The relevance of subgroup-specific treatment effects: the Studies Of Left Ventricular Dysfunction (SOLVD) revisited

Impact of a Patient's Baseline Risk on the Relative Benefit and Harm of a Preventive Treatment Strategy: Applying Trial Results in Clinical Decision Making

Background

For translating an overall trial result into an individual patient’s expected absolute treatment effect, differences in relative treatment effect between patients need to be taken into account. The aim of this study was to evaluate whether relative treatment effects of medication in 2 large contemporary trials are influenced by multivariable baseline risk of an individual patient.

Methods and Results

In 9361 patients from SPRINT (Systolic Blood Pressure Intervention Trial), risk of major adverse cardiovascular events was assessed using a newly derived risk model. In 18 133 patients from the RE‐LY (Randomized Evaluation of Long‐Term Anticoagulant Therapy) trial, risk of stroke or systemic embolism and major bleeding was assessed using the Global Anticoagulant Registry in the Field–Atrial Fibrillation risk model. Heterogeneity of trial treatment effect was assessed using Cox models of trial allocation, model linear predictor, and their interaction. There was no significant interaction between baseline risk and relative treatment effect from intensive blood pressure lowering in SPRINT (P=0.92) or from dabigatran compared with warfarin for stroke or systemic embolism in the RE‐LY trial (P=0.71). There was significant interaction between baseline risk and treatment effect from dabigatran versus warfarin in the RE‐LY trial (P<0.001) for major bleeding. Quartile‐specific hazard ratios for bleeding ranged from 0.40 (95% CI, 0.26–0.61) to 1.04 (95% CI, 0.83–1.03) for dabigatran, 110 mg, and from 0.61 (95% CI, 0.42–0.88) to 1.20 (95% CI, 0.97–1.50) for dabigatran, 150 mg, compared with warfarin.

Conclusions

Effect modification of relative treatment effect by individual baseline event risk should be assessed systematically in randomized clinical trials using multivariate risk prediction, not only in terms of treatment efficacy but also for important treatment harms, as a prespecified analysis.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01206062.

Clinical predictors of outcome in patients with inflammatory dilated cardiomyopathy

Objectives

The study objectives were to identify predictors of outcome in patients with inflammatory dilated cardiomyopathy (DCMi).

Methods

From 2004 to 2008, 55 patients with biopsy-proven DCMi were identified and followed up for 58.2±19.8 months. Predictors of outcome were identified in a multivariable analysis with a Cox proportional hazards analysis. The primary endpoint was a composite of death, heart transplantation and hospitalization for heart failure or ventricular arrhythmias.

Results

For the primary endpoint, a QTc interval >440msec (HR 2.84; 95% CI 1.03–7.87; p = 0.044), a glomerular filtration rate (GFR) <60ml/min/1.73m² (HR 3.19; 95% CI 1.35–7.51; p = 0.008) and worsening of NYHA classification during follow-up (HR 2.48; 95% CI 1.01–6.10; p = 0.048) were univariate predictors, whereas left ventricular ejection fraction at baseline, NYHA class at entry, atrial fibrillation, treatment with digitalis or viral genome detection were not significantly related to outcome. After multivariable analysis, a GFR <60ml/min/1.73m² (HR 3.04; 95% CI 1.21–7.66; p = 0.018) remained a predictor of adverse outcome.

Conclusions

In patients with DCMi, a prolonged QTc interval >440msec, a GFR<60ml/min/1.73m² and worsening of NYHA classification during follow-up were univariate predictors of adverse prognosis. In contrast, NYHA classification at baseline, left ventricular ejection fraction, atrial fibrillation, treatment with digitalis or viral genome detection were not related to outcome. After multivariable analysis, a GFR <60ml/min/1.73m² remained independently associated with adverse outcome.

Non-cardiovascular comorbidity, severity and prognosis in non-selected heart failure populations: A systematic review and meta-analysis

Background

Non-cardiovascular comorbidities are recognised as independent prognostic factors in selected heart failure (HF) populations, but the evidence on non-selected HF and how comorbid disease severity and change impacts on outcomes has not been synthesised. We identified primary HF comorbidity follow-up studies to compare the impact of non-cardiovascular comorbidity, severity and change on the outcomes of quality of life, all-cause hospital admissions and all-cause mortality.

Methods

Literature databases (Jan 1990–May 2013) were screened using validated strategies and quality appraisal (QUIPS tool). Adjusted hazard ratios for the main HF outcomes were combined using random effects meta-analysis and inclusion of comorbidity in prognostic models was described.

