Effect of stone composition on surgical stone recurrence: single center longitudinal analysis.

INTRODUCTION The objective of this study is to explore the association between urinary stone composition and surgical recurrence. MATERIALS AND METHODS: Patients who underwent kidney stone surgeries (between 2009-2017), were followed for > 1 year, and had ≥ 1 stone composition analyses were included in our analysis. Surgical stone recurrence (repeat surgery) was defined as the second surgery on the same kidney unit. Recurrence-free survival analysis was used. RESULTS: A total number of 1051 patients were included (52.7% men, average age 59.1 +/- 15.1 years). Over 4.7 +/- 2.5 years follow up, 26.7% of patients required repeat surgery. Patients' stone compositions were calcium oxalate (66.0%), uric acid (12.2%), struvite (10.0%), brushite (5.7%), apatite (5.1%) and cystine (1.0%). Results suggested that patients with cystine stones had the highest surgical recurrence risk; brushite had the second-highest surgical recurrence risk. Struvite, uric acid, and apatite stones were at higher risk compared with calcium oxalate stones (lowest risk in our cohort). When pre and postoperative stone size was controlled, patients with a history of uric acid, brushite, and cystine stones were at higher surgical risk. After controlling clinical and demographic factors, only brushite and cystine stones were associated with higher surgical recurrence. CONCLUSIONS: Patients with cystine stones had the highest surgical recurrence risk; brushite stones had the second highest surgical recurrence risk. Struvite, uric acid, and apatite stones were at higher risk compared with calcium oxalate stones. When pre and postoperative stone size, clinical and demographic factors were controlled, only those with brushite or cystine stones were at significantly higher risk of surgical recurrence.

Patients Attending Shared Medical Appointments for Metabolic Stone Prevention Have Decreased Stone Risk Factors.

INTRODUCTION: Shared medical appointments (SMAs) have decreased patients' wait time to initial stone clinic appointment, standardized education, and increased exposure to nutrition therapy. We assessed the effectiveness of SMAs in reducing patients' urinary stone risk factors. MATERIALS AND METHODS: Patients who established care in our stone clinic in an SMA between March 2012 and August 2015 were sequentially identified. After eliminating those without follow-up urine collections or whose urinary creatinine excretion between the two collections varied by >40%, 113 patients were included (M:F 63:50; 54 ± 15 years; body mass index [BMI] 30.6 ± 6.7). Results from before and after the SMA were compared with those from a similar cohort of patients who attended individual patient appointments (IPAs) for their first stone clinic visit (n = 63; M:F 37:26; 54 ± 14 years; BMI 30.1 ± 8.2). All patients received individualized medical therapy for stone prevention. RESULTS: After medical and nutritional therapy, SMA patients with elevated risk(s) at baseline achieved significant reductions in uric acid, calcium, and sodium; p ≤ 0.001 for all. Those with low urine magnesium, low urine volume, low urine pH, and/or low urine citrate at baseline achieved increases; p ≤ 0.0008 for all. IPA patients with elevated baseline risk factors achieved reductions in oxalate and uric acid (p ≤ 0.004 for both) but neither calcium nor sodium and an increase in citrate (p = 0.003) but not magnesium. CONCLUSIONS: Patients from SMAs reduced their stone recurrence risk and compared favorably with patients from IPAs. Contributing factors may include shorter time from stone event to appointment and more standardized education for patients attending SMAs.

Alkali replacement raises urinary citrate excretion in patients with topiramate-induced hypocitraturia.

AIMS: The aims of this study were to assess (1) the magnitude and temporality of decreased urinary citrate excretion in patients just starting topiramate and (2) the effect of alkali replacement on topiramate-induced hypocitraturia. METHODS: Study 1 was a prospective, non-intervention study in which patients starting topiramate for headache remediation provided pre- and post-topiramate 24 h urine collections for measurement of urine citrate. Study 2 was a clinical comparative effectiveness study in which patients reporting to our stone clinic for kidney stones and who were treated with topiramate were prescribed alkali therapy. Pre- and post-alkali 24 h urinary citrate excretion was compared. RESULTS: Data for 12 and 22 patients (studies 1 and 2 respectively) were evaluated. After starting topiramate, urinary citrate excretion dropped significantly by 30 days (P = 0.016) and 62% of patients had hypocitraturia (citrate <320 mg day(-1) ). At 60 days, urine citrate was even lower than at baseline (P = 0.0032) and 86% of patients had developed hypocitraturia. After starting alkali, urine citrate increased in stone-forming patients on topiramate (198 ± 120 to 408 ± 274 mg day(-1) ; P = 0.042 for difference). 85% of patients were hypocitraturic on topiramate alone vs. 40% after adding alkali. The increase in urinary citrate was greater in patients provided ≥ 90 mEq potassium citrate. CONCLUSIONS: Our study is the first to provide clinical evidence that alkali therapy can raise urinary citrate excretion in patients who form kidney stones while being treated with topiramate. Clinicians should consider alkali therapy for reducing the kidney stone risk of patients benefitting from topiramate treatment for migraine headaches or other conditions.

