Risk, Results, and Costs: Optimizing Clinical Trial Efficiency through Prognostic Enrichment

The "Small" Clinical Trial: Methods, Analysis, and Interpretation in Acute Care Cardiology

Clinical trials in acute care settings, particularly those involving small populations or high mortality contexts, present unique challenges in design and analysis. In this review we explore novel statistical approaches and methodological considerations for such trials, with a focus on cardiovascular therapies. We discuss the concept of "small" sample sizes and their limitations and cover various analytical frameworks, including frequentist and Bayesian approaches, and emphasize their implications for result interpretation and reproducibility. We examine end points such as "days alive and free specific to disease state," which combines mortality and morbidity measures, the win ratio for hierarchical end points, and ordinal scales that capture detailed patient outcomes. These methods potentially increase statistical power and provide more clinically relevant measures compared with traditional binary outcomes; an extensive use of simulations is used to clarify this point. The use of longitudinal ordinal models is presented as a promising method to capture complex patient trajectories over time, offering insights into treatment effects at various disease stages. We also address the potential of adaptive platform trials for rare conditions, allowing for more efficient use of limited patient populations. In this overview we aim to guide researchers and clinicians in selecting optimal trial designs and analytical strategies, to ultimately improve the quality, efficiency, and interpretability of evidence in acute care cardiology.

Biomarker-Based Risk Stratification Tool in Pediatric Acute Respiratory Distress Syndrome: Single-Center, Longitudinal Validation in a 2014-2019 Cohort

OBJECTIVES

The Pediatric Acute Respiratory Distress Syndrome Biomarker Risk Model (PARDSEVERE) used age and three plasma biomarkers measured within 24 hours of pediatric acute respiratory distress syndrome (ARDS) onset to predict mortality in a pilot cohort of 152 patients. However, longitudinal performance of PARDSEVERE has not been evaluated, and it is unclear whether the risk model can be used to prognosticate after day 0. We, therefore, sought to determine the test characteristics of PARDSEVERE model and population over the first 7 days after ARDS onset.

DESIGN

Secondary unplanned post hoc analysis of data from a prospective observational cohort study carried out 2014-2019.

SETTING

University-affiliated PICU.

PATIENTS

Mechanically ventilated children with ARDS.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Between July 2014 and December 2019, 279 patients with ARDS had plasma collected at day 0, 266 at day 3 (11 nonsurvivors, two discharged between days 0 and 3), and 207 at day 7 (27 nonsurvivors, 45 discharged between days 3 and 7). The actual prevalence of mortality on days 0, 3, and 7, was 23% (64/279), 14% (38/266), and 13% (27/207), respectively. The PARDSEVERE risk model for mortality on days 0, 3, and 7 had area under the receiver operating characteristic curve (AUROC [95% CI]) of 0.76 (0.69-0.82), 0.68 (0.60-0.76), and 0.74 (0.65-0.83), respectively. The AUROC data translate into prevalence thresholds for the PARDSEVERE model for mortality (i.e., using the sensitivity and specificity values) of 37%, 27%, and 24% on days 0, 3, and 7, respectively. Negative predictive value (NPV) was high throughout (0.87-0.90 for all three-time points).

CONCLUSIONS

In this exploratory analysis of the PARDSEVERE model of mortality risk prediction in a population longitudinal series of data from days 0, 3, and 7 after ARDS diagnosis, the diagnostic performance is in the "acceptable" category. NPV was good. A major limitation is that actual mortality is far below the prevalence threshold for such testing. The model may, therefore, be more useful in cohorts with higher mortality rates (e.g., immunocompromised, other countries), and future enhancements to the model should be explored.

Speech markers to predict and prevent recurrent episodes of psychosis: A narrative overview and emerging opportunities

Preventing relapse in schizophrenia improves long-term health outcomes. Repeated episodes of psychotic symptoms shape the trajectory of this illness and can be a detriment to functional recovery. Despite early intervention programs, high relapse rates persist, calling for alternative approaches in relapse prevention. Predicting imminent relapse at an individual level is critical for effective intervention. While clinical profiles are often used to foresee relapse, they lack the specificity and sensitivity needed for timely prediction. Here, we review the use of speech through Natural Language Processing (NLP) to predict a recurrent psychotic episode. Recent advancements in NLP of speech have shown the ability to detect linguistic markers related to thought disorder and other language disruptions within 2-4 weeks preceding a relapse. This approach has shown to be able to capture individual speech patterns, showing promise in its use as a prediction tool. We outline current developments in remote monitoring for psychotic relapses, discuss the challenges and limitations and present the speech-NLP based approach as an alternative to detect relapses with sufficient accuracy, construct validity and lead time to generate clinical actions towards prevention.

Prognostic factors associated with favourable functional outcome among adult patients requiring extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest: A systematic review and meta-analysis

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR), has demonstrated promise in the management of refractory out-of-hospital cardiac arrest (OHCA). However, evidence from observational studies and clinical trials are conflicting and the factors influencing outcome have not been well established.

METHODS

We conducted a systematic review and meta-analysis summarizing the association between pre-ECPR prognostic factors and likelihood of good functional outcome among adult patients requiring ECPR for OHCA. We searched Medline and Embase databases from inception to February 28, 2023 and screened studies with two independent reviewers. We performed meta-analyses of unadjusted and adjusted odds ratios, adjusted hazard ratios and mean differences separately. We assessed risk of bias using the QUIPS tool and certainty of evidence using the GRADE approach.

