Paper standard gamble: a paper-based measure of standard gamble utility for current health.

OBJECTIVES

To develop and validate a paper-based instrument that is simple to administer and produces a reliable estimate of patient standard gamble (SG) utilities for current health status.

METHODS

A 1-page paper questionnaire instrument, paper standard gamble (PSG), was designed to estimate SG utilities. We performed two studies to assess the validity of PSG. First we compared PSG and SG utilities for current health in patients with prostate cancer. They randomly received either PSG followed by SG or vice versa, always with an intervening SF-12. In the second validity study, we assessed the test-retest reliability of PSG by administering it to prostate cancer patients twice, at least 2 weeks apart.

RESULTS

In the first study, utilities were assessed in 64 men (32 per SG/PSG order group). A paired-comparison t test suggested no difference between SG and PSG (mean difference = -0.007; 95% confidence interval (Cl), -0.022 to 0.008). The concordance correlation coefficient was 0.92 (95% Cl, 0.79 to 0.99). In the second study, test and retest PSGs were available for 184 patients. The concordance correlation coefficient was 0.88 (95% Cl, 0.73 to 0.94).

CONCLUSIONS

These data suggest that PSG may serve as a reliable substitute for SG when current health utility is of interest. PSG may have particular advantages for acquisition of health-related quality-of-life data in longitudinal studies.