Cystine Stone Formers Have Impaired Health-Related Quality of Life Compared with Noncystine Stone Formers: A Case-Referent Study Piloting the Wisconsin Stone Quality of Life Questionnaire Among Patients with Cystine Stones

Abstract

Introduction: Cystinuria is a rare cause of urolithiasis. Affected patients have an earlier onset and more aggressive disease than patients with other stone etiologies. We assessed the health-related quality of life (HRQOL) of cystine stone-forming patients using the disease-specific Wisconsin Stone Quality of Life questionnaire (WISQOL).

Methods: Cystine patients treated in our stone clinics (n = 12) completed the WISQOL; information about medical and stone histories was gathered. Patients were matched with noncystine stone formers (n = 12) for gender, age, and comorbidities. In addition, a second control group (n = 90), also from our institution and consisting of mixed calcium stone formers, was included. WISQOL responses were compared between groups.

Results: Cystine patients had significantly lower total WISQOL scores than noncystine patients. Compared with noncystine stone formers, cystine stone formers also had lower HRQOL scores for subscales (domains) related to social impact, emotional impact, disease impact, and vitality (p ≤ 0.04 for all). On specific items, cystine patients reported significantly more sleep problems (p = 0.02), more bother with nocturia (p = 0.03), and feeling tired or fatigued (p = 0.02). Among those with current stones, cystine patients scored lower than noncystine patients for total score and in two of four domains.

Conclusions: Using a stone-specific questionnaire, patients with cystine stones have lower HRQOL compared with noncystine stone formers. Identifying and addressing specific areas of decrement in patients with cystine stones may improve disease management and patients' HRQOL.

Keywords: cystine; cystinuria; health-related quality of life; kidney stones; quality of life.