Table 5.

Logistic regression model for predictors of stone impaction

Predictive variable	Univariate			Multivariate
	Odds ratio	95% confidence interval	p value	Odds ratio	95% confidence interval	p value
Female gender	1.18	1.08–1.30	0.001	1.15	1.03–1.27	0.01
ASA-score
II	1.64	1.48–1.82	<0.001	1.59	1.43–1.77	<0.001
III	2.72	2.29–3.24	<0.001	2.58	2.14–3.11	<0.001
IV	3.43	1.69–6.98	0.001	3.58	1.72–7.45	0.001
Pre-operative positive urine culture	1.87	1.55–2.26	<0.001	1.21	1.14–1.29	<0.001
Total stone burden	1.29	1.23–1.36	<0.001	1.26	1.19–1.33	<0.001
Previous treatment	1.34	1.22–1.48	<0.001	1.23	1.11–1.36	<0.001

NS not significant, ASA 1 score reference category