To determine the minimal important difference () in generic and prostate‐specific health‐related quality of life () using distribution‐ and anchor‐based methods.
Prospective cohort study of 602 newly diagnosed prostate cancer patients recruited from an urban academic hospital and a eterans dministration hospital. Participants completed generic (‐36) and prostate‐specific surveys at baseline and at 3, 6, 12, and 24 months posttreatment. Anchor‐based and distribution‐based methods were used to develop estimates. We compared the proportion of participants returning to baseline based on estimates from the two methods.
estimates derived from combining distribution‐ and anchor‐based methods for the ‐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 estimates from the two methods were comparable.
This is the first study to assess the for generic and prostate‐specific using anchor‐based and distribution‐based methods. Although variation exists in the estimates derived from these two methods, the recovery patterns corresponding to these estimates were comparable.