Mild kidney disease as a risk factor for major bleeding in patients with atrial fibrillation undergoing percutaneous coronary stenting

Anemia and iron deficiency in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac tachyarrhythmia and has a rising global prevalence. Given the increasing burden of AF-related symptoms and complications, new approaches to management are required. Anemia and iron deficiency are common conditions in patients with AF. Furthermore, emerging evidence suggests that the presence of anemia may be associated with worse outcome in these patients. The role of anemia and iron deficiency has been extensively explored in other cardiovascular states, such as heart failure and ischemic heart disease. In particular, the role of iron repletion amongst patients with heart failure is now an established treatment modality. However, despite the strong bidirectional inter-relationship between AF and heart failure, the implications of anemia and iron-deficiency in AF have been scarcely studied. This area is of mechanistic and clinical relevance given the potential that treatment of these conditions may improve symptoms and prognosis in the increasing number of individuals with AF. In this review, we summarise the current published literature on anemia and iron deficiency in patients with AF. We discuss AF complications such as stroke, bleeding, and heart failure, in addition to AF-related symptoms such as exercise intolerance, and the potential impact of anemia and iron deficiency on these. Finally, we summarize current research gaps on anemia, iron deficiency, and AF, and underscore potential research directions.

Effect of Renal Dysfunction on the Risks for Ischemic and Bleeding Events in Patients With Atrial Fibrillation Receiving Percutaneous Coronary Intervention

There is a paucity of studies exploring whether the ischemia-bleeding trade-off could be different according to the stages of renal dysfunction in patients with atrial fibrillation (AF) who underwent percutaneous coronary intervention (PCI). Among 19,598 patients in a pooled database from 3 Japanese PCI studies (CREDO-Kyoto Cohort-2, RESET, and NEXT), 1,547 patients had concomitant AF. Patients were divided into 4 groups according to their renal function (Creatinine clearance [CCr] >60 ml/min: n = 703, 60≥ CCr >30 ml/min: n = 627, CCr ≤30 ml/min: n = 126, Dialysis: n = 91). The cumulative 3-year incidences of both the primary ischemic (ischemic stroke/myocardial infarction) and bleeding (GUSTO moderate/severe) outcome increased incrementally with worsening renal function (11.4%, 12.6%, 16.8%, and 31.7%, p <0.001, and 7.5%, 14.9%, 26.3%, and 29.5%, p <0.001, respectively). Compared with CCr >60 ml/min group, the excess adjusted risk for the primary ischemic outcome was significant only in dialysis group (hazards ratio [HR] 2.15, 95% confidence interval [CI] 1.22 to 3.69, p = 0.009), but not in 60≥ CCr >30 ml/min and CCr ≤30 ml/min groups (HR 0.89, 95% CI 0.62 to 1.29, p = 0.54, and HR 0.94, 95% CI 0.49 to 1.69, p = 0.83, respectively), whereas the excess adjusted risk for the primary bleeding outcome was significant in all 3 groups of renal dysfunction (HR 1.66, 95% CI 1.13 to 2.45, p = 0.01, HR 2.70, 95% CI 1.58 to 4.61, p <0.001, and HR 3.26, 95% CI 1.85 to 5.75, p <0.001, respectively). In conclusion, in AF patients receiving PCI, the worsening renal function was strongly associated with the increasingly higher risk for bleeding events, whereas the excess risk for ischemic events was significant only in patients on dialysis.

Renal Impairment and Prognosis of Patients with Atrial Fibrillation Undergoing Coronary Intervention - The AFCAS Trial

BACKGROUND

Renal impairment is a well-known risk factor for cardiovascular complications, but the effect of different stages of renal impairment on thrombotic/thromboembolic and bleeding complications in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) remains largely unknown. We sought to evaluate the incidence and clinical impact of four stages of renal impairment in patients with AF undergoing PCI.

METHODS

We assessed renal function by estimated glomerular filtration rate (eGFR) and outcomes in 781 AF patients undergoing PCI by using the data from a prospective European multicenter registry. End-points included all-cause mortality, major adverse cardiac and cerebrovascular events (MACCE) and bleeding events at 12 months.

RESULTS

A total of 195 (25%) patients had normal renal function (eGFR ≥90 mL/min), 290 (37%) mild renal impairment (eGFR 60-89), 263 (34%) moderate renal impairment (eGFR 30-59) and 33 (4%) severe renal impairment (eGFR <30). Degree of renal impairment remained an independent predictor of mortality and MACCE in an adjusted a Cox regression model. Even patients with mild renal impairment had a higher risk of all-cause mortality (HR 2.25, 95%CI 1.02-4.98, p=0.04) and borderline risk for MACCE (HR 1.56, 95%CI 0.98- 2.50, p=0.06) compared to those with normal renal function.

CONCLUSIONS

Renal impairment is common in patients with AF undergoing PCI and even mild renal impairment has an adverse prognostic effect in these patients requiring multiple antithrombotic medications.

Renal function, attributes and coagulation treatment in atrial fibrillation (R-FACT Study): retrospective, observational, longitudinal cohort study of renal function and antithrombotic treatment patterns in atrial fibrillation patients with documented eGFR in real-world clinical practices in Germany

AIMS

This retrospective, observational, longitudinal study aimed to document the distribution, changes in renal function [measured by estimated glomerular filtration (eGFR)] and antithrombotic treatment pattern in atrial fibrillation (AF) patients in real-world settings managed by general practitioners in Germany.

