Cost per case or total cost? The potential of prevention of hand injuries in young children – Retrospective and prospective studies

Table 3 Negative binomial regression of factors associated with the variation in number of ward days. All patients.^a).

Variable	IRR	95 % confidence interval
Fracture, sprain or dislocation caused by fall/hit	0.45**	0.27–0.75
Age	0.99***	0.99–1.00
Immigrant background	1.23*	1.00–1.51
Number of surgical sessions	3.46***	2.96–4.06
Admitted day after injury	0.77*	0.58–1.01
Admitted two or more days after injury	0.78*	0.63–0.98
Patient from Malmö city	0.58***	0.48–0.71
Alpha	0.53	0.41–0.67
Number of observations	533
Pseudo R²	0.18

Note: Significance levels indicated by stars: * p < 0.05; ** p < 0.01 and *** p < 0.001. IRR = incidence rate ratio.
^a) Reference person was a newborn child from categories A, B, D, E, F, G; from outside Malmö city and with Swedish background, admitted the same day as the injury and no operation session.

ISSN: 1471-2431