The relationship between ethnicity and stone composition in a large multi-ethnic London NHS Trust

Purpose Few studies have examined kidney stone composition of an ethnically diverse group living in the same location, we aimed to study this in an ethnically diverse NHS trust. Methods We reviewed all patients (n=312) with laboratory stone analysis and compared their ethnicity with their stone composition. Results Using a Chi Squared analysis there was no significant difference between stone composition in different ethnic groups (p=0.07). Uric acid stones were more common in the White-other group at 22.0% compared to 10.3% for White British, 5.2% for Asian and 9.52% for Black patients. Calcium oxalate stone were more common in the Asian population with 71.9% and Black population at 76.1%, compared with 56.7% in the White British population and 52.6% in the White-other population. Calcium phosphate stones were found commonly in the White British population (26.8%) compared to 18.6% for White-other, 16.7% for Asian and 9.5% for Black patients. Cystine and Struvite stones were found at low levels of between 0-3.4% in each group. Repeat stone formers with calcium oxalate, uric acid or cystine stones formed the same stone again 100.0% of the time. The odds for the Black population having a stone analysed (OR 0.62, CI 0.39-0.97, p=0.04) was significantly lower than the local population, and for the Asian population this was significantly higher (OR 1.31, CI1.05-1.62, p=0.01), Conclusion Uric acid stones are found more frequently in the White-other population and calcium oxalate stones are found more frequently in the Asian and black population. However, these results were not statistically significant. The odds ratio of having a stone was significantly higher in the Asian population and lower in the Black population.