Presentation Authors: Charles Polotti*, Bryan Tan, Nicole Borglum, Ephrem Olweny, New Brunswick, NJ
Introduction: WISQOL, the first validated, disease-specific measure of HRQoL in kidney stone patients is a psychometric health status instrument i.e. it records frequency and intensity of symptoms and behaviors related to urinary stone disease (USD). Alternatively, health utilities assess HRQoL on a 0-1 scale (0= death and 1=perfect health), and are the preferred metric for use in healthcare economic valuation. We sought to establish the statistical relationship between WISQOL scores and SF-6D and EQ-5D derived utility scores in USD patients. Construct validity of the utility measures was also assessed.
Methods: Consecutive adult USD patients, as well as young healthy controls without a history of USD were recruited. Each subject completed a health history survey, the SF-36 v2 and the EQ-5D questionnaires. USD patients additionally completed the WISQOL. SF-6D score was computed from 11 of the 36 items on the SF-36 v2 using validated, previously reported methodology._x000D_
Relationship between WISQOL and SF-6D / EQ-5D utility scores was examined using Pearson's correlation as well as multivariable regression with adjustment for baseline clinico-demographic characteristics. Utilities for USD patients vs. controls were compared using t-tests.
Results: 91 patients and 78 controls were enrolled. SF-6D and EQ-5D utilities were significantly lower in patients compared with controls (Table 1). For USD patients, SF-6D and EQ-5D utilities significantly correlated with WISQOL raw and sub-scale scores (Table 2). On multivariable regression, 75.8% and 32.2% of the variance in SF-6D and EQ-5D utility scores respectively, was predicted by WISQOL raw score (p < 0.0001 in each case).
Conclusions: WISQOL scores significantly correlated with, and had good predictive validity for the preference-based HRQoL scores in USD patients. SF-6D and EQ-5D utilities had excellent construct validity for USD. Our findings support these utilities as optimal preference-based HRQoL tools in USD.