Intra- and interindividual attack frequency variability of chronic cluster headache

Cephalalgia, vol. 43, pp. 3331024221139239

Abstract

BACKGROUND: The lack of knowledge about the intra- and interindividual attack frequency variability in chronic cluster headache complicates power and sample size calculations for baseline periods of trials, and consensus on their most optimal duration. METHODS: We analyzed the 12-week baseline of the ICON trial (occipital nerve stimulation in medically intractable chronic cluster headache) for: (i) weekly vs. instantaneous recording of attack frequency; (ii) intra-individual and seasonal variability of attack frequency; and (iii) the smallest number of weeks to obtain a reliable estimate of baseline attack frequency. RESULTS: Weekly median (14.4 [8.2-24.0]) and instantaneous (14.2 [8.0-24.5]) attack frequency recordings were similar (p = 0.20; Bland-Altman plot). Median weekly attack frequency was 15.3 (range 4.2-140) and highest during spring (p = 0.001) compared to the other seasons. Relative attack frequency variability decreased with increasing attack frequency (p = 0.010). We tabulated the weekly attack frequency estimation accuracies compared to, and the associated deviations from, the 12-week gold standard for different lengths of the observation period. CONCLUSION: Weekly retrospective attack frequency recording is as good as instantaneous recording and more convenient. Attack frequency is highest in spring. Participants with ≥3 daily attacks show less attack frequency variability than those with <3 daily attacks. An optimal balance between 90% accuracy and feasibility is achieved at a baseline period of seven weeks.The ICON trial is registered in ClinicalTrials.gov under number NCT01151631.

Authors 8

1. Roemer B. Brandt Aachen Department of Neurology, Leiden University Medical Center (LUMC)

   Leiden University Medical Center

   Affiliation as printed

   Department of Neurology, , Leiden University Medical Center, Leiden, The Netherlands

2. Wim M. Mulleners

   Canisius-Wilhelmina Ziekenhuis

   Affiliation as printed

   Department of Neurology, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands

3. Leopoldine A. Wilbrink

   Zuyderland Medisch Centrum

   Affiliation as printed

   Department of Neurology, Zuyderland Hospital, Heerlen, The Netherlands

4. Paul Brandt

   Eindhoven University of Technology

   Affiliation as printed

   Department of Electronic Systems, Technical University Eindhoven, The Netherlands

5. Erik W. van Zwet Aachen Department of Biomedical Data Sciences

   Leiden University · Leiden University Medical Center

   Affiliation as printed

   Department of Biomedical Data Sciences, Leiden University Medical Centre, Leiden, The Netherlands

6. Frank J.P.M. Huygen

   Erasmus MC

   Affiliation as printed

   Department of Anaesthesiology, Erasmus MC, Rotterdam, The Netherlands

7. Michel D. Ferrari Aachen Department of Neurology, Leiden University Medical Center (LUMC)

   Leiden University Medical Center

   Affiliation as printed

   Department of Neurology, , Leiden University Medical Center, Leiden, The Netherlands

8. Rolf Fronczek Aachen Department of Neurology, Leiden University Medical Center (LUMC)

   Leiden University Medical Center

   Affiliation as printed

   Department of Neurology, , Leiden University Medical Center, Leiden, The Netherlands