Nonparametric analysis of recurrent events and death

Coronary Atherosclerotic Plaque Activity and Risk of Myocardial Infarction

BACKGROUND

Total coronary atherosclerotic plaque activity across the entire coronary arterial tree is associated with patient-level clinical outcomes.

OBJECTIVES

We aimed to investigate whether vessel-level coronary atherosclerotic plaque activity is associated with vessel-level myocardial infarction.

METHODS

In this secondary analysis of an international multicenter study of patients with recent myocardial infarction and multivessel coronary artery disease, we assessed vessel-level coronary atherosclerotic plaque activity using coronary 18F-sodium fluoride positron emission tomography to identify vessel-level myocardial infarction.

RESULTS

Increased 18F-sodium fluoride uptake was found in 679 of 2,094 coronary arteries and 414 of 691 patients. Myocardial infarction occurred in 24 (4%) vessels with increased coronary atherosclerotic plaque activity and in 25 (2%) vessels without increased coronary atherosclerotic plaque activity (HR: 2.08; 95% CI: 1.16-3.72; P = 0.013). This association was not demonstrable in those treated with coronary revascularization (HR: 1.02; 95% CI: 0.47-2.25) but was notable in untreated vessels (HR: 3.86; 95% CI: 1.63-9.10; Pinteraction = 0.024). Increased coronary atherosclerotic plaque activity in multiple coronary arteries was associated with heightened patient-level risk of cardiac death or myocardial infarction (HR: 2.43; 95% CI: 1.37-4.30; P = 0.002) as well as first (HR: 2.19; 95% CI: 1.18-4.06; P = 0.013) and total (HR: 2.50; 95% CI: 1.42-4.39; P = 0.002) myocardial infarctions.

CONCLUSIONS

In patients with recent myocardial infarction and multivessel coronary artery disease, coronary atherosclerotic plaque activity prognosticates individual coronary arteries and patients at risk for myocardial infarction.

A simple and robust parametric shared frailty model for recurrent events with the competing risk of death: An application to the Carvedilol Prospective Randomized Cumulative Survival trial

Many non-fatal events can be considered recurrent in that they can occur repeatedly over time, and some researchers may be interested in the trajectory and relative risk of non-fatal events. With the competing risk of death, the treatment effect on the mean number of recurrent events is non-identifiable since the observed mean is a function of both the recurrent event and terminal event processes. In this paper, we assume independence between the non-fatal and the terminal event process, conditional on the shared frailty, to fit a parametric model that recovers the trajectory of, and identifies the effect of treatment on, the non-fatal event process in the presence of the competing risk of death. Simulation studies are conducted to verify the reliability of our estimators. We illustrate the method and perform model diagnostics using the Carvedilol Prospective Randomized Cumulative Survival trial which involves heart-failure events.

The Impact of Ferric Derisomaltose on Cardiovascular and Noncardiovascular Events in Patients With Anemia, Iron Deficiency, and Heart Failure With Reduced Ejection Fraction

BACKGROUND

In some countries, intravenous ferric derisomaltose (FDI) is only licensed for treating iron deficiency with anemia. Accordingly, we investigated the effects of intravenous FDI in a subgroup of patients with anemia in the IRONMAN (Effectiveness of Intravenous (IV) Iron Treatment Versus Standard Care in Patients With Heart Failure and Iron Deficiency) trial.

METHOD AND RESULTS

IRONMAN enrolled patients with heart failure, a left ventricular ejection fraction of ≤45%, and iron deficiency (ferritin <100 µg/L or transferrin saturation of <20%), 771 (68%) of whom had anemia (hemoglobin <12 g/dL for women and <13 g/dL for men). Patients were randomized, open label, to FDI (n = 397) or usual care (n = 374) and followed for a median of 2.6 years. The primary end point, recurrent hospitalization for heart failure and cardiovascular death, occurred less frequently for those assigned to FDI (rate ratio 0.78, 95% confidence interval 0.61-1.01; P = .063). First event analysis for cardiovascular death or hospitalization for heart failure, less affected by the coronavirus disease 2019 pandemic, gave similar results (hazard ratio 0.77, 95% confidence interval 0.62-0.96; P = .022). Patients randomized to FDI reported a better Minnesota Living with Heart Failure quality of life, for overall (P = .013) and physical domain (P = .00093) scores at 4 months.

CONCLUSIONS

In patients with iron deficiency anemia and heart failure with reduced left ventricular ejection fraction, intravenous FDI improves quality of life and may decrease cardiovascular events.

Intravenous iron for heart failure, iron deficiency definitions, and clinical response: the IRONMAN trial

BACKGROUND AND AIMS

What is the relationship between blood tests for iron deficiency, including anaemia, and the response to intravenous iron in patients with heart failure?

METHODS

In the IRONMAN trial, 1137 patients with heart failure, ejection fraction ≤ 45%, and either serum ferritin < 100 µg/L or transferrin saturation (TSAT) < 20% were randomized to intravenous ferric derisomaltose (FDI) or usual care. Relationships were investigated between baseline anaemia severity, ferritin and TSAT, to changes in haemoglobin from baseline to 4 months, Minnesota Living with Heart Failure (MLwHF) score and 6-minute walk distance achieved at 4 months, and clinical events, including heart failure hospitalization (recurrent) or cardiovascular death.

RESULTS

The rise in haemoglobin after administering FDI, adjusted for usual care, was greater for lower baseline TSAT (Pinteraction < .0001) and ferritin (Pinteraction = .028) and more severe anaemia (Pinteraction = .014). MLwHF scores at 4 months were somewhat lower (better) with FDI for more anaemic patients (overall Pinteraction = .14; physical Pinteraction = .085; emotional Pinteraction = .043) but were not related to baseline TSAT or ferritin. Blood tests did not predict difference in achieved walking distance for those randomized to FDI compared to control. The absence of anaemia or a TSAT ≥ 20% was associated with lower event rates and little evidence of benefit from FDI. More severe anaemia or TSAT < 20%, especially when ferritin was ≥100 µg/L, was associated with higher event rates and greater absolute reductions in events with FDI, albeit not statistically significant.

CONCLUSIONS

This hypothesis-generating analysis suggests that anaemia or TSAT < 20% with ferritin > 100 µg/L might identify patients with heart failure who obtain greater benefit from intravenous iron. This interpretation requires confirmation.

Simulation-based sample size calculations of marginal proportional means models for recurrent events with competing risks

In randomised controlled trials, the outcome of interest could be recurrent events, such as hospitalisations for heart failure. If mortality rates are non-negligible, both recurrent events and competing terminal events need to be addressed when formulating the estimand and statistical analysis is no longer trivial. In order to design future trials with primary recurrent event endpoints with competing risks, it is necessary to be able to perform power calculations to determine sample sizes. This paper introduces a simulation-based approach for power estimation based on a proportional means model for recurrent events and a proportional hazards model for terminal events. The simulation procedure is presented along with a discussion of what the user needs to specify to use the approach. The method is flexible and based on marginal quantities which are easy to specify. However, the method introduces a lack of a certain type of dependence. This is explored in a sensitivity analysis which suggests that the power is robust in spite of that. Data from a randomised controlled trial, LEADER, is used as the basis for generating data for a future trial. Finally, potential power gains of recurrent event methods as opposed to first event methods are discussed.

Overweight and obesity as risk factors for cervical cancer and detection of precancers among screened women: A nationwide, population-based cohort study

OBJECTIVE

Obesity is a known risk factor for many types of cancer. However, there is no clear evidence whether overweight and obesity increases the risk of cervical cancer. We investigated the association between body mass index (BMI) and detection of squamous and glandular cervical cancer and precancer.

METHODS

Based on the Medical Birth Registry, we conducted a nationwide cohort study in Denmark of 384,559 women with BMI ≥18.5 kg/m2 (pre-pregnancy BMI reported at the start of the pregnancy) having a cervical cytology screening at age 23-49 years within 5 years following the date of childbirth. The cohort was followed for 10 years from the first cervical cytology screening after the childbirth. We assessed absolute risks of cervical lesions according to BMI with the Aalen-Johansen estimator. We conducted Cox proportional hazards regression analyses to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). Analyses were adjusted for age, calendar year, parity, oral contraception use, HPV vaccination, smoking, country of origin, and education.

RESULTS

Overweight and obesity were associated with higher rates of cervical cancer (HR = 1.24, 95% CI 1.04-1.49 and HR = 1.14, 95% CI 0.91-1.43, respectively) and lower rates of cervical precancer detection (HR = 0.88, 95% CI 0.84-0.92 and HR = 0.67, 95% CI 0.63-0.71, respectively).

