Osteoarthritis Index delivered by mobile phone (m-WOMAC) is valid, reliable, and responsive

J Clin Epidemiol. 2011 Feb;64(2):182-90. doi: 10.1016/j.jclinepi.2010.03.013. Epub 2010 Jul 6.


Objectives: To evaluate the validity, reliability, responsiveness, and mode preference of electronic data capture (EDC) using the Western Ontario and McMaster (WOMAC) numerical rating scale (NRS) 3.1 Osteoarthritis (OA) Index on Motorola V3 mobile phones.

Study design and setting: Patients with OA undergoing hip or knee joint replacement were assessed preoperatively and 3-4 months postoperatively, completing the WOMAC Index in paper (p-WOMAC) and electronic (m-WOMAC) format in random order.

Results: Data were successfully and securely transmitted from patients in Australia to a server in the United States. Pearson correlations between the summated total index scores (TISs) for the p-WOMAC and m-WOMAC pre- and postsurgery were 0.98 and 0.99 (P<0.0001). There were no clinically important or statistically significant between-method differences in the adjusted total summated scores, pre- and postsurgery (adjusted mean differences=4.44, P=0.474 and 1.73, P=0.781, respectively). Internal consistency estimates of m-WOMAC reliability were 0.87-0.98. The m-WOMAC detected clinically important, statistically significant (P<0.0001) improvements in pain, stiffness, function, and TIS. No statistically significant differences in mode preference were detected.

Conclusions: There was close agreement and no significant differences between m-WOMAC and p-WOMAC scores. This study confirms the validity, reliability, and responsiveness of the Exco InTouch-engineered, Java-based m-WOMAC Index application. EDC with the m-WOMAC Index provides unique opportunities for using quantitative measurement in clinical research and practice.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Arthroplasty, Replacement, Hip / psychology
  • Arthroplasty, Replacement, Hip / rehabilitation*
  • Arthroplasty, Replacement, Knee / psychology
  • Arthroplasty, Replacement, Knee / rehabilitation*
  • Australia
  • Cell Phone*
  • Female
  • Humans
  • Male
  • Medical Records Systems, Computerized / instrumentation*
  • Middle Aged
  • Osteoarthritis / psychology
  • Osteoarthritis / rehabilitation*
  • Osteoarthritis / surgery
  • Outcome Assessment, Health Care
  • Pain Measurement / instrumentation
  • Pain Measurement / methods*
  • Patient Satisfaction
  • Reproducibility of Results
  • Severity of Illness Index
  • Surveys and Questionnaires
  • United States