# Quality of life changes in cluster headache: Convergent validity, responsiveness, and interpretability of the Cluster Headache Quality of Life scale as a patient‐reported outcome measure

## TL;DR

This study validates a quality of life scale for cluster headache patients, showing it effectively tracks changes and highlights mental health and daily activity as key factors.

## Contribution

The CHQ scale is validated as a reliable patient-reported outcome measure for tracking quality of life changes in cluster headache patients.

## Key findings

- The CHQ has high convergent validity and responsiveness for measuring quality of life changes.
- Mental health and activity restrictions correlate more strongly with quality of life than attack frequency.
- A change of ≤−3.5 points indicates clinically relevant improvement in quality of life.

## Abstract

Cluster headache (CH) significantly impacts patients' quality of life (QoL). We aim to validate the Cluster Headache Quality of Life scale (CHQ) for measuring QoL changes in patients with CH.

In this multicenter, prospective, longitudinal psychometric validation study, participants, all with chronic CH (CCH), completed the CHQ at a 3‐monthly interval alongside headache diaries and general QoL questionnaires (36‐item Short Form [SF‐36], Hospital Anxiety and Depression Scale [HADS], and EuroQol 5 Dimensions [EQ‐5D]). CHQ's ability to measure changes was validated in three steps following COSMIN guidelines: (1) convergent validity, (2) responsiveness, and (3) interpretability. Baseline scores were used for step 1; change scores for steps 2 and 3 (Δ baseline—follow‐up). Twelve correlation hypotheses were formulated and tested for steps 1 and 2. Validity was rated by % rejected hypotheses (high: ≤25%, moderate: 26%–50%, poor: ≥50%). Data were collected in the Netherlands (Leiden, Nijmegen, Heerlen) between 9 December 2021 and 18 November 2024.

For step 1, 117 participants were included (n = 70 for SF‐36/HADS analyses, n = 42 for EQ‐5D analyses) and 82 were included for steps 2 and 3 (n = 48 for SF‐36/HADS analyses, n = 29 for EQ‐5D analyses). At baseline, overall QoL was poor (CHQ: 60.9 ± 23.1, SF‐36: 46.7 ± 19.9) and worse in participants with more intense and frequent CH attacks (>CHQ scores: β = 2.92 (95% confidence interval [CI] 0.91 to 4.93), p = 0.005; β = 0.27 (95% CI 0.02 to 0.53), p = 0.033). Convergent and responsiveness validity was high (≤25% hypotheses rejected). CHQ baseline scores correlated strongly with the HADS, SF‐36, and EQ‐5D (ρ = 0.68, ρ = −0.60, ρ = −0.52), but weakly with attack frequency (ρ = 0.27). Change scores correlated strongly with HADS and SF‐36 (ρ = 0.51, ρ = −0.56) and moderately with EQ‐5D (ρ = −0.38). Step 3 indicated ≤ −3.5 points change as clinically relevant improvement and ≥7.5 points as deterioration.

The CHQ has a high validity to measure change in QoL. CH attack frequency influences QoL, but QoL is more strongly correlated with mental health and activity restrictions than attack frequency. Implementing the CHQ may improve understanding of disease burden, enabling more targeted treatment strategies and thus improving overall disease management.

People with cluster headache often experience significant disability and poor quality of life. We wanted to learn what factors most strongly influence quality of life for these patients and determine whether the Cluster Headache Quality of Life scale can reliably track changes over time as patients try new treatments. We found that mental health and ability to complete daily tasks affect quality of life more than the number of attacks a patient has, and that this survey can help doctors better understand the full impact of cluster headache and improve treatment decisions.