Priya Vart

Socioeconomic measures and CKD in the United States and The Netherlands

BACKGROUND AND OBJECTIVES According to the cost of health care utilization systems, there may be regional differences in the relative strength of association of income and education-based socioeconomic status measures with CKD. This study investigated the relative strength of the association of income and education with CKD in a United States and a Dutch population. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This cross-sectional study examined individuals who participated in the 1999-2002 National Health and Nutritional Examination Survey (NHANES) and in Prevention of Renal and Vascular End-stage Disease (PREVEND 1997-1998), general population-based cohorts in the United States and The Netherlands, respectively. The main outcome was CKD, defined as estimated GFR <60 ml/min per 1.73 m(2) (using creatinine) or albuminuria ≥ 30 mg/24 hours or albumin-to-creatinine ratio ≥ 30 mg/g. RESULTS In NHANES (n=6428), income was strongly associated with CKD (adjusted odds ratio, 2.34 [95% confidence interval (CI), 1.68 to 3.27]; P for trend<0.001) but education was not (adjusted odds ratio, 1.62 [95% CI, 0.87 to 2.25]; P for trend=0.05]. In contrast, in PREVEND (n=7983), low income was weakly associated with CKD whereas low education had a strong association. The fit of the logistic regression model estimating association of income and education with CKD was significantly improved only after income was added in NHANES (P<0.001) and education was added in PREVEND (P=0.01). Sensitivity analyses that used other CKD-defining variables and restricted analyses to participants <65 years of age resulted in similar findings. CONCLUSION In the United States, where access to health care is traditionally income dependent, income appeared more strongly associated with CKD than in The Netherlands, where education showed a stronger association.

Mediators of the Association Between Low Socioeconomic Status and Chronic Kidney Disease in the United States

Using data collected from 9,823 participants in the 2007-2008 and 2009-2010 cycles of the National Health and Nutrition Examination Survey, we formally investigated potentially modifiable factors linking low socioeconomic status (SES) to chronic kidney disease (CKD) for their presence and magnitude of mediation. SES was defined using the poverty income ratio. The main outcome was CKD, defined as estimated glomerular filtration rate <60 mL/minute/1.73 m(2) (using the Chronic Kidney Disease Epidemiology Collaboration equation) and/or urinary albumin:creatinine ratio ≥30 mg/g. In mediation analyses, we tested the contributions of health-related behaviors (smoking, alcohol intake, diet, physical activity, and sedentary time), comorbid conditions (diabetes, hypertension, obesity, abdominal obesity, and hypercholesterolemia), and access to health care (health insurance and routine health-care visits) to this association. Except for sedentary time and diet, all examined health-related behaviors, comorbid conditions, and factors related to health-care access mediated the low SES-CKD association and contributed 20%, 32%, and 11%, respectively, to this association. In race/ethnicity-specific analyses, identified mediators tended to explain more of the association between low SES and CKD in non-Hispanic blacks than in other racial/ethnic groups. In conclusion, potentially modifiable factors like health-related behaviors, comorbid conditions, and health-care access contribute substantially to the association between low SES and CKD in the United States, especially among non-Hispanic blacks.

Socioeconomic disparities in chronic kidney disease: a systematic review and meta-analysis.

CONTEXT Evidence on the strength of the association between low SES and chronic kidney disease (CKD; measured by low estimated glomerular filtration rate [eGFR], high albuminuria, low eGFR/high albuminuria, and renal failure) is scattered and sometimes conflicting. Therefore, a systematic review and meta-analysis was performed to summarize the strength of the associations between SES and CKD and identify study-level characteristics related to this association. EVIDENCE ACQUISITION Studies published through January 2013 in MEDLINE and Embase were searched. From 35 studies that met the inclusion criteria, association estimates were pooled per CKD measure in the meta-analysis (performed between 2013 and 2014). Meta-regression analysis was used to identify study-level characteristics related to the strength of the SES-CKD association. EVIDENCE SYNTHESIS Low SES was associated with low eGFR (OR=1.41, 95% CI=1.21, 1.62), high albuminuria (OR=1.52, 95% CI=1.22, 1.82), low eGFR/high albuminuria (OR=1.38, 95% CI=1.03, 1.74), and renal failure (OR=1.55, 95% CI=1.40, 1.71). Differences in SES measures across studies were not related to the strength of associations between low SES and any of the CKD measures (low GFR, p=0.63; high albuminuria, p=0.29; low eGFR/high albuminuria, p=0.54; renal failure, p=0.31). Variations in the strength of associations were related to the level of covariate adjustment for low eGFR (p<0.001) and high albuminuria (p<0.001). CONCLUSIONS Socioeconomic disparities in CKD were fairly strong, irrespective of how SES was measured. Variations in the strength of the associations were related to the level of covariate adjustment, particularly for low eGFR and high albuminuria.

Areca nut chewing and systemic inflammation: evidence of a common pathway for systemic diseases.

