U-PAIN cohort study among patients with chronic pain in specialised pain care: a feasibility study

To examine acceptability of study participation and feasibility of (1) recruitment, (2) data collection and (3) outcome measures for the prospective U-PAIN cohort.

Internal feasibility study of a prospective cohort.

64 patients, >18 years, with chronic pain at a multidisciplinary pain centre at a university hospital in Sweden.

Acceptability of study participation was measured with a study-specific 10-item Likert scale. A score <3 was considered feasible, for the two items that assessed respondent burden a higher score indicated lesser participant burden and a score >3 was feasible. Recruitment was assessed by participation rates at baseline and retention at the 1-year follow-up, with threshold values for feasibility at 75% and 80%, respectively. Data collection and outcome measures were examined by completions rates of study procedures (90% was considered feasible), sample scores, internal consistency (α>0.70 was considered feasible), and agreement between self-reported data and data retrieved from medical records on opioid use (ICC or κ>0.60 was considered feasible).

Acceptability for study procedures was feasible, but participation rates were low: 25%. The retention rate at 1-year follow-up was 81% for those included in the feasibility study, that is, filling out computerised patient-reported outcome measures, and 65% for those using paper and pencil format. The completion rates for the different data collection methods ranged from 83% to 95%. Agreement between self-reported opioid use and prescribed dose and between opioid use disorder according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and clinical International Classification of Diseases-10 (ICD-10) diagnoses for opioid dependence were almost perfect (κ=0.91 and κ=0.90, respectively).

This feasibility study has helped to explore and improve methods for recruitment, data collection and use of outcome measures for the U-PAIN cohort. Low participation rate and high refusal rate at baseline is a challenge that needs to be further addressed.