Faculty Bibliography

BACKGROUND:In animal studies, zinc supplementation inhibited phosphate-induced arterial calcification. We tested the hypothesis that higher intake of dietary zinc was associated with lower abdominal aortic calcification (AAC) among adults in the USA. We also explored the associations of AAC with supplemental zinc intake, total zinc intake and serum zinc level. METHODS:We performed cross-sectional analyses of 2535 participants from the National Health and Nutrition Examination Survey 2013-14. Dietary and supplemental zinc intakes were obtained from two 24-h dietary recall interviews. Total zinc intake was the sum of dietary and supplemental zinc. AAC was measured using dual-energy X-ray absorptiometry in adults ≥40 years of age and quantified using the Kauppila score system. AAC scores were categorized into three groups: no AAC (AAC = 0, reference group), mild-moderate (AAC >0-≤6) and severe AAC (AAC >6). RESULTS:Dietary zinc intake (mean ± SE) was 10.5 ± 0.1 mg/day; 28% had AAC (20% mild-moderate and 8% severe), 17% had diabetes mellitus and 51% had hypertension. Higher intake of dietary zinc was associated with lower odds of having severe AAC. Per 1 mg/day higher intake of dietary zinc, the odds of having severe AAC were 8% lower [adjusted odds ratio 0.92 (95% confidence interval 0.86-0.98), P = 0.01] compared with those without AAC, after adjusting for demographics, comorbidities and laboratory measurements. Supplemental zinc intake, total zinc intake and serum zinc level were not associated with AAC. CONCLUSIONS:Higher intake of dietary zinc was independently associated with lower odds of having severe AAC among noninstitutionalized US adults.

BACKGROUND AND OBJECTIVES:Studies of adults have demonstrated an association between metabolic acidosis, as measured by low serum bicarbonate levels, and CKD progression. We evaluated this relationship in children using data from the Chronic Kidney Disease in Children study. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:The relationship between serum bicarbonate and a composite end point, defined as 50% decline in eGFR or KRT, was described using parametric and semiparametric survival methods. Analyses were stratified by underlying nonglomerular and glomerular diagnoses, and adjusted for demographic characteristics, eGFR, proteinuria, anemia, phosphate, hypertension, and alkali therapy. RESULTS:Six hundred and three participants with nonglomerular disease contributed 2673 person-years of follow-up, and 255 with a glomerular diagnosis contributed 808 person-years of follow-up. At baseline, 39% (237 of 603) of participants with nonglomerular disease had a bicarbonate level of ≤22 meq/L and 36% (85 of 237) of those participants reported alkali therapy treatment. In participants with glomerular disease, 31% (79 of 255) had a bicarbonate of ≤22 meq/L, 18% (14 of 79) of those participants reported alkali therapy treatment. In adjusted longitudinal analyses, compared with participants with a bicarbonate level >22 meq/L, hazard ratios associated with a bicarbonate level of <18 meq/L and 19-22 meq/L were 1.28 [95% confidence interval (95% CI), 0.84 to 1.94] and 0.91 (95% CI, 0.65 to 1.26), respectively, in children with nonglomerular disease. In children with glomerular disease, adjusted hazard ratios associated with bicarbonate level ≤18 meq/L and bicarbonate 19-22 meq/L were 2.16 (95% CI, 1.05 to 4.44) and 1.74 (95% CI, 1.07 to 2.85), respectively. Resolution of low bicarbonate was associated with a lower risk of CKD progression compared with persistently low bicarbonate (≤22 meq/L). CONCLUSIONS:In children with glomerular disease, low bicarbonate was linked to a higher risk of CKD progression. Resolution of low bicarbonate was associated with a lower risk of CKD progression. Fewer than one half of all children with low bicarbonate reported treatment with alkali therapy. Long-term studies of alkali therapy's effect in patients with pediatric CKD are needed.

