Perioperative outcomes in the context of mode of anaesthesia for patients undergoing hip fracture surgery: systematic review and meta-analysis

Background: Previous meta-analyses on the anaesthetic management of patients undergoing surgery for hip fracture have focused on randomized trials. Furthermore, heterogeneity in outcome reporting across the studies has made it difficult to inform best practice guidelines for patient care. Methods: This systematic review examined how perioperative outcomes were reported and defined in the context of comparing modes of anaesthesia for hip fracture surgery. Outcomes were included from randomised and non-randomised studies published between January 2000 and July 2017. Meta-analyses were performed for regional versus general anaesthesia, with sensitivity analyses performed for spinal versus general anaesthesia. Results: By including data from 15 large observational studies in this meta-analysis, we have increased the number of patients for whom outcomes were assessed from approximately 3000 to 202 000. There was no significant difference in 30-day mortality [Odds ratio (OR) 1.15; 95% confidence interval (CI) 1.01, 1.32; I-2 87%; n = 200 464], prevalence of pneumonia (OR 1.10; 95% CI 0.93, 1.30; I-2 43%; n = 65 011), acute myocardial infarction (OR 0.96; 95% CI 0.88, 1.05; I-2 0%, n = 64 904), delirium (OR 1.07; 95% CI 0.72, 1.58; I-2 93%, n = 19 923) or renal failure (OR 0.94; 95% CI 0.54, 1.64; I-2 0%, n = 27 873) for regional compared to general anaesthesia. There was a small statistically significant difference for length of stay (standardized mean difference -0.03; 95% CI -0.05, -0.02; I-2 0%; n = 78 711) favouring regional anaesthesia, which is unlikely to be clinically significant. Sensitivity analyses for the same outcomes examining spinal only vs general anaesthesia showed minor statistical significance for length of stay favouring spinal. We also present data highlighting the scale of the inconsistencies in reported outcomes across 32 studies, making evaluation in a standardized manner very difficult. As an example, mortality was reported in nine different ways throughout the studies. Conclusions: We highlight the need for agreement on outcome definitions and for a minimum core outcome set to be measured and reportedinhip fracture studies. This would strengthen the evidence-based approach to delivering optimal care.