Temporal trends of acute nephrolithiasis in Auckland, New Zealand.

AIM

An increasing amount of evidence suggests that the occurrence of kidney stone disease has increased over the last 50 years. No data analysis on temporal trends in Auckland, New Zealand has ever been performed. The aim of this study was to investigate the changing pattern by age, ethnicity, and gender on stone incidence over a 10-year period.

METHODS

Demographic data was collected on all patients who presented with renal colic. Population numbers were provided by the New Zealand ministry of statistics using regular census data. The analysis was performed using Pearson's correlation coefficients and a Poisson regression model.

RESULTS

From 1997 to 2007, 17,532 new stones were coded as nephrolithiasis with an age range of 1-97. Disease incidence amongst Auckland residents was greater in 2007 than 1997 (0.131% or 131 per 100,000 population vs 0.102% or 102 per 100,000 population. p=0.012). The male to female ratio changed over time with a greater proportion of females presenting in 2007 than 1997 (0.47 vs 0.41, p<0.05). Pacific, Asian, and Maori incidence increased faster compared to European whilst those from the Middle East were the only group to have a stable rate (0.26% or 260/100,000 per year) over the 10-year period.

CONCLUSIONS

Incidence of kidney stone disease in the Auckland region has increased significantly from 1997 to 2007. Different ethnic groups had different rates of change, but all groups showed an increasing incidence over time, with the exception of those from the Middle East. A greater proportion of patients are female than 10 years ago.