CONCLUSIONS

Higher than normal BMI was associated with higher incidence rates of cervical cancer and lower rates of precancer detection, emphasizing the importance of further research in possible mechanisms behind this association.

Causal inference with recurrent and competing events

Many research questions concern treatment effects on outcomes that can recur several times in the same individual. For example, medical researchers are interested in treatment effects on hospitalizations in heart failure patients and sports injuries in athletes. Competing events, such as death, complicate causal inference in studies of recurrent events because once a competing event occurs, an individual cannot have more recurrent events. Several statistical estimands have been studied in recurrent event settings, with and without competing events. However, the causal interpretations of these estimands, and the conditions that are required to identify these estimands from observed data, have yet to be formalized. Here we use a formal framework for causal inference to formulate several causal estimands in recurrent event settings, with and without competing events. When competing events exist, we clarify when commonly used classical statistical estimands can be interpreted as causal quantities from the causal mediation literature, such as (controlled) direct effects and total effects. Furthermore, we show that recent results on interventionist mediation estimands allow us to define new causal estimands with recurrent and competing events that may be of particular clinical relevance in many subject matter settings. We use causal directed acyclic graphs and single world intervention graphs to illustrate how to reason about identification conditions for the various causal estimands based on subject matter knowledge. Furthermore, using results on counting processes, we show that our causal estimands and their identification conditions, which are articulated in discrete time, converge to classical continuous time counterparts in the limit of fine discretizations of time. We propose estimators and establish their consistency for the various identifying functionals. Finally, we use the proposed estimators to compute the effect of blood pressure lowering treatment on the recurrence of acute kidney injury using data from the Systolic Blood Pressure Intervention Trial.

Bayesian inference for a principal stratum estimand on recurrent events truncated by death

Recurrent events are often important endpoints in randomized clinical trials. For example, the number of recurrent disease-related hospitalizations may be considered as a clinically meaningful endpoint in cardiovascular studies. In some settings, the recurrent event process may be terminated by an event such as death, which makes it more challenging to define and estimate a causal treatment effect on recurrent event endpoints. In this paper, we focus on the principal stratum estimand, where the treatment effect of interest on recurrent events is defined among subjects who would be alive regardless of the assigned treatment. For the estimation of the principal stratum effect in randomized clinical trials, we propose a Bayesian approach based on a joint model of the recurrent event and death processes with a frailty term accounting for within-subject correlation. We also present Bayesian posterior predictive check procedures for assessing the model fit. The proposed approaches are demonstrated in the randomized Phase III chronic heart failure trial PARAGON-HF (NCT01920711).

Bayesian design of clinical trials using joint models for recurrent and terminating events

Joint models for recurrent event and terminating event data are increasingly used for the analysis of clinical trials. However, few methods have been proposed for designing clinical trials using these models. In this article, we develop a Bayesian clinical trial design methodology focused on evaluating the effect of an investigational product (IP) on both recurrent event and terminating event processes considered as multiple primary endpoints, using a multifrailty joint model. Dependence between the recurrent and terminating event processes is accounted for using a shared frailty. Inferences for the multiple primary outcomes are based on posterior model probabilities corresponding to mutually exclusive hypotheses regarding the benefit of IP with respect to the recurrent and terminating event processes. We propose an approach for sample size determination to ensure the trial design has a high power and a well-controlled type I error rate, with both operating characteristics defined from a Bayesian perspective. We also consider a generalization of the proposed parametric model that uses a nonparametric mixture of Dirichlet processes to model the frailty distributions and compare its performance to the proposed approach. We demonstrate the methodology by designing a colorectal cancer clinical trial with a goal of demonstrating that the IP causes a favorable effect on at least one of the two outcomes but no harm on either.

Understanding the Accumulation of Health-Related Inequities Over the Life Course Using the Mean Cumulative Count

Understanding how health inequities develop over time is necessary to inform interventions, but methods for doing so are underutilized. We provide an example of the accumulation of stressful life events using the mean cumulative count (MCC), which estimates the expected number of events per person as a function of time, allowing for censoring and competing events. Data came from the National Longitudinal Survey of Youth 1997, a nationally representative data set. To compare the MCC with standard practice, we present the proportions of persons experiencing 1, 2, and ≥3 stressful events and the cumulative probability of experiencing at least 1 event by the end of follow-up. Our sample included 6,522 individuals aged 18-33 years who were followed for a median of 14 years. Using the MCC, by age 20 years the expected number of encounters was 56 events per 100 participants for Black non-Hispanic persons, 47 per 100 for White non-Hispanic persons, and 50 per 100 for Hispanic persons. By age 33 years, inequities grew to 117, 99, and 108 events per 100 persons, respectively. The MCC revealed that inequities in stressful events accumulate over the course of early adulthood, partially driven by repeat events; this information was not evident from conventional approaches. This method can be used to identify intervention points for disrupting the accumulation of repeat events to improve health equity.

Nonparametric inference of general while-alive estimands for recurrent events

Measuring the treatment effect on recurrent events like hospitalization in the presence of death has long challenged statisticians and clinicians alike. Traditional inference on the cumulative frequency unjustly penalizes survivorship as longer survivors also tend to experience more adverse events. Expanding a recently suggested idea of the "while-alive" event rate, we consider a general class of such estimands that adjust for the length of survival without losing causal interpretation. Given a user-specified loss function that allows for arbitrary weighting, we define as estimand the average loss experienced per unit time alive within a target period and use the ratio of this loss rate to measure the effect size. Scaling the loss rate by the width of the corresponding time window gives us an alternative, and sometimes more photogenic, way of showing the data. To make inferences, we construct a nonparametric estimator for the loss rate through the cumulative loss and the restricted mean survival time and derive its influence function in closed form for variance estimation and testing. As simulations and analysis of real data from a heart failure trial both show, the while-alive approach corrects for the false attenuation of treatment effect due to patients living longer under treatment, with increased statistical power as a result. The proposed methods are implemented in the R-package WA, which is publicly available from the Comprehensive R Archive Network (CRAN).

Reproduction patterns among non-Hodgkin lymphoma survivors by subtype in Sweden, Denmark and Norway: A population-based matched cohort study

Previous studies concerning reproductive patterns among non-Hodgkin lymphoma (NHL) survivors are scarce and those available have reported conflicting results. Treatment regimens vary considerably between aggressive and indolent NHL and studies of reproductive patterns by subtypes are warranted. In this matched cohort study, we identified all NHL patients aged 18-40 years and diagnosed between 2000 and 2018 from the Swedish and Danish lymphoma registers, and the clinical database at Oslo University Hospital (n = 2090). Population comparators were matched on sex, birth year and country (n = 19 427). Hazard ratios (HRs) were estimated using Cox regression. Males and females diagnosed with aggressive lymphoma subtypes had lower childbirth rates (HRfemale : 0.43, 95% CI: 0.31-0.59, HRmale : 0.61, 95% CI: 0.47-0.78) than comparators during the first 3 years after diagnosis. For indolent lymphomas, childbirth rates were not significantly different from comparators (HRfemale : 0.71, 95% CI: 0.48-1.04, HRmale : 0.94, 95% CI: 0.70-1.27) during the same period. Childbirth rates reached those of comparators for all subtypes after 3 years but the cumulative incidence of childbirths was decreased throughout the 10-year follow-up for aggressive NHL. Children of NHL patients were more likely to be born following assisted reproductive technology than those of comparators, except for male indolent lymphoma patients. In conclusion, fertility counselling is particularly important for patients with aggressive NHL.

Using a Clinically Interpretable End Point Composed of Multiple Outcomes to Evaluate Totality of Treatment Effect in Comparative Oncology Studies

This cohort study demonstrates how to use cumulative event count curves to create a clinically meaningful end point by simultaneously considering recurrence, progression, and survival times from the individual patient.

