Changes in upper urinary tract stone composition in Australia over the past 30 years.

Objectives: To investigate upper urinary tract stone composition rates in Australia To investigate changes in stone composition in Australia over the past 30 years

Patients And Methods: The Institute for Clinical Pathology and Medical Research (ICPMR) database was used to obtain - stone composition statistics from 2009-2011 Historical comparisons of stone composition rates were obtained from previous Australian studies; Rofe; 1981, and Baker; 1993 for epidemiological data from the 1970s and 1980s respectively. Stone composition data was separated into gender and age-groups

Results: From the 791 stones analysed between 2009 and 2011, calcium oxalate remains the dominant type accounting for 64% of stones in our dataset, which compares to 68% from both the 1970s and 1980s. Uric acid stones contributed 16% of contemporary stone compositions, comparable to 16% in the 1970s and 17% in the 1980s. Struvite stones showed a decreasing trend from 14% in the 1970s, to 12% in the 1980s and 7% in the current data. For struvite stones, while the female 21-30 age-group was the most prolific for struvite stone formation in the 1980s, the peak group in contemporaneous records is 61-70 year-old men.

Conclusion: Stone composition in Australia has remained relatively static over the past 30 years. Modifications in diet and body habitus have not resulted in significant changes in the proportion of uric acid and calcium oxalate stones detected. The decreasing trend in the proportion of struvite stones most likely reflects improved management of urinary tract infections within the Australian population.