DEFINING THE MINIMUM LEVEL OF DETECTABLE CHANGE FOR THE ROLAND-MORRISQUESTIONNAIRE

Background and Purpose. The Roland-Morris Questionnaire (RMQ) is a Sel f-administered disability measure in which greater levels of disabilit y are reflected by higher numbers on a 24-point scale. The RMQ has bee n shown to yield reliable measurements, which are valid for inferring the level of disability, and to be sensitive to change over time for g roups of patients with low back pain. Little is known about the useful ness of this instrument in aiding decision making regarding individual patients. The purpose of this study was to determine the minimum leve l of detectable change when the RMQ is applied to individual patients. Subjects. The study sample consisted of 60 outpatients with low back pain. Methods. The RMQ was administered at the subjects' initial visit and again 4 to 6 weeks later. Conditional standard errors of measurem ent (CSEMs) were computed for initial and follow-up RMQ scores, and th ese values were used to estimate the minimum level of detectable chang e. Results. Minimum levels of detectable change at the 90% confidence level varied from 4 to 5 RMQ points. Conclusion and Discussion. The ma gnitude of CSEMs is sufficiently small to detect change in patients wi th initial scores in the central portion of the scale (4-20 RMQ points ); however, the magnitude is too large to detect improvement in patien ts with scores of less than 4 and deterioration in patients who have s cores greater than 20.