Table 2.

The odds ratio of having respiratory symptoms during or after physical activity at 11 years of age in a national cohort of extremely preterm born children according to treatment for patent ductus arteriosus (no surgery vs. surgery) in the neonatal period.

	PDA treatment	N (%)	Crude OR (95% CI)	p	aOR1 (95% CI)	p	aOR2 (95% CI)	p
Breathing problems	No surgery	9/56 (16)	3.4 (1.3–9.2)	0.02	2.6 (0.9–7.4)	0.08	3.2 (1.1–9.0)	0.03
	Surgery	13/33 (39)
Wheeze	No surgery	7/57 (12)	2.6 (0.9–7.7)	0.09	2.5 (0.8–7.9)	0.11	2.8 (0.9–8.8)	0.08
	Surgery	9/34 (27)
Scraping sound	No surgery	5/57 (9)	2.7 (0.8–9.3)	0.12	1.8 (0.5–6.8)	0.41	2.4 (0.7–8.7)	0.17
	Surgery	7/34 (21)

Breathing problems: proportion who answered “a little more than normal” or “a lot more than normal” to question 1: “Does the child have breathing problems beyond what is normal during physical exertion?” Wheeze: Proportion who answered “yes” to question 2: “During the last 12 months, has the child had heavy breathing or wheezing from the chest during or after physical exercise or play?” Scraping sound: proportion who answered “a little” or “a lot” to question 3: “Does the child make ≪scraping sounds≫ or other abnormal sounds from the throat during physical exertion?” aOR1, adjusted for total number of days on invasive mechanical ventilation. aOR2, adjusted for gestational age; CI, confidence interval; OR, odds ratio; PDA, patent ductus arteriosus. Values in bold indicates a p-value of less than 0.05.