Comparing the reliability of five participation instruments in persons with spinal conditions.

OBJECTIVE To compare the score distribution and reliability of 5 participation instruments developed using the International Classification of Functioning, Disability and Health. METHODS Individuals treated for spinal conditions at an acute hospital were followed-up and 545 participated. Subjects completed 5 participation instruments (Impact on Participation and Autonomy (IPA), Keele Assessment of Participation (KAP), Participation Measure-Post Acute Care (PM-PAC), Participation Objective Participation Subjective (POPS) and World Health Organization Disability Assessment Schedule II (WHODAS II)). Test-retest reliability was assessed in 139 subjects. The score distribution, internal consistency and test-retest reliability were assessed. RESULTS All the instruments demonstrated considerable ceiling effects, except for the POPS. Internal consistency (Cronbach's alpha) was > or = 0.70 for all domains. The IPA and WHODAS II had the highest test-retest values, with intra-class correlation coefficients > or = 0.70. The minimal detectable change as a percentage of the absolute scale score range was primarily between 20% and 30%. CONCLUSION The IPA, PM-PAC and WHODAS II have similar measurement properties. The KAP was designed for -population-based studies and the POPS includes objective and subjective information, which may explain some of the differences observed. Researchers and clinicians should select an instrument that will fulfil their measurement objectives and future studies should assess minimal important change.