Alcohol consumption and risks of more than 200 diseases in Chinese men

Alcohol consumption accounts for ~3 million annual deaths worldwide, but uncertainty persists about its relationships with many diseases. We investigated the associations of alcohol consumption with 207 diseases in the 12-year China Kadoorie Biobank of >512,000 adults (41% men), including 168,050 genotyped for ALDH2- rs671 and ADH1B- rs1229984 , with >1.1 million ICD-10 coded hospitalized events. At baseline, 33% of men drank alcohol regularly. Among men, alcohol intake was positively associated with 61 diseases, including 33 not defined by the World Health Organization as alcohol-related, such as cataract (n = 2,028; hazard ratio 1.21; 95% confidence interval 1.09-1.33, per 280 g per week) and gout (n = 402; 1.57, 1.33-1.86). Genotype-predicted mean alcohol intake was positively associated with established (n = 28,564; 1.14, 1.09-1.20) and new alcohol-associated (n = 16,138; 1.06, 1.01-1.12) diseases, and with specific diseases such as liver cirrhosis (n = 499; 2.30, 1.58-3.35), stroke (n = 12,176; 1.38, 1.27-1.49) and gout (n = 338; 2.33, 1.49-3.62), but not ischemic heart disease (n = 8,408; 1.04, 0.94-1.14). Among women, 2% drank alcohol resulting in low power to assess associations of self-reported alcohol intake with disease risks, but genetic findings in women suggested the excess male risks were not due to pleiotropic genotypic effects. Among Chinese men, alcohol consumption increased multiple disease risks, highlighting the need to strengthen preventive measures to reduce alcohol intake.

Heart Failure Following Anti-Inflammatory Medications in Patients With Type 2 Diabetes Mellitus

BACKGROUND

Fluid retention and endothelial dysfunction have been related to use of nonsteroidal anti-inflammatory drugs (NSAIDs), and type 2 diabetes mellitus (T2DM) has been linked to both a decline in kidney function and subclinical cardiomyopathy.

OBJECTIVES

The authors hypothesized that short-term use of NSAIDs could lead to subsequent development of incident heart failure (HF) in patients with T2DM.

METHODS

Using nationwide Danish registers, we identified patients diagnosed with T2DM during 1998 to 2021 and included patients without previous HF, rheumatic disease, or use of NSAIDs 120 days before diagnosis. Associations between NSAIDs and first-time HF hospitalization were investigated using a case-crossover design with 28-day exposure windows, and ORs with 95% CIs were reported.

RESULTS

Included were 331,189 patients with T2DM: 44.2% female, median age of 62 years (IQR: 52-71 years); 23,308 patients were hospitalized with HF during follow-up, and 16% of patients claimed at least 1 NSAID prescription within 1 year. Short-term use of NSAIDs was associated with increased risk of HF hospitalization (OR: 1.43; 95% CI: 1.27-1.63), most notably in subgroups with age ≥80 years (OR: 1.78; 95% CI: 1.39-2.28), elevated hemoglobin (Hb) A1c levels treated with 0 to 1 antidiabetic drug (OR: 1.68; 95% CI: 1.00-2.88), and without previous use of NSAIDs (OR: 2.71; 95% CI: 1.78-4.23).

CONCLUSIONS

NSAIDs were widely used and were associated with an increased risk of first-time HF hospitalization in patients with T2DM. Patients with advanced age, elevated HbA1c levels, and new users of NSAID seemed more susceptible. These findings could guide physicians prescribing NSAIDs.

Bivariate pseudo-observations for recurrent event analysis with terminal events

The analysis of recurrent events in the presence of terminal events requires special attention. Several approaches have been suggested for such analyses either using intensity models or marginal models. When analysing treatment effects on recurrent events in controlled trials, special attention should be paid to competing deaths and their impact on interpretation. This paper proposes a method that formulates a marginal model for recurrent events and terminal events simultaneously. Estimation is based on pseudo-observations for both the expected number of events and survival probabilities. Various relevant hypothesis tests in the framework are explored. Theoretical derivations and simulation studies are conducted to investigate the behaviour of the method. The method is applied to two real data examples. The bivariate marginal pseudo-observation model carries the strength of a two-dimensional modelling procedure and performs well in comparison with available models. Finally, an extension to a three-dimensional model, which decomposes the terminal event per death cause, is proposed and exemplified.

High-dose intravenous iron reduces myocardial infarction in patients on haemodialysis

AIMS

To investigate the effect of high-dose iron vs. low-dose intravenous (IV) iron on myocardial infarction (MI) in patients on maintenance haemodialysis.

METHODS AND RESULTS

This was a pre-specified analysis of secondary endpoints of the Proactive IV Iron Therapy in Hemodialysis Patients trial (PIVOTAL) randomized, controlled clinical trial. Adults who had started haemodialysis within the previous year, who had a ferritin concentration <400 μg per litre and a transferrin saturation <30% were randomized to high-dose or low-dose IV iron. The main outcome measure for this analysis was fatal or non-fatal MI. Over a median of 2.1 years of follow-up, 8.4% experienced a MI. Rates of type 1 MIs (3.2/100 patient-years) were 2.5 times higher than type 2 MIs (1.3/100 patient-years). Non-ST-elevation MIs (3.3/100 patient-years) were 6 times more common than ST-elevation MIs (0.5/100 patient-years). Mortality was high after non-fatal MI (1- and 2-year mortality of 40% and 60%, respectively). In time-to-first event analyses, proactive high-dose IV iron reduced the composite endpoint of non-fatal and fatal MI [hazard ratio (HR) 0.69, 95% confidence interval (CI) 0.52-0.93, P = 0.01] and non-fatal MI (HR 0.69, 95% CI 0.51-0.93; P = 0.01) when compared with reactive low-dose IV iron. There was less effect of high-dose IV iron on recurrent MI events than on the time-to-first event analysis.

CONCLUSION

In total, 8.4% of patients on maintenance haemodialysis had an MI over 2 years. High-dose compared to low-dose IV iron reduced MI in patients receiving haemodialysis.

EUDRACT REGISTRATION NUMBER

2013-002267-25.

Allogeneic stem cell transplantation compared to conservative management in adults with inborn errors of immunity

Allogeneic hematopoietic stem cell transplantation (alloSCT) is curative for severe inborn errors of immunity (IEIs), with recent data suggesting alloSCT in adulthood is safe and effective in selected patients. However, questions remain regarding the indications for and optimal timing of transplant. We retrospectively compared outcomes of transplanted vs matched nontransplanted adults with severe IEIs. Seventy-nine patients (aged ≥ 15 years) underwent alloSCT between 2008 and 2018 for IEIs such as chronic granulomatous disease (n = 20) and various combined immune deficiencies (n = 59). A cohort of nontransplanted patients from the French Centre de Référence Déficits Immunitaires Héréditaires registry was identified blindly for case-control analysis, with ≤3 matched controls per index patient, without replacement. The nontransplanted patients were matched for birth decade, age at last review greater than index patient age at alloSCT, chronic granulomatous disease or combined immune deficiencies, and autoimmune/lymphoproliferative complications. A total of 281 patients were included (79 transplanted, 202 nontransplanted). Median age at transplant was 21 years. Transplant indications were mainly lymphoproliferative disease (n = 23) or colitis (n = 15). Median follow-up was 4.8 years (interquartile range, 2.5-7.2). One-year transplant-related mortality rate was 13%. Estimated disease-free survival at 5 years was higher in transplanted patients (58% vs 33%; P = .007). Nontransplanted patients had an ongoing risk of severe events, with an increased mean cumulative number of recurrent events compared with transplanted patients. Sensitivity analyses removing patients with common variable immune deficiency and their matched transplanted patients confirm these results. AlloSCT prevents progressive morbidity associated with IEIs in adults, which may outweigh the negative impact of transplant-related mortality.

Intravenous ferric derisomaltose in patients with heart failure and iron deficiency in the UK (IRONMAN): an investigator-initiated, prospective, randomised, open-label, blinded-endpoint trial

BACKGROUND

For patients with heart failure, reduced left ventricular ejection fraction and iron deficiency, intravenous ferric carboxymaltose administration improves quality of life and exercise capacity in the short-term and reduces hospital admissions for heart failure up to 1 year. We aimed to evaluate the longer-term effects of intravenous ferric derisomaltose on cardiovascular events in patients with heart failure.

METHODS

IRONMAN was a prospective, randomised, open-label, blinded-endpoint trial done at 70 hospitals in the UK. Patients aged 18 years or older with heart failure (left ventricular ejection fraction ≤45%) and transferrin saturation less than 20% or serum ferritin less than 100 μg/L were eligible. Participants were randomly assigned (1:1) using a web-based system to intravenous ferric derisomaltose or usual care, stratified by recruitment context and trial site. The trial was open label, with masked adjudication of the outcomes. Intravenous ferric derisomaltose dose was determined by patient bodyweight and haemoglobin concentration. The primary outcome was recurrent hospital admissions for heart failure and cardiovascular death, assessed in all validly randomly assigned patients. Safety was assessed in all patients assigned to ferric derisomaltose who received at least one infusion and all patients assigned to usual care. A COVID-19 sensitivity analysis censoring follow-up on Sept 30, 2020, was prespecified. IRONMAN is registered with ClinicalTrials.gov, NCT02642562.

