Impact of Confounding on Cost, Survival, and Length-of-Stay Outcomes for Neonates with Hypoplastic Left Heart Syndrome Undergoing Stage 1 Palliation Surgery

Race-Conscious Research Using Extracorporeal Life Support Organization Registry Data: A Narrative Review

Race-conscious research identifies health disparities with 1) rigorous and responsible data collection, 2) intentionality and considered analyses, and 3) interpretation of results that advance health equity. Individual registries must overcome specific challenges to promote race-conscious research, and this paper describes ways to achieve this with a focus on the international Extracorporeal Life Support Organization (ELSO) registry. This article reviews ELSO registry publications that studied race with outcomes to consider whether research outputs align with race-conscious concepts and describe the direction of associations reported. Studies were identified via secondary analysis of a comprehensive scoping review on ECMO disparities. Of 32 multicenter publications, two (6%) studied race as the primary objective. Statistical analyses, confounder adjustment, and inclusive, antibiased language were inconsistently used. Only two (6%) papers explicitly discussed mechanistic drivers of inequity such as structural racism, and five (16%) discussed race variable limitations or acknowledged unmeasured confounders. Extracorporeal Life Support Organization registry publications demonstrated more adverse ECMO outcomes for underrepresented/minoritized populations than non-ELSO studies. With the objective to promote race-conscious ELSO registry research outputs, we provide a comprehensive understanding of race variable limitations, suggest reasoned retrospective analytic approaches, offer ways to interpret results that advance health equity, and recommend practice modifications for data collection.

Social Drivers of Health and Pediatric Extracorporeal Membrane Oxygenation Outcomes

BACKGROUND

Relationships between social drivers of health (SDoH) and pediatric health outcomes are highly complex with substantial inconsistencies in studies examining SDoH and extracorporeal membrane oxygenation (ECMO) outcomes. To add to this literature with emerging novel SDoH measures, and to address calls for institutional accountability, we examined associations between SDoH and pediatric ECMO outcomes.

METHODS

This single-center retrospective cohort study included children (<18 years) supported on ECMO (2012-2021). SDoH included Child Opportunity Index (COI), race, ethnicity, payer, interpreter requirement, urbanicity, and travel-time to hospital. COI is a multidimensional estimation of SDoH incorporating traditional (eg, income) and novel (eg, healthy food access) neighborhood attributes ([range 0-100] higher indicates healthier child development). Outcomes included in-hospital mortality, ECMO run duration, and length of stay (LOS).

RESULTS

540 children on ECMO (96%) had a calculable COI. In-hospital mortality was 44% with median run duration of 125 hours and ICU LOS 29 days. Overall, 334 (62%) had cardiac disease, 92 (17%) neonatal respiratory failure, 93 (17%) pediatric respiratory failure, and 21 (4%) sepsis. Median COI was 64 (interquartile range 32-81), 323 (60%) had public insurance, 174 (34%) were from underrepresented racial groups, 57 (11%) required interpreters, 270 (54%) had urban residence, and median travel-time was 89 minutes. SDoH including COI were not statistically associated with outcomes in univariate or multivariate analysis.

CONCLUSIONS

We observed no significant difference in pediatric ECMO outcomes according to SDoH. Further research is warranted to better understand drivers of inequitable health outcomes in children, and potential protective mechanisms.

Attributable mortality benefit of digoxin treatment in hypoplastic left heart syndrome after the Norwood operation: An instrumental variable-based analysis using data from the Pediatric Health Information Systems Database

BACKGROUND

Observational studies have demonstrated an association between the use of digoxin and reduced interstage mortality after Norwood operation for hypoplastic left heart syndrome (HLHS). Digoxin use has increased significantly but remains variable between different hospitals, independent of case-mix. Instrumental variable analyses have the potential to overcome unmeasured confounding, the major limitation of previous observational studies and to generate an estimate of the attributable benefit of treatment with digoxin.

METHODS

A cohort of neonates with HLHS born from January 1, 2007 to December 31, 2021 who underwent Norwood operation at Pediatric Health Information Systems Database hospitals and survived >14 days after operation were studied. Using hospital-specific, 6-month likelihood of administering digoxin as an instrumental variable, analyses adjusting for both unmeasured confounding (using the instrumental variable) and measured confounders with multivariable logistic regression were performed.

