Validity of summing painful joint sites to assess joint-pain comorbidity in hip or knee osteoarthritis

Liseth Siemons*, Peter M. ten Klooster, Mart A. F. J. van de Laar, Cornelia H. M. van den Ende, Thomas J. Hoogeboom

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background: Previous studies in patients with hip and knee osteoarthritis (OA) have advocated the relevance of assessing the number of painful joint sites, other than the primary affected joint, in both research and clinical practice. However, it is unclear whether joint-pain comorbidities can simply be summed up. Methods: A total of 401 patients with hip or knee OA completed questionnaires on demographic variables and joint-pain comorbidities. Rasch analysis was performed to evaluate whether a sum score of joint-pain comorbidities can be calculated. Results: Self-reported joint-pain comorbidities showed a good fit to the Rasch model and were not biased by gender, age, disease duration, BMI, or patient group. As a group, joint-pain comorbidities covered a reasonable range of severity levels, although the sum score had rather low reliability levels suggesting it cannot discriminate well among patients. Conclusions: Joint-pain comorbidities, in other than the primary affected joints, can be summed into a joint pain comorbidity score. Nevertheless, its use is discouraged for individual decision making purposes since its lacks discriminative power in patients with minimal or extreme joint pain.
Original languageEnglish
Article number234
JournalBMC Musculoskeletal Disorders
Publication statusPublished - 9 Aug 2013


  • Hip or knee osteoarthritis
  • Joint-pain comorbidities
  • Rasch analysis
  • Sum score
  • Validity

Cite this