FINDINGS

Between Aug 25, 2016, and Oct 15, 2021, 1869 patients were screened for eligibility, of whom 1137 were randomly assigned to receive intravenous ferric derisomaltose (n=569) or usual care (n=568). Median follow-up was 2·7 years (IQR 1·8-3·6). 336 primary endpoints (22·4 per 100 patient-years) occurred in the ferric derisomaltose group and 411 (27·5 per 100 patient-years) occurred in the usual care group (rate ratio [RR] 0·82 [95% CI 0·66 to 1·02]; p=0·070). In the COVID-19 analysis, 210 primary endpoints (22·3 per 100 patient-years) occurred in the ferric derisomaltose group compared with 280 (29·3 per 100 patient-years) in the usual care group (RR 0·76 [95% CI 0·58 to 1·00]; p=0·047). No between-group differences in deaths or hospitalisations due to infections were observed. Fewer patients in the ferric derisomaltose group had cardiac serious adverse events (200 [36%]) than in the usual care group (243 [43%]; difference -7·00% [95% CI -12·69 to -1·32]; p=0·016).

INTERPRETATION

For a broad range of patients with heart failure, reduced left ventricular ejection fraction and iron deficiency, intravenous ferric derisomaltose administration was associated with a lower risk of hospital admissions for heart failure and cardiovascular death, further supporting the benefit of iron repletion in this population.

FUNDING

British Heart Foundation and Pharmacosmos.

Prognosis and Survival in Idiopathic Pulmonary Fibrosis in the Era of Antifibrotic Therapy in Italy: Evidence from a Longitudinal Population Study Based on Healthcare Utilization Databases

The aim was to evaluate the determinants of acute exacerbation (AE) and death in new cases of idiopathic pulmonary fibrosis (IPF) using administrative databases in the Marche Region. Adults at their first prescription of antifibrotics or hospitalization with a diagnosis of IPF occurring in 2014-2019 were considered as new cases. Multiple Cox regression was used to estimate the risk of AE and of all-cause mortality adjusted by demographic and clinical characteristics, stratifying patients according to antifibrotic treatment. Overall, 676 new cases of IPF were identified and 276 deaths and 248 AE events occurred. In never-treated patients, the risk of AE was higher in patients with poor health conditions at diagnosis; the risk of death was higher in males, in patients aged ≥75 and in those with poor health conditions at baseline. The increasing number of AEs increased the risk of death in treated and never-treated patients. Within the limits of an observational study based on secondary data, the combined use of healthcare administrative databases allows the accurate analysis of progression and survival of IPF from the beginning of the antifibrotic therapy era, suggesting that timely and early diagnosis is critical to prescribing the most suitable treatment to increase survival and maintain a healthy life expectancy.

Comparative effectiveness of Empagliflozin in reducing the burden of recurrent cardiovascular hospitalizations among older adults with diabetes in routine clinical care

BACKGROUND

The effect of sodium glucose cotransporter 2 inhibitors (SGLT2i) on the total (first and recurrent) burden of cardiovascular (CV) hospitalizations, including hospitalization for heart failure, myocardial infarction, and stroke, is poorly understood.

OBJECTIVE

To assess the effect of empagliflozin, an SGLT2i, on total CV hospitalizations among older adults with T2D.

METHODS

Using data from Medicare fee-for-service (08/2014-09/2017), we identified 1:1 propensity score-matched cohorts of patients with T2D initiating empagliflozin versus sitagliptin or empagliflozin versus glucagon-like peptide-1 receptor agonists (GLP-1RA), balancing >140 baseline covariates. We compared the risk of first and recurrent hospitalizations with any CV condition as the primary discharge diagnosis (ICD-9: 390-459; ICD-10: I00-I99), hospitalizations for heart failure (HHF), and myocardial infarctions (MI) or stroke. We estimated treatment effects based on the Ghosh-Lin semiparametric model for recurrent events as primary and joint frailty model as secondary analysis.

RESULTS

We included 11,429 matched-pairs of empagliflozin and sitagliptin initiators and 17,502 matched-pairs of empagliflozin and GLP1-RA initiators with an average age of 72 years. Empagliflozin was associated with a reduced risk of total CV hospitalizations (0.80 [0.69-0.93] vs sitagliptin; 0.88 [0.77-1.00] vs GLP-1RA) and total HHF (0.70 [0.51-0.98] vs sitagliptin; 0.76 [0.56-1.03] vs GLP1-RA) over a mean follow up of 6.3 months. No differences between treatments were observed for MI or stroke. Results were consistent for joint frailty models.

CONCLUSION

Empagliflozin, compared to sitagliptin or to a lesser extent GLP1-RA, was associated with a reduction in the burden of total CV hospitalizations and HHF in older patients with T2D.

Tobacco smoking and risks of more than 470 diseases in China: a prospective cohort study

BACKGROUND

Tobacco smoking is estimated to account for more than 1 million annual deaths in China, and the epidemic continues to increase in men. Large nationwide prospective studies linked to different health records can help to periodically assess disease burden attributed to smoking. We aimed to examine associations of smoking with incidence of and mortality from an extensive range of diseases in China.

METHODS

We analysed data from the prospective China Kadoorie Biobank, which recruited 512 726 adults aged 30-79 years, of whom 210 201 were men and 302 525 were women. Participants who had no major disabilities were identified through local residential records in 100-150 administrative units, which were randomly selected by use of multistage cluster sampling, from each of the ten diverse study areas of China. They were invited and recruited between June 25, 2004, and July 15, 2008. Upon study entry, trained health workers administered a questionnaire assessing detailed smoking behaviours and other key characteristics (eg, sociodemographics, lifestyle, and medical history). Participants were followed up via electronic record linkages to death and disease registries and health insurance databases, from baseline to Jan 1, 2018. During a median 11-year follow-up (IQR 10-12), 285 542 (55·7%) participants were ever hospitalised, 48 869 (9·5%) died, and 5252 (1·0%) were lost to follow-up during the age-at-risk of 35-84 years. Cox regression yielded hazard ratios (HRs) associating smoking with disease incidence and mortality, adjusting for multiple testing.

FINDINGS

At baseline, 74·3% of men and 3·2% of women (overall 32·4%) ever smoked regularly. During follow-up, 1 137 603 International Classification of Diseases, 10th revision (ICD-10)-coded incident events occurred, involving 476 distinct conditions and 85 causes of death, each with at least 100 cases. Compared with never-regular smokers, ever-regular smokers had significantly higher risks for nine of 18 ICD-10 chapters examined at age-at-risk of 35-84 years. For individual conditions, smokers had significantly higher risks of 56 diseases (50 for men and 24 for women) and 22 causes of death (17 for men and nine for women). Among men, ever-regular smokers had an HR of 1·09 (95% CI 1·08-1·11) for any disease incidence when compared with never-regular smokers, and significantly more episodes and longer duration of hospitalisation, particularly those due to cancer and respiratory diseases. For overall mortality, the HRs were greater in men from urban areas than in men from rural areas (1·50 [1·42-1·58] vs 1·25 [1·20-1·30]). Among men from urban areas who began smoking at younger than 18 years, the HRs were 2·06 (1·89-2·24) for overall mortality and 1·32 (1·27-1·37) for any disease incidence. In this population, 19·6% of male (24·3% of men residing in urban settings and 16·2% of men residing in rural settings) and 2·8% of female deaths were attributed to ever-regular smoking.

INTERPRETATION

Among Chinese adults, smoking was associated with higher risks of morbidity and mortality from a wide range of diseases. Among men, the future smoking-attributed disease burden will increase further, highlighting a pressing need for reducing consumption through widespread cessation and uptake prevention.

FUNDING

British Heart Foundation, Cancer Research UK, Chinese Ministry of Science and Technology, Kadoorie Charitable Foundation, UK Medical Research Council, National Natural Science Foundation of China, Wellcome Trust.

Quantifying Treatment Effects in Trials with Multiple Event-Time Outcomes

BACKGROUND

Data on the occurrence times of multiple outcomes, reflecting the temporal profile of disease burden/progression, have been used to estimate treatment effects in various recent randomized trials. Most procedures for analyzing these data require specific model assumptions. When the assumptions are not met, the results may be misleading. Robust, model-free procedures for study design and analysis that enable clinically meaningful interpretations are warranted.

