Concordance of historical questions used in risk-stratifying patients with headache☆

Abstract 

Study Objective

We sought to determine whether the manner and order in which historical questions used to risk stratify for subarachnoid hemorrhage are asked significantly alter the response/concordance.

Methods

Adult patients complaining of headache in the emergency department were presented with 1 of 2 questionnaires each containing 2 variations of the pertinent question and differing only in their order. Data were primarily analyzed using the κ statistic to determine whether rates of concordance are greater than would be expected by chance alone. And, as a secondary outcome, a sample of 120 was predetermined to be adequate to achieve 80% power in detecting a difference of 20% to 25% between questionnaires comparing the influence of order on concordance.

Results

The agreement corrected for chance for version 2, κ = 0.51, is higher than the agreement corrected for chance for version 1, κ = 0.28, a difference of 0.23 with a 95% confidence interval (−0.03 to 0.49; P = .08; SE, 0.13). The percentages of patients who answered the questions concordantly were 60% and 75%, respectively, for versions 1 and 2. The difference is 15% with a 95% confidence interval of (−2% to 32%, P = .08).

Conclusion

Although not statistically significant, our study indicates that up 38% answer these 2 very similar questions discordantly. Also, there appears to be a higher degree of concordance (15%) when patients are first asked, “When was the last time you had a headache this bad?”