Hospital variation in nitric oxide use for premature infants

Abstract

Objective: To describe inter-center hospital variation in inhaled nitric oxide (iNO) administration to infants born prior to 34 weeks' gestation at US children's hospitals.

Methods: This was a retrospective cohort study using the Pediatric Health Information System to determine the frequency, age at first administration, and length of iNO use among 22 699 consecutive first admissions of unique <34 weeks' gestation infants admitted to 37 children's hospitals from January 1, 2007, through December 31, 2010.

Results: A total of 1644 (7.2%) infants received iNO during their hospitalization, with substantial variation in iNO use between hospitals (range across hospitals: 0.5%-26.2%; P < .001). The age at which iNO was started varied by hospital (mean: 20.0 days; range: 6.0-65.1 days, P < .001), as did the duration of therapy (mean: 13.1 days; range: 1.0-31.1 days; P < .001). Preterm infants who received iNO were less likely to survive (36.3% mortality vs 8.3%; odds ratio: 6.27; P < .001). The association between the use of iNO and mortality persists in propensity score-adjusted analyses controlling for demographic factors and diagnoses associated with the use of iNO (odds ratio: 3.79; P < .0001).

Conclusions: iNO practice patterns in preterm infants varied widely among institutions. Infants who received iNO were less likely to survive, suggesting that iNO is used in infants already at high risk of death. Adherence to National Institutes of Health consensus guidelines may decrease variation in iNO use.

FIGURE 1

Study data are from 37 children’s hospitals. A, Histogram of the proportions of patients receiving iNO at each hospital. Rates of iNO use varied from 0.4% to 26.2% across NICUs (P < .0001). B, Histogram of the average ages at which patients first received iNO at each hospital. The hospital-specific means of the age of initiation ranged from 5.5 to 83.4 days (P < .001). C, Histogram of the average number of days of iNO received by a patient at each hospital. The hospital-specific means of the number of days of iNO received ranged from 1.0 to 32.0 (P < .001). D, Scatter plot of the association between hospitals’ rates of iNO use and the average number of days of iNO use, with regression line (r = 0.65; P < .001).

FIGURE 2

Study data are from 37 children’s hospitals. The horizontal axis is the number of patients meeting inclusion and exclusion criteria in this study for each hospital, divided by 3.5 years. The vertical axis is the rate of iNO use (% of patients) for each hospital. The red line is the linear regression of iNO use on volume.

FIGURE 3

The horizontal axis represents deciles of the sample, grouped according to increasing probability that the patients would receive iNO (ie, the estimated propensity score). Within each decile, the mortality rates (with 95% CIs) were plotted for patients who did (blue points, line, and error bars) or did not receive iNO (in red).