Risk-adjusted hospital mortality rates for stroke: evidence from the Australian Stroke Clinical Registry (AuSCR)

We thank Sutherland and colleagues for their comments on our article, and for identifying discrepant data in Box 2 and Appendix 4, now corrected.1 International guidelines explicitly refer to including stroke severity in risk adjustment.2 We maintain that stroke severity is required for reliable mortality rate comparisons. Stroke severity may modify individual hospital rankings by up to 25%.2 We have subsequently conducted new analyses using linked administrative and stroke registry data to permit inclusion of ICD-10 coded comorbidities, including calculating an Elixhauser Comorbidity Index.3 Consistent with our original findings, models with the stroke severity variable still provided the best fit for standardising mortality among the hospitals. Therefore, the registry data offer an important adjunct to work undertaken by different organisations focused on performance monitoring using administrative data, and are likely to be more acceptable to clinicians.