Statistical modelling of survival for babies with oesophageal atresia

We examined variables associated with survival for oesophageal atresia between 1996 and 2014.

Possible explanatory variables: birth weight, gestation, cardiac anomalies (any or major), renal anomalies (any or severe), primary anastomosis, leak, secondary oesophageal surgery, tracheomalacia, aortopexy, tracheostomy, gastrostomy, fundoplication, karyotype, neurological status. Variables were assessed with logistic regression and a new model assessed with Kaplan-Meier graphs.

104/120 (87%) babies survived. Median gestation 37weeks, 4 (3%) born before 28weeks. Mean birth weight 2.3 (SD 0.7) kg, 17 (14%) less than 1500g. Frequency (%) of explanatory variables: Major cardiac anomaly 21 (18%), any cardiac anomaly 48 (40%), severe renal anomaly 10 (8%), any renal anomaly 25 (21%), primary anastomosis 105 (88%), anastomotic leak 16 (13%), symptomatic tracheomalacia 28 (23%), aortopexy 17 (14%), tracheostomy 12 (10%), neurological anomaly 7 (6%), fundoplication 15 (13%), gastrostomy 30 (25%), secondary oesophageal surgery 8 (7%), abnormal karyotype 6 (5%). Multivariate analysis showed only renal (OR 0.04, 0.007 0.2) p=0.001, cardiac (OR 0.1, 0.002 0.6) p=0.01 and a primary anastomosis (OR 12.2, 1.8 81.6) p=0.01 (R2=0.48), or major cardiac (OR 0.04, 0.007 0.29) p=0.001 and severe renal anomalies (OR 0.009, 0.001 0.12) p<0.001 alone were significant (R2=0.57).

Survival is dependent on cardiac and renal anomalies. Birth weight is not significant. We propose a new classification system: 1: neither severe renal nor major cardiac anomaly, 2: either severe renal or major cardiac anomaly, 3: severe renal and major cardiac anomaly.