Category: Clinical Stones: Outcomes

MP8-6 - Relationship between the Wisconsin Stone Quality of Life (WISQOL) and preference-based / health utility measures of health-related quality of life (HRQoL) in kidney stone patients

Fri, Sep 21
10:00 AM - 12:00 PM

Introduction & Objective :

The WISQOL was recently developed as the first disease-specific, validated measure of HRQoL in kidney stone patients. It is a psychometric health status measure that records the frequency and intensity of symptoms and behaviors related to the presence of kidney stones. Alternatively, HRQoL can be measured using health utilities, which quantify patient preferences for specific health outcomes on a 0-1 scale, where 0 represents death and 1 perfect health. We elicited health utilities in kidney stone patients, and examined the relationship between WISQOL scores and health utilities, in patients with active stone disease. 


Methods :

Consecutive adult kidney stone patients seen at our institution’s stone clinic were recruited. Each patient completed the WISQOL, the short-form 36 (SF-36 v2) and the EQ-5D questionnaires. Health utilities were elicited using the SF-6D and the EQ-5D, which are widely validated generic health utility instruments. The SF-6D is a multi-attribute utility instrument derived from the SF-36. Relationship between health utility scores and WISQOL scores was examined using the Pearson product-moment correlation test. Least squares regression analysis was used to examine the contribution of the WISQOL health status measures to each of the preference-based scores.

Results :

55 patients with a mean (SD) age of 51.8 (12.1) years, who were 54.6% female and 61% white were enrolled. 68.5% were recurrent stone formers and 53.1% had a history of prior stone surgery. Mean (SD) EQ-index, SF-6D and total WISQOL scores were 0.80 (0.19), 0.68 (0.15) and 64 (30) respectively.  EQ-index and SF-6D scores significantly correlated with total WISQOL score and each of the WISQOL sub-scale scores (Pearson’s r > 0.6; p<0.0001 in each case). On regression analysis, 44.5% of the variance in EQ-index score and 75.6% of the variance in SF-6D score was accounted for by WISQOL total score (p<0.0001 in each case). WISQOL sub-scales scores individually accounted for 32-42% of the variance in EQ-index score, and 60-70% of the variance in SF-6D score (p≤0.0002 in each case).

Conclusions :

WISQOL total and sub-scale scores strongly correlate with patient preference scores derived from the EQ-5D and SF-6D health utility measures in patients with urolithiasis. These findings suggest that the EQ-5D and SF-6D are suitable, sensitive tools for eliciting patient preferences for health states related to kidney stone disease. Further validation studies are needed.

Ephrem O. Olweny

Assistant Professor of Urology
Rutgers-Robert Wood Johnson Medical School
New Brunswick, New Jersey

I currently serve as Assitant Professor of Urology at Rutgers-Robert Wood Johnson Medical School. My clinical area of focus is kidney stone disease and laparoscopic / robotic upper urinary tract surgery for malignant and benign disease.

Bryan Tan

Rutgers-Robert Wood Johnson Medical School
New Brunswick, New Jersey

Nicole Borglum

Rutgers-Robert Wood Johnson Medical School
New Brunswick, New Jersey