METHODS AND RESULTS

Data were extracted from the German Longitudinal Patient Database. A total of 15,900 patients with AF were identified. Among 1660 having eGFR available at baseline, 3.4% had severely impaired eGFR, 9.7% and 25.6% had moderate severe decrease and moderate decrease in eGFR, respectively, and 61.3% had mildly decreased/normal eGFR. Patients with moderately and severely decreased eGFR tended to be older. The proportion of patients with a CHADS2 score ≥ 2 was 92.9% in those with severely decreased eGFR, and 87.0% and 79.1% in those with moderately severe and moderately decreased eGFR. During follow up, 52.1% of patients with severely decreased eGFR, and 26.3% to 23.7% of patients with moderately decreased eGFR were not treated by antithrombotic. When comparing baseline with follow-up eGFR, 55.0% of patients showed decreased eGFR. Age, diabetes, dyslipidaemia and history of myocardial infarction were identified as significant predictors for renal function deterioration based on results from multivariate Cox regression model.

CONCLUSIONS

Moderate-to-severe renal dysfunction is prevalent (~38%) in German AF patients with documented eGFR managed in actual clinical practices. The risk of stroke, as measured by the CHADS2 score, was associated with decreased renal function. Treatment with anticoagulation therapies decreased with decreasing renal function, despite increasing risk of stroke. Anticoagulation treatments remain suboptimal during the 12-month follow up in patients with moderate or severe renal impairment.

A distribution-based method for assessing the differences between clinical trial target populations and patient populations in electronic health records

OBJECTIVE

To improve the transparency of clinical trial generalizability and to illustrate the method using Type 2 diabetes as an example.

METHODS

Our data included 1,761 diabetes clinical trials and the electronic health records (EHR) of 26,120 patients with Type 2 diabetes who visited Columbia University Medical Center of New-York Presbyterian Hospital. The two populations were compared using the Generalizability Index for Study Traits (GIST) on the earliest diagnosis age and the mean hemoglobin A1c (HbA1c) values.

RESULTS

Greater than 70% of Type 2 diabetes studies allow patients with HbA1c measures between 7 and 10.5, but less than 40% of studies allow HbA1c<7 and fewer than 45% of studies allow HbA1c>10.5. In the real-world population, only 38% of patients had HbA1c between 7 and 10.5, with 12% having values above the range and 52% having HbA1c<7. The GIST for HbA1c was 0.51. Most studies adopted broad age value ranges, with the most common restrictions excluding patients >80 or <18 years. Most of the real-world population fell within this range, but 2% of patients were <18 at time of first diagnosis and 8% were >80. The GIST for age was 0.75.

CONCLUSIONS

We contribute a scalable method to profile and compare aggregated clinical trial target populations with EHR patient populations. We demonstrate that Type 2 diabetes studies are more generalizable with regard to age than they are with regard to HbA1c. We found that the generalizability of age increased from Phase 1 to Phase 3 while the generalizability of HbA1c decreased during those same phases. This method can generalize to other medical conditions and other continuous or binary variables. We envision the potential use of EHR data for examining the generalizability of clinical trials and for defining population-representative clinical trial eligibility criteria.

Renal impairment in a "real-life" cohort of anticoagulated patients with atrial fibrillation (implications for thromboembolism and bleeding)

Renal dysfunction is highly prevalent among patients with atrial fibrillation (AF) and confers an increased risk of thrombotic and bleeding complications. We evaluated the effect of renal function on prognosis in anticoagulated patients with AF and assessed the changes in renal function during a long-term follow-up period. We recruited 978 consecutive stable anticoagulated patients with AF from our outpatient anticoagulation clinic (international normalized ratio 2.0 to 3.0 within the previous 6 months). The estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease equation at inclusion and 2 years of follow-up. Adverse events were recorded during follow-up (thrombotic/vascular events, major bleeding episodes, and mortality). Longitudinal changes in renal function were analyzed in 886 patients (90.6%). At baseline, the median eGFR using the Modification of Diet in Renal Disease equation was 70.24 ml/min/1.73 m(2) (interquartile range 46.79 to 72.52). During follow-up, a low eGFR was associated with thrombotic/vascular events, with every 30 ml/min/1.73 m(2) eGFR decrease (hazard ratio 1.42, 95% confidence interval [CI] 1.11 to 1.83, p = 0.006), bleeding (hazard ratio 1.44, 95% CI 1.08 to 1.94, p = 0.015), and mortality (hazard ratio 1.47, 95% CI 1.13 to 1.91, p = 0.004). After excluding patients with a baseline eGFR <30 ml/min/1.73 m(2), the mean eGFR in our cohort decreased >10 ml/min/1.73 m(2) in 181 patients (21%) during the follow-up period. The variables associated with severe renal impairment during follow-up were heart failure (odds ratio 3.58, 95% CI 1.36 to 9.42, p = 0.010), basal eGFR (odds ratio 6.34, 95% CI 2.44 to 16.50, p <0.001), and CHADS2 (Congestive heart failure, Hypertension, Age >75 years, Diabetes mellitus, and previous Stroke or transient ischemic attack [doubled]) score (odds ratio 1.63, 95% CI 1.19 to 2.23, p = 0.003). In conclusion, the presence of impaired renal function was closely related to thrombotic/vascular events, bleeding, and mortality in anticoagulated patients with AF. During follow-up, 1/5 of the patients had significant impairment in renal function. Importantly, normal or mild renal dysfunction at baseline did not exclude the subsequent development of severe renal dysfunction during the follow-up period.