BACKGROUND:The prevalence of urinary stone disease (USD) and asthma is rising and has recently been associated in a pediatric population. OBJECTIVE:To investigate the association between asthma and USD in a nationally representative adult population. DESIGN, SETTING, AND PARTICIPANTS:We analyzed the National Health and Nutrition Examination Survey 2007-2014, a US population-based cross-sectional study. A history of asthma and USD was obtained by self-report to questionnaires. USD severity was represented by graded stratification into non-stone formers, single stone formers, and recurrent stone formers (>2 stones). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS:Odds ratios (ORs) for asthma were calculated for respondents with USD and separately for the graded USD groups. Survey-weighted logistic regression models included adjustments for demographics (model A), medical information (model B), and for relevant medications (model C). RESULTS AND LIMITATIONS:A total of 20 906 participants aged ≥20 yr were included in the analysis. Of these, 9.2% reported of having a history of kidney stones. Logistic regression analysis adjusted for demographics, medical conditions, and medications showed that stone formers had significantly increased odds of asthma (odds ratio=1.23; 95% confidence interval: 1.03-1.47; p=0.023). Separate logistic regression analysis demonstrated a graded association between single and recurrent stone formers and the odds of having asthma (p=0.01), which remained significant in the 20-50-yr-old population and the diabetic population, especially for recurrent stone formers. Causal relationships were limited by cross-sectional nature of the study. CONCLUSIONS:Increasing severity of USD is associated with an increase in odds for asthma among American adults, providing impetus for future studies into the mechanisms explaining this phenomenon. PATIENT SUMMARY:In this report, we looked at self-reported histories of asthma and urinary stone disease (USD) using information from a large US population. We found that asthma was associated with USD; however, further studies are needed to elucidate this relationship.

PURPOSE OF REVIEW/OBJECTIVE:Vitamin D deficiency is common in patients with kidney disease and many patients receive vitamin D supplementation. Several large, well-designed clinical trials have been published in the last few years evaluating the effects of vitamin D supplementation on important outcomes for patients with kidney disease including effects on cardiovascular disease, secondary hyperparathyroidism, and kidney disease progression. RECENT FINDINGS/RESULTS:Several negative trials have been published showing no effect of cholecalciferol supplementation on cardiovascular events, kidney disease progression, and albuminuria. Long-term supplementation does not appear to be associated with kidney stone disease. Vitamin D supplementation decreases parathyroid hormone (PTH) levels and high levels of 25-hydroxyvitamin D may be required for maximal suppression. SUMMARY/CONCLUSIONS:There appear to be no effects of vitamin D supplementation on noncalcemic outcomes including progression of kidney disease, albuminuria, or cardiovascular disease. The primary reason to use vitamin D in kidney disease remains to lower PTH levels.

PURPOSE:Urge urinary incontinence significantly impacts quality of life. We investigated the association between urge urinary incontinence and socioeconomic status in a nationally representative adult population. MATERIALS AND METHODS:We analyzed the 2005 to 2016 NHANES (National Health and Nutrition Examination Survey), a United States population based, cross-sectional study. Urge urinary incontinence was determined by self-report of leaking urine before reaching the toilet. Socioeconomic status was represented by the poverty income ratio, which reflects the family income relative to poverty thresholds specific to that year and household size. Survey weighted logistic regression models were used to analyze the relationship between socioeconomic status and the poverty income ratio. Multiplicative terms were applied to test for interaction in prespecified subgroups of interest. RESULTS:or greater, or less than a high school education on the association of urge urinary incontinence with the poverty income ratio. CONCLUSIONS:This study revealed a significant association between urge urinary incontinence and socioeconomic status after meaningful adjustment for covariates. Health care interventions targeting low socioeconomic status individuals with urge urinary incontinence are needed to address this disparity.

RATIONALE & OBJECTIVE:Metabolic acidosis associated with chronic kidney disease (CKD) may contribute to muscle dysfunction and bone disease. We aimed to test whether treatment with sodium bicarbonate improves muscle and bone outcomes. STUDY DESIGN:Multicenter, randomized, placebo-controlled, clinical trial. SETTING & PARTICIPANTS:149 patients with CKD stages 3 and 4 between July 2011 and April 2016 at 3 centers in Cleveland, OH, and the Bronx, NY. INTERVENTION:Sodium bicarbonate (0.4 mEq per kg of ideal body weight per day) (n=74) or identical-appearing placebo (n=75). OUTCOMES:Dual primary outcomes were muscle function assessed using sit-to-stand test and bone mineral density. Muscle biopsies were performed at baseline and 2 months. Participants were seen at baseline and 2, 6, 12, and 24 months. RESULTS:. Baseline characteristics did not differ between groups. Mean serum bicarbonate levels in the intervention arm during follow-up were 26.4±2.2, 25.5±2.3, 25.6±2.6, and 24.4±2.8 mEq/L (at 2, 6, 12, and 24 months). These were significantly higher than in the placebo group (P<0.001). Compared to the placebo group, participants randomly assigned to sodium bicarbonate treatment had no significant differences in sit-to-stand time (5 repetitions: P=0.1; and 10 repetitions P=0.07) or bone mineral density (P=0.3). Sodium bicarbonate treatment caused a decrease in serum potassium levels that was of borderline statistical significance (P=0.05). There were no significant differences in estimated glomerular filtration rates, blood pressure, weight, serious adverse events, or levels of muscle gene expression between the randomly assigned groups. LIMITATIONS:Initial mean serum bicarbonate level was in the normal range. CONCLUSIONS:Sodium bicarbonate therapy in patients with CKD stages 3 and 4 significantly increases serum bicarbonate and decreases potassium levels. No differences were found in muscle function or bone mineral density between the randomly assigned groups. Larger trials are required to evaluate effects on kidney function. FUNDING:National Institutes of Health grant. TRIAL REGISTRATION:Registered at ClinicalTrials.gov with study number NCT01452412.