Results

There were 68 primary HF studies covering nine non-cardiovascular comorbidities. Most were on diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD) and renal dysfunction (RD) for the outcome of mortality (93%) and hospital admissions (16%), median follow-up of 4 years. The adjusted associations between HF comorbidity and mortality were DM (HR 1.34; 95% CI 1.2, 1.5), COPD (1.39; 1.2, 1.6) and RD (1.52; 1.3, 1.7). Comorbidity severity increased mortality from moderate to severe disease by an estimated 78%, 42% and 80% respectively. The risk of hospital admissions increased up to 50% for each disease. Few studies or prognostic models included comorbidity change.

Conclusions

Non-cardiovascular comorbidity and severity significantly increases the prognostic risk of poor outcomes in non-selected HF populations but there is a major gap in investigating change in comorbid status over time. The evidence supports a step-change for the inclusion of comorbidity severity in new HF interventions to improve prognostic outcomes.

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We synthesise the prognosis evidence on non-CVD comorbidity and severity in non-selected HF

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Most studies focused on three comorbid diseases for mortality and admissions and none for QoL

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COPD, diabetes and CKD increased mortality and admission risk in non-selected HF

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Severity studies were few but where available, risk increased with disease severity

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Comorbidity severity is important but has yet to be included in HF prognostic models

Disease risk score as a confounder summary method: systematic review and recommendations

PURPOSE

To systematically examine trends and applications of the disease risk score (DRS) as a confounder summary method.

METHODS

We completed a systematic search of MEDLINE and Web of Science® to identify all English language articles that applied DRS methods. We tabulated the number of publications by year and type (empirical application, methodological contribution, or review paper) and summarized methods used in empirical applications overall and by publication year (<2000, ≥2000).

RESULTS

Of 714 unique articles identified, 97 examined DRS methods and 86 were empirical applications. We observed a bimodal distribution in the number of publications over time, with a peak 1979-1980, and resurgence since 2000. The majority of applications with methodological detail derived DRS using logistic regression (47%), used DRS as a categorical variable in regression (93%), and applied DRS in a non-experimental cohort (47%) or case-control (42%) study. Few studies examined effect modification by outcome risk (23%).

CONCLUSION

Use of DRS methods has increased yet remains low. Comparative effectiveness research may benefit from more DRS applications, particularly to examine effect modification by outcome risk. Standardized terminology may facilitate identification, application, and comprehension of DRS methods. More research is needed to support the application of DRS methods, particularly in case-control studies.

Effects of renin-angiotensin system blockades on cardiovascular outcomes in patients with diabetes mellitus: A systematic review and meta-analysis

AIM

To determine whether renin-angiotensin system (RAS) blockade is beneficial for cardiovascular outcomes in patients with diabetes mellitus (DM) using meta-analysis.

METHODS

The MEDLINE and Cochrane library databases were searched for randomized controlled trials published up to June 2010. We also reviewed reference lists from identified trials and review articles to identify any other relevant studies, and the ClinicalTrials.gov website to identify randomized controlled trials that were registered as completed but not yet published. A random-effects model was used to combine the estimates for risk ratios (RR).

RESULTS

Eligible studies were randomized controlled trials (including post hoc analyses) assessing the effects of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers on cardiovascular events compared to controls in patients with DM. Nineteen clinical trials with 41,042 patients and 6039 cardiovascular events were identified. RAS blockade significantly reduced the risk of major cardiovascular events (RR 0.92, 95% confidence interval [CI] 0.84-1.00, I(2) statistic 53%) and myocardial infarction (RR 0.82, 95% CI 0.72-0.94, I(2)=55%). There were trends towards fewer strokes and lower all-cause mortality but these were not statistically significant.

CONCLUSIONS

The available evidence shows that treatment with RAS blockade can routinely be considered for diabetic patients to reduce major cardiovascular events.

Coexisting chronic obstructive pulmonary disease and heart failure: implications for treatment, course and mortality

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease (COPD) and heart failure are prevalent comorbidities affecting a huge proportion of the world population, responsible for significant morbidity and mortality. Their coexistence is more frequent than previously recognized and poses important diagnostic and therapeutic challenges. Prognosis of patients with concurrent heart failure and COPD has not been comprehensively addressed. With this review, we intend to emphasize the diagnosis and prognosis implications of the two coexisting conditions and to highlight the therapeutic constraints posed by the combination.

RECENT FINDINGS

Progressively, more attention has been given to the interplay between COPD and heart failure. The combination is frequent, but largely unrecognized due to overlapping clinical manifestations. Patients presenting with both conditions seem to have an ominous course. Despite the overwhelming evidence supporting cardioselective beta-blockade safety and tolerability in COPD patients, beta-blockers are underprescribed to heart failure patients with concomitant COPD.

