Influence of Weight and Body Size on the Pharmacokinetics of Heart Failure Pharmacotherapy: A Systematic Review.

OBJECTIVE: To conduct a review of studies evaluating the influence of body size and weight (WT) on the pharmacokinetics (PK) of drugs recommended for heart failure (HF) treatment. DATA SOURCES: A systematic search of the MEDLINE (1946 to April 2023) and EMBASE (1974 to April 2023) databases was conducted for articles that focused on the impact of WT or body size on the PK of drugs of interest used in HF patients. STUDY SELECTION AND DATA EXTRACTION: Articles written in English or French related to the aim of our study were retained for analysis. DATA SYNTHESIS: Of 6493 articles, 20 were retained for analysis. Weight was associated with the clearance of digoxin, carvedilol, enalapril, and candesartan as well as the volume of distribution of eplerenone and bisoprolol. There was no documented direct impact of WT on the PK of furosemide, valsartan, and metoprolol, although these studies were limited or confounded by the small sample size, adjustment of PK factors by WT, or the use of the Cockroff-Gault equation for the evaluation of creatinine clearance, which includes WT. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: This review highlights and summarizes the available data on the importance of WT on the PK of HF treatment. CONCLUSION: Considering the significant impact of WT on most HF drugs in this review, it may be important to further investigate it in the context of personalized therapy, particularly in patients presenting extreme WTs.

CYP2D6 polymorphism and its impact on the clinical response to metoprolol: A systematic review and meta-analysis.

AIMS: CYP2D6 genetic polymorphisms are associated with metoprolol pharmacokinetics. Whether the clinical response to metoprolol is also affected remains uncertain. METHODS: We conducted a systematic review on the effects of CYP2D6 polymorphism on the clinical response to metoprolol. Searches were conducted using MEDLINE. Meta-analyses were performed on the impact of CYP2D6-inferred phenotypes on heart rate (HR) reduction, diastolic (DBP) and systolic (SBP) blood pressure reduction, average daily doses, all-type adverse events and bradycardia. RESULTS: Our qualitative assessment indicated inconsistent results in individual studies and endpoints, but CYP2D6 poor metabolizers (PM) generally presented a greater reduction in HR. The meta-analysis of 15 studies, including a total of 1146 individuals, found a reduction in HR of 3 beats/min (P = .017), and of SBP and DBP by 3 mmHg (P = .0048) for PM compared to non-PM individuals using similar metoprolol doses. Bradycardia appeared more frequent by 4-fold for PM, although significant heterogeneity was observed regarding bradycardia, which limits the scope of this finding. CONCLUSION: Patients without any CYP2D6 metabolic capacities appear to have increased reduction in DBP, HR and SBP during metoprolol treatment and may be at a higher risk of bradycardia compared to patients with active CYP2D6 phenotypes. Further prospective data are required to determine whether CYP2D6 is associated with clinical events in patients treated with metoprolol, as well as to demonstrate the clinical utility of an individualized approach of prescribing metoprolol using CYP2D6-inferred phenotypes.

Exome Genotyping Identifies Pleiotropic Variants Associated with Red Blood Cell Traits.

Red blood cell (RBC) traits are important heritable clinical biomarkers and modifiers of disease severity. To identify coding genetic variants associated with these traits, we conducted meta-analyses of seven RBC phenotypes in 130,273 multi-ethnic individuals from studies genotyped on an exome array. After conditional analyses and replication in 27,480 independent individuals, we identified 16 new RBC variants. We found low-frequency missense variants in MAP1A (rs55707100, minor allele frequency [MAF] = 3.3%, p = 2 × 10(-10) for hemoglobin [HGB]) and HNF4A (rs1800961, MAF = 2.4%, p < 3 × 10(-8) for hematocrit [HCT] and HGB). In African Americans, we identified a nonsense variant in CD36 associated with higher RBC distribution width (rs3211938, MAF = 8.7%, p = 7 × 10(-11)) and showed that it is associated with lower CD36 expression and strong allelic imbalance in ex vivo differentiated human erythroblasts. We also identified a rare missense variant in ALAS2 (rs201062903, MAF = 0.2%) associated with lower mean corpuscular volume and mean corpuscular hemoglobin (p < 8 × 10(-9)). Mendelian mutations in ALAS2 are a cause of sideroblastic anemia and erythropoietic protoporphyria. Gene-based testing highlighted three rare missense variants in PKLR, a gene mutated in Mendelian non-spherocytic hemolytic anemia, associated with HGB and HCT (SKAT p < 8 × 10(-7)). These rare, low-frequency, and common RBC variants showed pleiotropy, being also associated with platelet, white blood cell, and lipid traits. Our association results and functional annotation suggest the involvement of new genes in human erythropoiesis. We also confirm that rare and low-frequency variants play a role in the architecture of complex human traits, although their phenotypic effect is generally smaller than originally anticipated.

