How to Explain When NEC Rates Persist – Even When a NICU Does Everything “Right”

Written by the NEC Society’s scientific advisor, Ravi Patel, MD, MSc, Associate Professor of Pediatrics, Emory University School of Medicine

Five years ago, we embarked on a quality improvement effort to decrease the rates of NEC at our center. I want to share our experience. While we do not completely understand what causes NEC, research in the last two decades has dramatically improved our understanding of the pathogenesis and epidemiology of NEC. We know the strongest risk factor for NEC is prematurity, with the smallest infants at highest risk. We know that feeding mother’s own milk is a safe and effective approach to prevent NEC. At the time, we were beginning to understand the importance of the microbiome in NEC. Epidemiologic studies showing treatments that alter the microbiome such as acid suppression medications and prolonged antibiotics may increase the risk of NEC, gave us additional targets for prevention. Reducing exposure to these medications, when possible, could potentially help decrease the risk of NEC. Furthermore, although their use is limited in the US, probiotics are one of the most studied interventions in neonatal medicine that have been shown to effectively decrease NEC.

Towards that end, five years ago we began improvement efforts to decrease our rates of NEC. The experience of other centers provided optimism that this was possible (Table 1).

Table 1. Examples of quality improvement efforts reporting decreases in NEC

First author, year Setting (number of infants) Change in NEC rates
Aziz et al, 2012 1 center (n=480) 5% to 1%
Lee et al, 2012 11 centers (n=1833) 7% to 2%
Patel et al, 2014 1 center (n=232) 10% to 3%
Lee et al, 2014 25 NICUs (n=6026) 10% to 8%
Alshaik et al, 2015 1 center (n=454) 9% to 5%
Ellbsury et al, 2016 330 NICUs (n=58,555) 7% to 3%
Stefanescu et al, 2016 1 center (n=299) 6% to 2%
Talavera et al. 2016 8 centers (n=606) 8% to <4%

Adapted from Patel et al. Clin Perinatol, 2017 (

We set a goal to decrease the rate of NEC from 15% to 5% among our very low birth weight (VLBW) infants. We targeted what we considered were the major drivers of NEC and worked methodically to apply interventions to address these drivers (Figure 1).

Figure 1. Key driver diagramFigure1_Ravi_blog

Over the ensuing five years, we had many improvements (Figure 2): we increased human milk feeding to 100% of infants, nearly eliminated the use of acid suppression medications, and began supplementing the probiotic, Lactobacillus rhamnosus GG. In addition, we routinely provided delayed cord clamping and developed an evidence-based feeding protocol with high adherence. By all measures, we were providing effective care, based on the best available evidence.

Figure 2. Run charts of process measures (interventions)

We were confident that we were providing important treatments that could potentially reduce NEC because we closely measured our care. And yet, we didn’t reach our aim to reduce NEC rates to below 5% (Figure 3).

Figure 3. Rates of NEC over time

So how can one explain when NEC rates persist, even when a NICU does everything “right?”

I think our experience highlights the opportunity and how imperative it is to better understand the disease. NEC likely has many forms with different causes. Some centers may be more vulnerable to particular causes than others. Hence, what may cause NEC at one center at a specific point in time, may be completely different at another center. How changes in potential risk factors influence the risk of NEC for individual infants and populations remains understudied. Additionally, improving early survival of the most immature infants over time may change the case-mix and make year-to-year comparisons challenging. Finally, NEC is a multifactorial disease. I believe quality improvement efforts need to address as many factors as possible with high reliability to be successful. Targeting one driver may not yield lasting and effective improvements to care. We continue to work on addressing the major drivers of NEC that we envisioned when we began working on this project five years ago (Figure 1). We know persistence and patience are essential to take on such a challenging disease as NEC. Working around a theory, as reflected in our key driver diagram, has helped our center stay focused. We hope that our experience can help other centers.

I am still optimistic that we can prevent NEC and we can build a world without this devastating disease. However, some risk factors for NEC may not be modifiable. We currently do not know enough about what factors influence the underlying susceptibility to NEC for an individual infant. So, preventing every case of NEC may prove difficult until we gain new and better insights. However, given how devastating this disease is, if we were able to prevent even a single case of NEC in our five years of ongoing quality improvement efforts, I consider my time well spent.


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