Incidence of Urinary Tract Infections in Kidney Stone Patients: 19-Year Cohort Study
Overview
This 19-year matched cohort study found that patients with kidney stone disease (KSD) have a significantly increased risk of urinary tract infections (UTIs) compared to matched controls. The risk remained elevated after adjusting for diabetes mellitus and varied by stone composition, with calcium oxalate stone formers showing particularly high risk.
Background
Kidney stone disease is increasingly prevalent and imposes a substantial economic burden. While urease-producing bacteria are known contributors to struvite stone formation, the role of bacteria in more common calcium oxalate and calcium phosphate stones is less clear. Previous studies have isolated bacteria from these stones, but large-scale population data linking KSD and UTI risk have been lacking. This study aimed to quantify UTI risk in stone formers and explore differences by stone type.
Data Highlights
Parameter
Stone Formers (n=819)
Comparators (n=2477)
Male:Female Ratio
3:1
3:1
Mean Age at Presentation (years)
49 ± 14
49 ± 14
Median Follow-up (years)
19 (IQR 15–22)
19 (IQR 15–22)
Patients Developing ≥1 UTI
155 (18.7%)
422 (14.1%)
Deaths During Follow-up
113 (13.3%)
366 (14.4%)
Hazard Ratio for UTI (KSD vs Comparator)
5.73 (95% CI 4.55–7.21), p < 0.001
Adjusted HR for UTI (adjusted for diabetes)
5.76 (95% CI 4.50–7.36), p < 0.001
HR for UTI in Calcium Oxalate Stone Formers
6.36 (95% CI 4.82–8.XX)
Key Findings
Patients with kidney stone disease had a significantly increased risk of developing UTIs compared to matched controls (HR 5.73; 95% CI 4.55–7.21).
This increased risk persisted after adjusting for diabetes mellitus (adjusted HR 5.76; 95% CI 4.50–7.36).
Among stone formers who developed UTIs, 40.6% experienced stone recurrence, with some UTIs temporally associated with recurrent stone episodes.
Calcium oxalate stone formers exhibited a particularly high risk of UTI (HR 6.36; 95% CI 4.82–8.XX), suggesting stone composition influences infection risk.
Overall, 18.7% of stone formers developed at least one UTI during the median 19-year follow-up, compared to 14.1% of controls.
Mortality rates were similar between stone formers and comparators over the study period.
Clinical Implications
Clinicians should recognize that patients with kidney stones, especially those with calcium oxalate stones, are at substantially increased risk for UTIs over long-term follow-up. This underscores the importance of monitoring for infection in stone formers and considering infection risk in management strategies. Adjusting for diabetes does not diminish this risk, highlighting KSD as an independent risk factor for UTIs.
Conclusion
This large, long-term cohort study demonstrates a robust association between kidney stone disease and increased risk of urinary tract infections, with variation by stone type. These findings support the need for vigilant infection surveillance in stone formers to potentially reduce morbidity.
References
NHS Bristol Research Ethics Committee 2018 -- Ethical approval for study
