Video Abstract
To estimate the effect of NICU admission of low-acuity infants born at 35 weeks’ gestation versus care in a mother/baby unit, on inpatient and outpatient medical outcomes.
This retrospective cohort study included 5929 low-acuity infants born at 350/7 to 356/7 weeks’ gestation at 13 Kaiser Permanente Northern California hospitals with level II or level III NICUs between January 1, 2011, and December 31, 2021. Exclusion criteria included congenital anomalies and early respiratory support or antibiotics. We used multivariable regression and regression discontinuity analyses to control for confounding variables.
Infants admitted to the NICU within 2 hours of birth (n = 862, 14.5%) had a 58 hour adjusted (98-hour unadjusted) longer length of stay. NICU admission was associated with an increased probability of a length of stay ≥96 hours (67% vs 21%; adjusted odds ratio [aOR], 4.94; 95% confidence interval [CI], 3.96–6.16). Regression discontinuity results suggested a similar (57 hour) increase in length of stay. Readmission risk, primarily for jaundice, was lower for those admitted to the NICU (3% vs 6%; aOR, 0.43; 95% CI, 0.27–0.69). Infants admitted to the NICU were slightly less likely to be receiving exclusive breast milk at 6-month follow-up (15% vs 25%; aOR, 0.73; 95% CI, 0.55–0.97; adjusted marginal risk difference −5%).
Admitting low-acuity infants born at 35 weeks’ gestation to the NICU was associated with decreased readmission, but with longer length of stay and decreased exclusive breast milk feeding at 6 months. Routine NICU admission may be unnecessary for low-acuity infants born at 35 weeks’ gestation.
Comments
Admissions Of Low-Acuity 35-Week Infants to NICU May Affect The Healthcare Quality Metrics
In the study, authors noted SGA as a strong predictor for the length of stay (LOS) >96 hours, aAR = 1.82 (95% CI 1.28–2.57). Among the SGA, there was also a difference of 38.2% (43.8% – 5.4%) between the NICU and mother/baby unit admission rates. SGA infants are at increased risk for feeding issues, including breastfeeding and feeding intolerance, and temperature issues. The hospital policy should take SGA into account. In cases where intrauterine growth restriction is documented, initial admission to NICU could be justified.
With these hospital admission policies, the quality metrics need to be adjusted. Decreasing LOS at the cost of readmission could neutralize the overall performance quality. The other point we should consider when admitting low-risk infants to NICU is the case mix index (CMI), a health quality and reimbursement benchmark. The CMI is the average relative diagnosis-related group (DRG) weight of a hospital’s inpatient discharge, which is calculated by adding the Medicare Severity-Diagnosis Related Group (MS-DRG) weight for each discharge and dividing the total by the number of discharges. For example, the NICU discharges 5 infants. The MS-DRGs were 2.5+3.5+4+3.5+5. By adding them, we get 18.5; now, dividing this by the total discharges, we get a CMI of 3.7. Now let’s make the MS-DRGs lower; 2+1.5+1.2+1.8+3. By adding them, we get 9.5; now, dividing this by the total discharges, we get a CMI of 1.9. Hence CMI reflects the diversity, clinical complexity, and resource needs of the hospital’s patients. Admission of low-acuity 35-week infants with lesser complexity and resource-intensive caseload would decrease the CMI.