In this study of premature infants born in CPQCC hospitals, we found that contrary to well established guidelines, 23.1% of mothers of infants with birth weight < 1500 grams or born < 34 weeks gestation did not receive ANS. Moreover, this phenomenon was disproportionately evident among more vulnerable women (i.e. no prenatal care, Hispanic women). Mothers giving birth after 30 weeks gestation were less likely to receive ANS. Additionally, we found wide variation in the use of ANS among different hospitals, which was evident even after risk adjustment. We also found that participating in webcasts and workshops in a quality improvement collaborative several years prior to the study period was associated with higher ANS administration.
Our findings are consistent with existing literature indicating 15-25% of eligible infants are not exposed to ANS and suggest specific targets for reducing inequalities in care.(6
) Through a new data linkage strategy, we were able to combine neonatal clinical data from CPQCC with maternal clinical and socio-demographic data from California Vital Records. In unadjusted analyses, younger mothers were at higher risk for not receiving ANS, as has been described in other studies.(6
) There were also differences by race / ethnicity; however, after risk adjustment, the most prominent factors associated with not receiving ANS were neonatal level of care and lack of prenatal care (). Mothers in this higher risk cohort may have greater benefit from ANS, considering that their infants may be more vulnerable to being medically underserved or subject to disparities in access to care.
We also found obstetrical conditions such as vaginal birth increased the likelihood of not receiving ANS. Although the lack of ANS in these cases may be related to the urgency of delivery, they still represent lost opportunities for improvement in quality of care. Although optimal neonatal benefit for ANS occurs after 24 hours of exposure prior to delivery, there is still likely to be some benefit if delivery occurs prior to this time.(15
) Furthermore, 10.1% of mothers with prolonged
rupture of membranes (> 18 hours) did not receive ANS. More than 80% of prolonged rupture of membranes was accounted for by infants born prior to 32 weeks gestation in this cohort. The American College of Obstetricians and Gynecologists recommends ANS for all infants up to 32 weeks gestation, even in the setting of premature membrane rupture, so lack of sufficient time could not have accounted for this finding in our cohort.(3
In addition to socio-demographic and medical risk factors, we found that the rate of non-administration of ANS increased rapidly in infants delivering between 30 and 34 weeks gestation, with a six-fold increase in adjusted odds of not receiving ANS at 34 weeks. The reasons for this are unclear. It may represent a difference in the imminence of birth on maternal presentation at later gestational ages, or it may reflect reduced attention to the potential adverse consequences of “moderately preterm” birth. There has been recent interest in the increased risk of morbidity and mortality in late preterm infants (34 and 37 weeks gestation).(18
) The recognition that degree of prematurity presents something akin to a dose-dependent risk should also lead to closer attention of the “moderately preterm” infant born from 30 to 34 weeks gestation. These infants are at even higher risk than late preterm infants for respiratory and other morbidities, yet we found that the ANS rates in this population were markedly lower than infants born at younger gestational ages.(22
) Given the evidence of benefit of ANS to 34 6/7 weeks, there is opportunity to improve care for mothers with threatened preterm birth at these intermediate gestational ages.(23
Risk adjusted hospital-specific ANS rates for eligible infants varied widely (), indicating substantial variation that cannot be explained by hospital characteristics. Considering that there remained large hospital variation in practice after risk adjustment suggests that there are substantial opportunities for improving ANS rates at many facilities.
The evidence that ANS administration reduces the risk of neonatal death, respiratory distress syndrome, and other morbidities in premature infants has led to it being the standard of care for at least the past decade.(3
) Due to the evidence supporting its use, ANS administration increased dramatically in the 1990’s, from 23.8% in 1991 to 71.6% in 1999 in the Vermont Oxford Network.(26
) Although the causes of this rise have not been studied in detail, directed quality improvement interventions have been used successfully to increase ANS rates.(7
One such effort occurred within CPQCC from 1999 to 2000. Details of the dissemination strategy have been described previously.(7
) An ANS toolkit was developed and disseminated. A series of interactive workshops and webcasts were then provided. Although the toolkit was available to all CPQCC members, not all hospitals participated in the workshops. ANS rates increased from 76% in 1998 to 86% in 2001.(7
The sustainability of QI initiatives is an increasing area of scrutiny. There have been a dearth of studies on long-term effects of quality improvement collaborative efforts, and specifically none which have looked at the sustainability of efforts to improve ANS administration.(29
) For our analysis, we considered those hospitals which sent representatives to participate in the workshops and webcasts as the quality intervention participants. We found that the efforts of this group were associated with long-term change; participating hospitals had higher rates of ANS administration than other hospitals 5 to 7 years after the end of the intervention. Furthermore, there was evidence of holding the gains of the previous collaborative with ANS rates in the QI participants remaining at 85%.
Limitations of our study include those related to the obstetrical data collected. ANS administration is categorized by the CPQCC as any dose of ANS given prior to delivery, as opposed to a complete course. Therefore, our reported rate of ANS administration likely overestimates the rate of the more optimal complete ANS course. We were unable to determine if some mothers may have been admitted to the hospital just prior to delivery, without enough time for ANS administration. Finally, the comparison of ANS rates by quality improvement collaborative participation was not the result of a randomized controlled design. There may be some degree of selection bias in that hospitals that participated may have other factors relevant to their success. Nevertheless, the higher ANS administration rates in quality improvement participants are encouraging, as it suggests that the collaborative effort was associated with a sustained improvement at those hospitals. As quality improvement becomes a higher priority in medicine, further research should focus on not just the effectiveness of quality improvement, but its sustainability.
We found that there is still a concerning proportion of eligible patients at risk for not receiving ANS. It may be the case that relatively “easy” patients to identify and treat such as those who are followed through prenatal care with identification of high risk conditions are generally being treated appropriately. On the other hand, mothers who present without prenatal care and / or mothers who present suddenly without warning with imminent delivery may be at highest risk for not receiving ANS. There also may be some complacency toward ANS administration at later, yet still eligible, gestational ages. Quality improvement initiatives to target such mothers may be the next priority in further efforts to increase ANS rates. Our study showed that a collaborative effort by CPQCC may have had a lasting change on participating hospitals, an encouraging result in this era of quality improvement.