SUMMARY

COPD and heart failure coexistence is often overlooked. COPD diagnosis can remain unsuspected in heart failure patients due to similar symptoms. Although beta-blockers are well tolerated in COPD patients, they are overall less prescribed in this challenging population. COPD, at least at severe degrees of airflow obstruction, predicts a worse prognosis in heart failure patients.

Heart failure and chronic obstructive pulmonary disease: diagnostic pitfalls and epidemiology

Heart failure (HF) and chronic obstructive pulmonary disease (COPD) are global epidemics incurring significant morbidity and mortality. The combination presents many diagnostic challenges. Clinical symptoms and signs frequently overlap. Evaluation of cardiac and pulmonary function is often problematic and occasionally misleading. Echocardiography and pulmonary function tests should be performed in every patient. Careful interpretation is required to avoid misdiagnosis and inappropriate treatment. Airflow obstruction, in particular, must be demonstrated when clinically euvolaemic. Very high and very low concentrations of natriuretic peptides have high positive and negative predictive values for diagnosing HF in those with both conditions. Intermediate values are less informative. Both conditions are systemic disorders with overlapping pathophysiological processes. In patients with HF, COPD is consistently an independent predictor of death and hospitalization. However, the impact on ischaemic and arrhythmic events is unknown. Greater collaboration is required between cardiologists and pulmonologists to better identify and manage concurrent HF and COPD. The resulting symptomatic and prognostic benefits outweigh those attainable by treating either condition alone.

Heart failure with preserved ejection fraction: hypertension, diabetes, obesity/sleep apnea, and hypertrophic and infiltrative cardiomyopathy

The detailed pathophysiology of heart failure with preserved ejection fraction (HF-PEF) remains an area of active research and controversy; however, abnormalities of diastolic function are generally believed to play an important role. Most commonly, diastolic dysfunction occurs as a consequence of myocyte hypertrophy, endomyocardial fibrosis, and abnormalities of intracellular calcium handling that are related to normal myocardial aging and accelerated by comorbidities such as hypertension, diabetes, coronary artery disease, and obesity. In this article, three fundamental risk factors are considered for "secondary" diastolic dysfunction and HF-hypertension, diabetes, and obesity-with an emphasis on the clinical epidemiology, pathophysiologic mechanisms, and treatment implications of each. The article concludes with a brief discussion of "primary" diastolic HF due to infiltrative or restrictive cardiomyopathies.

Predictors of improved left ventricular systolic function in an urban cardiomyopathy program

After long-term therapy, some patients with systolic heart failure (HF) display improved left ventricular (LV) function over time, a response that is associated with improved long-term outcomes. To investigate predictors of improved LV function in an ethnically diverse HF cohort, we selected 71 patients with HF who had baseline ejection fractions (EF) <40%, follow-up EFs > or =50%, and >20% increases on follow-up echocardiography performed > or =6 months later. Their clinical features were compared with 142 age- and gender-matched control patients with baseline EFs <40% and no change or worse EFs on follow-up echocardiography. The baseline EFs were similar between patients and controls. Compared with controls, patients had a lower prevalence of diabetes mellitus (19.7% vs 36.6%, p = 0.01), a lower prevalence of an ischemic cause of disease (8.4% vs 35.2%, p <0.001), but a higher prevalence of a hypertensive cause of cardiomyopathy (29.6% vs 12%, p <0.001). Fewer patients than controls used aspirin (p = 0.04) or statins (p = 0.001) or had previous cardiac procedures (p = 0.009). In a multivariate conditional logistic regression model adjusting for age, gender, disease cause, statin use, cardiac procedures, change in heart rate, and follow-up time, hypertensive etiology was most strongly associated with improved LV function (adjusted odds ratio 9.73, 95% confidence interval 1.44 to 52.76, p = 0.02). In conclusion, patients with hypertensive causes of HF are more likely to demonstrate improved LV function over time than patients with ischemic causes of HF. Because long-term prognosis and indication for defibrillator implantation may be affected by changes in LV function, the present study provides additional support for the importance of evaluating the cause of HF to guide management.

FDA and CPMP rulings on subgroup analyses

The extent to which subgroup analyses should affect the interpretation and conclusions in a trial report is a contentious matter, and guidelines regarding this issue have been established by the US Food and Drug Administration (FDA) and the EU Committee for Proprietary Medicinal Products (CPMP). Subgroup analyses should be set out in the protocol of clinical trials. The treatment effect itself may vary within a subgroup or covariate. In some cases, interactions are anticipated or are of particular a priori interest; hence a subgroup analysis or a statistical model including interactions is part of the planned analysis. However, subgroup or interaction analyses are often merely exploratory and should be clearly identified as such in the protocol. When exploratory, these analyses should be interpreted cautiously. Market approval of a compound is based on the overall trial results, and, importantly, no drug has so far been approved or not-approved either in the US or in the EU on the basis of subgroup analysis. However, subgroup analysis can influence the approval or can even be required, and therefore it can influence the labelling of the Summary Characteristics of a Product. Two examples in heart failure are given by the Val-HeFT trial comparing valsartan to placebo and the MERIT-HF trial comparing metoprolol to placebo, from which some remarkable regulatory issues arose that were debated by the FDA and CPMP.

