The Pelvic Girdle Questionnaire: Responsiveness and Minimal Important Change in Women With Pregnancy-Related Pelvic Girdle Pain, Low Back Pain, or Both.

Abstract

The Pelvic Girdle Questionnaire (PGQ) is a condition-specific measure for women with pelvic girdle pain (PGP). The PGQ includes items relating to activity/participation and bodily symptoms and has reliability, validity, and feasibility for use in research and clinical practice. The purposes of this study were to examine the responsiveness of the PGQ, to determine the minimal important change (MIC) for the PGQ, and to compare the PGQ with other outcome measures. This study used a prospective cohort design. A total of 801 women responded to a booklet of questionnaires in the last trimester of their pregnancy and within 3 months post partum. Responsiveness analyses followed recommendations from the Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) checklist. The responsiveness of the PGQ was tested by examining correlations between the change scores of the total PGQ and the other patient-reported outcome measures. A total of 606 women (76%) reported PGP, low back pain, or both. Of these women, 441 (73%) responded to the follow-up questionnaire post partum. The PGQ (both subscale and total scores) discriminated most accurately between participants who improved and those who did not improve, with an area under the receiver operator characteristic curve of 72%. The MIC values indicated that a change score smaller than 25 for the total score and activity subscale score and a change score of 20 for the symptom subscale score should be regarded as insignificant. Baseline PGQ scores had a large impact on the MIC estimates for the absolute change scores but not on the relative percentage change scores. Five of 6 hypotheses were supported (83%). The type of anchor and definition of important change used might be weaknesses in women whose status is changing from pregnant to post partum. The PGQ showed acceptable responsiveness in women with PGP, low back pain, or both.