Table 1.

Patient demographics of infants undergoing PDA ligation in the 3 centres – Centre A – Cambridge, Centre B – Guys and St Thomas, Centre C – Great Ormond Street. Results are expressed as median (95% confidence interval).

Demographic	Centre A n = 21	Centre B n = 35	Centre C n = 28	p value*
Birth weight (grams) Median (95% CI)	820 (649–1020)	770 (710–840)	807 (728–980)	0.67
Birth gestation (weeks) Median (95% CI)	27 (24–28)	25 (25–26)	26 (25–27)	0.32
Ligation weight (grams) Median (95% CI)	963 (781–1169)	1050 (910–1170)	950 (795–1100)	0.66
Ligation age (days) Median (95% CI)	23 (20–31)	31 (25–41)	27 (21–30)	0.05

*Kruskall Wallis test