Table 4.

Results of the mixed effect regression models: length of intensive care unit stay, oxygen supplementation, and overall hospitalization were the dependent variables. Study periods (reference 2018–19) were the predictive variables

Outcome	Study periods	ß	Lower 95% confidence interval	Upper 95% confidence interval	p
Length of intensive care unit stay	2020–21	0.194	-0.468	0.856	0.565
	2021–22	0.035	-0.224	0.293	0.793
	2022–23	0.101	-0.175	0.377	0.474
Length of oxygen supplementation	2020–21	-0.637	-1.429	0.155	0.115
	2021–22	0.750	0.441	1.059	< 0.001
	2022–23	1.121	0.793	1.450	< 0.001
Whole duration of hospital stay	2020–21	-0.110	-1.068	0.849	0.822
	2021–22	-0.060	-0.440	0.319	0.754
	2022–23	0.637	0.233	1.042	0.002

Models were adjusted for age, sex, gestational age at birth, underlying chronic disease (yes vs no), history of breastfeeding, number of older siblings (no older sibling vs one or more older siblings) and testing positive for respiratory syncytial virus