Diurnal variation of urine composition in calcium oxalate stone disease during treatment with bendroflumethiazide

Attitudes of urologists on metabolic evaluation for urolithiasis: outcomes of a global survey from 57 countries

Although stone disease is an important health problem with high incidence and recurrence rates, it is a preventable disease. Attitudes and practices of urologists regarding the prevention of recurrence continue to be a subject of debate. In this context, an online survey study was conducted involving 305 urologists from 57 different countries. The first 7 questions collected demographic data about the urologists and the remaining 23 questions were about the recurrence and metabolic evaluation, medical treatment, and follow-up of urinary stone disease. Most urologists (85.2%) thought that metabolic examination was important. Approximately one-third of the participants (34.1%) performed 24-hour urine analysis and stone analysis was ordered by 87.5% of the urologists. Metabolic analysis was performed for all patients by 14.7% of the participants. For pediatric patients this rate was 68.5%, and for adults with recurrence the rate was 81.6%. Reasons cited by the urologists for not performing metabolic analysis included not feeling confident doing so (18.3%), having limited facilities in their hospital (26.5%), having an excessive daily workload (31.8%), patient-related factors (27.5%), and referring patients to other departments for metabolic evaluation (20.9%). Although majority of the responding urologists do consider the metabolic analysis as vital important, they seemed not to be willing to perform these tests with the same degree of enthusiasm in their daily practice. Our results show that urologists need support in performing and interpreting 24-hour urine analysis, improving their knowledge levels, and communicating with patients. Urology residency training should focus more on the prevention of urinary stone recurrence in addition to the surgical training.

Composition of Urine Collected from Non-Stone-Forming Chinese Persons during Different Short-Term Periods of the Day

The purpose of this study in a small group of non-stone-forming Chinese persons was to measure the levels of supersaturation with calcium oxalate and calcium phosphate and pH with the aim of confirming if any of the different short-term urine samples were better for risk evaluation than a 24-h sample. Nine normal men and 1 woman collected urine during 4 periods of the day. Period 1 between 08 and 12 h, Period 2 between 12 and 18 h, Period 3 between 18 and 22 h, and Period 4 between 22 and 08 h. Each sample was analysed for calcium, oxalate, citrate, magnesium and phosphate, and estimates of supersaturation with calcium oxalate (CaOx) and calcium phosphate (CaP) were expressed in terms of AP(CaOx) and AP(CaP) index. An estimate of the solute load of CaOx was also calculated. Urine composition for 24-h urine (Period 24) was obtained mathematically from the analysed variables. Urine composition corresponding to 14-h urine portions 22-12 h (Period 14N) and 08-22 h (Period 14 D) were calculated. The lowest pH levels were recorded in Period 1 urine. The highest level of AP(CaOx) index was recorded during Period 1, and the product AP(CaOx) index × 107 × hydrogen ion concentration was significantly higher in Period 1 urine than in 24-h urine (p = 0.02). Also, the product SL(CaOx) × 107 × hydrogen ion concentration was significantly higher in Period 1 urine (p = 0.02). Low AP (CaP) index levels were recorded in Period 4, but also in all periods following dietary loads of calcium and phosphate. With the important reservation that the analytical results were obtained from non-stone-forming persons, the conclusion is that analysis of urine samples collected between 08 and 12 h might be an alternative to 24-h urine. The risk evaluation might advantageously be expressed either in terms of the product AP(CaOx) index × 107 × hydrogen ion concentration or the product SL(CaOx) × 107 × hydrogen ion concentration.

Urine and stone analysis for the investigation of the renal stone former: a consensus conference

The Consensus Group deliberated on a number of questions concerning urine and stone analysis over a period of months, and then met to develop consensus. The Group concluded that analyses of urine and stones should be routine in the diagnosis and treatment of urinary stone diseases. At present, the 24-h urine is the most useful type of urine collection, and accepted methods for analysis are described. Patient education is also important for obtaining a proper urine sample. Graphical methods for reporting urine analysis results can be helpful both for the physician and for educating the patient as to proper dietary changes that could be beneficial. Proper analysis of stones is also essential for diagnosis and management of patients. The Consensus Group also agreed that research has shown that evaluation of urinary crystals could be very valuable, but the Group also recognizes that existing methods for assessment of crystalluria do not allow this to be part of stone treatment in many places.