Table 4.

The association between epidural use and primary and secondary outcomes among subset of matched patients who underwent open surgery (N = 8,005 patients, 1,611 of which had an epidural).

Primary analysis	Average relative effect odds ratio* (95% CI)‡	P-value‡
Cardiopulmonary complications/mortality	0.58 (0.35, 0.95)	0.03
Secondary analyses	Odds ratio§ (98.75% CI)||	P-value||
Stroke	1.19 (0.23, 6.18)	0.80
Renal complications	0.47 (0.20, 1.15)	0.03
Surgical complications¶	0.96 (0.78, 1.19)	0.63
Hazard ratio** (98.75% CI)
Time to discharge alivea	1.10 (1.02, 1.18)	< 0.001

^*Odds ratio estimated using an average relative effect generalized estimating equations model using an unstructured covariance matrix.

^‡Significance criterion of 0.05 was used for the primary analysis.

^§Odds ratios estimated from separate logistic regression models.

^||Significance criterion of 0.0125 used for each secondary analysis (i.e., 0.05/4, Bonferroni).

^¶9 patients removed from analysis due to missing surgical complications data.

^**Hazard ratio estimated using Cox proportional hazards regression. Patients who died before discharge were censored to the longest observed hospital length of stay.

^a10 patients who did not receive an epidural excluded from analysis due to unreported hospital length of stay.