Differences in physical activity (steps per day) and fatigue (CFQ score) between SEID-positive and SEID-negative patients 30 weeks after inclusion
| Variables | SEID-positive, mean | SEID-negative, mean | Difference* | P value* |
| Steps per day, number | ||||
| Baseline | 4342 | 4823 | ||
| Week 30 | 4667 | 4518 | −498 | 0.326 |
| CFQ total sum score | ||||
| Baseline | 20.7 | 18.1 | ||
| Week 30 | 19.0 | 20.4 | 1.86 | 0.413 |
*Based on analysis of covariance models in which differences and P values are adjusted for baseline values of outcome variables as well as allocation to clonidine/placebo during the first 8 weeks of the trial.
CFQ, Chalder Fatigue Questionnaire; SEID, systemic exertion intolerance disease.