Do multiple ureteroscopies alter long-term renal function? A study using estimated glomerular filtration rate.

BACKGROUND AND PURPOSE: Although considered standard of care for symptomatic urolithiasis, few data are available that evaluate the effects of multiple ureteroscopies (URS) with laser lithotripsies on long-term renal function. We investigated this relationship in a population with preexisting mild to moderate kidney disease. Previous studies have been limited by estimates of glomerular filtration rate (eGFR) calculated from creatinine level during acute stone obstruction, and inclusion of patients with a history of other stone procedures, such as shockwave lithotripsy (SWL) or percutaneous nephrolithotomy (PCNL). METHODS: Charts were reviewed for patients with a baseline eGFR below 90 mL/min/1.73 m(2) who underwent at least two URS for nephrolithiasis at our institution from 2004 to 2012. Patients undergoing SWL or PCNL at any point in their history were excluded. A total of 26 patients, with a mean of 2.3±0.6 URS procedures, were included. The eGFR was recorded at baseline before acute stone presentation and surgery, and at the last recorded follow-up visit. Stone location, total stone burden, and comorbidities were also recorded. RESULTS: The mean eGFR changed from 68.0±13.3 to 75.4±23.0 mL/min/1.73m(2) (mean increase of 10.1±25.0%; mean annual increase of 3.8±15.3%) over a mean follow-up period of 28.1 months (range 5-75 mos). There was no significant difference in eGFR change between patients with stones treated in the kidney alone vs the ureter and kidney combined (12.1% vs 8.3% mean increase; P=0.74). Age, presence of diabetes mellitus or hypertension, baseline creatinine level, total stone burden, and number of URS performed were not significantly associated with change in eGFR. CONCLUSIONS: Using eGFR measured before acute stone presentation, our results suggest that multiple ureteroscopies for stones are not detrimental to long-term renal function, even in patients with preexisting stage 2-3 chronic kidney disease.

Hydrochlorothiazide compared to chlorthalidone in reduction of urinary calcium in patients with kidney stones.

Prevention of recurrent calcium stone disease includes treatment with thiazide and thiazide-type diuretics to reduce urinary calcium (UCa) levels, with the reduction in UCa correlating with risk of stone recurrence. There has been a recent trend of using lower doses of these medications and change from chlorthalidone (CTL) use to hydrochlorothiazide (HCTZ) use. It is unknown whether low doses of HCTZ are effective in lowering UCa levels to target levels. We hypothesize that HCTZ is associated with less reduction in UCa than is CTL when comparing currently used doses. Retrospective observational study of stone-formers was seen in metabolic stone clinic during a 3 years period. Data included patient demographics, co-morbidities, and 24 h urine electrolyte composition. Primary outcome was the change in 24 h UCa. 322 patients were identified with 112 meeting criteria and used in analysis. The majority were placed on HCTZ (n = 42) or CTL (n = 47) 25 mg QD. Patients on CTL 25 mg had a greater reduction in UCa (164 mg; 41 %) than those on HCTZ (85 mg; 21 %), p = 0.01. Neither CTL nor HCTZ at 12.5 mg QD significantly lowered UCa. There was a decrease in serum [K] of 0.5 Meq/L (p = 0.001) in patients on CTL 25 mg daily, but no significant difference in severe hypokalemia or arrhythmia compared to HCTZ. Our data show that CTL is associated with greater reduction in 24 h UCa compared to similarly dosed HCTZ.

Shared medical appointments for patients with kidney stones new to medical management decrease appointment wait time and increase patient knowledge.

PURPOSE: Urolithiasis is associated with pain and other health related quality of life decrements. Lack of access to multidisciplinary care is a barrier to prevention. We developed a shared medical appointment to improve access as well as patient education and exposure to multidisciplinary care. MATERIALS AND METHODS: A total of 112 patients (51 ± 14 years, range 19 to 87) were seen in 27 shared medical appointments during 14 months. Patients were seen using existing clinic space, staff and providers. We targeted new patients for the shared medical appointments. We incorporated presentations as well as multidisciplinary rounding in a group setting to provide care for the participants. Patients were surveyed to measure satisfaction as well as knowledge of key prevention concepts. RESULTS: Appointment wait time decreased steadily from 180±77 days before shared medical appointments to 84±39 days. The number of patients seen per month increased by 43%. The number of new clinic patients, which includes those seen in shared medical appointments and in individual appointments, who received nutrition education and intervention increased from approximately 50% before shared medical appointments to nearly 75%. Patients who attended a shared medical appointment overwhelmingly (87%) rated their satisfaction as excellent or very good; 90% of patients said they would recommend this kind of visit to others. Posttests revealed that patients in shared medical appointments had superior knowledge (p<0.02) than controls. CONCLUSIONS: Shared medical appointments can be an efficient way to evaluate and manage new patients for urolithiasis prevention. Patient satisfaction was high and knowledge about prevention was higher than that of patients seen in individual appointments.