RATIONALE & OBJECTIVE/OBJECTIVE:Lower rates of hypertension awareness, treatment, and control have been observed in Hispanics/Latinos compared with non-Hispanic whites. These factors have not been studied in Hispanics/Latinos with chronic kidney disease (CKD). We sought to describe the prevalence, awareness, treatment, and control of hypertension in Hispanic/Latino adults with CKD. STUDY DESIGN/METHODS:Cross-sectional cohort. SETTING & PARTICIPANTS/METHODS:US.Hispanics/Latinos aged 18 to 74 years enrolled in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) with CKD. Comparisons were made with the National Health and Nutrition Examination Survey (NHANES) 2007 to 2010. EXPOSURE/METHODS:or urinry albumin-creatinine ratio ≥ 30 mg/g creatinine. OUTCOMES/RESULTS:Hypertension was defined as systolic blood pressure (BP) ≥ 140 or diastolic BP ≥ 90 mm Hg or use of antihypertensives. For hypertension control, 2 thresholds were examined: <140/90 and <130/80 mm Hg. RESULTS:The prevalence of hypertension was 51.5%; among those with hypertension, hypertension awareness and treatment were present in 78.1% and 70.4%, respectively. A low prevalence of BP control was observed (32.6% with BP < 140/90 mm Hg; 17.9% with BP < 130/80 mm Hg). Health insurance coverage was associated with higher odds of BP < 140/90 mm Hg (OR, 1.98; 95% CI, 1.15-3.43). Compared with non-Hispanic whites with CKD in NHANES, HCHS/SOL participants with CKD had a lower prevalence of hypertension but a lower rate of BP control (32.6% vs 48.6% for BP < 140/90 mm Hg). LIMITATIONS/CONCLUSIONS:Use of a single measurement of creatinine, cystatin C, and urinary albumin excretion to define CKD. Single-visit measurement of BP. CONCLUSIONS:Hispanics/Latinos with CKD residing in the United States have very low rates of BP control. The association of health insurance coverage with hypertension control suggests that improved access to health care may improve outcomes for this growing population.

RATIONALE & OBJECTIVE/OBJECTIVE:Group-based care provides an opportunity to increase patient access to providers without increasing physician time and is effective in the management of chronic diseases in the general population. This model of care has not been investigated in chronic kidney disease (CKD). STUDY DESIGN/METHODS:Randomized controlled trial in adults (n = 50); observational study in adolescents (n = 10). SETTING & PARTICIPANTS/METHODS:Adults and adolescents with CKD and hypertension in the Bronx, NY. INTERVENTION/METHODS:Group-based care (monthly sessions over 6 months) versus usual care in adults. All adolescents received group-based care and were analyzed separately. OUTCOMES/RESULTS:Participant attendance and satisfaction with group-based care were used to evaluate intervention feasibility. The primary clinical outcome was change in mean 24-hour ambulatory blood pressure. Secondary outcomes included physical activity, medication adherence, quality of life, and sodium intake as assessed by 24-hour urinary sodium excretion and food frequency questionnaires. RESULTS:Among adults randomly assigned to group-based care, attendance was high (77% of participants attended ≥3 sessions) and most reported higher satisfaction. Mean 24-hour ambulatory systolic blood pressure decreased by -4.2 (95% CI, -13.3 to 5.8) mm Hg in group-based care patients compared with usual care at 6 months but this was not statistically significant. Similarly, we did not detect significant differences in health-related behaviors (such as medication adherence, sodium intake, and physical activity) or quality-of-life measures between the 2 groups. Among the adolescents, attendance was very poor; self-reported satisfaction, although high, did not change from baseline compared with the 6-month follow-up. LIMITATIONS/CONCLUSIONS:Small study size, missing data. CONCLUSIONS:Group-based care is feasible and acceptable among adults with hypertension and CKD. However, a larger trial is needed to determine the effect on blood pressure and health-related behaviors. Patient participation may limit the effectiveness of group-based care models in adolescents. FUNDING/BACKGROUND:National Institutes of Health R34 DK102174. TRIAL REGISTRATION/BACKGROUND:https://clinicaltrials.gov/show/NCT02467894.