10: Compared to what?: Statistical considerations for evaluating change in the urinary microbiome

Music City Center 

The discovery of the urinary microbiome has ignited investigations into the mechanisms of disease and potential interventions for improved bladder health. Characterizing a patient's "baseline" is key to properly evaluate change due to exposures and treatments such as probiotics, antibiotics, and surgical intervention. In our previously published prospective observational study, we found that urological surgery altered the urinary microbiome, with differences in recovery to baseline in premenopausal versus postmenopausal women. This study is a secondary analysis of these data, capitalizing on additional samples to describe assay variability, evaluate stability across multiple available baseline samples (screening, pre-operative), and estimate the minimal detectable change in key microbiome features (diversity indices and prevalence/relative abundance of specific microbes). These data can inform those conducting longitudinal clinical studies in this field, where for convenience a urine sample at a single timepoint is most often collected to establish a baseline. Power analyses and sampling design should account for expected variability of the dynamic ecosystem in the bladder.

microbiome

clinical research 

Biometrics Section