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Reliability and clinically important improvement thresholds for osteoarthritis pain and function scales: a
Jasvinder A Singh1, Ruili Luo, Glenn C Landon
1From the Medicine Service, Birmingham VA Medical Center and Department of Medicine, University of Alabama; Center for Surgical Medical Acute Care Research and Transitions, Birmingham VA Medical Center; Division of Epidemiology, School of Public Health, University of Alabama, Birmingham, Alabama; Departments of Health Sciences Research and Orthopedic Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota; Section of Rheumatology and Clinical Immunology, University of Texas, M.D. Anderson Cancer Center; St. Luke's Episcopal Health System, Houston, Texas, USA.
The Intermittent and Constant Osteoarthritis Pain (ICOAP) score and KOOS-PS/HOOS-PS scales show good reliability for hip arthritis but lower reliability for knee arthritis. Clinically meaningful change thresholds were estimated for knee arthritis patients.
Area of Science:
- Orthopedics
- Rheumatology
- Clinical Outcomes Research
Background:
- Osteoarthritis (OA) significantly impacts joint pain and function.
- Reliable and clinically meaningful outcome measures are crucial for assessing OA treatment effectiveness.
- Existing patient-reported outcome measures (PROMs) require validation for specific joint conditions.
Purpose of the Study:
- To evaluate the reliability and establish clinically meaningful thresholds for the ICOAP pain scale, KOOS-PS, HOOS-PS, and HOOS-QOL/KOOS-QOL in patients with knee or hip OA.
- To determine the psychometric properties of these PROMs for use in clinical practice and research.
Main Methods:
- A cohort of 195 patients with knee (n=141) or hip (n=54) OA completed validated questionnaires at baseline and 2-week follow-up.
- Reliability was assessed using intraclass correlation coefficients (ICC).
- Minimum clinically important difference (MCID) and moderate improvement were calculated in a subgroup reporting joint status change.
Main Results:
- Reliability (ICC) was higher for hip OA (ICOAP: 0.86, HOOS-PS: 0.82) compared to knee OA (ICOAP: 0.63, KOOS-PS: 0.66).
- KOOS-QOL (0.79) and HOOS-QOL (0.67) demonstrated moderate to good reliability.
- MCID and moderate improvement thresholds were estimated for knee OA: ICOAP (18.5, 26.7), KOOS-PS (2.2, 15.0), and KOOS-QOL (8.0, 15.6).
Conclusions:
- The ICOAP pain and KOOS-PS/HOOS-PS scales exhibit reasonable reliability for hip OA but lower reliability for knee OA.
- Clinically meaningful change thresholds were established for pain and function in knee OA patients using these PROMs.
- Further research may be needed to refine these measures for knee OA assessment.
