Daily measurements of pain in patients with hip osteoarthritis may not be more precise than retrospective measurements, but retrospective measurements may be less reliable in patients with more intense intermittent pain, according to a study published in Arthritis Care & Research.
In this study, researchers used a linear mixed-effects model to analyze data from a previous randomized controlled trial of 203 patients who received general practitioner care and exercise therapy or only general practitioner care for hip osteoarthritis. Patients were asked to rate their pain daily for the first 6 weeks of the trial (n=185), and at the 6-week follow-up they were asked to rate the pain they experienced in the previous week.
Of the 185 participants, 94 were randomly assigned to follow exercise therapy and 91 to the control group. The overall estimate of pain during the first 6 weeks was comparable in the 2 groups.
Patients with a higher intensity — but not frequency — of intermittent pain had a higher frequency, and higher mean and maximal amplitude of peaks in pain scores. Retrospective measurements were found to be less reliable in patients with severe intermittent pain (Cronbach’s α = 0.642) than in other subgroups (Cronbach’s α > 0.843).
Study limitations include the lack of daily measurements between 6 weeks and 3 months, the time point at which the largest treatment effects were observed.
“In this specific trial in patients with hip osteoarthritis, daily pain measurements during the first 6 weeks did not provide additional or more precise information compared with the retrospective measurements at 6-week follow-up. However, the reliability of retrospective measurements may be lower in patients with a higher intensity of intermittent pain,” noted the study authors.
Teirlinck CH, Sonneveld DS, et al. Daily pain measurements and retrospective pain measurements in hip osteoarthritis patients with intermittent pain [published online July 19, 2018]. Arthritis Care Res. doi:10.1002/acr.23711