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Four Methods of Estimating the Minimal Important Difference Score Were Compared to Establish a Clinically Significant Change in Headache Impact Test

Citation

Coeytaux, Remy R.; Kaufman, Jay S.; Chao, Ryon; Mann, J. Douglas; & DeVellis, Robert F. (2006). Four Methods of Estimating the Minimal Important Difference Score Were Compared to Establish a Clinically Significant Change in Headache Impact Test. Journal of Clinical Epidemiology, 59(4), 374-380.

Abstract

Objective: To estimate the smallest decrease in Headache Impact Test (HIT) scores that reflects meaningful clinical change among patients with chronic daily headache (CDH).
Study Design and Setting: We applied four methods of estimating the minimum important difference (MID) to data from 71 patients with CDH who participated in a clinical trial. The HIT was administered at baseline and at the 6-week follow-up assessment. Patients were considered to have experienced meaningful improvement if they reported that their headache condition was “somewhat better” or “much better” at the 6-week follow-up.
Results: Mean HIT scores at baseline and 6 weeks for all patients were 64.5 (standard deviation SD = 6.0) and 62.6 (SD = 5.7), respectively. HIT scores decreased 3.7 (SD = 4.4) and 1.4 (SD = 3.6) units, respectively, among patients who reported “somewhat better” change and those who reported no change at 6 weeks. Estimates of the MID of the HIT ranged from -2.7 to -2.3.
Conclusions: The method that we judge to be most valid estimated the MID of the HIT at -2.3 units (95% confidence interval = -4.3, -0.3). This suggests that a between-group difference in HIT change scores of 2.3 units over time among patients with CDH reflects improvement in patients' headache condition that may be considered clinically significant.

URL

http://dx.doi.org/10.1016/j.jclinepi.2005.05.010

Reference Type

Journal Article

Year Published

2006

Journal Title

Journal of Clinical Epidemiology

Author(s)

Coeytaux, Remy R.
Kaufman, Jay S.
Chao, Ryon
Mann, J. Douglas
DeVellis, Robert F.