METHODS

For each treatment group, we constructed and summarized the estimated mean cumulative count of events over time by the area under the curve (AUC), which can be interpreted as the mean total event-free time lost from multiple undesirable outcomes. A higher curve, and resulting larger AUC, implies a worse treatment. The treatment effect is quantified by the ratio and/or difference of AUCs. The timing and occurrence of recurrent heart failure hospitalizations (HFHs) and cardiovascular (CV) death from Prospective Comparison of ARNI with ARB Global Outcomes in HF with Preserved Ejection Fraction (PARAGON-HF), comparing sacubitril/valsartan with valsartan, are presented for illustration. We also discuss the design of future studies on the basis of the proposed method.

RESULTS

With 48 months of follow-up, estimated AUCs, representing the total event-free time lost to HFHs and CV death, were 11.3 and 13.1 event-months for sacubitril/valsartan and valsartan, respectively. The ratio of these AUCs was 0.86 (95% confidence interval, 0.75 to 1.00; P=0.049), a 14% reduction of disease burden favoring combination therapy. A future study, similar to PARAGON-HF, designed using the new proposal would require fewer patients would than a conventional time-to-first-event analysis.

CONCLUSIONS

The proposed method is robust and model-free and provides a clinically interpretable, time-scale summary of the treatment effect. (Funded by National Institutes of Health.).

Dapagliflozin across the range of ejection fraction in patients with heart failure: a patient-level, pooled meta-analysis of DAPA-HF and DELIVER

Whether the sodium-glucose cotransporter 2 inhibitor dapagliflozin reduces the risk of a range of morbidity and mortality outcomes in patients with heart failure regardless of ejection fraction is unknown. A patient-level pooled meta-analysis of two trials testing dapagliflozin in participants with heart failure and different ranges of left ventricular ejection fraction (≤40% and >40%) was pre-specified to examine the effect of treatment on endpoints that neither trial, individually, was powered for and to test the consistency of the effect of dapagliflozin across the range of ejection fractions. The pre-specified endpoints were: death from cardiovascular causes; death from any cause; total hospital admissions for heart failure; and the composite of death from cardiovascular causes, myocardial infarction or stroke (major adverse cardiovascular events (MACEs)). A total of 11,007 participants with a mean ejection fraction of 44% (s.d. 14%) were included. Dapagliflozin reduced the risk of death from cardiovascular causes (hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.76-0.97; P = 0.01), death from any cause (HR 0.90, 95% CI 0.82-0.99; P = 0.03), total hospital admissions for heart failure (rate ratio 0.71, 95% CI 0.65-0.78; P < 0.001) and MACEs (HR 0.90, 95% CI 0.81-1.00; P = 0.045). There was no evidence that the effect of dapagliflozin differed by ejection fraction. In a patient-level pooled meta-analysis covering the full range of ejection fractions in patients with heart failure, dapagliflozin reduced the risk of death from cardiovascular causes and hospital admissions for heart failure (PROSPERO: CRD42022346524).

Rationale and design of a randomised trial of intravenous iron in patients with heart failure

OBJECTIVES

For patients with a reduced left ventricular ejection fraction (LVEF) heart failure with reduced ejection fraction (HFrEF) and iron deficiency, administration of intravenous iron improves symptoms, exercise capacity and may in the following 12 months, reduce hospitalisations for heart failure. The Effectiveness of Intravenous iron treatment versus standard care in patients with heart failure and iron deficiency (IRONMAN) trial evaluated whether the benefits of intravenous iron persist in the longer term and impact on morbidity and mortality.

METHODS

IRONMAN is a prospective, randomised, open-label, blinded endpoint (PROBE) event-driven trial. Patients aged ≥18 years with HFrEF (LVEF ≤45%) and evidence of iron deficiency (ferritin <100 µg/L and/or TSAT <20%) were enrolled if they had either a current or recent hospitalisation for heart failure or elevated plasma concentrations of a natriuretic peptide. Participants were randomised to receive, or not to receive, intravenous ferric derisomaltose in addition to guideline-recommended therapy for HFrEF. Every 4 months, intravenous iron was administered if either ferritin was <100 µg/L or, provided ferritin was ≤400 µg/L, TSAT was <25%. The primary endpoint is a composite of total hospitalisations for heart failure and cardiovascular death. Hospitalisation and deaths due to infection are safety endpoints.

RESULTS

Trial recruitment was completed across 70 UK hospital sites in October 2021. Participants were followed until the end of March 2022. We plan to report the results by November 2022.

CONCLUSIONS

IRONMAN will determine whether repeated doses of intravenous ferric derisomaltose are beneficial and safe for the long-term treatment of a broad range of patients with HFrEF and iron deficiency.

TRIAL REGISTRATION NUMBER

NCT02642562.

Health literacy and prognosis of heart failure: a prospective propensity-matched study in the community

AIMS

Health literacy (HL), the ability to obtain and understand health information, is critical to self-care in chronic disorders. A low HL is common among these patients and has been associated with a worse prognosis. Nevertheless, the relationship between HL and the prognosis of heart failure (HF) with reduced (HFrEF) vs. preserved (HFpEF) ejection fraction remains unsettled. To analyse the relationship between HL and the prognosis of patients with incident HFrEF and HFpEF.

METHODS AND RESULTS

Prospective study over 10 years (2010-19) on 6444 patients diagnosed with incident HF. The main outcomes were mortality, hospitalizations, and visits to emergency services. The independent relationship between HL and the prognosis, stratifying patients for cardiovascular comorbidity after propensity score-matching was analysed.After matching 5355 HF patients, 1785 with low HL (874 with HFrEF and 911 with HFpEF) vs. 3570 with adequate HL (1748 with HFrEF and 1822 with HFpEF), during a median follow-up of 5.41 years, 3874 patients died (72.3%) and 3699 patients were hospitalized (69.1%). After adjustment for potential confounders, an adequate HL was associated with a lower all-cause and cardiovascular mortality, less hospitalizations, and less 30-day readmissions [relative risk (RR) for HF <0.72 (0.66-0.86), RR for HFrEF <0.69 (0.63-0.95), and RR for HFpEF <0.62 (0.55-0.88), P < 0.001 in all cases], both for patients with HFrEF and HFpEF. Analyses of recurrent hospitalizations gave larger HL effects than time-to-first-event analyses.

CONCLUSIONS

In this propensity-matched study, a low HL is associated with a worse prognosis of patients with incident HFrEF and HFpEF.

Adverse Events Associated With Coprescription of Phosphodiesterase Type 5 Inhibitors and Oral Organic Nitrates in Male Patients With Ischemic Heart Disease : A Case-Crossover Study

BACKGROUND

Concomitant use of oral organic nitrates (nitrates) and phosphodiesterase type 5 (PDE5) inhibitors is contraindicated.

OBJECTIVE

To measure temporal trends in the coprescription of nitrates and PDE5 inhibitors and to measure the association between cardiovascular outcomes and the coprescription of nitrates with PDE5 inhibitors.

DESIGN

Case-crossover design.

SETTING

Nationwide study of Danish patients from 2000 to 2018.

PATIENTS

Male patients with International Classification of Diseases, 10th Revision (ICD-10) codes for ischemic heart disease (IHD), including those who had a continuing prescription for nitrates and a new, filled prescription for PDE5 inhibitors.

MEASUREMENTS

Two composite outcomes were measured: 1) cardiac arrest, shock, myocardial infarction, ischemic stroke, or acute coronary arteriography and 2) syncope, angina pectoris, or drug-related adverse event.

RESULTS

From 2000 to 2018, 249 541 male patients with IHD were identified. Of these, 42 073 patients had continuing prescriptions for nitrates. During this period, the prescription rate for PDE5 inhibitors in patients with IHD who were taking nitrates increased from an average of 0.9 prescriptions (95% CI, 0.5 to 1.2 prescriptions) per 100 persons per year in 2000 to 19.5 prescriptions (CI, 18.0 to 21.1 prescriptions) in 2018. No statistically significant association was found between the coprescription of nitrates with PDE5 inhibitors and the risk for either composite outcome (odds ratio [OR], 0.58 [CI, 0.28 to 1.13] for the first outcome and OR, 0.73 [CI, 0.40 to 1.32] for the second outcome).

LIMITATION

An assumption was made that concurrently filled prescriptions for nitrates and PDE5 inhibitors equaled concomitant use.

CONCLUSION

From 2000 to 2018, the use of PDE5 inhibitors increased 20-fold among Danish patients with IHD who were taking nitrates. A statistically significant association between concomitant use of these medications and cardiovascular adverse events could not be identified.