Type 2 diabetes mellitus: a cardiovascular perspective

Diabetes mellitus is a disease, which is at the epitome of cardiovascular risk factors causing considerable morbidity and mortality. In addition to microvascular complications, there is two- to six-fold increased risk of macrovascular diseases, such as coronary artery disease, peripheral artery disease and stroke. While the mortality from coronary artery disease in patients without diabetes has declined over the past 20 years, the mortality in men with type 2 diabetes mellitus has not changed. Furthermore, the prevalence of diabetes in the UK has increased by 30% since 1991 and the same among the world population in 2010 is expected to be twice in 1990. This dramatic increase has serious implications from a cardiovascular perspective and thus the aggressive management of blood pressure, dyslipidaemia and blood glucose in diabetes is of vital importance. The aim of this review is to evaluate the current evidence and to discuss the implications of type 2 diabetes and its relevance to clinical practice in cardiology. We address this broad subject in discussing (i) the pathophysiology of cardiovascular disease in the setting of type 2 diabetes and (ii) the prevalence of cardiovascular risk, complications and prognostic implications in type 2 diabetes, with a discussion of current therapeutic interventions for the prevention or delay of these consequences where relevant.

New insights into diastolic heart failure: role of diabetes mellitus

Heart failure affects nearly 5 million people in the United States and is a major contributor to mortality, hospitalization, and medical costs. Approximately 40% of patients with heart failure have preserved left ventricular systolic function, thus exhibiting diastolic heart failure. More common in women and the elderly, this condition is associated with hypertension, coronary artery disease, and/or atrial fibrillation. With the exception of the Digitalis Investigation Group (DIG) and the Candesartin in Heart Failure: Assessment of Reduction in Mortality and Morbidity (CHARM)-Preserved trials, no completed large randomized clinical trial has addressed the management of such patients. Symptomatic treatment involves administration of diuretics and nitrates, but long-term management with angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, aldosterone antagonists, beta-blockers, and calcium channel blockers targets the underlying disorders. Recent studies found that diabetes mellitus produces functional, biochemical, and morphologic myocardial abnormalities independent of coronary atherosclerosis and hypertension. These abnormalities may result in impaired left ventricular diastolic function, contributing importantly to heart failure with normal systolic function. Although tight glycemic control decreases the risk of heart failure in patients with diabetes, the effects of different diabetic treatment regimens on heart failure with normal systolic function are unknown and remain subject to future investigation.

Managing the patient with diabetes mellitus and heart failure: issues and considerations

Heart failure affects nearly 5 million Americans and is associated with high morbidity and mortality rates. It is now recognized that activation of multiple neurohormonal systems is intrinsic in the pathophysiology of heart failure. Patients with diabetes mellitus are at high risk for heart failure, and some of the complications of diabetes (e.g., insulin resistance) contribute to the development and progression of heart failure, partly because of their effects on neurohormonal systems. Pharmacologic intervention directed toward these systems (i.e., angiotensin-converting enzyme [ACE] inhibition, use of aldosterone antagonists, and beta-adrenergic blockade) has been shown to decrease the morbidity and mortality associated with heart failure. Despite this knowledge, ACE inhibitors, aldosterone antagonists, and beta-blockers are grossly underused, and deaths and hospitalizations due to heart failure have steadily increased. Guidelines for the management of heart failure recommend the use of ACE inhibitors and beta-blockers in patients with mild, moderate, or severe disease. Aldosterone antagonists are recommended in severe heart failure, and recent data also support their use in mild to moderate heart failure. Concerns about the increased incidence of hypoglycemia, worsening dyslipidemia, and decreased insulin sensitivity with beta-blocker use may be preventing physicians from prescribing these agents for patients with diabetes with heart failure. Although evidence from earlier clinical trials justifies some of these concerns, newer vasodilating beta-blockers (e.g., carvedilol) have been shown to have a neutral or positive effect on dyslipidemia and insulin resistance. beta-Blockade in conjunction with ACE inhibition should be standard therapy for all patients with diabetes who have heart failure. Furthermore, early in-hospital initiation of neurohormonal intervention can provide earlier benefit to these patients.