Development of a Questionnaire to Assess the Impact of Chronic Low Back Pain for Use in Regulated Clinical Trials

Abstract

Chronic low back pain (CLBP) is the most common chronic pain condition and is associated with clinical, economic, social, and public health impacts. The effect of CLBP on patients' health-related quality of life (HRQoL) is significant. The symptoms and impacts most often associated with CLBP include pain and disability; patients most affected are often crippled by the condition. CLBP also affects patients' mental, physical, and psychosocial well-being. A variety of self-report measures have been developed for the assessment of CLBP, such as the Roland Morris Disability Questionnaire (RMDQ); however, existing measures may not meet current regulatory expectation for the development, documentation, and use of patient-reported outcomes (PRO) questionnaires (U.S. Department of Health and Human Services, Food and Drug Administration, 2009). This report describes the qualitative development of the Chronic Low Back Pain Impact Questionnaire (CLBP-IQ), created for use in clinical trials. A total of 22 CLBP patients recruited by clinicians participated in concept elicitation interviews to identify target measurement concepts. An instrument development team generated the instructions, items, and response options guided by patient input. Cognitive debriefing interviews were conducted with 21 patients recruited by the same clinicians who recruited for concept elicitation interviews. During cognitive interviews, a draft instrument composed of 28 items was presented to individuals with CLBP to evaluate its readability and comprehensiveness. All research activities were conducted in the US. During concept elicitation interviews, participants reported a variety of physical, emotional, and social impacts associated with CLBP. Participants also reported CLBP impacts on sleep, energy, daily activities, work, household activities, leisure activities, cognition, self-care, and sex life. Impacts deemed simple, important, and relevant to CLBP patients became targets of measurement for the CLBP-IQ. During cognitive debriefing, seventeen items were interpreted as intended by at least 90% of participants, and no items were interpreted incorrectly by more than five patients (24%). Additionally, seventeen items were experienced by at least 90% of participants, and no single item was experienced by less than 67% of participants (n=14). The CLBP-IQ was developed in accordance with current US Food and Drug Administration guidance on instrument development. Results from both concept elicitation and cognitive debriefing interviews support the content validity of the CLBP-IQ in patients with CLBP. Future development should proceed with psychometric evaluation.