PRIMARY FUNDING SOURCE

Ib Mogens Kristiansens Almene Fond and Helsefonden.

On recurrent-event win ratio

The win ratio approach proposed by Pocock et al. (2012) has become a popular tool for analyzing composite endpoints of death and non-fatal events like hospitalization. Its standard version, however, draws on the non-fatal event only through the first occurrence. For statistical efficiency and clinical interpretability, we construct and compare different win ratio variants that make fuller use of recurrent events. We pay special attention to a variant called last-event-assisted win ratio, which compares two patients on the cumulative frequency of the non-fatal event, with ties broken by the time of its latest episode. It is shown that last-event-assisted win ratio uses more data than the standard win ratio does but reduces to the latter when the non-fatal event occurs at most once. We further prove that last-event-assisted win ratio rejects the null hypothesis with large probability if the treatment stochastically delays all events. Simulations under realistic settings show that the last-event-assisted win ratio test consistently enjoys higher power than the standard win ratio and other competitors. Analysis of a real cardiovascular trial provides further evidence for the practical advantages of the last-event-assisted win ratio. Finally, we discuss future work to develop meaningful effect size estimands based on the extended rules of comparison. The R-code for the proposed methods is included in the package WR openly available on the Comprehensive R Archive Network.

Patients in complete remission after R-CHOP(-like) therapy for diffuse large B-cell lymphoma have limited excess use of health care services in Denmark

For most patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL), R-CHOP immunochemotherapy leads to complete remission and 60-70% of patients remain progression-free after 5 years. Given a median age of 65, it is relevant to disentangle how DLBCL and DLBCL therapy influence health care use among the survivors. In this nationwide study, the health care use among Danish DLBCL patients diagnosed in 2007-2015, who achieved complete remission after R-CHOP(-like) therapy, was explored and compared to matched comparators from the Danish general population. The post-remission 5-year risk of hospitalization was significantly higher among DLBCL survivors (55%) compared to matched comparators (49%, P < 0.001). DLBCL survivors had on average 10.3 (9.3-11.3) inpatient bed days within 5 years of response evaluation, whereas matched comparators had 8.4 (7.9-8.8). The rate of outpatient visits was also significantly higher(excluding routine follow-up visits, incidence rate ratio, 1.3, P < 0.001), but translated into only a very small absolute difference of <1 outpatient visits within 5 years between DLBCL survivors (4.2 visits, 95% CI, 4.0-4.4) and matched comparators (3.8 visits, 95% CI, 3.7-3.9). In conclusion, DLBCL survivors have an increased incidence of hospital visits due to a wide range of conditions, but in absolute terms the excess use of health care services in DLBCL survivors was small.

INFERR-Iron infusion in haemodialysis study: INtravenous iron polymaltose for First Nations Australian patients with high FERRitin levels on haemodialysis-a protocol for a prospective open-label blinded endpoint randomised controlled trial

Background

The effectiveness of erythropoiesis-stimulating agents, which are the main stay of managing anaemia of chronic kidney disease (CKD), is largely dependent on adequate body iron stores. The iron stores are determined by the levels of serum ferritin concentration and transferrin saturation. These two surrogate markers of iron stores are used to guide iron replacement therapy. Most Aboriginal and/or Torres Islander Australians of the Northern Territory (herein respectfully referred to as First Nations Australians) with end-stage kidney disease have ferritin levels higher than current guideline recommendations for iron therapy. There is no clear evidence to guide safe and effective treatment with iron in these patients. We aim to assess the impact of intravenous iron treatment on all-cause death and hospitalisation with a principal diagnosis of all-cause infection in First Nations patients on haemodialysis with anaemia, high ferritin levels and low transferrin saturation

Methods

In a prospective open-label blinded endpoint randomised controlled trial, a total of 576 participants on maintenance haemodialysis with high ferritin (> 700 μg/L and ≤ 2000 μg/L) and low transferrin saturation (< 40%) from all the 7 renal units across the Northern Territory of Australia will be randomised 1:1 to receive intravenous iron polymaltose 400 mg once monthly (200 mg during 2 consecutive haemodialysis sessions) (Arm A) or no IV iron treatment (standard treatment) (Arm B). Rescue therapy will be administered when the ferritin levels fall below 700 μg/L or when clinically indicated. The primary outcome will be the differences between the two study arms in the risk of hospitalisation with all-cause infection or death. An economic analysis and several secondary and tertiary outcomes analyses will also be performed.

Discussion

The INFERR clinical trial will address significant uncertainty on the safety and efficacy of iron therapy in First Nations Australians with CKD with hyperferritinaemia and evidence of iron deficiency. This will hopefully lead to the development of evidence-based guidelines. It will also provide the opportunity to explore the causes of hyperferritinaemia in First Nations Australians from the Northern Territory.

Trial registration

This trial is registered with The Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12620000705987. Registered 29 June 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05854-w.

Readmissions, Death and Its Associated Predictors in Heart Failure With Preserved Versus Reduced Ejection Fraction

Background

Data on rehospitalizations for heart failure (HF) in Asia are scarce. We sought to determine the burden and predictors of HF (first and recurrent) rehospitalizations and all‐cause mortality in patients with HF and preserved versus reduced ejection fraction (preserved EF, ≥50%; reduced EF, <40%), in the multinational ASIAN‐HF (Asian Sudden Cardiac Death in Heart Failure) registry.

Methods and Results

Patients with symptomatic (stage C) chronic HF were followed up for death and recurrent HF hospitalizations for 1 year. Predictors of HF hospitalizations or all‐cause mortality were examined with Cox regression for time to first event and other methods for recurrent events analyses. Among 1666 patients with HF with preserved EF (mean age, 68±12 years; 50% women), and 4479 with HF with reduced EF (mean age, 61±13 years; 22% women), there were 642 and 2302 readmissions, with 28% and 45% attributed to HF, respectively. The 1‐year composite event rate for first HF hospitalization or all‐cause death was 11% and 21%, and for total HF hospitalization and all‐cause death was 17.7 and 38.7 per 100 patient‐years in HF with preserved EF and HF with reduced EF, respectively. In HF with preserved EF, consistent independent predictors of these clinical end points included enrollment as an inpatient, Southeast Asian location, and comorbid chronic kidney disease or atrial fibrillation. The same variables were predictive of outcomes in HF with reduced EF except atrial fibrillation, and also included Northeast Asian location, older age, elevated heart rate, decreased systolic blood pressure, diabetes, smoking, and non‐usage of beta blockers.

Conclusions

One‐year HF rehospitalization and mortality rates were high among Asian patients with HF. Predictors of outcomes identified in this study could aid in risk stratification and timely interventions.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01633398.

Statistical models for composite endpoints of death and non-fatal events: a review

The proper analysis of composite endpoints consisting of both death and non-fatal events is an intriguing and sometimes contentious topic. The current practice of analyzing time to the first event often draws criticisms for ignoring the unequal importance between component events and for leaving recurrent-event data unused. Novel methods that address these limitations have recently been proposed. To compare the novel versus traditional approaches, we review three typical models for composite endpoints based on time to the first event, composite event process, and pairwise hierarchical comparisons. The pros and cons of these models are discussed with reference to the relevant regulatory guidelines, such as the recently released ICH-E9(R1) Addendum "Estimands and Sensitivity Analysis in Clinical Trials". We also discuss the impact of censoring when the model assumptions are violated and explore sensitivity analysis strategies. Simulation studies are conducted to assess the performance of the reviewed methods under different settings. As demonstration, we use publicly available R-packages to analyze real data from a major cardiovascular trial.

Effects of initial invasive vs. initial conservative treatment strategies on recurrent and total cardiovascular events in the ISCHEMIA trial

AIMS

The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial prespecified an analysis to determine whether accounting for recurrent cardiovascular events in addition to first events modified understanding of the treatment effects.

METHODS AND RESULTS

Patients with stable coronary artery disease (CAD) and moderate or severe ischaemia on stress testing were randomized to either initial invasive (INV) or initial conservative (CON) management. The primary outcome was a composite of cardiovascular death, myocardial infarction (MI), and hospitalization for unstable angina, heart failure, or cardiac arrest. The Ghosh-Lin method was used to estimate mean cumulative incidence of total events with death as a competing risk. The 5179 ISCHEMIA patients experienced 670 index events (318 INV, 352 CON) and 203 recurrent events (102 INV, 101 CON). A single primary event was observed in 9.8% of INV and 10.8% of CON patients while ≥2 primary events were observed in 2.5% and 2.8%, respectively. Patients with recurrent events were older; had more frequent hypertension, diabetes, prior MI, or cerebrovascular disease; and had more multivessel CAD. The average number of primary endpoint events per 100 patients over 4 years was 18.2 in INV [95% confidence interval (CI) 15.8-20.9] and 19.7 in CON (95% CI 17.5-22.2), difference -1.5 (95% CI -5.0 to 2.0, P = 0.398). Comparable results were obtained when all-cause death was substituted for cardiovascular death and when stroke was added as an event.

