Table 3. Pre-op comorbidities by surgical center.

Center	Smoking				Hypertension				Diabetes				Osteoporosis osteopenia			Total n
	n	%	P†		n	%	P†		n	%	P†		n	%	P†
1	23	13.5	0.48		64	37.6	0.27		26	15.3	0.44		4	2.4	0.76	170
2	15	31.9	0.01		7	14.9	0.01		7	14.9	0.70		2	4.3	0.31	47
3	6	4.8	<0.01		45	35.7	0.56		16	12.7	0.95		1	0.8	0.36	126
4	27	25.2	0.12		32	29.9	0.55		9	8.4	0.20		2	1.9	0.95	107
Total	71	15.8	1.00		148	32.9	1.00		58	12.9	1.00		9	2.0	1.00	450

^†, P value for each center in comparison to average value for all centers.