Is there a potential association between spironolactone and the risk of new-onset diabetes in a cohort of older patients with heart failure?

PURPOSE: Some evidence suggests that spironolactone may have a deleterious effect on glucose homeostasis. The objective of this study was to assess whether spironolactone use is associated with a higher risk of developing diabetes in a large cohort of patients with heart failure (HF). METHODS: Two Quebec government administrative databases were used to identify a cohort of hospitalized patients discharged between January 1995 and December 2009 with a primary discharge diagnosis of HF and without secondary discharge diagnosis of diabetes. Patients were categorized as new users of spironolactone and non-users. The primary outcome was defined as new-onset diabetes (NOD) during 5 years of follow-up and was ascertained using ICD codes for diabetes or use of hypoglycemic agents. RESULTS: Among the 2974 patients that were included in the cohort analysis, 769 were given a new prescription of spironolactone. The incidence rate of NOD was similar among spironolactone users (5.0 per 100 person-years) and non-users (4.9 per 100 person-years). There was no significant association between the use of spironolactone and NOD in the crude, unadjusted model (hazard ratio (HR) 1.01; 95% confidence interval (CI) 0.80-1.28; p = 0.9217), and it remained unchanged in the adjusted Cox proportional hazard model (HR = 0.92; 95% CI = 0.72-1.18; p = 0.5227). The results were consistent with those observed in sensitivity analyses of a 1:3 propensity score-matched cohort (HR = 0.97; CI = 0.76-1.25; p = 0.8169). CONCLUSION: We found no evidence supporting the claim that use of spironolactone is associated with a higher risk of diabetes among patients hospitalized for HF.

A comparison of the effects of selective and non-selective mineralocorticoid antagonism on glucose homeostasis of heart failure patients with glucose intolerance or type II diabetes: A randomized controlled double-blind trial.

Mineralocorticoid receptor antagonists (MRAs) decrease morbidity and mortality in patients with heart failure (HF). However, spironolactone, a non-selective MRA, has been shown to exert a harmful effect on glucose homeostasis. The objective of this multicenter, randomized, controlled, double-blind trial was to compare the effects of spironolactone to those of the selective MRA eplerenone on glucose homeostasis among 62 HF patients with glucose intolerance or type II diabetes. Trial registration number:NCT01586442.

Cardiopulmonary, biomarkers, and vascular responses to acute hypoxia following cardiac transplantation.

Previous studies have suggested good adaptation of cardiac transplant (CTx) recipients to exposure to a high altitude. No studies have investigated the cardiopulmonary and biomarker responses to acute hypoxic challenges following CTx. Thirty-six CTx recipients and 17 age-matched healthy controls (HC) were recruited. Sixteen (16) patients (42%) had cardiac allograft vasculopathy (CAV). Cardiopulmonary responses to maximal and submaximal exercise at 21% O2 , 20-minutes hypoxia (11.5% O2 ), and following a 10-minute exposure to 11.5% O2 using 30% of peak power output were completed. Vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), suppression of tumorigenicity 2 (ST2) were measured at baseline and at peak stress. Endothelial peripheral function was assessed using near-infrared spectroscopy. Compared with HC, CTx presented a lesser O2 desaturation both at rest (-19.4 ± 6.8 [CTx] vs -24.2 ± 6.0% O2 [HC], P < 0.05) and following exercise (-23.2 ± 4.9 [CTx] vs -26.2 ± 4.7% O2 [HC], P < 0.05). CTx patients exhibited a significant decrease in peak oxygen uptake. IL-6 and VEGF levels were significantly higher in CTx recipients in basal conditions but did not change in response to acute stress. CTx patients exhibit a favorable ventilatory and overall response to hypoxic stress. These data provide further insights on the good adaptability of CTx to exposure to high altitude.

