Determining health-related quality of life and health state utility values of recurrent urinary tract infections in women.

Introduction And Hypothesis: Health state utility values estimate an individual's valuation of their health-related quality of life. Despite prevalence of recurrent urinary tract infections (rUTIs), the health state utility value of rUTIs is unknown. The primary aim was to determine the utility value of rUTIs using the standard gamble (SG). The secondary aim was to compare the SG utility value with that derived from the EuroQol 5 dimensions (EQ-5D) and visual analog scale (VAS). We hypothesized that a utility value would be successfully derived from the SG and would differ from that derived using the EQ-5D and VAS.

Methods: Nonpregnant, adult English-speaking female patients with a diagnosis of rUTI were recruited and completed the EQ-5D, VAS, and SG (n = 25). Utility values were evaluated using Wilcoxon signed-rank tests and Spearman's rho correlation.

Results: Health state utility values varied depending on the assessment tool used: EQ-5D 0.76 (IQR 0.52), VAS 0.70 (IQR 0.30), and SG 0.85 (IQR 0.25). There were differences between VAS and the other two assessment methods (p<0.001), as well as between EQ-5D and SG (p=0.013). Spearman correlation demonstrated a moderately positive correlation between EQ-5D and VAS values (r(25) = 0.59, p=0.0019).

Conclusions: Our data suggest that 0.85 reflects the true health state utility value of rUTIs among nonpregnant adult English-speaking women. The utility value for recurrent UTIs is worse (lower) than that previously published for nonrecurrent UTIs, reflecting the ability of the SG to convey the compounding impact of recurrent disease. In this study, neither the EQ-5D nor the VAS produced results consistent with those found using the SG, which suggests limited validity in this population.