FINDINGS

We included 29 observational and randomized studies involving 7,397 patients. Factors with moderate or high certainty of association with increased survival with favourable functional outcome include pre-arrest patient factors, such as younger age (odds ratio (OR) 2.13, 95% CI 1.52 to 2.99) and female sex (OR 1.37, 95% CI 1.11 to 1.70), as well as intra-arrest factors, such as shockable rhythm (OR 2.79, 95% CI 2.04 to 3.80), witnessed arrest (OR 1.68 (95% CI 1.16 to 2.42), bystander CPR (OR 1.55, 95% CI 1.19 to 2.01), return of spontaneous circulation (OR 2.81, 95% CI 2.19 to 3.61) and shorter time to cannulation (OR 1.14, 95% CI 1.17 to 1.69 per 10 minutes).

INTERPRETATION

The findings of this review confirm several clinical concepts wellestablished in the cardiac arrest literature and their applicability to the patient for whom ECPR is considered - that is, the impact of pre-existing patient factors, the benefit of timely and effective CPR, as well as the prognostic importance of minimizing low-flow time. We advocate for the thoughtful consideration of these prognostic factors as part of a risk stratification framework when evaluating a patient's potential candidacy for ECPR.

Pulmonary Hypertension: A Contemporary Review

Major advances in pulmonary arterial hypertension, pulmonary hypertension (PH) associated with lung disease, and chronic thromboembolic PH cast new light on the pathogenetic mechanisms, epidemiology, diagnostic approach, and therapeutic armamentarium for pulmonary vascular disease. Here, we summarize key basic, translational, and clinical PH reports, emphasizing findings that build on current state-of-the-art research. This review includes cutting-edge progress in translational pulmonary vascular biology, with a guide to the diagnosis of patients in clinical practice, incorporating recent PH definition revisions that continue emphasis on early detection of disease. PH management is reviewed including an overview of the evolving considerations for the approach to treatment of PH in patients with cardiopulmonary comorbidities, as well as a discussion of the groundbreaking sotatercept data for the treatment of pulmonary arterial hypertension.

Temperature control after cardiac arrest

Most of the patients who die after cardiac arrest do so because of hypoxic-ischemic brain injury (HIBI). Experimental evidence shows that temperature control targeted at hypothermia mitigates HIBI. In 2002, one randomized trial and one quasi-randomized trial showed that temperature control targeted at 32-34 °C improved neurological outcome and mortality in patients who are comatose after cardiac arrest. However, following the publication of these trials, other studies have questioned the neuroprotective effects of hypothermia. In 2021, the largest study conducted so far on temperature control (the TTM-2 trial) including 1900 adults comatose after resuscitation showed no effect of temperature control targeted at 33 °C compared with normothermia or fever control. A systematic review of 32 trials published between 2001 and 2021 concluded that temperature control with a target of 32-34 °C compared with fever prevention did not result in an improvement in survival (RR 1.08; 95% CI 0.89-1.30) or favorable functional outcome (RR 1.21; 95% CI 0.91-1.61) at 90-180 days after resuscitation. There was substantial heterogeneity across the trials, and the certainty of the evidence was low. Based on these results, the International Liaison Committee on Resuscitation currently recommends monitoring core temperature and actively preventing fever (37.7 °C) for at least 72 h in patients who are comatose after resuscitation from cardiac arrest. Future studies are needed to identify potential patient subgroups who may benefit from temperature control aimed at hypothermia. There are no trials comparing normothermia or fever control with no temperature control after cardiac arrest.

Targeted temperature management following out-of-hospital cardiac arrest: a systematic review and network meta-analysis of temperature targets

PURPOSE

Targeted temperature management (TTM) may improve survival and functional outcome in comatose survivors of out-of-hospital cardiac arrest (OHCA), though the optimal target temperature remains unknown. We conducted a systematic review and network meta-analysis to investigate the efficacy and safety of deep hypothermia (31-32 °C), moderate hypothermia (33-34 °C), mild hypothermia (35-36 °C), and normothermia (37-37.8 °C) during TTM.

METHODS

We searched six databases from inception to June 2021 for randomized controlled trials (RCTs) evaluating TTM in comatose OHCA survivors. Two reviewers performed screening, full text review, and extraction independently. The primary outcome of interest was survival with good functional outcome. We used GRADE to rate our certainty in estimates.

RESULTS

We included 10 RCTs (4218 patients). Compared with normothermia, deep hypothermia (odds ratio [OR] 1.30, 95% confidence interval [CI] 0.73-2.30), moderate hypothermia (OR 1.34, 95% CI 0.92-1.94) and mild hypothermia (OR 1.44, 95% CI 0.74-2.80) may have no effect on survival with good functional outcome (all low certainty). Deep hypothermia may not improve survival with good functional outcome, as compared to moderate hypothermia (OR 0.97, 95% CI 0.61-1.54, low certainty). Moderate hypothermia (OR 1.23, 95% CI 0.86-1.77) and deep hypothermia (OR 1.27, 95% CI 0.70-2.32) may have no effect on survival, as compared to normothermia. Finally, incidence of arrhythmia was higher with moderate hypothermia (OR 1.45, 95% CI 1.08-1.94) and deep hypothermia (OR 3.58, 95% CI 1.77-7.26), compared to normothermia (both high certainty).

CONCLUSIONS

Mild, moderate, or deep hypothermia may not improve survival or functional outcome after OHCA, as compared to normothermia. Moderate and deep hypothermia were associated with higher incidence of arrhythmia. Routine use of moderate or deep hypothermia in comatose survivors of OHCA may potentially be associated with more harm than benefit.