RESULTS

The study population included 5,148 subjects treated at 47 hospitals of which 63% were male and 46% non-Hispanic white. Of these, 44% (n = 2,184) were prescribed digoxin. Treatment with digoxin was associated with superior 1-year transplant-free survival in unadjusted analyses (85% vs 82%, P = .02). This survival benefit persisted in an instrumental-variable analysis (OR: 0.71, 95% CI: 0.54-0.94, P = .01), which can be converted to an absolute risk reduction of 5% (number needed to treat of 20).

CONCLUSIONS

In this observational study of patients with HLHS after Norwood using instrumental variable techniques, a significant benefit in 1-year transplant-free survival attributable to digoxin was demonstrated. In the absence of clinical trial data, this should encourage the use of digoxin in this vulnerable population.

Health Disparities in Extracorporeal Membrane Oxygenation Utilization and Outcomes: A Scoping Review and Methodologic Critique of the Literature

OBJECTIVES

To map the scope, methodological rigor, quality, and direction of associations between social determinants of health (SDoH) and extracorporeal membrane oxygenation (ECMO) utilization or outcomes.

DATA SOURCES

PubMed, Web of Science, Embase, and Cochrane Library databases were systematically searched for citations from January 2000 to January 2023, examining socioeconomic status (SES), race, ethnicity, hospital and ECMO program characteristics, transport, and geographic location (context) with utilization and outcomes (concept) in ECMO patients (population).

STUDY SELECTION

Methodology followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses scoping review extension. Two reviewers independently evaluated abstracts and full text of identified publications. Exclusion criteria included non-English, unavailable, less than 40 patients, and periprocedural or mixed mechanical support.

DATA EXTRACTION

Content analysis used a standardized data extraction tool and inductive thematic analysis for author-proposed mediators of disparities. Risk of bias was assessed using the Quality in Prognosis Studies tool.

DATA SYNTHESIS

Of 8,214 citations screened, 219 studies were identified. Primary analysis focuses on 148 (68%) including race/ethnicity/SES/payer variables including investigation of ECMO outcomes 114 (77%) and utilization 43 (29%). SDoH were the primary predictor in 15 (10%). Overall quality and methodologic rigor was poor with advanced statistics in 7%. Direction of associations between ECMO outcomes or utilization according to race, ethnicity, SES, or payer varied. In 38% adverse outcomes or lower use was reported in underrepresented, under-resourced or diverse populations, while improved outcomes or greater use were observed in these populations in 7%, and 55% had no statistically significant result. Only 26 studies (18%) discussed mechanistic drivers of disparities, primarily focusing on individual- and hospital-level rather than systemic/structural factors.

CONCLUSIONS

Associations between ECMO utilization and outcomes with SDoH are inconsistent, complicated by population heterogeneity and analytic shortcomings with limited consideration of systemic contributors. Findings and research gaps have implications for measuring, analyzing, and interpreting SDoH in ECMO research and healthcare.

Considering the Genetic Architecture of Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is among the most severe cardiovascular malformations and understanding its causes is crucial to making progress in prevention and treatment. Genetic analysis is a broadly useful tool for dissecting complex causal mechanisms and it is playing a significant role in HLHS research. However, unlike classical Mendelian disorders where a relatively small number of genes are largely determinative of the occurrence and severity of the disease, the picture in HLHS is complex. De novo single-gene and copy number variant (CNV) disorders make an important contribution, but there is emerging evidence for causal contributions from lower penetrance and common variation. Integrating this emerging knowledge into clinical diagnostics and translating the findings into effective prevention and treatment remain challenges for the future.

Unmeasured confounding in nonrandomized studies: quantitative bias analysis in health technology assessment

Evidence generated from nonrandomized studies (NRS) is increasingly submitted to health technology assessment (HTA) agencies. Unmeasured confounding is a primary concern with this type of evidence, as it may result in biased treatment effect estimates, which has led to much criticism of NRS by HTA agencies. Quantitative bias analyses are a group of methods that have been developed in the epidemiological literature to quantify the impact of unmeasured confounding and adjust effect estimates from NRS. Key considerations for application in HTA proposed in this article reflect the need to balance methodological complexity with ease of application and interpretation, and the need to ensure the methods fit within the existing frameworks used to assess nonrandomized evidence by HTA bodies.

