Content validation of the COST for patient questionnaire (COPAQ) for patients with low back pain: a qualitative study

INTRODUCTION: The costs of low back pain (LBP) are complex and difficult to estimate. This study aims to adapt the Cost for Patients Questionnaire (CoPaQ) for use in LBP populations. MATERIALS AND METHODS: In a cross-sectional qualitative study, we conducted cognitive interviews to assess the CoPaQ's suitability for addressing costs related to LBP. Three groups of participants were included (n = 5 each): (i) persons with a history of LBP or …