Impact of race on heart rate characteristics monitoring in very low birth weight infants

Abstract

Background: A multicenter RCT showed that displaying a heart rate characteristics index (HRCi) predicting late-onset sepsis reduced mortality for VLBW infants. We aimed to assess whether HRCi display had a differential impact for Black versus White infants.

Methods: We performed secondary data analysis of Black and White infants enrolled in the HeRO RCT. We evaluated the predictive performance of the HRCi for infants with Black or White maternal race. Using models adjusted for birth weight, we assessed outcomes and interventions for a race × randomization interaction.

Results: Among 2607 infants, Black infants had lower birth weight, gestational age, length of stay, and ventilator days, while sepsis and mortality were similar. The HRCi performed equally for sepsis prediction in Black and White infants. We found no differential effect of randomization by race on sepsis, mortality, antibiotic days, length of stay, or ventilator days. However, there was a differential randomization effect by race for blood cultures per patient: White RR 1.11 (95% CrI 1.04-1.18), Black RR 1.00 (0.93-1.07).

Conclusions: The HRCi performed similarly for sepsis prediction in Black and White infants. Randomization to HRCi display increased blood cultures in White but not in Black infants, while the impact on other outcomes or interventions was similar.

Impact: Predictive analytics, such as heart rate characteristics (HRC) monitoring for late-onset neonatal sepsis, should have equal impact among patients of different race. Infants with Black or White maternal race randomized to HRC display had similar outcomes, but randomization to the study arm increased a related clinical intervention, blood cultures, in White but not in Black infants. This study provides evidence of a differential effect of predictive models on clinical care by race. The work will promote consideration and analysis of equity in the implementation of predictive analytics.

Figure 1.

Box and Whisker plots of HRC index by race and study arm. The whisker ends correspond with the 5^th and 95^th percentiles, the box boundaries indicate the 25^th and 75^th percentiles, and the horizontal line represents the median or 50^th percentile of the HRC index distributions. There were no differences between HRC index values by study arm for either White or Black patients, indicating that randomization was unbiased. The higher HRC indices among Black patients corresponds with the higher daily rate of late onset sepsis among Black patients when compared with White patients.

Figure 2.

Calibration curves for HRC predicted versus observed sepsis by race. The smooth red line and blue dashed line represent the predicted risk of sepsis based on HRC index percentile for Black and White patients, respectively. The red circles and blue triangles indicate the observed rate of sepsis for Black and White patients, respectively, within each decile of predicted risk. The agreement between the predicted and observed rates of infection indicates the HRC index is well calibrated for both Black and White patients.

Figure 3.

Predicted number of antibiotics days (left) and number of blood cultures (right) by infant race and study arm, adjusted for birth weight and site. Panels show posterior medians with 95% Credible Intervals.