Abstract
Objective:
This study evaluates the evolving surgical management of renal stones in Australia over the past 15 years.
Methods:
The National Australian Medicare and Australian Institute of Health and Welfare (AIWH) data were used to obtain the annual number of hospital presentations for urolithiasis and surgical procedures for upper urinary tract stones from 2005 to 2020. The four treatment modalities observed included nephrolithotomy, shockwave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL) and endoscopic lithotripsy.
Results:
The total number of renal colic presentations in Australian hospitals and urology procedures claimed by Medicare has increased during the past 15 years. A total of 218,999 urological procedures were claimed by Medicare for renal stones over 15 years. There has been a dramatic rise in endoscopic lithotripsy surgery for stones. In 2005–2006, endoscopic lithotripsy comprised 56.6% of total stonework claimed by Medicare, and this proportion jumped to 88.9% in 2019–2020. All other modalities saw a decline in absolute and relative numbers.
Conclusion:
Endoscopic management of upper renal tract stones predominates in the current management of renal stone disease in Australia. Epidemiology audits such as this study can provide insight into national disease trends and guide future healthcare policies and resource planning.
Level of evidence:
2b
Introduction
Prevalence rates for renal tract stones vary from 1% to 20% across the globe. Currently in Australia, the annual incidence of urinary calculi is approximately 131 per 100,000 Australians. 1 Stone incidence is influenced by various factors such as geographical location, warmer climate, ethnicity, genetics and diet. 2 The surgical management of upper renal tract stone disease has evolved significantly over the past three decades due to scientific advances in endoscopic and laser technology. 3 However, there is limited published up-to-date Australian data on trends for surgical management of urolithiasis.
Surgical treatment for upper renal tract stones includes ureteroscopic lithotripsy (URS), extracorporeal shock-wave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), combined procedures or less commonly open surgery. Professional organisations such as the American Urology Association (AUA) and the European Association of Urology (EAU) have published guidelines on the management of renal stone disease including indications for medical versus surgical treatment. Uncomplicated ureteric stones can sometimes be managed conservatively with medical expulsive therapy (such as alpha-blockers) if the stone meets certain size criteria. Stone size criteria for conservative stone management slightly varies between the two organisations, and the cut-off for medical expulsion therapy is stone size ⩽10 mm based on the AUA guideline, while the EUA recommends medical therapy for small stone < 6 mm. Although slight variations exist regarding the treatment modality of choice for certain stones based on location and size criteria, both AUA and EAU guidelines recommend URS as the first-line treatment for ureteric stones > 10 mm in size since URS carries higher stone-free rates. There is a slight variation in the surgical approach for larger proximal ureteric stones; AUA endorses equivalence between shockwave lithotripsy and ureteroscopy for proximal ureteric stones > 10 mm in size whereas EUA recommends ureteroscopy.4–6 Both AUA and EUA recommend PCNL as the preferential surgical option for stones > 20 mm owing to the increased stone-free rate. Staged URS or SWL in the setting or large stones can be offered as the second-line treatment if PCNL is not suitable. 5
Innovations in minimally invasive surgery and laser technology over the decades have revolutionised stone management and contributed to the decline in open stone surgery. In the age of endourology, we have seen a shift towards stone lithotripsy management worldwide. 7 We hypothesise that endoscopic lithotripsy surgery for urolithiasis is becoming more popular in Australia. This study evaluates the evolving surgical management of upper renal tract stones in Australia over the past 15 years. National trends in stone disease are highly informative as it paints a picture of our contemporary urology practice.
Methods
A retrospective, population-based cohort study was conducted to evaluate hospital presentations and surgical procedures performed for urolithiasis during 2005 to 2020 in Australia. The Medicare database was used to obtain the annual number of procedures performed for upper renal tract stone disease between 2005 to 2020. Medicare Australia database captures all procedures claimed through the Medicare Benefits Schedule (MBS) by a registered health practitioner, while the Australian Institute of Health and Welfare (AIHW) is an independent statutory Australian Government agency that provides relevant statistics on healthcare service provision. The AIWH database was used to determine the annual number of emergency acute renal colic presentations across Australia over the past 15 years. The AIHW database records acute patient presentations of most medium- and large-sized public and private hospitals across all states in Australia. As such, the AIWH does not capture presentations to community general practitioners. The Australian Bureau of Statistics database was used to obtain Australia’s population. Medicare Benefit Scheme (MBS) item numbers were used and separated into four modalities of treatment (Table 1). Both Medicare annual data and the AIWH database were collected over financial years which starts from 1 July and ends the next year on 30 June. Demographic information such as gender and age were available within the Medicare procedure database, but patient characteristics such as ethnicity were not provided.
