OBJECTIVE:To determine the minimal important difference (MID) in generic and prostate-specific health-related quality of life (HRQoL) using distribution- and anchor-based methods.
STUDY DESIGN AND SETTING: Prospective cohort study of 602 newly diagnosed prostate cancer patients recruited from an urban academic hospital and a Veterans Administration hospital. Participants completed generic (SF-36) and prostate-specific HRQoL surveys at baseline and at 3, 6, 12, and 24 months posttreatment. Anchor-based and distribution-based methods were used to develop MID estimates. We compared the proportion of participants returning to baseline based on MID estimates from the two methods.
RESULTS: MID estimates derived from combining distribution- and anchor-based methods for the SF-36 subscales are physical function = 7, role physical = 14, role emotional = 12, vitality = 9, mental health = 6, social function = 9, bodily pain = 9, and general health = 8; and for the prostate-specific scales are urinary function = 8, bowel function = 7, sexual function = 8, urinary bother = 9, bowel bother = 8, and sexual bother = 11. Proportions of participants returning to baseline values corresponding to MID estimates from the two methods were comparable.
CONCLUSIONS: This is the first study to assess the MID for generic and prostate-specific HRQoL using anchor-based and distribution-based methods. Although variation exists in the MID estimates derived from these two methods, the recovery patterns corresponding to these estimates were comparable.
Written by:
Jayadevappa R, Malkowicz SB, Wittink M, Wein AJ, Chhatre S. Are you the author?
Division of Urology, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia; Veterans Administration Medical Center, Perelman Center for Advanced Medicine, Philadelphia, PA.
Reference: Health Serv Res. 2012 Mar 14. Epub ahead of print.
doi: 10.1111/j.1475-6773.2012.01395.x
PubMed Abstract
PMID: 22417225
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