Pleiotropy among common genetic loci identified for cardiometabolic disorders and C-reactive protein.

Pleiotropic genetic variants have independent effects on different phenotypes. C-reactive protein (CRP) is associated with several cardiometabolic phenotypes. Shared genetic backgrounds may partially underlie these associations. We conducted a genome-wide analysis to identify the shared genetic background of inflammation and cardiometabolic phenotypes using published genome-wide association studies (GWAS). We also evaluated whether the pleiotropic effects of such loci were biological or mediated in nature. First, we examined whether 283 common variants identified for 10 cardiometabolic phenotypes in GWAS are associated with CRP level. Second, we tested whether 18 variants identified for serum CRP are associated with 10 cardiometabolic phenotypes. We used a Bonferroni corrected p-value of 1.1×10-04 (0.05/463) as a threshold of significance. We evaluated the independent pleiotropic effect on both phenotypes using individual level data from the Women Genome Health Study. Evaluating the genetic overlap between inflammation and cardiometabolic phenotypes, we found 13 pleiotropic regions. Additional analyses showed that 6 regions (APOC1, HNF1A, IL6R, PPP1R3B, HNF4A and IL1F10) appeared to have a pleiotropic effect on CRP independent of the effects on the cardiometabolic phenotypes. These included loci where individuals carrying the risk allele for CRP encounter higher lipid levels and risk of type 2 diabetes. In addition, 5 regions (GCKR, PABPC4, BCL7B, FTO and TMEM18) had an effect on CRP largely mediated through the cardiometabolic phenotypes. In conclusion, our results show genetic pleiotropy among inflammation and cardiometabolic phenotypes. In addition to reverse causation, our data suggests that pleiotropic genetic variants partially underlie the association between CRP and cardiometabolic phenotypes

Usefulness of high-sensitivity C-reactive protein to predict mortality in patients with atrial fibrillation (from the Atherosclerosis Risk In Communities [ARIC] Study)

High-sensitivity C-reactive protein (hs-CRP) is a marker for the risk of cardiovascular and overall mortality. However, information about the association between hs-CRP and mortality in patients with atrial fibrillation is scarce. A total of 293 participants of the Atherosclerosis Risk In Communities study with a history of AF and hs-CRP levels available were studied. During a median follow-up of 9.4 years, 134 participants died (46%). The hazard ratio of all-cause mortality associated with the highest versus the lowest tertile of hs-CRP was 2.52 (95% confidence interval 1.49 to 4.25) after adjusting for age, gender, history of cardiovascular diseases, and cardiovascular risk factors. A similar trend was observed for cardiovascular mortality (57 events; hazard ratio 1.90, 95% confidence interval 0.81 to 4.45). The Congestive heart failure, Hypertension, Age >75 years, Diabetes, and previous Stroke or transient ischemic attack (CHADS2) score was also associated with all-cause and cardiovascular mortality, with an adjusted hazard ratio of 3.39 (95% confidence interval 1.91 to 6.01) and 8.71 (95% confidence interval 2.98 to 25.47), respectively, comparing those with a CHADS2 score >2 versus a CHADS2 score of 0. Adding hs-CRP to a predictive model including the CHADS2 score was associated with an improvement of the C-statistic for total mortality (from 0.627 to 0.677) and for cardiovascular mortality (from 0.700 to 0.718). In conclusion, high levels of hs-CRP constitute an independent marker for the risk of mortality in patients with atrial fibrillation

Supplementary Material for: Kidney Measures with Diabetes and Hypertension on Cardiovascular Disease: The Atherosclerosis Risk in Communities Study

<b><i>Background:</i></b> Whether the association of chronic kidney disease (CKD) with cardiovascular risk differs based on diabetes mellitus (DM) and hypertension (HTN) status remains unanswered. <b><i>Methods:</i></b> We investigated 11,050 participants from the Atherosclerosis Risk in Communities Study (fourth examination (1996-1998)) with follow-up for cardiovascular outcomes (coronary disease, heart failure and stroke) through 2009. Using the Cox regression models, we quantified cardiovascular risk associated with estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (ACR) in individuals with and without DM and/or HTN and assessed their interactions. <b><i>Results:</i></b> Individuals with DM and HTN generally had higher cardiovascular risk relative to those without at all the levels of eGFR and ACR. Cardiovascular risk increased with lower eGFR and higher ACR regardless of DM and HTN status (e.g. adjusted hazards ratio (HR) for eGFR 30-44 vs. 90-104 ml/min/1.73 m², 2.32 (95% CI, 1.66-3.26) in non-diabetics vs. 1.83 (1.25-2.67) in diabetics and 2.45 (2.20-5.01) in non-hypertensives vs. 1.51 (1.27-1.81) in hypertensives and corresponding adjusted HR for ACR 30-299 vs. <10 mg/g, 1.70 (1.45-2.00) vs. 1.34 (1.10-1.64) and 1.42 (1.10-1.85) vs. 1.57 (1.36-1.81), respectively). Only the ACR-DM interaction reached significance, with a shallower relative risk gradient among diabetics than among non-diabetics (p = 0.02). Analysis of individual cardiovascular outcomes showed similar results. <b><i>Conclusion:</i></b> Although individuals with DM and HTN generally had higher cardiovascular risk relative to those without these complications, both low eGFR and high ACR were associated with cardiovascular diseases regardless of the presence or absence of DM and HTN. These findings reinforce the importance of CKD in cardiovascular outcomes

