Predictors of hospital readmission in infants less than 3 months old

FeBRILe3: Safety Evaluation of Febrile Infant Guidelines Through Prospective Bayesian Monitoring

OBJECTIVES

Despite evidence supporting earlier discharge of well-appearing febrile infants at low risk of serious bacterial infection (SBI), admissions for ≥48 hours remain common. Prospective safety monitoring may support broader guideline implementation.

METHODS

A sequential Bayesian safety monitoring framework was used to evaluate a new hospital guideline recommending early discharge of low-risk infants. Hospital readmissions within 7 days of discharge were regularly assessed against safety thresholds, derived from historic rates and expert opinion, and specified a priori (8 per 100 infants). Infants aged under 3 months admitted to 2 Western Australian metropolitan hospitals for management of fever without source were enrolled (August 2019-December 2021), to a prespecified maximum 500 enrolments.

RESULTS

Readmission rates remained below the prespecified threshold at all scheduled analyses. Median corrected age was 34 days, and 14% met low-risk criteria (n = 71). SBI was diagnosed in 159 infants (32%), including urinary tract infection (n = 140) and bacteraemia (n = 18). Discharge occurred before 48 hours for 192 infants (38%), including 52% deemed low-risk. At study completion, 1 of 37 low-risk infants discharged before 48 hours had been readmitted (3%), for issues unrelated to SBI diagnosis. In total, 20 readmissions were identified (4 per 100 infants; 95% credible interval 3, 6), with >0.99 posterior probability of being below the prespecified noninferiority threshold, indicating acceptable safety.

CONCLUSIONS

A Bayesian monitoring approach supported safe early discharge for many infants, without increased risk of readmission. This framework may be used to embed safety evaluations within future guideline implementation programs to further reduce low-value care.

A Comparison of Methods Examining Time-to-Readmission in the First Year of Life

BACKGROUND AND OBJECTIVES

Readmissions analyses typically calculate time-to-readmission relative to hospital discharge. For newborns, this definition can be challenging when comparing groups with disparate birth stays. We compare 2 approaches to calculate readmissions and examine 1 year readmissions for newborns with versus without neonatal opioid withdrawal syndrome (NOWS; mean length of stay = 17 vs 2 days).

METHODS

Using birth discharge data from the Pediatric Health Information System (PHIS), we compared crude and adjusted 1 year readmissions by NOWS diagnosis using Cox regression models predicting time-to-readmission from: (1) birth discharge; and (2) birth (day-of-life), with left truncation allowing for delayed entry into the at-risk period at birth discharge.

RESULTS

We included N = 155 885 birth discharges (n = 1467 with NOWS). At 1 year, 10% of infants with NOWS versus 6% without had been readmitted. Readmission risk was highest within 1 week since discharge or birth for newborns without NOWS, whereas those with NOWS were at higher risk later into infancy. NOWS was associated with a higher adjusted hazard of 1 year readmissions since discharge (adjusted hazard ratio [aHR]=1.58; 95% CI: 1.20-2.08) and a higher adjusted hazard of 1 year readmissions since birth (aHR = 1.56; 95% CI: 1.21-2.03). Estimates vary by choice of index date, particularly at early time-points, converging later into infancy.

CONCLUSIONS

Our findings underscore the importance of methodological decisions for newborn readmissions. Although results were similar at 1 year with nearly identical adjusted hazards, approaches differed substantially through the neonatal period.