Pregnancy after heart transplantation: a well-thought-out decision? The Quebec provincial experience - a multi-centre cohort study.

Despite reports of successful pregnancies in heart transplant (HTx) recipients, many centers recommend their patients against maternity. We reviewed our provincial experience of pregnancy in HTx recipients by performing charts review of all known gestations following HTx in the province of Quebec (Canada), stratified between planned and unplanned pregnancies. Long-term survival was compared to HTx recipient women of childbearing age who did not become pregnant. Eighteen pregnancies, 56% unplanned, occurred in eight patients, 10.1 (2.6-27.0) years after HTx. Immunosuppression was CNI-based, with a mean dose increase of 48.3% (tacrolimus) and 26.5% (cyclosporine), without rejection. Cardiometabolic complications were high compared to the general Canadian population, including preeclampsia (15.4% vs. 5.5%), hypertension (38.5% vs. 4.6%), and diabetes (15.4% vs. 5.6%). Mean gestational age was 35.1 (23.4-39.6) weeks (72.2% live births; 53.8% prematurity). Mean birthweight was 2418 (660-3612) g. Serum creatinine increased during pregnancy, becoming significant after delivery (P = 0.0239), and returning to preconception level in all but three patients within a year. After 4.6 (1.2-17.2) years of follow-up, two rejection episodes occurred in one patient. Long-term mortality was similar to overall HTx women (Kaplan-Meier; P = 0.8071). Pregnancy in HTx carries high cardiometabolic complications and decreased kidney function, but is feasible with acceptable outcomes and no impact on mother's survival.

Older adults with heart failure treated with carvedilol, bisoprolol, or metoprolol tartrate: risk of mortality.

PURPOSE: The long-term use of ß-blockers has been shown to improve clinical outcomes among patients with heart failure (HF). However, a lack of data persists in assessing whether carvedilol or bisoprolol are superior to metoprolol tartrate in clinical practice. We endeavored to compare the effectiveness of ß-blockers among older adults following a primary hospital admission for HF. METHODS: We conducted a cohort study using Quebec administrative databases to identify patients who were using ß-blockers, carvedilol, bisoprolol, or metoprolol tartrate after the diagnosis of HF. We characterized the patients by the type of ß-blocker prescribed at discharge of their first HF hospitalization. An adjusted multivariate Cox proportional hazards model was used to compare the primary outcome of all-cause mortality. We also conducted analyses by matching for a propensity score for initiation of ß-blocker therapy and assessed the effect on primary outcome. RESULTS: Among 3197 patients with HF with a median follow-up of 2.8 years, the crude annual mortality rates (per 100 person-years) were at 16, 14.9, and 17.7 for metoprolol tartrate, carvedilol, and bisoprolol, respectively. Adjusted hazard ratios of carvedilol (hazard ratio 0.92; 0.78-1.09) and bisoprolol (hazard ratio 1.04; 0.93-1.16) were not significantly different from that of metoprolol tartrate in improving survival. After matching for propensity score, carvedilol and bisoprolol showed no additional benefit with respect to all-cause mortality compared with metoprolol tartrate. CONCLUSIONS: Our evidence suggests no differential effect of ß-blockers on all-cause mortality among older adults with HF. Copyright © 2016 John Wiley & Sons, Ltd.

Pharmacogenomics to Revive Drug Development in Cardiovascular Disease.

