Unfortunately, COVID forced this year’s AUA annual meeting into a virtual format.

Fortunately, the decision was made late, which led to the inclusion of many exceptional kidney stone abstracts in this year’s AUA program. In light of this, there were over 100 moderated posters and over 50 podium presentations (including video presentations) related to kidney stone disease. Due to the enormity and quality of the presentations, this write-up is but a short glimpse at some of the impactful stone abstracts. That said, I highly encourage you to review the rest of the kidney stone abstracts as they are excellent and are all available on the AUA annual meeting website (https://www.aua2021.org).

In the area of kidney stone prevention, empirical vs selective preventive treatment for kidney stone disease was described in 2 abstracts from the same group using medical claims data. They determined that empirical therapy can be effective at preventing stone recurrence and that thiazides were the most effective (PD21-05). The same research group also determined that kidney stone patients at high risk for recurrence had a lower risk of stone related events when obtaining 24-hour urine testing prior to prescribing preventive therapy (PD14-09). Importantly, selective therapy is necessary in some stone patient populations but probably not all. Also in the area of kidney stone prevention, 2 abstracts (PD21-08 and PD21-12) examined alkali agents and found that LithoLyte®, KSPtabs™ and baking soda were all effective alkali supplements (increasing urinary pH and citrate). Their side effect profiles were found to be similar to prescription potassium citrate. This information can be useful for patients who either can’t afford, cannot tolerate or desire a nonprescription alternative for urinary alkalization. Two groups also examined the impact of proton pump inhibitors (PPIs) on kidney stone disease. The first abstract (MP07-11) found a decrease in urinary magnesium on 24-hour urine collection in patients on omeprazole. The second abstract (PD14-12), using electronic medical records, found that patients on PPIs had a higher risk of incident stone formation. This increase in stone formation can most likely be attributed to the low urinary magnesium induced by the PPI.

Shifting focus to the surgical management of kidney stones, PD54-10 was the first report on comminution of stones in humans by burst wave lithotripsy. This innovative technology has seen considerable evolution from bench to now clinical use. Using this handheld device, 63% of stones that were treated (22) were broken into ≤2 mm fragments within 10 minutes and 82% within 50 minutes. Importantly, there were minimal to no adverse events. This novel technology will likely change the way we surgically manage kidney stone disease in the very near future. The EDGE group reported on the 6-year followup of the basketing vs dusting trial (PD54-11). It was determined that there was no difference in terms of surgical reinterventions, symptomatic stone events, stone recurrence, emergency department visits and readmissions. Therefore, it is clear that outcomes depend more on a number of stone and patient related factors and not necessarily on the stone fragmentation technique being used. Also presented at this year’s AUA was a study from the Endourological Society TOWER group examining the success of extracorporeal shock wave lithotripsy (SWL) for distal calculi (MP06-19). In this retrospective study of 384 patients using the Storz Modulith® SLX lithotripter, it was determined that the stone-free rate was 70% for stones with an average size of 6.5 mm. Failure was associated with larger stones (mean size 7.12 mm; see figure). Surprisingly, body mass index was not a significant predictor of failure. Interestingly, the majority of cases (81.3%) were done in the supine position. Finally, 2 abstracts examined ambulatory percutaneous nephrolithotomy (aPCNL) retrospectively and found it to be safe and effective even in patients who were more complex (MP06-02). In addition, aPCNL was found to reduce cost by 30% when compared to standard percutaneous nephrolithotomy (MP06-03). Initial, unplanned and overall costs all favored aPCNL. It is clear that aPCNL will play a significant role in the future surgical management of kidney stone disease.

Figure. Stone size according to treatment success.

Two noteworthy abstracts examined kidney stones during pregnancy. The first (MP54-12) found that first-time stone formers during pregnancy have an increased risk of developing stone disease within 4 years after pregnancy. The second abstract (PD14-03) examined pregnant patients presenting with obstructive pyelonephritis and determined that they had reduced odds of decompression as well as increased odds of delayed decompression when compared to nonpregnant patients. Furthermore, delays in decompression were associated with increased maternal-fetal complications. These abstracts further emphasize the importance of treating pregnant stone patients appropriately and in a timely manner in order to avoid complications.

There was also a thought-provoking abstract examining racial and ethnic disparities in emergency care of kidney stone patients (PD03-01). Analysis of the Healthcare Cost and Utilization Project examined over 200,000 kidney stone patients and found that White patients were more likely to return to the emergency department compared to Black and Hispanic patients. Medicaid and Medicare patients were also more likely to revisit the emergency department, as were patients from rural populations.

Finally, regarding patient quality of life and kidney stone disease, the Wisconsin Stone Quality of Life (WisQOL) Consortium presented a short form of the WisQOL questionnaire (MP19-05). This version has only 6 items (original WisQOL has 28 items) with only 2 domains. This newly developed version was found to be both short and suitable for efficient assessments. Regarding ureteral stents, the Urinary Stone Disease Research Network study presented the patient’s perspective regarding the symptoms associated with the placement of a ureteral stent (PD14-05). This abstract provided great insight into the patient’s perspective, which should help further research in this area. Finally, the Canadian Endourology Group presented early work on the validation of a new short and concise ureteral stent symptom score (MP06-11). After developing the questionnaire, it was pilot tested and found to be acceptable among patients, and was evaluated to be at a grade 5 readability level. Once validated, this new stent symptom questionnaire will be concise and will be appropriate not only for research, but also for clinical objectives.

This concludes the brief overview of the stone disease abstracts from the 2021 AUA annual meeting. Although the meeting was once again virtual this year, the richness of research in our field of kidney stone disease was clearly apparent. I look forward to seeing everyone next year in New Orleans.