The real-life reliability of the modified Rankin scale used in a stroke unit and a rehabilitation ward.

PURPOSE

The modified Rankin scale (mRS) is the gold standard for measuring stroke-related disability in clinical trials and everyday practice. However, inter-observer variability is a source of bias that may undermine the reliability of retrospective studies. It may also depend on clinical backgrounds of different assessing physician. Our aim was to prospectively assess real-life consistency between stroke unit physicians (SUPs) and physical and rehabilitation medicine physicians (PRMPs) using mRS in patients transferred directly from a stroke unit (SU) to a rehabilitation ward (RW).

METHODS

We enrolled 48 consented stroke patients transferred within the same hospital from SU to RW. Patients were scored in mRS by a SUP and a PRMP at the day of transfer as a standard of care. The reference mRS score (REF) was obtained by a single- blinded stroke physician using the Rankin Focused Assessment form to guide an interview.

RESULTS

An mRS score was reported for all patients admitted to the RW and 33 patients discharged from the SU. The overall agreement was 75.8% between the assessments of SUPs and PRMPs (κ = 0.58), 72.7% between SUPs and the REF (κ = 0.55) and 70.0% between PRMPs and the REF (κ = 0.49). A similar agreement was observed for PRMPs and the REF in the sensitivity cohort of 48 patients (66.7%; κ = 0.46). Patients with the REF mRS of 2 ( = 6) were often scored as 3 both by SUPs (4/6) and PRMPs (5/6). In patients with the REF mRS of 3 or 4 there was no clear tendency towards overrating disability.

CONCLUSIONS

The reliability of mRS scoring in everyday practice is modest and does not seem to depend on clinical background of assessing physician.