Investment in cardiovascular drug development is on the decline as large cardiovascular outcomes trials require considerable investments in time, efforts and financial resources. Pharmacogenomics has the potential to help revive the cardiovascular drug development pipeline by providing new and better drug targets at an earlier stage and by enabling more efficient outcomes trials. This article will review some of the recent developments highlighting the value of pharmacogenomics for drug development. We discuss how genetic biomarkers can enable the conduct of more efficient clinical outcomes trials by enriching patient populations for good responders to the medication. In addition, we assess past drug development programs which support the added value of selecting drug targets that have established genetic evidence supporting the targeted mechanism of disease. Finally, we discuss how pharmacogenomics can provide valuable evidence linking a drug target to clinically relevant outcomes, enabling novel drug discovery and drug repositioning opportunities.

Long-term evolution, secular trends, and risk factors of renal dysfunction following cardiac transplantation.

Recent reports suggest that individuals who underwent heart transplantation in the last decade have improved post-transplant kidney function. The objectives of this retrospective study were to describe the incidence and to identify fixed and time-dependent predictors of renal dysfunction in cardiac recipients transplanted over a 25-year period (1983-2008). To illustrate temporal trends, patients (n = 306) were divided into five groups based on year of transplantation. The primary endpoint was the estimated glomerular filtration rate (eGFR) at year 1. Secondary endpoints were time to moderate (eGFR <60 ml/min/1.73 m(2) ) and severe renal dysfunction (eGFR <30 ml/min/1.73 m(2) ). Risk factor analyses relied on multivariable regression models. Kidney function was mildly impaired before transplant (median eGFR=61.0 ml/min/1.73 m(2) ), improved at discharge (eGFR=72.3 ml/min/1.73 m(2) ; P < 0.001), decreased considerably in the first year (eGFR = 54.7 ml/min/1.73 m(2) ; P < 0.001), and deteriorated less rapidly thereafter. At year 1, 2004-2008 recipients exhibited a higher eGFR compared with all other patients (P < 0.001). Factors independently associated with eGFR at year 1 and with moderate and severe renal dysfunction included age, gender, pretransplant eGFR, blood pressure, glycemia, and use of prednisone (P < 0.05). In summary, kidney function worsens constantly up to two decades after cardiac transplantation, with the greatest decline occurring in the first year. Corticosteroid minimization and treatment of modifiable risk factors (hypertension, diabetes) may minimize renal deterioration.

Sirolimus Immunoprophylaxis and Renal Histological Changes in Long-Term Cardiac Transplant Recipients: A Pilot Study.

BACKGROUND: The effects of sirolimus (SIR), as a substitution for calcineurin inhibitor (CNI) immunoprophylaxis, on renal function in very-long-term cardiac transplant recipients have been a matter of controversy. OBJECTIVE: To assess the impacts of SIR as a substitution for CNI on renal function up to 24 months in long-term cardiac recipients as well as the renal histological changes in patients with suspected CNI-induced nephrotoxicity. METHODS: A total of 23 cardiac transplant recipients aged 57.7 ± 11.2 years, 91 months post-cardiac transplantation were recruited; 15 patients were randomized to CNI-free immune suppression with SIR, and 8 patients were allocated to continue their CNI regimens. Serum creatinine and calculated serum creatinine clearance were measured at prespecified time points up to 24 months. Renal structure and function were assessed by renal biopsies, renal ultrasound, and magnetic resonance imaging at baseline. RESULTS: There were no significant changes in creatinine clearance during the course of the study in patients treated with SIR. However, SIR-treated patients exhibited a significant decrease in 24-hours and nighttime systolic and diastolic blood pressures. Typical findings of significant hypertensive renal disease were detected in 9 of the 11 (82%) patients. Features of chronic CNI toxicity were detected in 6 (55%) patients. CONCLUSIONS: There is a very high rate of hypertensive renal disease concomitantly with some degree of CNI toxicity in long-term cardiac transplant recipients with renal dysfunction. This very high rate of hypertension-related disease may limit the impact of SIR on improving renal function long term following cardiac transplantation.

High-sensitivity C-reactive protein in heart failure with preserved ejection fraction: Findings from TOPCAT.

