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Case ascertainment in stroke studies: the risk of selection bias
Author(s) -
Appelros P.,
Högerås N.,
Terént A.
Publication year - 2003
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1034/j.1600-0404.2003.02120.x
Subject(s) - stroke (engine) , medicine , selection bias , incidence (geometry) , register (sociolinguistics) , population , case fatality rate , demography , physical therapy , environmental health , pathology , mechanical engineering , linguistics , philosophy , physics , sociology , optics , engineering
Objectives – The purpose was to compare the completeness of case ascertainment in two stroke registers, one local population‐based, the other a national quality register (Riks‐Stroke), and to examine if patient characteristics could be affected by selection bias. Material and methods – By the way of linking and matching computer files, the completeness of case ascertainment was evaluated. Results – In the local stroke incidence study 377 patients were included. Of them, 63% were reported to the hospital‐based national quality register. The case‐fatality was lower in the national register. A larger proportion of the patients in the national register appeared to have been treated in a stroke unit and undergone rehabilitation, and computerized tomography seemed to have been performed in a larger proportion. Conclusions – Because of selection bias, outcome data get skewed when case ascertainment does not embrace all stroke cases. A community‐based stroke register is the golden standard when measuring stroke incidence.