Procedure and associated MBS item number.
MBS: Medicare benefits schedule.
Ethics approval was not required as data were obtained from an open-access administrative national database which is readily available to the public online, and all data were anonymised.
Results
According to AIWH principal diagnoses in Australia data cubes, the absolute number of presentations for urolithiasis in Australian hospitals has steadily increased over the 15-year period except for 2019 to 2020 (Table 2). Similarly, there is a steady increase in urolithiasis presentations relative to Australia’s population growth per capita (per 100,000) over 15 years except for 2020 (Figure 1).
Number of hospital presentation for urolithiasis from 2005 to 2020.
Per capita rate of urolithiasis presentation to hospitals in Australia, 2005 to 2020.
Medicare database shows similar trends among the number of urology procedures claimed for renal tract calculi. A total of 218,999 urological procedures were claimed by Medicare for renal stones during the study period 2005 to 2020. Overall, there has been a gradual rise in Medicare claims for stone procedures over the last 15 years with a slight decline in numbers during 2019–2020 (Figure 2). During July 2005 to June 2006, a total of 9683 urological procedures were claimed under Medicare for upper renal tract stone disease. Over the 15 years, the annual number had almost doubled to 19,189 during July 2019 to June 2020 period. Even accounting for Australia’s population growth, the per capita rate of interventions has increased from 47 per 100,000 in 2005 to 77 per 100,000 in 2020 (Figure 3). Most of this rise can be attributed to a higher number of endoscopic procedures being performed.
Total procedures claimed by Medicare for urolithiasis, 2005 to 2020.
Rate per capita for stone procedures, 2005 to 2020.
Figure 4 compares the number of procedures claimed under Medicare Australia for the different treatment modalities between 2005 and 2020.
Number of procedures claimed under Medicare for stone disease during 2005 to 2020.
Percutaneous nephrolithotomy
The annual rates of PCNL claimed by Medicare have slowly declined over the 15-year period. During 2005–2006, a total of 525 PCNLs were completed, and this made up 2.6% of the annual stone operative load. By 2020, the annual number had decreased to 262 and represented only 1.4% of total stone procedures for that year.
Shockwave lithotripsy
Over the course of this audit, a steady decline in the number of SWLs was observed. During 2005–2006, a total of 3589 SWL procedures were claimed by Medicare, making up to 37.1% of total stone procedures performed during that year. During 2019–2020, the annual number of SWL claimed by Medicare had decreased to 1838 and comprised 9.6% of stone procedures for that year. This represents a 27.5% absolute reduction in SWL procedures over 15 years. Overall, there has been a reduction in the total number and proportion of these cases compared with the total annual operative load.
Ureteroscopy with lithotripsy or basket
Lithotripsy is the only treatment modality for the stone disease that has continuously risen over 15 years in Australia. In 2005–2006, an absolute total of 5484 ureteroscopy cases were claimed by Medicare, this made up just over half of the total casework at 56.6%. By 2019–2020, however, a total of 17,051 cases were claimed by Medicare and the proportion of patients getting this modality of treatment for stone disease jumped to 88.9%. This represents an absolute increase of 32.3%. It is clear from our observations that most patients receive management for upper tract stone disease in contemporary urology practice via ureteroscopy with lithotripsy or basket.
