The use of mannitol in partial nephrectomy for renal function preservation: meta-analysis and systematic review of comparative studies

Abstract

Objective: We aimed to assess the effect and safety of mannitol use in partial nephrectomy for renal function preservation. Methods: A systematic literature search was performed. Randomised controlled trials and non-randomised controlled trials comparing with versus without mannitol use in partial nephrectomy were screened and evaluated according to Cochrane Collaboration recommendations. Outcomes assessed were percentage change from preoperative estimated glomerular filtration rate, estimated blood loss and complications. The standardised mean difference (SMD) and risk ratio (RR) with corresponding 95% confidence intervals were extrapolated. Effect estimates were pooled using the inverse variance method with a random-effects model. Subgroup analysis was performed according to study design and follow-up duration. Grading of recommendations, assessment, development and evaluations assessment was used to rate the quality of evidence. Results: A total of 1136 patients from two randomised controlled trials ( n=264) and six non-randomised controlled trials ( n=872) were included. The included randomised controlled trials had some concerns regarding a high risk of bias; while the non-randomised controlled trials were all retrospective studies with moderate to serious concern for risk of bias. Overall pooled effect estimates for short and long-term follow-up showed no significant differences between intervention groups for percentage change from preoperative estimated glomerular filtration rate (SMD 0.09, 95% confidence interval (CI) −0.11, 0.29; SMD −0.06, 95% CI −0.22, 0.06, respectively). Likewise, no between-group difference was noted for intraoperative blood loss and complication rates (SMD 0.05, 95% CI −0.08, 0.17; RR 1.07, 95% CI 0.6, 1.82, respectively). Conclusion: The pooled effect estimates from both randomised and non-randomised comparative studies illustrated no overall short-term or long-term advantage with mannitol use in partial nephrectomy for the preservation of estimated glomerular filtration rate. Likewise, no difference was noted for intraoperative blood loss or complication rates. However, to date there is only a very low to low quality of evidence available to extrapolate conclusions. Level of evidence: Very low to low