Cumulative In-Hospital Costs Associated With Single-Ventricle Palliation

Background

In the SVR (Single Ventricle Reconstruction) Trial, 1-year survival in recipients of right ventricle to pulmonary artery shunts (RVPAS) was superior to that in those receiving modified Blalock-Taussig-Thomas shunts (MBTTS), but not in subsequent follow-up. Cost analysis is an expedient means of evaluating value and morbidity.

Objectives

The purpose of this study was to evaluate differences in cumulative hospital costs between RVPAS and MBTTS.

Methods

Clinical data from SVR and costs from Pediatric Health Information Systems database were combined. Cumulative hospital costs and cost-per-day-alive were compared serially at 1, 3, and 5 years between RVPAS and MBTTS. Potential associations between patient-level factors and cost were explored with multivariable models.

Results

In total, 303 participants (55% of the SVR cohort) from 9 of 15 sites were studied (48% MBTTS). Observed total costs at 1 year were lower for MBTTS ($701,260 ± 442,081) than those for RVPAS ($804,062 ± 615,068), a difference that was not statistically significant (P = 0.10). Total costs were also not significantly different at 3 and 5 years (P = 0.21 and 0.32). Similarly, cost-per-day-alive did not differ significantly for either group at 1, 3, and 5 years (all P > 0.05). In analyses of transplant-free survivors, total costs and cost-per-day-alive were higher for RVPAS at 1 year (P = 0.05 for both) but not at 3 and 5 years (P > 0.05 for all). In multivariable models, aortic atresia and prematurity were associated with increased cost-per-day-alive across follow-up (P < 0.05).

Conclusions

Total costs do not differ significantly between MBTTS and RVPAS. The magnitude of longitudinal costs underscores the importance of efforts to improve outcomes in this vulnerable population.

Outcomes Following Norwood Procedures: Analysis of a "Small Volume" Program

BACKGROUND

Institutional survival following Norwood procedures is traditionally correlated with a center's surgical volume. Multiple single and multi-institutional studies conducted at large-volume centers have recently demonstrated improved survival following Norwood procedures. We report both short- and long-term outcomes at a single, small-volume institution and comment on factors potentially influencing outcomes at this institution.

METHODS

All patients undergoing Norwood procedures from January 1, 2005, to January 1, 2020, at our institution were included in this study. Kaplan-Meier survival and Cox regression risk factor analyses were performed in addition to first interstage risk factor scoring to compare observed versus expected survival.

RESULTS

The cohort included 113 patients. Kaplan-Meier freedom from death or transplant was 88%, 80%, and 76% at 1, 5, and 10 years, respectively. Freedom from death following hospital discharge after Norwood procedures was 94%, 87%, and 83% at 1, 5, and 10 years, respectively. The presence of genetic syndromes was a significant risk factor for mortality. First interstage observed-to-expected mortality following discharge was 0.57 (P = .04). Postoperative length of stay was comparable to that reported for the period 2015 to 2018 in the Society of Thoracic Surgeons Database.

CONCLUSIONS

Survival outcomes at this single, small-volume institution were similar to those reported by large-volume centers and multi-institutional collaborative studies. These results may be related to structural and functional features that have been demonstrated to influence outcomes in other studies. These factors are achievable by small-volume programs with sufficient resource allocation.

Maternal post-traumatic stress and depression symptoms and outcomes after NICU discharge in a low-income sample: a cross-sectional study

Background

Having a preterm newborn and the experience of staying in the neonatal intensive care unit (NICU) has the potential to impact a mother’s mental health and overall quality of life. However, currently there are few studies that have examined the association of acute post-traumatic stress (PTS) and depression symptoms and infant and maternal outcomes in low-income populations.

Design/ methods

In a cross-sectional study, we examined adjusted associations between positive screens for PTS and depression using the Perinatal Post-traumatic stress Questionnaire (PPQ) and the Patient Health-Questionnaire 2 (PHQ-2) with outcomes using unconditional logistic and linear regression models.

