Geographical variation in the management of urolithiasis in Australia

Assessment of the impact of geogenic and climatic factors on global risk of urinary stone disease

Urinary Stone Disease (USD) or urolithiasis has plagued humans for centuries, and its prevalence has increased over the past few decades. Although USD pathology could vary significantly among individuals, previous qualitative assessments using limited survey data demonstrated that the prevalence of USD might exhibit a distinctive geographical distribution (the so-called "stone belt"), without any knowledge about the characteristics and contribution factors of the belt. Here, we argue that the spatial distribution of USD can at least partly be explained by geogenic and climatic factors, as it correlates with the ambient geo-environmental conditions modulated by lithology/mineralogy, water quality and climate. Using a Bayesian risk model, we assessed the global risk of USD based on updated big data of four key geogenic factors: phosphorite mines (inventory >1600 points), carbonate rocks (at the scale of 1:40 million), Ca²⁺/Mg²⁺ molar ratio of river water (1.27 million samples distributed over 17,000 sampling locations), and mean air temperature (0.5^o × 0.5° resolution) representing the climate. We quantitatively identified possible contributions of the factors to USD and delineated the regions with the high USD risk which stretched from southern North America, via the Mediterranean region, northeastern Africa, southern China to Australia, and roughly coincide with the world's major areas of carbonate outcropping. Under current climate conditions, the areas with the probabilities for the USD prevalence of ≥50% and ≥30% covered 3.7% and 20% of the Earth's land surface, respectively. By the end of the 21st century, such total areas could rise to 4.4% and 25% as a result of global warming. Since the USD data used in this study were quite heterogeneous, the prediction results needed further calibration with additional high-quality prevalence data in the future.

Variation in ureteric re-implantation for Australian children

BACKGROUND

Management options for vesicoureteric reflux are numerous, increasingly diversifying and debated. There is longstanding anecdotal opinion of inexplicable regional variation in vesicoureteric reflux management in Australia. This study investigates temporal trends in ureteric re-implantation for children, and variation between states and territories.

METHODS

Ureteric re-implantation data for children aged 0-14 years were retrieved from the Medicare Benefits Scheme item reports database for the 20-year period from 1998-2017. Claims data were population adjusted for each state then standardized for age using Australian Bureau of Statistics records. National and regional trends were calculated using joinpoint regression. Comparison between eastern (New South Wales, Victoria, Queensland, Tasmania, Australian Capital Territory) and western or central (Western Australia, South Australia) states was performed using the Mann-Whitney U-test.

RESULTS

There were 4919 procedure rebate claims during the study period. A national decrease in claim rates of 6.3% per 100 000 children was identified (P < 0.001). This was derived from significant decreases observed in eastern states. There was a threefold higher claim rate in Western Australia and South Australia per annum compared to the remainder of the country (4.0 versus 12.6 per 100 000; P < 0.001). For the most recent 5 years of the study period, this difference increased to a sevenfold higher rate (1.6 versus 11.1; P < 0.001).

CONCLUSION

There has been a dramatic nationwide decline in the rate of ureteric re-implantation procedure claims. Regional disparity between each side of the country is widening. Further research is required to determine if this degree of variation is warranted or unwarranted. The observed regional variation facilitates opportunity for a nationwide pragmatic clinical trial.

Regional Variation in Shock Wave Lithotripsy Utilization Among Medicare Patients with Nephrolithiasis

OBJECTIVE

To characterize shock wave lithotripsy (SWL) utilization and assess for regional variation in the use of this procedure across the United States.

MATERIALS AND METHODS

We examined SWL and URS utilization among Medicare Beneficiaries with a diagnosis of nephrolithiasis for the years 2006, 2009, and 2014. Adjusted utilization rates were calculated per 1000 beneficiaries accounting for age, sex, and race. Utilization rates were examined nationally and by hospital referral region (HRR).

RESULTS

A total of 511,495, 604,493, and 806,652 Medicare beneficiaries had a diagnosis of nephrolithiasis in 2006, 2009, and 2014, respectively. The adjusted rate of SWL per 1000 beneficiaries with nephrolithiasis decreased from 59.4/1000 in 2006 to 52.2/1000 and 45.5/1000 in 2009 and 2014 (13.9% decrease, P < .001). Variation was observed in SWL utilization; up to a 12-fold difference between HRRs (9.2/1000 in Winchester, VA to 105.8/1000 in Lincoln, NE). The adjusted rate of URS per 1000 beneficiaries increased by 10.2% (P < .001) between 2006 and 2014. However, the percent decrease in SWL utilization did not correlate with the percent increase in URS utilization when examined by HRR (P = .66).

CONCLUSION

Variation exists in the utilization of SWL among Medicare beneficiaries (12-fold difference). This variation is likely secondary to a series of supply, urologist, and patient-specific factors. SWL utilization decreased between 2006 and 2014, while URS increased. Stone procedure type is likely highly dependent on where patients receive their urologic care.