Cystatin C versus Creatinine in Determining Risk Based on Kidney Function

<p>BACKGROUND</p><p>Adding the measurement of cystatin C to that of serum creatinine to determine the estimated glomerular filtration rate (eGFR) improves accuracy, but the effect on detection, staging, and risk classification of chronic kidney disease across diverse populations has not been determined.</p><p>METHODS</p><p>We performed a meta-analysis of 11 general-population studies (with 90,750 participants) and 5 studies of cohorts with chronic kidney disease (2960 participants) for whom standardized measurements of serum creatinine and cystatin C were available. We compared the association of the eGFR, as calculated by the measurement of creatinine or cystatin C alone or in combination with creatinine, with the rates of death (13,202 deaths in 15 cohorts), death from cardiovascular causes (3471 in 12 cohorts), and end-stage renal disease (1654 cases in 7 cohorts) and assessed improvement in reclassification with the use of cystatin C.</p><p>RESULTS</p><p>In the general-population cohorts, the prevalence of an eGFR of less than 60 ml per minute per 1.73 m(2) of body-surface area was higher with the cystatin C-based eGFR than with the creatinine-based eGFR (13.7% vs. 9.7%). Across all eGFR categories, the reclassification of the eGFR to a higher value with the measurement of cystatin C, as compared with creatinine, was associated with a reduced risk of all three study outcomes, and reclassification to a lower eGFR was associated with an increased risk. The net reclassification improvement with the measurement of cystatin C, as compared with creatinine, was 0.23 (95% confidence interval [CI], 0.18 to 0.28) for death and 0.10 (95% CI, 0.00 to 0.21) for end-stage renal disease. Results were generally similar for the five cohorts with chronic kidney disease and when both creatinine and cystatin C were used to calculate the eGFR.</p><p>CONCLUSIONS</p><p>The use of cystatin C alone or in combination with creatinine strengthens the association between the eGFR and the risks of death and end-stage renal disease across diverse populations.</p>

Relative risks of chronic kidney disease for mortality and end-stage renal disease across races are similar

Item does not contain fulltextSome suggest race-specific cutpoints for kidney measures to define and stage chronic kidney disease (CKD), but evidence for race-specific clinical impact is limited. To address this issue, we compared hazard ratios of estimated glomerular filtration rates (eGFR) and albuminuria across races using meta-regression in 1.1 million adults (75% Asians, 21% Whites, and 4% Blacks) from 45 cohorts. Results came mainly from 25 general population cohorts comprising 0.9 million individuals. The associations of lower eGFR and higher albuminuria with mortality and end-stage renal disease (ESRD) were largely similar across races. For example, in Asians, Whites, and Blacks, the adjusted hazard ratios (95% confidence interval) for eGFR 45-59 versus 90-104 ml/min per 1.73 m(2) were 1.3 (1.2-1.3), 1.1 (1.0-1.2), and 1.3 (1.1-1.7) for all-cause mortality, 1.6 (1.5-1.7), 1.4 (1.2-1.7), and 1.4 (0.7-2.9) for cardiovascular mortality, and 27.6 (11.1-68.7), 11.2 (6.0-20.9), and 4.1 (2.2-7.5) for ESRD, respectively. The corresponding hazard ratios for urine albumin-to-creatinine ratio 30-299 mg/g or dipstick 1+ versus an albumin-to-creatinine ratio under 10 or dipstick negative were 1.6 (1.4-1.8), 1.7 (1.5-1.9), and 1.8 (1.7-2.1) for all-cause mortality, 1.7 (1.4-2.0), 1.8 (1.5-2.1), and 2.8 (2.2-3.6) for cardiovascular mortality, and 7.4 (2.0-27.6), 4.0 (2.8-5.9), and 5.6 (3.4-9.2) for ESRD, respectively. Thus, the relative mortality or ESRD risks of lower eGFR and higher albuminuria were largely similar among three major races, supporting similar clinical approach to CKD definition and staging, across races