Results

One hundred sixty-nine parents answered the questionnaire with 150 complete responses. The majority of our sample was Hispanic (68%), non-English speaking (67%) and reported an annual income of <$20,000 (58%). 33% of the participants had a positive PPQ screen and 34% a positive PHQ-2 screen. After adjusting for confounders, we identified that a positive PHQ-2 depression score was associated with a negative unit (95% CI) change on the infant’s Vineland Adaptive Behavior Scales, second edition of − 9.08 (− 15.6, − 2.6) (p < 0.01). There were no significant associations between maternal stress and depression scores and infant Bayley Scales of Infant Development III scores or re-hospitalizations or emergency room visits. However, positive PPQ and screening score were associated with a negative unit (95% CI) unit change on the maternal Multicultural Quality of Life Index score of − 8.1 (− 12, − 3.9)(p < 0.01) and − 7.7 (− 12, − 3) (p = 0.01) respectively.

Conclusions

More than one-third of the mothers in this sample screened positively for PTS and depression symptoms. Screening scores positive for stress and depression symptoms were associated with a negative change in some infant development scores and maternal quality of life scores. Thoughtful screening programs for maternal stress and depression symptoms should be instituted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-020-03536-0.

The association of care transitions measure-15 score and outcomes after discharge from the NICU

BACKGROUND

Our objectives were (1) to describe Care Transitions Measure (CTM) scores among caregivers of preterm infants after discharge from the neonatal intensive care unit (NICU) and (2) to describe the association of CTM scores with readmissions, enrollment in public assistance programs, and caregiver quality of life scores.

METHODS

The study design was a cross-sectional study. We estimated adjusted associations between CTM scores (validated measure of transition) with outcomes using unconditional logistic and linear regression models and completed an E-value analysis on readmissions to quantify the minimum amount of unmeasured confounding.

RESULTS

One hundred sixty-nine parents answered the questionnaire (85% response rate). The majority of our sample was Hispanic (72.5%), non-English speaking (67.1%) and reported an annual income of <$20,000 (58%). Nearly 28% of the infants discharged from the NICU were readmitted within a year from discharge. After adjusting for confounders, we identified that a positive 10-point change of CTM score was associated with an odds ratio (95% CI) of 0.74 (0.58, 0.98) for readmission (p = 0.01), 1.02 (1, 1.05) for enrollment in early intervention, 1.03 (1, 1.05) for enrollment in food assistance programs, and a unit change (95% CI) 0.41 (0.27, 0.56) in the Multicultural Quality of Life Index score (p < 0.0001). The associated E-value for readmissions was 1.6 (CI 1.1) suggesting moderate confounding.

CONCLUSION

The CTM may be a useful screening tool to predict certain outcomes for infants and their families after NICU discharge. However, further work must be done to identify unobserved confounding factors such as parenting confidence, problem-solving and patient activation.

Hypoplastic Left Heart: Stage-I Will be Performed Interventionally, Soon

The hypoplasia of left-sided heart structures shows great variability and complexity. What the many variants have in common is that their heart structures are neither fully developed before nor after birth. Fetuses and newborns require an individual therapy depending on anatomy and function of the heart. Fetal interventions focus on improving left heart structures by catheter-based interventions and maternal hyperoxygenation which promotes growth as the left ventricular preload and blood flow within the cavity increase. Stage-I management of newborns with single ventricle physiology is usually based on the Norwood/Sano surgery or the Hybrid approach. Two more steps are required to ultimately achieve a Fontan circulation. Some centers also use the Hybrid approach for subsequent Norwood operation beyond the neonatal period. After the Hybrid approach, a comprehensive stage-II or corrective surgery is performed, the latter if a bi-ventricular circulation is possible. With progressively improved catheter-based interventions, particularly ductal stenting and manipulations of the atrial septum, the next advance is to develop a bespoke flow restrictor that can be easily inserted into the branches of the pulmonary artery. The main goal is to avoid complex heart operations under general anesthesia, followed by substantial intensive care in the neonatal period, especially for patients with complex heart defects. Based on the current state of the art of surgical treatment of hypoplastic left heart syndrome and variants with the Norwood surgery or the Hybrid approach, our main focus is on an alternative percutaneous transcatheter technique in the sense of a completely non-surgical stage-I approach.