003) concentrations were associated with lower Gleason sum ≥7 disease risk. Other cytokines were not as clearly associated with risk. Conclusions: Men with a prediagnostic circulating TH1 profile and higher IL6 may have a lower risk of prostate cancer, including aggressive disease. Whether this profile reflects (i) an intraprostatic immune environment in benign tissue that protects against prostate cancer, (ii) the immune milieu in response to a prostate adenocarcinoma that inhibits tumor growth and detectability, and/or (iii) a systemic immune profile that mediates the influence of modifiable factors on risk, warrants additional study. Impact: Identifying specific inflammatory cytokines associated with prostate cancer may lead to improved prevention and treatment strategies. Cancer Epidemiol Biomarkers Prev; 23(11); 2561–7. ©2014 AACR.

Is There Something Better than the Best Marker of Kidney Function

Measurement of kidney function is critical both for clinical decision-making and research. Direct measurement of GFR using urinary or plasma clearance of exogenously administered markers, such as 125I-iothalamate, is considered the gold standard method to assess kidney function. These procedures,

Obesity and synergistic risk factors for chronic kidney disease in African American adults: the Jackson Heart Study

Background African Americans are at high risk for chronic kidney disease (CKD). Obesity may increase the risk for CKD by exacerbating features of the metabolic syndrome and promoting glomerular hyperfiltration. Whether other factors also affecting these pathways may amplify or mitigate obesity-CKD associations has not been investigated. Methods We studied interactions between obesity and these candidate factors in 2043 African Americans without baseline kidney disease enrolled in the Jackson Heart Study. We quantified obesity as body mass index (BMI), sex-normalized waist circumference and visceral adipose volume measured by abdominal computed tomography at an interim study visit. Interactions were hypothesized with (i) metabolic risk factors (dietary quality and physical activity, both quantified by concordance with American Heart Association guidelines) and (ii) factors exacerbating or mitigating hyperfiltration (dietary protein intake, APOL1 risk status and use of renin-angiotensin system blocking medications). Using multivariable regression, we evaluated associations between obesity measures and incident CKD over the follow-up period, as well as interactions with metabolic and hyperfiltration factors. Results Assessed after a median of 8 years (range 6-11 years), baseline BMI and waist circumference were not associated with incident CKD. Higher visceral adipose volume was independently associated with incident CKD (P = 0.008) in a nonlinear fashion, but this effect was limited to those with lower dietary quality (P = 0.001; P-interaction = 0.04). In additional interaction models, higher waist circumference was associated with greater risk of incident CKD among those with the low-risk APOL1 genotype (P = 0.04) but not those with a high-risk genotype (P-interaction = 0.02). Other proposed factors did not modify obesity-CKD associations. Conclusions. Higher risks associated with metabolically active visceral adipose volume and interactions with dietary quality suggest that metabolic factors may be key determinants of obesity-associated CKD risk. Interactions between obesity and APOL1 genotype should be considered in studies of African Americans.