Discussion
This retrospective population-based cohort study provides a broad overview of contemporary patterns of surgical management for renal tract stones in Australia. Our data illustrates the increasing popularity of endoscopic surgery over the past 15 years; it currently has established its place as the mainstay treatment modality in Australia. The shift in the pattern of stone treatment towards endoscopic surgery can be explained by improvement and greater accessibility of endoscopic technology and flexible laser fibres. 3
The overall increase in stone procedures claimed by Medicare is most likely a reflection of an increase in the incidence of stone disease. This is supported by multiple epidemiology studies that have found the prevalence of renal stone disease is rising worldwide. 3 It is also possible that as surgical options for renal tract stones have become less invasive, surgical management has become easier to justify and hence more commonly performed. Endoscopic surgery has allowed easier access to the treatment of smaller stones which may explain the overall increase in the number of surgeries for upper renal tract stones. Thus, it is possible that the trend of increased number of stone procedures is a reflection of reduced intervention threshold in patients who may have been considered for conservative management as well as asymptomatic individuals. 8
Although PCNL remains the treatment of choice for large renal stones, its use has diminished for smaller stones with the emergence of endoscopic laser fragmentation. Our data showed that PCNL represents only a small component of upper tract stone treatment in Australia, and the demand for these is overall declining. Perhaps, this trend reflects earlier stone detection and improvements in endoscopic lithotripsy technology.
Similarly, the proportion of SWL procedures performed over time has decreased in Australia. SWL requires optimal stone (stone location, size and composition) and patient factors (non-pregnant, shorter skin-to-stone distance). A recent Australian study on upper renal tract stone composition over the past 30 years found stone composition patterns have remained relatively static in Australia over the decades. 9 On the other hand, published guidelines advocate the role of URS in the management of urolithiasis and the continued improvement in endoscopic technology has supported this trend.3,5,6 Furthermore, access to SWL and its role in the emergency settings are barriers to the utilisation of SWL.
Interestingly, our data depicted a gradual increase in hospital presentations for urinary stones over the last 15 years except for the year 2019-2020. We hypothesise that the fall in presentation numbers during that year may have been contributed by the COVID-19 pandemic which saw a major impact on healthcare services worldwide. Fear and anxiety within the communities translated to changes in the pattern of hospital presentations for various emergency conditions. Epidemiology studies from around the globe found a reduction in general urological and urolithiasis presentations during COVID-19. 10 Furthermore, the AIWH database captures hospital presentations for acute renal colic and does not take into consideration patients referred routinely from the community general practitioner. It is possible that patients with acute renal colic or urolithiasis were presenting to general practitioners rather than hospitals during COVID-19, and therefore, the recorded number of urolithiasis presentations for that year was not accurately captured. It will be of interest to observe the ongoing trends in renal colic presentations over the following years in Australia. Perhaps, delayed presentations during the pandemic may give rise to larger stone burden at the time of referral to urology in the future years. As such, it will be interesting to see whether PCNL numbers will increase in the near future.
There are some limitations with our study due to the limitations of data available from MBS and AIWH. The database did not provide details of stone size, multiplicity, composition, and location which are factors that can impact the selection of treatment modality. Furthermore, complications such as readmission or re-intervention for stones were not made available in the database. Therefore, our study numbers do not distinguish from stones that required multiple interventions, for example, multiple lithotripsy surgery for large stone or high stone burden in a single patient. Similarly, patients who have both ureteric and renal stones treated in a single procedure may have been billed more than one item number on Medicare. Although this could impact the total number of endoscopic procedures presented in our paper, this cannot be confirmed by our data. Despite the limitations in datasets driven by the classification of disease code systems, they provide a large database of diseases and serve as informative tools that can be used to map general epidemiological trends. Further research examining the cost, benefits and complication rates of each treatment modality will add to our paper. Our study illustrates obvious trends in the Australian urology practice of stone treatment and highlights an overall growing preference towards endoscopic stone treatment. Results from our Australian study mirror current worldwide trends of urolithiasis treatment.3,8,11 The observed changes in urology practice can have important economic implications and may provide useful guidance for future resource planning and better funding allocation, especially in public hospitals.
Conclusion
This study shows an increase in the hospital presentation of urolithiasis and endoscopic stone surgery from 2005 to 2020. Our study is the first in Australia to encompass trends in surgical stone management during the COVID-19 pandemic. Over the past 15 years there has been a shift in the surgical management of upper renal tract stones and our findings provide a unique insight into evolving landscape in the management of stone disease in Australia.
Footnotes
Conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.
Funding
The authors received no financial support for the research, authorship and/or publication of this article.
Ethical approval
Was not obtained for this study as data was obtained from open-access national database available to the public online and all data were anonymised.
