Table 2.

Results of the first stage using logistic regression analysis^a

		THA b			TKA c
		(n = 16,646)			(n = 17,535)
Variable	OR d	95% CI	p-value	OR d	95% CI	p-value
Age over 65	0.57	0.46–0.72	< 0.001	0.65	0.53–0.80	< 0.001
Male	0.74	0.60–0.91	0.004	0.82	0.66–1.03	0.09
Charlson index	1.17	1.04–1.31	0.008	1.14	1.03–1.26	0.01
Cemented	0.77	0.60–0.99	0.04	1.70	0.75–3.85	0.2
Hybrid	0.92	0.69–1.23	0.6	2.23	0.91–5.47	0.08
Previous THA (TKA)	1.15	0.85–1.57	0.4	0.80	0.56–1.13	0.2
THA (TKA) before change in law	0.96	0.75–1.22	0.7	0.92	0.72–1.18	0.5
Volume 200–300	1.29	1.01–1.64	0.04	1.02	0.78–1.34	0.9
Volume > 300	1.02	0.65–1.62	0.9	0.85	0.62–1.17	0.3

^a Explained variable 1 if the patient filed a claim, otherwise 0.

^b THA: total hip arthroplasty.

^c TKA: total knee arthroplasty.

^d OR: odds ratio.