Twenty two trials, involving 2567 predominantly female and elderly patients, comparing regional anaesthesia with general anaesthesia were included. All trials had methodological flaws and many do not reflect current anaesthetic practice. Pooled results from eight trials showed regional anaesthesia to be associated with a decreased mortality at one month (56/811 (6.9%) versus 86/857 (10.0%)); however, this was of borderline statistical significance (relative risk (RR) 0.69, 95% confidence interval (CI) 0.50 to 0.95). The results from six trials for three month mortality were not statistically significant, although the confidence interval does not exclude the possibility of a clinically relevant reduction (86/726 (11.8%) versus 98/765 (12.8%), RR 0.92, 95% CI 0.71 to 1.21). The reduced numbers of trial participants at one year, coming exclusively from two trials, preclude any useful conclusions for long-term mortality (80/354 (22.6%) versus 78/372 (21.0%), RR 1.07, 95% CI 0.82 to 1.41).
Regional anaesthesia was associated with a reduced risk of deep venous thrombosis (39/129 (30%) versus 61/130 (47%); RR 0.64, 95% CI 0.48 to 0.86). However, this finding is insecure due to possible selection bias in the subgroups in whom this outcome was measured. Regional anaesthesia was also associated with a reduced risk of acute postoperative confusion (11/117 (9.4%) versus 23/120 (19.2%), RR 0.50, 95% CI 0.26 to 0.95).
There was insufficient evidence to draw any conclusions from a further four included trials, involving a total of 179 participants, which compared other methods of anaesthesia (a 'light' general with spinal anaesthesia; intravenous ketamine; nerve blocks).