BACKGROUND: Inflammation plays a central role in the genesis and progression of heart failure with preserved ejection fraction (HFpEF). C-reactive protein (CRP) is widely used as means to assess systemic inflammation, and elevated levels of CRP have been associated with poor HF prognosis. Identification of chronic low-grade inflammation in outpatients can be performed measuring high-sensitivity CRP (hsCRP). The clinical characteristics and outcome associations of a pro-inflammatory state among outpatients with HFpEF requires further study. AIMS: Using a biomarker subset of TOPCAT-Americas (NCT00094302), we aim to characterize HFpEF patients according to hsCRP levels and study the prognostic associations of hsCRP. METHODS: hsCRP was available in a subset of 232 participants. Comparisons were performed between patients with hsCRP <2 mg/L and ≥ 2 mg/L. Cox regression models were used to study the association between hsCRP and the study outcomes. RESULTS: Compared to patients with hsCRP <2 mg/L (n = 89, 38%), those with hsCRP ≥2 mg/L (n = 143, 62%) had more frequent HF hospitalizations prior to randomization, chronic obstructive pulmonary disease, orthopnea, higher body mass index, and worse health-related quality-of-life. A hsCRP level ≥ 2 mg/L was associated with an increased risk of cardiovascular death and HF hospitalizations: hsCRP ≥2 mg/L vs <2 mg/L adjusted HR 2.36, 95%CI 1.27-4.38, P = 0.006. Spironolactone did not influence hsCRP levels from baseline to month 12: gMean ratio = 1.11, 95%CI 0.87-1.42, P = 0.39. CONCLUSIONS: A hsCRP ≥2 mg/L identified HFpEF patients with a high risk of HF events and cardiovascular mortality. Spironolactone did not influence hsCRP levels at 12 months.

A Genome-Wide Association Study of Oxypurinol Concentrations in Patients Treated with Allopurinol.

Cohort studies have identified several genetic determinants that could predict the clinical response to allopurinol. However, they have not been commonly used for genome-wide investigations to identify genetic determinants on allopurinol metabolism and concentrations. We conducted a genome-wide association study of a prior cross-sectional investigation of patients from the Montreal Heart Institute Biobank undergoing allopurinol therapy. Four endpoints were investigated, namely plasma concentrations of oxypurinol, the active metabolite of allopurinol, allopurinol, and allopurinol-riboside, as well as allopurinol daily dosing. A total of 439 participants (mean age 69.4 years; 86.4% male) taking allopurinol (mean daily dose 194.5 mg) and who had quantifiable oxypurinol concentrations were included in the genome-wide analyses. Participants presented with multiple comorbidities and received concomitant cardiovascular medications. No association achieved the predefined genome-wide threshold values for any of the endpoints (all p > 5 × 10-8). Our results are consistent with prior findings regarding the difficulty in identifying genetic determinants of drug concentrations or pharmacokinetics of allopurinol and its metabolites, as well as allopurinol daily dosing. Given the size of this genome-wide study, collaborative investigations involving larger and diverse cohorts may be required to further identify pharmacogenomic determinants of allopurinol and measure their clinical relevance to personalize allopurinol therapy.

Circulating biomarkers in patients with heart failure and preserved ejection fraction.

Patients with heart failure with preserved ejection fraction (HF-PEF) comprise a growing proportion of the overall HF burden. The pathophysiology of HF-PEF is complex, and relates to the interplay between cardiac risk factors (notably diabetes/insulin resistance, hypertension), systemic inflammation, and comorbid medical illness (e.g. chronic kidney disease) that conspire to promote endothelial dysfunction, ventricular-vascular stiffening, and diastolic dysfunction. Efficient diagnosis and optimal therapy remain challenging in this population. Imaging, electrocardiographic, and circulating biomarkers, as well as pharmacogenetics, may help to facilitate HF diagnosis, stratify risk, and individualize therapy. In this review, we focus on established and emerging circulating biomarkers in HF-PE, including circulating biomarkers of myocyte stress, myocyte injury, renal function, systemic inflammation, and fibrosis. Such markers have contributed to better understanding of the pathophysiologic mechanisms relevant to HF-PEF, and may eventually help to facilitate more effective and personalized management of this syndrome.