BackgroundAreca nut, the seed of fruit of an oriental palm, known as Areca catechu, is commonly chewed in many countries. Diabetes, hypertension, cardiovascular diseases, oropharyngeal and oesophageal cancers have been associated with areca nut chewing and the mechanism by which areca nut chewing increases the risk of systemic diseases remains elusive. We hypothesize that systemic inflammation may be elevated among areca nut users, which is linked with many systemic diseases. Therefore, this present study was conducted to examine the systemic inflammation among areca nut chewers and healthy controls.MethodsThis was an observational cross sectional study carried out on areca nut chewers and healthy individuals in Karachi, Pakistan. Participants were selected from a region of the city by invitation request sent from door to door. Information was collected regarding the socio-demographic profile and the pattern of use, and a blood sample was obtained to measure the level of C-reactive protein (CRP). We carried out multiple logistic regressions to investigate the association between socio-demographic profile, areca nut chewing and CRP levels.ResultsWe carried out final analysis on 1112 individuals of which 556 were areca nut chewers and 556 were the age, gender and area matched controls. Areca nut chewers had a significantly higher proportion of men (15.1%, n = 84) who had an elevated CRP (>10 mg/dl) as compared to controls (5.2%, n = 29). Multivariate analyses showed that areca nut chewers had significantly higher odds of an elevated CRP (OR = 3.23, 95% CI 2.08-5.02, p value <0.001) as compared to controls. Increase in amount of areca nut consumption had a significant dose–response relationship with systemic inflammation (p for trend <0.001). Further analysis revealed that areca nut chewers with tobacco additives were two times more likely to have an elevated CRP as compared to raw areca nut users. These associations remained unchanged after adjustments for age, BMI and years of full time education.ConclusionsAreca nut chewing has a significant association with systemic inflammation. Further work is required to confirm that systemic inflammation is the main pathway by which areca nut use increases the risk of systemic diseases.

Added Value of Screening for CKD among the Elderly or Persons with Low Socioeconomic Status

BACKGROUND AND OBJECTIVE Three screening approaches were compared for their ability to detect CKD cases, and identify patients with CKD who have a higher rate of incident cardiovascular disease (CVD) events and renal function decline. Approach 1 was the traditional CKD screening approach, targeting only individuals with known diabetes, hypertension, or CVD history. Approach 2 was defined as Approach 1+elderly, and Approach 3 as Approach 1+low-socioeconomic status (SES) individuals. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Data on 3411 individuals from the general population in The Netherlands were examined. Individuals aged >60 years were classified as elderly. Persons with low SES was defined as those with primary school or below primary school education. CKD was diagnosed during outpatient clinic visits. Individuals were followed for 9.4±2.6 years during four screening rounds. RESULTS At baseline, 16%, 29%, and 25% of the general population was to be screened and 36%, 59%, and 51% of the CKD (n=263) cases were detected in Approaches 1, 2, and 3, respectively. The numbers of individuals needed to screen to detect one CKD case were 5.6 in Approach 1 and 6.5 each in Approach 2 and 3. In Approach 2 the hazard ratio for incident CVD events was 1.87 (95% confidence interval [95% CI], 1.35 to 2.61) in detected and 1.92 (95% CI, 1.01 to 3.64) in undetected CKD cases compared with persons without CKD, whereas in Approach 3 these values were 2.31 (95% CI, 1.64 to 3.25) and 1.28 (95% CI, 0.77 to 2.13), respectively. In Approach 2, the rate of renal function decline was -1.37 ml/min per 1.73 m(2) per year in detected and -1.13 ml/min per 1.73 m(2) per year in undetected CKD cases. In Approach 3, these figures were -1.41 and -1.14 ml/min per 1.73 m(2) per year, respectively. CONCLUSIONS Adding persons with low SES, rather than adding elderly persons, to the traditional high-risk groups may help detect more persons with CKD who have a higher rate of future CVD events and renal function decline.

Relevance of correction for drift and day-to-day variation in cystatin C measurement: a post-hoc analysis of the PREVEND cohort, with independent replication in the ESTHER cohort

Abstract Background: Despite standard laboratory quality control, drift and day-to-day variability in cystatin C measurements can be observed. We investigated whether correction for drift and day-to-day variation in cystatin C measurements improves the association of estimated glomerular filtration rate (eGFR) with chronic kidney disease (CKD) risk factors and prognosis. Methods: Plasma samples of the PREVEND study (Dutch cohort study, n=8592) were used to measure cystatin C (Gentian assay) on 243 random days. A correction factor was calculated for each measurement day. GFR was estimated with CKD-EPI equation using routinely measured cystatin C (eGFRcysC) and corrected cystatin C (eGFRcysC corr). Participants were categorized in six categories of eGFRcysC and eGFRcysC corr: ≥120, 90–119, 75–89, 60–74, 45–59 and <45 mL/min/1.73m2. Independent replication was performed in the ESTHER study (German cohort study, n=9949). Results: Compared to non-reclassified participants, participants re-classified upward had significantly lower age, body mass index, blood pressure, cholesterol, glucose and albuminuria, whereas the opposite was true for participants reclassified downward. CKD risk factors explained more variance in eGFRcysC corr than in eGFRcysC (p<0.001). Compared to non-reclassified participants, risk of incident cardiovascular events (n=789, follow-up 9.3±2.7 years) tended to be higher in downward reclassified and lower in upward reclassified participants. Net reclassification improvement for incident cardiovascular events using eGFRcysC corr was positive (0.102, p=0.019). The ESTHER study showed similar results. Conclusions: Correction for drift and day-to-day variation in cystatin C measurement improves eGFR using cystatin C for its association with CKD risk factors and incident cardiovascular events.

