Meta-Analysis
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World J Meta-Anal. Nov 26, 2014; 2(4): 171-178
Published online Nov 26, 2014. doi: 10.13105/wjma.v2.i4.171
Hydrocephalus after subarachnoid hemorrhage: A meta-analytic comparison of aneurysm treatments
Shih-Shan Lang, Matthew R Sanborn, Connie Ju, Akiff Premjee, Sherman C Stein, Michelle J Smith
Shih-Shan Lang, Matthew R Sanborn, Connie Ju, Akiff Premjee, Sherman C Stein, Michelle J Smith, Department of Neurosurgery, University of Pennsylvania Medical Center, Philadelphia, PA 19104, United States
Author contributions: Lang SS, Stein SC and Smith MJ designed the research; Ju C and Premjee A collected the data and assisted in the analysis; Stein SC performed analyses and assisted in the writing; Lang SS, Sanborn MR and Smith MJ wrote most of the paper; all authors participated in editing the manuscript.
Correspondence to: Sherman C Stein, MD, Clinical Professor of Neurosurgery, Department of Neurosurgery, University of Pennsylvania Medical Center, Philadelphia, 3400 Spruce Street, Philadelphia, PA 19104, United States. sherman.stein@uphs.upenn.edu
Telephone: +1-215-4400919 Fax: +1-215-4403798
Received: April 23, 2014
Revised: August 7, 2014
Accepted: August 27, 2014
Published online: November 26, 2014
Processing time: 223 Days and 9.3 Hours
Abstract

AIM: To compare two treatments for ruptured cerebral aneurysm with reference to the relative risk of developing hydrocephalus.

METHODS: We reviewed the English language literature on the risk of developing hydrocephalus after aneurysm treatment. Data were divided by type of study (randomized controlled trial, cohort trial, nonrandomized comparison, prospectively- and retrospectively-collected observational study). They were also divided by type of aneurysm treatment (microvascular - clipping, or endovascular - coiling). Additional predictive variables collected for each publication were average age, gender distribution, measures of hemorrhage volume and subarachnoid hemorrhage severity, aneurysm locations, time to treatment, duration of follow-up and date of publication. We employed meta-analysis to calculate pooled risk ratios of developing hydrocephalus in cases receiving aneurysm clipping vs those receiving coiling. Meta-regression was used to correct pooled results for covariates.

RESULTS: Because indications for the two treatments are different, there is little clinical equipoise for treating most cases. The single randomized, controlled trial dealt with a small subset of ruptured aneurysms. Neither this nor pooled values from other studies which compared the two treatments had the power to demonstrate significant differences between the two treatments. Nor was there an apparent difference when observational data were meta-analytically pooled. However, when meta-regression was used to correct for predictive variables known to differ between the two treatment groups, a highly-significant difference appeared. Coiling is used more commonly in older, sicker patients with aneurysms in certain locations. These cases are more likely to develop hydrocephalus. When corrected for these covariates, the risk of hydrocephalus was found to be significantly lower in coiled vs clipped cases (P = 0.014).

CONCLUSION: Pooled observational data were necessary to demonstrate that coiling ruptured cerebral aneurysms is associated with a lower risk of developing hydrocephalus than is clipping.

Keywords: Subarachnoid hemorrhage; Cerebral aneurysm; Hydrocephalus; Meta-analysis; Meta-regression; Observational data

Core tip: Several treatment comparisons in clinical medicine are not amenable to randomized controlled trials. The conditions may be too rare for trials to obtain adequate statistical power. There may be a lack of clinical equipoise on the part of patients or clinicians. Comparisons of different treatments are nevertheless still important and can only be addressed by pooling observational data.