The impact of bilateral stone disease on patients’ disease progression and health related quality of life

Purpose Patients with recurring kidney stone events can expect significant morbidity and functional impairment. Few studies have evaluated the effect of bilateral kidney stones on disease progression and quality of life. We wanted to determine the association of bilateral stone disease on age of onset, and the impact on number of stone events and individual kidney stone disease specific Health Related Quality of Life (HRQOL) by analysing the validated and prospectively collected Wisconsin Stone Quality of Life (WISQOL) database. Material and Methods We studied 2,906 stone patients from 16 centers in North America after having completed the WISQOL questionnaire from 2014 to 2019. Kidney stone formers were assessed if kidney stones were bilateral or unilateral on imaging. Analysis with a Chi-square test compared categorical variables. Bilateral kidney stone disease and its impact on HRQOL was evaluated through a multivariable linear regression model. Results Of 2,906 kidney stone formers, 1,340 had unilateral kidney stones and 1,566 had bilateral kidney stones. We observed more frequently that patients with bilateral stones had an increased number of depression/anxiety symptoms, renal tubular acidosis, and rheumatoid arthritis (all p<0.05). Patients with bilateral stones had a younger mean (SD) age of kidney stone disease onset (37.2±15.8 vs 46.4±15.9 years of age, p<0.001). Bilateral kidney stone formers had a higher mean (SD) number of stone events (11.3±21.8) than unilateral kidney stone formers (3.0±5.1) (p<0.001). Within our multivariable analysis, we found that HRQOL was negatively affected by the presence of bilateral stones for kidney stone patients (β=-11.2 (CI:-19.5 - -3.0) points, p<0.05). Conclusion Bilateral kidney stone formers had a younger age of kidney stone disease onset and a higher number of stone events compared to unilateral kidney stone disease formers. Presence of bilateral kidney stone disease negatively impacted HRQOL.