Page 22 - Cardiac abnormalities after aneurysmal subarachnoid hemorrhage

Chapter 2
Eligibility
Two investigators (I.B. and D.H.) assessed eligibility of studies independently. Criteria for inclusion of studies in this review were: publication after 1960 in the English, French or German language. All studies had to report on cardiac abnormalities and outcome following aneurysmal SAH. Cardiac abnormalities were defined as echocardiographic wall motion abnormalities (WMAs), diastolic dysfunction, or biochemical evidence of myocardial damage (defined as elevated troponin levels, or elevated CK-MB levels), or elevated brain natriuretic peptide levels (BNP and NT- pro-BNP), or ECG changes. SAH had to be documented by either CT scanning or cerebrospinal fluid examination. Studies with less than ten patients, case reports, and reviews were excluded.
To avoid selection bias, only studies that included consecutive patients were eligible. When a study group published more articles on the same dataset, only the report with the largest number of patients was eligible for data extraction.
Quality assessment of studies
To systematically assess the quality of the studies, we modified the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) checklist (https://www.strobe-statement.org). Although this checklist is designed to improve the reporting of observational studies for optimal data extraction and interpretation, we used the list as a quality assessment tool. For every article, each of the 22 STROBE items was assigned a zero or one by two independent observers (I.B. and F.V.), and summed as the STROBE score. Several STROBE items consist of sub-items. These sub-items were also scored as zero or one and averaged. Disagreement was solved by direct communication between the two observers. The following items were assessed: cohort identification in title or abstract possible (item 1a), abstract informative and addressing key items (item 1b), background/rationale reported (item 2), objectives given with hypothesis (item 3), study design given (item 4), setting, locations and data collection period given (item 5), in- and exclusion criteria given and sources and methods of selection of patients given (item6a), period and methods of follow- up given (item 6b), variables of interest defined (cardiac data and outcome measures) (item 7), method of assessment of variable of interest given (item 8a), comparability of assessment methods across groups given (item 8b), sources of bias given (item 9), rationale for sample size given (item 10), statistical methods given (item 11a), missing data described (item 11b), subgroup- and sensitivity analysis given (item 11c), analysis of quantitative variables given (item 12a), continuous and grouped
20