Apolipoprotein B Attenuates Albuminuria-Associated Cardiovascular Disease in Prevention of Renal and Vascular Endstage Disease (PREVEND) Participants

Whether urinary albumin excretion relates to higher levels of atherogenic apolipoprotein B fractions in the nondiabetic population is uncertain. Such a relationship could explain, in part, the association of elevated urinary albumin excretion with cardiovascular disease risk. We assessed the relationship of urinary albumin excretion with apolipoprotein B fractions and determined whether the association of elevated urinary albumin excretion with incident cardiovascular events is modified by high apolipoprotein B fraction levels. We performed a prospective study on 8286 nondiabetic participants (580 participants with cardiovascular disease; 4.9 years median follow-up time) with fasting lipids, apolipoprotein B, and urinary albumin excretion determined at baseline. With adjustment for sex and age, micro- and macroalbuminuria were associated with increased apolipoprotein B fractions (non-HDL cholesterol, LDL cholesterol, triglycerides, and apolipoprotein B). All four apolipoprotein B fractions modified associations of urinary albumin excretion with incident cardiovascular disease (hazard ratios for interaction terms ranged from 0.89 to 0.94 with 95% confidence intervals ranging from 0.84 to 0.99 and P values ranging from 0.001 to 0.02 by Cox proportional hazards modeling). These interactions remained present after additional adjustment for conventional risk factors, eGFR, cardiovascular history, and lipid-lowering and antihypertensive drug treatments. Such modification was also observed when urinary albumin excretion was stratified into normo-, micro-, and macroalbuminuria. We conclude that there is an association between elevated urinary albumin excretion and apolipoprotein B fraction levels and a negative interaction between these variables in their associations with incident cardiovascular events. Elevated urinary albumin excretion may share common causal pathways with high apolipoprotein B fractions in the pathogenesis of cardiovascular disease.

Joint Effect of Hypertension and Elevated Serum Phosphorus on the Risk of Mortality in National Health and Nutrition Examination Survey‐III

Background Elevated serum phosphorus might aggravate the effect of hypertension on mortality. The objective of this study was to examine the joint effect of hypertension and serum phosphorus on the risk of mortality. Methods and Results A large prospective (n=15 833), population-based cohort of participants from the National Health and Nutritional Examination Survey III was examined to test potential synergism between hypertension, elevated serum phosphorus, and the risk of mortality. Interaction on additive scale and multiplicative scale was estimated. After a median follow-up of 14.3 years, 1691 cases of cardiovascular mortality and 3875 cases of all-cause mortality were identified. Interaction was observed between hypertension and elevated serum phosphorus on the additive scale for cardiovascular mortality (relative excess risk due to interaction, 0.99, 95% CI: 0.06; 1.92, adjusted for age, gender, race, and estimated glomerular filtration rate). No statistically significant interaction was found between hypertension and serum phosphorus for all-cause mortality on the additive scale. No significant interaction was detected on the multiplicative scale. In sensitivity analysis, excluding participants who died in first 2 years and adjustment for additional confounders resulted in essentially similar findings. Conclusions The joint effect of hypertension and elevated serum phosphorus was larger than the sum of the independent effects on cardiovascular mortality but not on all-cause mortality. Future studies should investigate whether controlling elevated serum phosphorus in hypertensive individuals helps in prevention of extra risk of cardiovascular mortality.

Socioeconomic Status and Incidence of Hospitalization With Lower‐Extremity Peripheral Artery Disease: Atherosclerosis Risk in Communities Study

Background Compared to coronary heart disease, heart failure, and stroke, the relationship between low socioeconomic status (SES) and peripheral artery disease (PAD) is less well established. We examined the association between SES and incidence of hospitalization with PAD and explored whether this association can be explained by traditional cardiovascular risk factors and healthcare access. Methods and Results A total of 12 517 participants in the Atherosclerosis Risk in Communities (ARIC) Study (1987‐1989) with no prior PAD were examined. Individual‐level SES was assessed from household income (low <

GlycA, a novel proinflammatory glycoprotein biomarker, and high-sensitivity C-reactive protein are inversely associated with sodium intake after controlling for adiposity: the Prevention of Renal and Vascular End-Stage Disease study

12 000/year, medium