Females present higher dose-adjusted drug concentrations of metoprolol and allopurinol/oxypurinol than males.

Females present a higher risk of adverse drug reactions. Sex-related differences in drug concentrations may contribute to these observations but they remain understudied given the underrepresentation of females in clinical trials. The aim of this study was to investigate whether anthropometric and socioeconomic factors and comorbidities could explain sex-related differences in concentrations and dosing for metoprolol and oxypurinol, the active metabolite of allopurinol. We conducted an analysis of two cross-sectional studies. Participants were self-described "White" adults taking metoprolol or allopurinol selected from the Montreal Heart Institute Hospital Cohort. A total of 1007 participants were included in the metoprolol subpopulation and 459 participants in the allopurinol subpopulation; 73% and 86% of the participants from the metoprolol and allopurinol subpopulations were males, respectively. Females presented higher age- and dose-adjusted concentrations of both metoprolol and oxypurinol (both p < 0.03). Accordingly, females presented higher unadjusted and age-adjusted concentration:dose ratio of both metoprolol and allopurinol/oxypurinol compared to males (all p < 3.0 × 10-4 ). Sex remained an independent predictor of metoprolol concentrations (p < 0.01), but not of oxypurinol concentrations, after adjusting for other predictors. In addition to sex, age, daily dose, use of moderate to strong CYP2D6 inhibitors, weight, and CYP2D6 genotype-inferred phenotype were associated with concentrations of metoprolol (all p < 0.01). Daily dose, weight, estimated glomerular filtration rate (eGFR), and employment status were associated with oxypurinol concentrations (all p < 0.01). Females present higher dose-adjusted concentrations of metoprolol and oxypurinol than males. This suggests the need for sex-specific dosing requirements for these drugs, although this hypothesis should be validated in prospective studies.

Impact of amiodarone use on metoprolol concentrations, α-OH-metoprolol concentrations, metoprolol dosing and heart rate: A cross-sectional study.

Small studies suggest that amiodarone is a weak inhibitor of cytochrome P450 (CYP) 2D6. Inhibition of CYP2D6 leads to increases in concentrations of drugs metabolized by the enzyme, such as metoprolol. Considering that both metoprolol and amiodarone have ß-adrenergic blocking properties and that the modest interaction between the two drugs would result in increased metoprolol concentrations, this could lead to a higher risk of bradycardia and atrioventricular block. The primary objective of this study was to evaluate whether metoprolol plasma concentrations collected at random timepoints from patients enrolled in the Montreal Heart Institute Hospital Cohort could be useful in identifying the modest pharmacokinetic interaction between amiodarone and metoprolol. We performed an analysis of a cross-sectional study, conducted as part of the Montreal Heart Institute Hospital Cohort. All participants were self-described "White" adults with metoprolol being a part of their daily pharmacotherapy regimen. Of the 999 patients being treated with metoprolol, 36 were also taking amiodarone. Amiodarone use was associated with higher metoprolol concentrations following adjustment for different covariates (p = .0132). Consistently, the association between amiodarone use and lower heart rate was apparent and significant after adjustment for all covariates under study (p = .0001). Our results highlight that single randomly collected blood samples can be leveraged to detect modest pharmacokinetic interactions.

Optimization of pharmacotherapies for ambulatory patients with heart failure and reduced ejection fraction is associated with improved outcomes.

