Omar M et al, 2015: Does stone removal help patients with recurrent urinary tract infections?
Omar M, Abdulwahab-Ahmed A, Chaparala H, Monga M.
Glickman Urological and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio.
PURPOSE: To evaluate the impact of surgical extraction of non-obstructing asymptomatic stones on recurrent urinary tract infections, and identify predictors of patients who may be rendered infection-free.
MATERIALS AND METHODS: A retrospective chart review identified patients with recurrent UTIs that underwent surgical stone extraction and were rendered stone-free. Demographic variables as well as procedure, infectious etiology, stone composition, and SIRS rate were also
recorded. Patients were divided into two groups; the 1st group had no evidence of recurrent infection following surgery while the 2nd group developed recurrent infection. Univariate analysis was performed using Wilcoxon's signed-rank test and Fisher's exact test. Logistic regression was used for multivariate analysis.
RESULTS: 120 patients with recurrent UTIs and a non-obstructive renal stone were identified. Surgical management included SWL (32%), URS (7%), and PCNL (61%). 48% (58/120) remained infection-free after surgery, while 52% (62/120) had a recurrence of infection. Factors associated with a higher risk of recurrent infections included type 2 DM (OR 1.73, p=0.01), hypertension (OR 2.8, p=0.007), and African-American ethnicity (OR13.7, p=0.009). E.coli infections were more likely to resolve (OR 0.34, p=0.01). In contrast, Enterococcus infections were more likely to persist (OR 2.5, p=0.04). Upon analysis via multiple logistic regression analysis, only race, HTN, and presence of E. coli infections were significant predictors of infection clearance.
CONCLUSIONS: 50% patients with recurrent UTIs and asymptomatic renal calculi may be rendered stone-free following extraction. Patients with risk factors for recurrent infections after surgery should be counseled that stone extraction might not eradicate their infection.
J Urol. 2015 Oct;194(4):997-1001. doi: 10.1016/j.juro.2015.04.096. Epub 2015 Apr 30.
The conclusion is wrong:” 50% patients with recurrent UTIs and asymptomatic renal calculi may be rendered stone-free following extraction”. All patients were rendered stone free. They wanted to say “… may be rendered infection free”
The authors statement “The relationship between nephrolithiasis and UTI is unclear” remains valid after having read the article. “Unfortunately the likelihood that recurrent UTIs will be eradicated with removal of asymptomatic renal calculi approaches 50%,” Thus the predictive value of stone removal to eradicate infection is like flipping a coin. I do not agree that “this study identifies specific risk factors for failure to eradicate infections” There are no causal but only statistical relations offered.
“ESWL’s bactericidal effect has been studied in the hopes of utilizing the shockwaves for clearance of recurrent infections associated with stones. Results of in-vivo studies have ranged from a 0-82% decrease in bacterial viability, though differences in experimental models make direct comparisons difficult”. There are no references given for this statement.