Trying to understand routine stroke outcome data: the need for adequate casemix adjustment and some practical considerations.
OBJECTIVE
To determine how far the difference in published stroke case fatality between the Western General Hospital (WGH), Edinburgh and the Falkirk and District Royal Infirmary (FDRI) for the period 1990-93 can be explained by adjusting more fully for casemix.


METHODS
The cases were ascertained and followed prospectively at the WGH and retrospectively at the FDRI; casemix correction was performed using a validated logistic regression model.


METHODS
The WGH is a teaching hospital and the FDRI a district general hospital.


METHODS
Four hundred and thirty seven patients with a verified acute stroke at the WGH; 471 patients assigned a cerebrovascular disease discharge diagnostic code at the FDRI.


METHODS
Thirty day case fatality.


RESULTS
About half of the difference in the two hospitals' published stroke case fatality could be accounted for by variation in measured casemix. The residual difference in adjusted case fatality might have been due to differences in the structure of stroke care or simply to remaining differences in casemix. Full investigation of the cause was prevented by the destruction of the deceased patients records.


CONCLUSIONS
Comparisons of routinely collected stroke outcomes will remain difficult to interpret unless casemix is properly accounted for and deceased patients' records stored for several years.
Weir
N U
NU
Department of Clinical Neurosciences, Western General Hospital Crewe Road, Edinburgh.
Signorini
D F
DF
Dennis
M S
MS
Murdoch
P S
PS
D000368:Aged; D006302:Health Services Research; D017052:Hospital Mortality; D006767:Hospitals, District / Q000592:standards / Q000706:statistics & numerical data*; D006784:Hospitals, Teaching / Q000592:standards / Q000706:statistics & numerical data*; D006801:Humans; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D020379:Risk Adjustment; D012606:Scotland / Q000453:epidemiology; D020521:Stroke / Q000401:mortality*