CONCLUSIONS

In stable CAD patients with moderate or severe myocardial ischaemia enrolled in ISCHEMIA, an initial INV treatment strategy did not prevent either net recurrent events or net total events more effectively than an initial CON strategy.

CLINICAL TRIAL REGISTRATION

ISCHEMIA ClinicalTrials.gov number, NCT01471522, https://clinicaltrials.gov/ct2/show/NCT01471522.

Methodological challenges in the analysis of recurrent events for randomised controlled trials with application to cardiovascular events in LEADER

Analysis of recurrent events is becoming increasingly popular for understanding treatment effects in randomised controlled trials. The analysis of recurrent events can improve efficiency and capture disease burden compared to standard time-to-first event analyses. However, the added knowledge about the multi-state process comes at the cost of modelling complexity. High mortality rates can complicate matters even more. A case study using data from a randomised controlled trial, LEADER, is presented to highlight interpretation of common methods as well as potential pitfalls when analysing recurrent events in the presence of a competing risk. The presented methods either target features of the underlying intensity functions or marginal traits of a multi-state process which includes terminal events or not. In particular, approaches to handle death as a part of an event and as a competing risk are discussed. A new method targeting the marginal mean function for a composite endpoint, which includes both death as a component and as a competing risk, will be introduced. Finally, recommendations for how to capture meaningful treatment effects in randomised controlled trials when analysing recurrent and terminal events will be made.

A comparison of semiparametric approaches to evaluate composite endpoints in heart failure trials

In heart failure (HF) trials efficacy is usually assessed by a composite endpoint including cardiovascular death (CVD) and heart failure hospitalizations (HFHs), which has traditionally been evaluated with a time-to-first-event analysis based on a Cox model. As a considerable fraction of events is ignored that way, methods for recurrent events were suggested, among others the semiparametric proportional rates models by Lin, Wei, Yang, and Ying (LWYY model) and Mao and Lin (Mao-Lin model). In our work we apply least false parameter theory to explain the behavior of the composite treatment effect estimates resulting from the Cox model, the LWYY model, and the Mao-Lin model in clinically relevant scenarios parameterized through joint frailty models. These account for both different treatment effects on the two outcomes (CVD, HFHs) and the positive correlation between their risk rates. For the important setting of beneficial outcome-specific treatment effects we show that the correlation results in composite treatment effect estimates, which are decreasing with trial duration. The estimate from the Cox model is affected more by the attenuation than the estimates from the recurrent event models, which both demonstrate very similar behavior. Since the Mao-Lin model turns out to be less sensitive to harmful effects on mortality, we conclude that, among the three investigated approaches, the LWYY model is the most appropriate one for the composite endpoint in HF trials. Our investigations are motivated and compared with empirical results from the PARADIGM-HF trial (ClinicalTrials.gov identifier: NCT01035255), a large multicenter trial including 8399 chronic HF patients.

Survival analyses in cardiovascular research, part II: statistical methods in challenging situations

This article is the second of a series of 2 educational articles. In the first article, we described the basic concepts of survival analysis, summarizing the common statistical methods and providing a set of recommendations to guide the strategy of survival analyses in randomized clinical trials and observational studies. Here, we introduce stratified Cox models and frailty models, as well as the immortal time bias arising from a poor assessment of time-dependent variables. To address the issue of multiplicity of outcomes, we provide several modelling strategies to deal with other types of time-to-event data analyses, such as competing risks, multistate models, and recurrent-event methods. This review is illustrated with examples from previous cardiovascular research publications, and each statistical method is discussed alongside its main strengths and limitations. Finally, we provide some general observations about alternative statistical methods with less restrictive assumptions, such as the win ratio method, the restrictive mean survival time, and accelerated failure time model.

Feasibility and effectiveness of a multidimensional post-discharge disease management programme for heart failure patients in clinical practice: the HerzMobil Tirol programme

AIMS

It remains unclear whether transitional care management outside of a clinical trial setting provides benefits for patients with acute heart failure (AHF) after hospitalization. We evaluated the feasibility and effectiveness of a multidimensional post-discharge disease management programme using a telemedical monitoring system incorporated in a comprehensive network of heart failure nurses, resident physicians, and secondary and tertiary referral centres (HerzMobil Tirol, HMT), METHODS AND RESULTS: The non-randomized study included 508 AHF patients that were managed in HMT (n = 251) or contemporaneously in usual care (UC, n = 257) after discharge from hospital from 2016 to 2019. Groups were retrospectively matched for age and sex. The primary endpoint was time to HF readmission and all-cause mortality within 6 months. Multivariable Cox proportional hazard models were used to assess the effectiveness. The primary endpoint occurred in 48 patients (19.1%) in HMT and 89 (34.6%) in UC. Compared with UC, management by HMT was associated with a 46%-reduction in the primary endpoint (adjusted HR 0.54; 95% CI 0.37-0.77; P < 0.001). Subgroup analyses revealed consistent effectiveness. The composite of recurrent HF hospitalization and death within 6 months per 100 patient-years was 64.2 in HMT and 108.2 in UC (adjusted HR 0.41; 95% CI 0.29-0.55; P < 0.001 with death considered as a competing risk). After 1 year, 25 (10%) patients died in HMT compared with 66 (25.7%) in UC (HR 0.38; 95% CI 0.23-0.61, P < 0.001).

CONCLUSIONS

A multidimensional post-discharge disease management programme, comprising a telemedical monitoring system incorporated in a comprehensive network of specialized heart failure nurses and resident physicians, is feasible and effective in clinical practice.

Oral fluoroquinolones and risk of aortic or mitral regurgitation: a nationwide nested case-control study

AIMS

Reports have suggested an increased risk of aortic and mitral regurgitation associated with oral fluoroquinolones (FQs) resulting in a safety warning published by the European Medicines Agency (EMA). However, these findings have not yet been replicated.

METHODS AND RESULTS

Using Danish administrative registers, we conducted a nested case-control study in a nationwide cohort of individuals between 2005 and 2018. Cases were defined as the first occurrence of aortic or mitral regurgitation. Exposure of interest was the use of oral FQs. Hazard ratios (HRs) with 95% confidence intervals (95% CI) were obtained by fitting time-dependent Cox regression models, with penicillin V as comparator, to assess the association between FQ use and incident valvular regurgitation. We identified 38 370 cases of valvular regurgitation with 1 115 100 matched controls. FQ exposure was not significantly associated with increased rates of aortic or mitral regurgitation (HR 1.02, 95% CI 0.95-1.09) compared with penicillin V users. Investigating the cumulative defined daily doses (cDDD) of FQs yielded similar results with no significant association between increasing FQ use and valvular regurgitation (e.g. HR 1.08, 95% CI 0.95-1.23 for cDDD >10 compared with cDDD 1-5). These results were consistent across several analyses including a cohort of patients with hypertension and using a case definition based on valvular surgical interventions.

CONCLUSIONS

In a nationwide nested case-control study, FQs were not significantly associated with increased rates of valvular regurgitation. Our findings do not support a possible causal connection between FQ exposure and incident valvular regurgitation.

Heart Failure Hospitalization in Adults Receiving Hemodialysis and the Effect of Intravenous Iron Therapy

OBJECTIVES

This study sought to examine the effect of intravenous iron on heart failure events in hemodialysis patients.

BACKGROUND

Heart failure is a common and deadly complication in patients receiving hemodialysis and is difficult to diagnose and treat.

METHODS

The study analyzed heart failure events in the PIVOTAL (Proactive IV Iron Therapy in Hemodialysis Patients) trial, which compared intravenous iron administered proactively in a high-dose regimen with a low-dose regimen administered reactively. Heart failure hospitalization was an adjudicated outcome, a component of the primary composite outcome, and a prespecified secondary endpoint in the trial.

