Inter-method reliability of paper surveys and computer assisted telephone interviews in a randomized controlled trial of yoga for low back pain

Abstract

Background: Little is known about the reliability of different methods of survey administration in low back pain trials. This analysis was designed to determine the reliability of responses to self-administered paper surveys compared to computer assisted telephone interviews (CATI) for the primary outcomes of pain intensity and back-related function, and secondary outcomes of patient satisfaction, SF-36, and global improvement among participants enrolled in a study of yoga for chronic low back pain.

Results: Pain intensity, back-related function, and both physical and mental health components of the SF-36 showed excellent reliability at all three time points; ICC scores ranged from 0.82 to 0.98. Pain medication use showed good reliability; kappa statistics ranged from 0.68 to 0.78. Patient satisfaction had moderate to excellent reliability; ICC scores ranged from 0.40 to 0.86. Global improvement showed poor reliability at 6 weeks (ICC = 0.24) and 12 weeks (ICC = 0.10).

Conclusion: CATI shows excellent reliability for primary outcomes and at least some secondary outcomes when compared to self-administered paper surveys in a low back pain yoga trial. Having two reliable options for data collection may be helpful to increase response rates for core outcomes in back pain trials.

Trial registration: ClinicalTrials.gov: NCT01761617. Date of trial registration: December 4, 2012.

Figure 1

Mean low back pain intensity over time using all available paper-only data and CATI-only data. Bars indicate 95% confidence interval. CATI: computer assisted telephone interview.

Figure 2

Mean RMDQ over time using all available paper-only data and CATI-only data. Bars indicate 95% confidence interval. RMDQ: modified Roland Morris Disability Questionnaire (0-23 where higher scores reflect worse back pain-related function); CATI: computer assisted telephone interview.