- VLBW —
- very low birth weight
- VON —
- Vermont Oxford Network
The observation of variation in neonatal outcomes has led investigators to examine variations in practice as potential causes (eg, the association between supplemental oxygen use and retinopathy of prematurity).1 The move to benchmark care against other units has become widespread, and several benchmark organizations, of which perhaps the best example is the Vermont Oxford Network (VON), are generating wide-ranging comparative data. However, teasing out the complex relationships between practices and outcomes has not proven easy, and eliciting practice change can be even harder.
In addition to bedside clinical practices, higher-level organizational factors may also contribute to both positive and negative effects on outcomes. In large, multicenter studies, the centralization of care, access, NICU volume, and nurse staffing have all been implicated in the variation in neonatal mortality rates seen across centers.2–5 Aggregating data across large populations can obscure the relationship between bedside practices and outcomes, but it increases the power of comparisons and allows the influence of organizational factors to be explored.
In this issue of Pediatrics, Adams et al6 use data from the VON to provide a robustly designed comparison of 2 near-complete populations to overcome some of the challenges in previous studies. The 2 cohorts comprised 84% of the United States and 95% of the Swiss very low birth weight (VLBW) populations. The investigators used uniform definitions and adjusted outcomes for both patient- and unit-level characteristics. The primary outcome was a composite of mortality and morbidity. Multivariate analysis was used to adjust outcomes for confounders. Propensity score matching was used to adjust for both confounding and differences in cohort sizes. The adjusted risk ratio for the primary outcome was 44% lower in the Swiss Neonatal Network compared with the United States contributors to the VON. Adjusted risk ratios for component morbidities also were lower in the Swiss data compared with those of the United States, but mortality rates were similar. Notably, adjustment for hospital ownership, activity, size, and staffing reduced differences in morbidities.
The researchers also found wide variability in clinical practices. After case mix adjustment and indirect standardization, the rates of antenatal steroid administration, continuous positive airway pressure use, and human milk feedings at discharge were higher than expected among the Swiss cohort, and the rates of delivery room intubation, NICU positive pressure mechanical ventilation, and postnatal steroids were higher than expected in the United States cohort.
That VLBW outcomes in Switzerland are better than in the United States should come as no surprise. Despite spending a higher proportion of gross domestic product on health care than any other industrialized nation, the United States consistently ranks well below other developed countries in most measures of health care quality. In 2014, the Commonwealth Fund noted that of 11 industrialized countries, the US health care system ranked last and Switzerland ranked second.7 In terms of VLBW outcomes and among 10 national and regional networks (not including the United States), Switzerland had the lowest rate of composite adverse outcomes.8 Neonatal morbidities have shown little temporal variation in a network of US hospitals9 and vary equally widely across European regions.10
The study by Adams et al6 has its limitations. Even with sophisticated adjustment and propensity scoring, the possibility of residual confounding remains high. There were few measures of antenatal care, and the contribution of each morbidity to the composite is disproportionate. Combinations of morbidities may be better predictors of 2-year outcomes than individual conditions11 and may be better markers of important longer-term outcomes and economic costs.
When possible, Adams et al6 controlled for nonmodifiable variables, leaving the unexplained variations in outcomes as opportunities for positive change. This means not simply targeting clinical practices but also organizational structures (eg, the Commonwealth Fund report noted that the United States also ranked lowest in access and equity). Working together in networks to reduce practice variation, planning optimally sized services with adequate staffing, and establishing effective postnatal transfer systems when maternal transport cannot be achieved antenatally are issues that must be addressed.
The traditional reliance of clinical practice on randomized clinical trials has led to a large number of underpowered trials, which make much less of an impact in population outcomes than might be expected. The development of new trial strategies (such as comparative effectiveness trials using large, routinely collected data sets) may help to more effectively clarify the importance of the small, detailed steps we necessarily target in conventional clinical trials.12 Learning from our differences and ensuring that we gather all the potentially better practices into our individualized clinical strategies in well-planned services are important goals.
Finally, we must recognize that as we increase our understanding of the individual biologic and genetic underpinnings of disease, risk for complications, and responses to treatment, it is likely that a uniform approach to a given population may not represent best practice for a given individual. As we embark on our journey toward precision medicine, we must understand that population-based studies can take us only so far; although they may help us achieve the greatest good for the greatest number of people, there will always be a place for an individualized patient approach within well-organized and well-managed services.
- Accepted February 9, 2018.
- Address correspondence to James J. Cummings, MD, MS, Pediatrics, The Bernard and Millie Duker Children’s Hospital at Albany Medical Center, 47 New Scotland Ave, Mailcode 101, Albany, NY 12208. E-mail:
Opinions expressed in these commentaries are those of the authors and not necessarily those of the American Academy of Pediatrics or its Committees.
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
FUNDING: No external funding.
POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.
COMPANION PAPER: A companion to this article can be found online at www.pediatrics.org/cgi/doi/10.1542/peds.2017-3436.
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- Copyright © 2018 by the American Academy of Pediatrics