BACKGROUND: In heart failure, specific target doses for each drug are recommended, but some patients receive suboptimal dosing, others are undertreated or remain chronically in a titration phase, despite having no apparent contraindication or intolerance. We assessed the association of different levels of adherence to guidelines with outcomes in patients with heart failure and reduced ejection fraction (HFrEF). METHODS: Medical records of patients with HFrEF followed at our heart failure (HF) clinic for at least 6 months (n = 511) were reviewed and patients categorized as: 1) optimized (25.4%); 2) in-titration (29.0%); 3) undertreated (32.7%); and 4) intolerant/contraindicated (12.9%). Risk of mortality or HF events (hospitalization, emergency visit or ambulatory administration of intravenous diuretics) within one year was assessed using Cox regression models and Kaplan-Meier curves. RESULTS: Compared to optimized patients, those intolerant (HR: 4.60 [95%CI: 2.23-9.48]; p < 0.0001) had the highest risk of outcomes, followed by those undertreated (3.45 [1.78-6.67]; p = 0.0002) and in-titration (1.99 [0.97-4.06]; p = 0.0588). Overall predictors of outcomes included loop diuretics' use (4.54 [2.39-8.60]), undertreatment (2.38 [1.22-4.67]), intolerance/ contraindication to triple therapy (3.08 [1.47-6.42]), peripheral vascular disease (2.13 [1.29-3.50]) and NYHA class III-IV (1.89 [1.25-2.85]); all p < 0.05. CONCLUSION: Level of adherence to guidelines is associated with outcomes, with intolerant/contraindicated patients having the worst prognosis and those undertreated and in-titration at intermediate risk compared to those optimized. Up-titration of therapy should be attempted whenever possible, considering patients' limitations, to potentially improve outcomes.

PRKCB is associated with calcineurin inhibitor-induced renal dysfunction in heart transplant recipients.

OBJECTIVES: Single nucleotide polymorphisms (SNPs) in the transforming growth factor-ß1 gene (TGFB1) have been inconsistently associated with calcineurin inhibitor (CNI)-induced renal dysfunction following cardiac transplantation. The impact of genetic variants related to the renin-angiotensin-aldosterone system (RAAS) and natriuretic peptides, which are implicated in CNI nephrotoxicity, is unknown. The primary objective of this study was to validate the association between two common variants in TGFB1 (rs1800470, rs1800471) and postcardiac transplant renal function. The secondary objective was to investigate the effect of candidate genes related to the RAAS, natriuretic peptides, and other elements involved in the intracellular signaling of these pathways. METHODS: We conducted a retrospective cohort study of 158 heart transplant recipients treated with CNIs, and evaluated the association between select SNPs and the estimated glomerular filtration rate as calculated by the Modification of Diet in Renal Disease simplified formula. A total of 273 SNPs distributed in 44 genes were tested. RESULTS: No association was observed between TGFB1 variants and renal function. One polymorphism in the protein kinase C-ß gene (PRKCB; rs11074606), which is implicated in the RAAS intracellular signaling, was significantly associated with post-transplant estimated glomerular filtration rate after adjusting for possible confounders (P=0.00049). This marker is in linkage disequilibrium with two variants located in putative regulatory regions of the gene (rs2283541, rs1013316). CONCLUSION: Our results suggest that PRKCB may be a potential predictor of CNI-induced nephrotoxicity in heart transplant recipients, and could therefore be a promising candidate to identify patients who are most susceptible to this adverse drug reaction.

Construction of a femininity score in the UK Biobank and its association with angina diagnosis prior to myocardial infarction.

Gender captures social components beyond biological sex and can add valuable insight to health studies in populations. However, assessment of gender typically relies on questionnaires which may not be available. The aim of this study is to construct a gender metric using available variables in the UK Biobank and to apply it to the study of angina diagnosis. Proxy variables for femininity characteristics were identified in the UK Biobank and regressed on sex to construct a composite femininity score (FS) validated using tenfold cross-validation. The FS was assessed as a predictor of angina diagnosis before incident myocardial infarction (MI) events. The FS was derived for 315,937 UK Biobank participants. In 3059 individuals with no history of MI at study entry who had an incident MI event, the FS was a significant predictor of angina diagnosis prior to MI (OR 1.24, 95% CI 1.10-1.39, P < 0.001) with a significant sex-by-FS interaction effect (P = 0.003). The FS was positively associated with angina diagnosis prior to MI in men (OR 1.37, 95% CI 1.19-1.57, P < 0.001), but not in women. We have provided a new tool to conduct gender-sensitive analyses in observational studies, and applied it to study of angina diagnosis prior to MI.