Anyone who has had a urinary stone knows: the colic is one thing, the worry about the next stone is another. And that worry is justified, because according to the current German guideline on urolithiasis, the recurrence rate is up to 50%—meaning every second stone is not the last. This is exactly where a research and development project comes in that we at Medipee have been working on for several years. Important to note upfront: the analyzer and our associated app Uroli are not yet an available product today—but we have already gained initial study experience and would like to put our approach into context here.
Two parameters that reveal urinary stones: pH value and specific gravity
Two risk factors are particularly important in the development of urinary stones: pH value and the urine’s specific gravity. The pH value indicates how acidic or alkaline the urine is and therefore reflects your diet very directly—an persistently acidic environment particularly promotes uric acid and calcium oxalate stones. Specific gravity, in turn, indicates how concentrated the urine is and what your body’s fluid balance is like. In general, it can be said: an acidic environment and highly concentrated urine—i.e., insufficient fluid intake—significantly promote the formation of urinary stones. The guideline of the German Society of Urology also explicitly recommends increasing fluid intake as part of metaphylaxis, with target values for urine volume—a mechanism that is directly reflected in specific gravity.
Urine analysis as biofeedback: making behavior visible
Our idea is that regular analysis of these two parameters in everyday life can function like a biofeedback system. Biofeedback essentially means making unconscious bodily functions or behavioral patterns visible so that they can be changed in a targeted way. Applied to urinary stones, this means: your urine reflects what you have eaten and drunk in the days before. If you have this mirror available immediately and regularly, an abstract recommendation (“drink more, eat less meat”) becomes concrete, measurable feedback. You can see right away how fluid intake and diet affect your urine—and adjust just as quickly. In this way, Uroli is intended to go beyond mere data collection and support people in gradually changing their lifestyle toward stone prevention.
The gap in discharge management
In inpatient and outpatient urological care, a stone is now removed minimally invasively in most cases—a major technical advance. What often falls short in everyday care, however, is the subsequent education on recurrence prevention. Discharge consultations are brief, outpatient clinics are busy, and metaphylaxis—i.e., long-term prevention of a new stone—requires time, patience, and a structured discussion about diet, drinking habits, and lifestyle. Many patients leave the hospital without a clear idea of how they can actually prevent their next stone. With a recurrence rate of up to 50%, this is not a minor issue, but the main reason we address this topic at all.
Our approach is intended to help close precisely this gap in care—not as a replacement for medical care, but as a bridge between doctor’s visits. A tool that continues unobtrusively in everyday life at home where the clinical discharge consultation ends.
Uroli as a companion: data plus knowledge
The planned Uroli app is intended not only to present the measurement data in a structured way, but also to offer a comprehensive knowledge section on urinary stones. Here, we want to consolidate information and guidance on how to prevent urolithiasis in a targeted manner—from the different stone types and dietary and fluid-related measures to the recommendations of the current guideline. The goal is that, in the end, you will not only know what your current values indicate, but also what you can derive from them.
What our study experience has shown so far
We did not leave our concept on the drawing board. In initial studies, we were able to observe that pH value and specific gravity can be reliably recorded in everyday life at home, and that users noticeably adjust their drinking and eating habits through this direct feedback. This very feedback loop—see the measurement value, adjust behavior, see the new measurement value—is the core of our biofeedback concept and the reason we continue to work on this approach.
Sources
AWMF / DGU – S2k guideline “Diagnostics, Therapy and Metaphylaxis of Urolithiasis” (registry number 043-025): register.awmf.org/de/leitlinien/detail/043-025
European Association of Urology (EAU) – Guidelines on Urolithiasis: uroweb.org/guidelines/urolithiasis
Knoll T et al. – “Update of the S2k guideline on diagnostics, therapy and metaphylaxis of urolithiasis: What’s new?”, Die Urologie 2019: doi.org/10.1007/s00120-019-01033-7
German Society of Urology – press release on the updated S2k guideline on urolithiasis (2019): urologenportal.de/neue-empfehlungen-zur-volkskrankheit-harnsteine
