Development and internal validation of an early postnatal nomogram for bronchopulmonary dysplasia in very preterm infants with positive respiratory tract Ureaplasma urealyticum results.

内容摘要

Evidence suggests that Ureaplasma urealyticum (UU) colonization is associated with the onset and progression of bronchopulmonary dysplasia (BPD) in very preterm infants. However, clinically practical tools for early postnatal risk stratification in very preterm infants with positive respiratory tract UU results remain lacking. This study aimed to develop a 72-h early postnatal prediction model for BPD in very preterm infants with positive respiratory tract UU results using variables available by the end of the first 72&#xa0;h after birth. This retrospective study included very preterm infants (gestational age&#x2009;<&#x2009;32&#x2009;+&#x2009;0&#xa0;weeks) with a positive UU result from respiratory tract sampling within 48&#xa0;h after admission at Qilu Hospital, Shandong University, between January 2020 and December 2024. Candidate predictors were restricted to perinatal and early postnatal variables available by the end of the first 72&#xa0;h after birth; therefore, the model was intended for early postnatal risk stratification rather than delivery-room or immediate-at-birth prediction. LASSO regression with tenfold cross-validation was used for variable selection. Variables with non-zero coefficients at &#x3bb;1se were entered into a full multivariable logistic regression model, and a parsimonious four-variable logistic regression model was refitted for nomogram construction. Internal validation of the final four-variable model was performed using bootstrap resampling (B&#x2009;=&#x2009;500). Of 270 infants assessed for eligibility, 260 were included in the final analysis, including 90 infants with BPD and 170 without BPD. Gestational age, endotracheal intubation, neutrophil count, and lymphocyte count were retained in the final model and incorporated into a nomogram. The model showed high apparent discrimination in the derivation cohort, with an apparent C-index of 0.950 (95% CI, 0.925-0.975) and an apparent Brier score of 0.084. Bootstrap internal validation yielded an optimism-corrected C-index of 0.945, an optimism-corrected calibration intercept of 0.010, and an optimism-corrected calibration slope of 0.875. These findings indicate good internal performance but should be interpreted cautiously because the model was developed in a single-center cohort and lacks external validation. We developed a 72-h early postnatal prediction model for BPD risk stratification in very preterm infants with positive respiratory tract UU results. The model should be interpreted as a 72-h early postnatal risk-stratification tool rather than a delivery-room prediction model. The model showed promising internal performance in this single-center cohort, but external validation is required before clinical implementation.