237PROMs for Health Related Quality of Life (HRQOL)
Table 9.5 shows reliability, validity, and responsiveness to change for SF-36,
PROMIS PF-10, and HAQ-DI as well as GAQ. A recent systematic review also
summarized this evidence [ 58 ].
Generic HRQOL
SF-36 Scores
SF- 36 consists of 36 items evaluating eight subscales with scores ranging from 0 to
100, with 100 being better health. The minimally clinically important difference
(MCID) for the SF-36 scales was defi ned as improvement of >5 points on subscales
and >2.5 points on summary scale scores [ 10 ].
Validation Data for SF-36 in Chronic Gout
Discrimination thresholds: An observational cohort study assessed whether long-
term therapy with urate-lowering therapy (ULT) and colchicine lead to an improve-
ment in HRQOL. The MCIDs were observed at fi rst and second year. It was observed
that at one year the effect sizes for SF-36 domains were large for PCS and pain, 0.91
and 1.09, respectively, whereas the effect sizes were smaller for physical function,
general health, mental health, vitality social functioning, and emotional scales
(0.20–0.49) [ 42 ]. For bodily pain scale, 69 % of patients achieved MCID, and for
MCS 38 % patients achieved MCID [ 42 ].
At 12 weeks, 66 % of patients with acute gout in the canakinumab group had a
greater than 10 point reduction in SF-36 bodily pain (range, 0–100; lower = less
pain) compared to 57 % patients in the triamcinolone acetonide group [ 59 ].
Signifi cant improvements were reported in a higher number of SF-36 domains (6 of
8) in the biweekly pegloticase compared to monthly pegloticase (3 of 8). Table 9.6
shows the changes from baseline to week 25 in all three groups: pegloticase
biweekly, pegloticase monthly, and placebo [ 9 ].
SF-36 Physical Functioning (PF) Subscale Score
SF-36 PF-10 is a subscale of SF- 36. The items on PF-10 are scored from 1 to 3 and
the scores obtained on each item are summed and transformed to range from 0 to
- The mean (SD) PF-10 score was 61.94 (29.33). PF-10 had a strong negative
correlation with HAQ-DI and HAQ-II, −0.75 and −0.79, respectively, and positive
correlations with other SF-36 domains ranging from 0.30 to 0.68 [ 43 ].
9 PROMs for Gouty Arthritis