Potential for Urolithiasis-related Research Using the Novel Medicare-Litholink Database.

INTRODUCTION: To overcome the data availability hurdle of observational studies on urolithiasis, we linked claims data with 24-hour urine results from a large cohort of adults with urolithiasis. This database contains the sample size, clinical granularity, and long-term follow-up needed to study urolithiasis on a broad level. METHODS: We identified adults enrolled in Medicare with urolithiasis who had a 24-hour urine collection processed by Litholink (2011 to 2016). We created a linkage of their collections results and paid Medicare claims. We characterized them across a variety of sociodemographic and clinical factors. We measured frequencies of prescription fills for medications used to prevent stone recurrence, as well as frequencies of symptomatic stone events, among these patients. RESULTS: In total, there were 11,460 patients who performed 18,922 urine collections in the Medicare-Litholink cohort. The majority were male (57%), White (93.2%), and lived in a metropolitan county (51.5%). Results from their initial urine collections revealed abnormal pH to be the most common abnormality (77.2%), followed by low volume (63.8%), hypocitraturia (45.6%), hyperoxaluria (31.1%), hypercalciuria (28.4%), and hyperuricosuria (11.8%). Seventeen percent had prescription fills for alkali monotherapy, and 7.6% had prescription fills for thiazide diuretic monotherapy. Symptomatic stone events occurred in 23.1% at 2 years of follow-up. CONCLUSIONS: We successfully linked Medicare claims with results from 24-hour urine collections performed by adults that were processed by Litholink. The resulting database is a unique resource for future studies on the clinical effectiveness of stone prevention strategies and urolithiasis more broadly.

Medical expulsive therapy versus early endoscopic stone removal for acute renal colic: an instrumental variable analysis.

PURPOSE: The use of medical expulsive therapy to hasten stone passage potentially decreases expenditures around episodes of renal colic. However, these efficiency gains may be mitigated if patients treated with medical expulsive therapy have frequent health care encounters due to pain while waiting for the stones to pass. MATERIALS AND METHODS: Using claims data (2002 to 2006) we identified adult men with acute renal colic. We compared 6-week payments as well as frequency of hospitalization and emergency department revisits associated with an initial course of medical expulsive therapy with those for early endoscopic stone removal. To account for unmeasured confounding we performed an instrumental variable analysis, exploiting variation in recommended treatments based on the day of the week that a patient's first emergency department visit occurred. RESULTS: Overall 1,835 and 4,397 men underwent medical expulsive therapy or early endoscopic stone removal, respectively. Although minimal differences existed between men with respect to the day of the week of emergency department presentation, weekend encounters were strongly associated with receiving medical expulsive therapy (p <0.001). Two-stage least squares regression revealed 6-week payments to be tenfold lower for men on medical expulsive therapy who were candidates for either treatment (p <0.001). While there was no difference in frequency of hospitalization, these men were more likely to have a repeat emergency department visit compared to those who underwent endoscopic stone removal (68.8% vs 39.6%, respectively, p = 0.025). CONCLUSIONS: Findings on medical expulsive therapy are mixed, with lower 6-week payments but more frequent repeat emergency department visits. These data inform patients who are candidates for medical expulsive therapy or endoscopic stone removal when making decisions about their care.

The risk of urolithiasis recurrence may be reduced with anti-nanobacterial therapy.

Urolithiasis is a common disorder responsible for serious human suffering and economic cost to society. Approximately 13% of men and 7% of women in the United States will be diagnosed with urolithiasis at some time in their lives with a recurrence rate of more than 50% in 5 years. Even if some risk factors are defined for stone formation, none of them can fully explain the etiopathogenesis. A controversial pathogen bacteria called 'nanobacteria' (NB) has been associated with several diseases including stone formation in some studies. It is thought to be the nidi for the stone formation after its' isolation from the renal stones and the occurrence of the stone after the percutaneus renal injection of NB. The clinical trials demonstrated that the eradication of NB prevented the calcifications in coronary arteries and prostate with an acceptable level by performing a novel combination therapy called 'ComET' which comprises a tetracycline antibiotic, nutraceutical and EDTA. Based on these findings, we hypothesize that the risk of urolithiasis recurrence may be reduced with combined anti-nanobacterial therapy. Long term prospective studies should be designed for evaluating the patients with positive NB cultures. If our hypotheses can be further supported with clinical trials it may change the approach of the medical management for urolithiasis.