RESULTS

Overall, 2,141 participants were followed for a median of 2.1 years. A first fatal or nonfatal heart failure event occurred in 51 (4.7%) of 1,093 patients in the high-dose iron group and in 70 (6.7%) of 1,048 patients in the low-dose group (HR: 0.66; 95% CI: 0.46-0.94; P = 0.023). There was a total of 63 heart failure events (including first and recurrent events) in the high-dose iron group and 98 in the low-dose group, giving a rate ratio of 0.59 (95% CI: 0.40-0.87; P = 0.0084). Most patients presented with pulmonary edema and were mainly treated by mechanical removal of fluid. History of heart failure and diabetes were independent predictors of a heart failure event.

CONCLUSIONS

Compared with a lower-dose regimen, high-dose intravenous iron decreased the occurrence of first and recurrent heart failure events in patients undergoing hemodialysis, with large relative and absolute risk reductions. (UK Multicentre Open-label Randomised Controlled Trial Of IV Iron Therapy In Incident Haemodialysis Patients; 2013-002267-25).

Semiparametric analysis of zero-inflated recurrent events with a terminal event

Recurrent event data frequently arise in longitudinal studies and observations on recurrent events could be terminated by a major failure event such as death. In many situations, there exist a large fraction of subjects without any recurrent events of interest. Among these subjects, some are unsusceptible to recurrent events, while others are susceptible but have no recurrent events being observed due to censoring. In this article, we propose a zero-inflated generalized joint frailty model and a sieve maximum likelihood approach to analyze zero-inflated recurrent events with a terminal event. The model provides a considerable flexibility in formulating the effects of covariates on both recurrent events and the terminal event by specifying various transformation functions. In addition, Bernstein polynomials are employed to approximate the unknown cumulative baseline hazard (intensity) function. The estimation procedure can be easily implemented and is computationally fast. Extensive simulation studies are conducted and demonstrate that our proposed method works well for practical situations. Finally, we apply the method to analyze myocardial infarction recurrences in the presence of death in a clinical trial with cardiovascular outcomes.

Disease-specific hospitalizations among 5-year survivors of Wilms tumor: A Nordic population-based cohort study

BACKGROUND

With modern therapy, over 90% of Wilms tumor patients can expect to become long-term survivors, and focus on morbidity and late effects become increasingly important. We provide a novel evaluation and insight to subsequent hospitalizations in 5-year survivors of Wilms tumor.

METHODS

As part of the Adult Life after Childhood Cancer in Scandinavia (ALiCCS) study, we identified 5-year survivors of Wilms tumor. Based on stratified random sampling, we constructed a population comparison cohort. Outcomes of interest were overall hospitalizations; hospitalizations for specific organ systems and disease-specific categories. Standardized hospitalization rate ratios (SHRR) and absolute excess risks (AER) were calculated.

RESULTS

We included 913, 5-year survivors of Wilms tumor and 152 231 population comparisons. Survivors of Wilms tumor had an increased overall risk of being hospitalized (SHRR 1.8; 95% confidence interval (CI) 1.7-2.0). The hospitalization risk was increased within all major organ systems: urinary and genital organs (SHRR 2.5; 95% CI 2.1-3.0), endocrine (SHRR 2.5; 95% CI 1.9-3.3), cardiovascular (SHRR 2.2; 95% CI 1.7-2.9), and gastrointestinal (SHRR 1.5; 95% CI 1.3-1.8). Risks for specific diseases are reported in the study.

CONCLUSIONS

Survivors of Wilms tumor had higher risks than population comparisons for a wide range of diseases, with the highest risks seen for urinary, endocrine, and cardiovascular disorders. Five to 20 years after the Wilms tumor diagnosis, 43% of survivors had been hospitalized at least once versus 29% of population comparisons. The overall AER was 2.3, which translates into 0.2 extra hospitalizations in 10 years for every Wilms tumor survivor.

Semiparametric recurrent event vs time-to-first-event analyses in randomized trials: Estimands and model misspecification

Insights regarding the merits of recurrent event and time-to-first-event analyses are needed to provide guidance on strategies for analyzing intervention effects in randomized trials involving recurrent event responses. Using established asymptotic results we introduce a framework for studying the large sample properties of estimators arising from semiparametric proportional rate function models and Cox regression under model misspecification. The asymptotic biases and power implications are investigated for different data generating models, and we study the impact of dependent censoring on these findings. Illustrative applications are given involving data from a cystic fibrosis trial and a carcinogenicity experiment, following which we summarize findings and discuss implications for clinical trial design.

Dapagliflozin and Recurrent Heart Failure Hospitalizations in Heart Failure With Reduced Ejection Fraction: An Analysis of DAPA-HF

Patients with heart failure (HF) and reduced ejection fraction will experience multiple hospitalizations for heart failure during the course of their disease. We assessed the efficacy of dapagliflozin on reducing the rate of total (ie, first and repeat) hospitalizations for heart failure in the DAPA-HF trial (Dapagliflozin and Prevention of Adverse-Outcomes in Heart Failure).

Increased risk of neonatal complications and infections in children of kidney-transplanted women: A nationwide controlled cohort study

Information related to short- and long-term risks of children born to kidney-transplanted women remains limited. With the aim of investigating the risk of neonatal complications, and the short- and long-term risk of infections in offspring of kidney-transplanted women, all children born to kidney-transplanted women in Denmark from 1964 to 2016 were identified in a nationwide retrospective matched cohort study. A total of 124 children of kidney-transplanted women were identified and matched on gender, birth year, and number of siblings at birth 1:10 with children born to nontransplanted women identified in the Danish general population. Prevalence of low birth weight (37.9%, risk ratio [RR] = 12.61; 95% confidence interval [CI], 8.5-18.5), premature birth (46.0%, RR = 11.32; 95% CI, 8.1-15.7) and malformations (11.3%, RR = 1.98; 95% CI, 1.2-3.4) was increased in children of kidney-transplanted women compared with controls. Similarly, prevalence of hospitalization due to infection was increased during the first year of life (21.0%, RR = 1.94; 95% CI, 1.3-2.8), from age 1 to 5 (34.2%, RR = 1.89; 95% CI, 1.4-2.5), and overall (41.9%, RR = 1.67; 95% CI, 1.3-2.1). The risk of infection was also higher in children of kidney-transplanted mothers born preterm or with low birth weight compared with similar controls. In conclusion, risk of neonatal complications, malformations, and both early and late infection were increased in children born to kidney-transplanted women.

Pregnancy outcomes in women with neurofibromatosis 1: a Danish population-based cohort study

BACKGROUND

The probability of a pregnancy, live birth, stillbirth and abortion has never been assessed in women with neurofibromatosis 1 (NF1) in a large population-based study.

METHODS

We included 1006 women (15-49 years) registered with NF1 in the Danish National Patient Registry or followed in two national Centers for Rare Diseases and 10 020 women from the Danish population. Information on pregnancy outcomes was ascertained from health registries. Cumulative incidence, mean cumulative count, hazard ratios (HRs) and proportion ratios (PRs) with 95% CIs were calculated.

RESULTS

The cumulative incidence of a first pregnancy at age 50 years was slightly lower in women with NF1 (74%; 95% CI 70 to 77) than in population comparisons (78%; 95% CI 77 to 79). When all pregnancies were included, two pregnancies were expected per woman at age of 50 years, irrespective of a NF1 diagnosis. The hazard of a pregnancy did not differ between women with NF1 (HR 1.03; 95% CI 0.95 to 1.11) and the comparisons after adjustment for somatic and psychiatric disease. The proportion of pregnancies that resulted in a live birth was 63% (783/1252) among women NF1 and 68% (8432/12 465) among the comparisons, yielding a PR of 0.95 (95% CI 0.90 to 1.00). The proportions of stillbirths (PR 2.83; 95% CI 1.63 to 4.93) and spontaneous abortions (PR 1.40; 95% CI 1.09 to 1.79) were increased in women with NF1.

CONCLUSIONS

A similar hazard for pregnancy was observed for women with NF1 and population comparisons after adjustment for potential medical consequences of NF1. However, women with NF1 experienced more spontaneous abortions and stillbirths.

Non-parametric recurrent events analysis with BART and an application to the hospital admissions of patients with diabetes

Much of survival analysis is concerned with absorbing events, i.e., subjects can only experience a single event such as mortality. This article is focused on non-absorbing or recurrent events, i.e., subjects are capable of experiencing multiple events. Recurrent events have been studied by many; however, most rely on the restrictive assumptions of linearity and proportionality. We propose a new method for analyzing recurrent events with Bayesian Additive Regression Trees (BART) avoiding such restrictive assumptions. We explore this new method via a motivating example of hospital admissions for diabetes patients and simulated data sets.