Page 24 - Cardiac abnormalities after aneurysmal subarachnoid hemorrhage
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Chapter 2
as the Glasgow Outcome Scale (dichotomized at ≤ 3), or the modified Rankin scale (dichotomized at >3). If studies used another dichotomy or another outcome scale, we used the numbers of patients with poor outcome provided by the authors, without adjusting to our preferred definition of poor outcome.
Several studies used different definitions of DCI. Given this heterogeneity of definitions, we recorded the number of patients with DCI as given by the authors, without adjusting these numbers to a predefined definition of DCI.
Data analysis
The relation between the three outcome measures and the 22 determinants was analyzed. The crude proportions of the extracted variables were calculated. Cross- tables were made to calculate Risk Ratios (RR) for each determinant and outcome in each article. The pooled RRs with their corresponding 95% confidence intervals (95% CI) were calculated by means of Cochrane’s Review Manager 4.2. Using the same program, statistical heterogeneity of the effects was tested. This is indicated as I2. A value greater than 50% may be considered substantial heterogeneity.6
Results
Study Characteristics
In the initial PubMed search 2169 studies were found that reported on cardiac abnormalities after aneurysmal SAH (figure 1).
22