Supplementary Material for: Race, Mineral Homeostasis and Mortality in Patients with End-Stage Renal Disease on Dialysis

<b><i>Background:</i></b> Abnormalities in mineral homeostasis are ubiquitous in patients on dialysis, and influenced by race. In this study, we determine the race-specific relationship between mineral parameters and mortality in patients initiating hemodialysis. <b><i>Methods:</i></b> We measured the levels of fibroblast growth factor 23 (FGF23) and 25-hydroxyvitamin D (25 D) in 184 African American and 327 non-African American hemodialysis patients who enrolled between 1995 and 1998 in the Choices for Healthy Outcomes in Caring for ESRD Study. Serum calcium, phosphorus, parathyroid hormone (PTH) and total alkaline phosphatase levels were averaged from clinical measurements during the first 4.5 months of dialysis. We evaluated the associated prospective risk of mortality using multivariable Cox proportional hazards models stratified by race. <b><i>Results:</i></b> PTH and total alkaline phosphatase levels were higher, whereas calcium, phosphorus, FGF23 and 25 D levels were lower in African Americans compared to those of non-African Americans. Higher serum phosphorus and FGF23 levels were associated with greater mortality risk overall; however, phosphorus was only associated with risk among African Americans (HR 5.38, 95% CI 2.14-13.55 for quartile 4 vs. 1), but not among non-African Americans (p-interaction = 0.04). FGF23 was associated with mortality in both groups, but more strongly in African Americans (HR 3.91, 95% CI 1.74-8.82 for quartiles 4 vs. 1; p-interaction = 0.09). Serum calcium, PTH, and 25 D levels were not consistently associated with mortality. The lowest and highest quartiles of total alkaline phosphatase were associated with higher mortality risk, but this did not differ by race (p-interaction = 0.97). <b><i>Conclusions:</i></b> Aberrant phosphorus homeostasis, reflected by higher phosphorus and FGF23, may be a risk factor for mortality in patients initiating hemodialysis, particularly among African Americans

Associations of kidney disease measures with mortality and end-stage renal disease in individuals with and without hypertension: a meta-analysis

BACKGROUND: Hypertension is the most prevalent comorbidity in individuals with chronic kidney disease. However, whether the association of the kidney disease measures, estimated glomerular filtration rate (eGFR) and albuminuria, with mortality or end-stage renal disease (ESRD) differs by hypertensive status is unknown. METHODS: We did a meta-analysis of studies selected according to Chronic Kidney Disease Prognosis Consortium criteria. Data transfer and analyses were done between March, 2011, and June, 2012. We used Cox proportional hazards models to estimate the hazard ratios (HR) of mortality and ESRD associated with eGFR and albuminuria in individuals with and without hypertension. FINDINGS: We analysed data for 45 cohorts (25 general population, seven high-risk, and 13 chronic kidney disease) with 1,127,656 participants, 364,344 of whom had hypertension. Low eGFR and high albuminuria were associated with mortality irrespective of hypertensive status in the general population and high-risk cohorts. All-cause mortality risk was 1.1-1.2 times higher in individuals with hypertension than in those without hypertension at preserved eGFR. A steeper relative risk gradient in individuals without hypertension than in those with hypertension at eGFR range 45-75 mL/min per 1.73 m(2) led to much the same mortality risk at lower eGFR. With a reference eGFR of 95 mL/min per 1.73 m(2) in each group to explicitly assess interaction, adjusted HR for all-cause mortality at eGFR 45 mL/min per 1.73 m(2) was 1.77 (95% CI 1.57-1.99) in individuals without hypertension versus 1.24 (1.11-1.39) in those with hypertension (p for overall interaction=0.0003). Similarly, for albumin-creatinine ratio of 300 mg/g (vs 5 mg/g), HR was 2.30 (1.98-2.68) in individuals without hypertension versus 2.08 (1.84-2.35) in those with hypertension (p for overall interaction=0.019). We recorded much the same results for cardiovascular mortality. The associations of eGFR and albuminuria with ESRD, however, did not differ by hypertensive status. Results for chronic kidney disease cohorts were similar to those for general and high-risk population cohorts. INTERPRETATION: Chronic kidney disease should be regarded as at least an equally relevant risk factor for mortality and ESRD in individuals without hypertension as it is in those with hypertension. FUNDING: US National Kidney Foundation