Asymptomatic Renal Calculi in Recurrent Urinary Tract Infections

Treatment of Asymptomatic Renal Calculi in Recurrent UTIs: a Prospective Observational Cohort Study

This study will assess patients who have recurrent urinary tract infections and kidney stones which are not blocking the kidney or causing other problems. Currently, we don't know if taking out these stones will improve recurrent urinary tract infections or not. Patients will make a decision with their surgeon about removing or monitoring their stone(s). Whether or not their infections continue with surgery or monitoring will be noted, and this information may help to inform future treatment decisions. The purpose of this study is to assess if treatment of these asymptomatic stones affects the rate of recurrent urinary tract infections.

Urinary tract infections (UTIs) are common and have a large burden of disease at the population level. This study will assess the effectiveness of removing kidney stones in patients who have recurrent UTIs.

The role of upper urinary tract calculi in UTIs is not well understood. Although there is some evidence that some metabolic stones, such as calcium oxalate, can harbor bacteria, it is not known if this is clinically significant or if these contribute to clinical infections.

This study aims to advance the level of evidence in the treatment of non-obstructing urolithiasis in the context of recurrent UTIs.

The aim of this study is to:

1. Assess the effects of treatment of non-obstructing upper urinary tract calculi on recurrent UTIs in the first prospective observational trial in this area

Patients who meet inclusion criteria will make a decision about treating their asymptomatic stones or not with their surgeon as per usual clinical care. The primary outcome will be the rate of recurrent urinary tract infections for patients, comparing patients who did and did not have their stones treated.

Patient data is securely stored in de-identified fashion in REDCAP database, following all the secure protocols of the institutions involved. The recruitment goal is 80 patients based on power calculations to detect the effect size. Statistical analysis will be performed between the two groups, with t-test used for normally distributed numerical data and fisher's exact or chi-square tests for categorical data.

Inclusion Criteria (all of the following):

• recurrent UTIs, defined as 3 positive urine cultures of specific organisms with symptoms within 12 months (or 2 positive cultures with symptoms within 6 months) prior to clinical assessment
• non-obstructing renal stone(s) on imaging within 6 months of initial visit

Exclusion Criteria:

• age < 18 years
• pregnancy
• hydronephrosis or evidence of obstruction
• presence of a foreign body in urinary tract (e.g. Foley, ureteral stent, nephrostomy tube) at the time of UTI diagnosis
• concurrent bladder calculi
• Urinary diversion or previous surgery involving segments of bowel interposed into the urinary tract (ileal conduit, ileal ureter etc.)