Health-related quality of life (HRQoL) in cystine compared with non-cystine stone formers

Abstract

Cystinuria is a genetic cause of recurrent kidney stones which may be more recurrent and larger than more common non-cystine stones. They may have a greater impact on health-related quality of life (HRQoL). We measured this impact by surveying HRQoL in patients with stones, comparing non-cystine stone formers (NCSF) to cystine stone formers (CYSF) and both groups to normative values of the US population. We used SF-36v2 via an internet instrument. CYSF patients were recruited via cystinuria-related websites, two patient advocacy groups, and an active endourology practice. NCSF patients were recruited from the same practice and by email. Total n surveyed with scorable data: 214 CYSF and 81 NCSF. The participants included 128 men and 161 women. The group of CYSF were significantly younger (39 vs. 54 years) and suffered longer from kidney stones (255 vs. 136 months). CYSF patients had significantly more episodes of stones than NCSF patients in the last year (N = 108 CYSF, N = 20 NCSF). More frequent stones in the last year and mental comorbidities most often predicted worse scores in the individual HRQoL domains. However, cystine stone composition was a significant predictor of worse scores only for role emotional. Better scores in all SF-36 domains were associated with greater time since the last kidney stone event. Although kidney stones are often transient, kidney stone formers, regardless of stone composition, have a worse HRQoL than the standard US population, which has a normative score of 50, such as general health (41.2 ± 12.8), bodily pain (46.5 ± 11.8) and mental health (45.1 ± 12.6). CYSF are more frequent and severe stone formers compared with NCSF with a resulting greater, direct impact on the HRQoL of CYSF patients. Whether preventive strategies for cystinuria are being properly utilized by practitioners, and which strategies are most effective, should be established.