Introduction: D-mannose intake is used as a preventive measure against recurrent urinary tract infections (RUTIs) (1). However, response to D-mannose varies, and it is unknown if measuring baseline D-mannosuria can distinguish a group of favorable responders that may be targeted for long-term preventive therapy.
Methods: Following IRB approval, consecutive non-neurogenic women attending a specialized tertiary care center urology clinic with a history of RUTIs were invited to the study. Participants provided a urine sample (baseline), took their home-dose of D-mannose, and provided a second urine sample one hour later (post). Urine samples were processed according to a D-mannosuria assay technique reported previously by our group (2). Baseline ratios were compared to those post D-mannose to determine if the level had increased in the urine (responder) or not. Differences in age, ratio at baseline, and ratio after D-mannose intake between responders and non-responders were tested using Student t-tests.
Results: From July 2020 to March 2021, 26 patients met study criteria. Thirteen patients had a lower or unchanged ratio of baseline to post D-mannose, whereas 13 had an increase above 20% compared to baseline. In those taking 2 gm, 12 had a low or unchanged trend and 7 had a notable increase after one hour. Comparison of urinary baseline D-mannose/creatinine ratios was significantly different between the responder (mean = 0.337 ± 0.158) and (mean = 0.692 ± 0.444; p = 0.016) non-responder groups. Urinary post D-mannose/creatinine ratios did not significantly differ between the two groups (p = 0.46).
Conclusions: Baseline D-mannosuria was found to be significantly lower in those with an elevation above their baseline level, possibly suggesting an internal regulatory mechanism to add more D-mannose in urine to protect against bacterial invasion when the natural levels are low. Conversely, those with a high D-mannosuria level at baseline presumably did not need to add any more D mannose in their urine and therefore did not mount an added response in their urine upon taking D-mannose orally. This office based measurement can prove useful to determine the long-term efficacy of D-mannose intake in reducing RUTI episodes. 1.Kyriakides, R. Eur Urol Focus 2020 2.Mehta, I. Bioanalysis 2018
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