Clinical Factors That Impact Peezy Midstream Urine Collection Device Failure

Objectives: For urobiome analysis, urine collection technique is important. The Peezy device is currently considered in NIH-funded urobiome studies, however, the device failure rates are consequential. Identifying factors that lead to Peezy failure may help guide its utilization. Our primary aim was to determine whether urine flow rate affects Peezy failure among a slow-urine flow rate group (cases) when compared to normal-flow controls. We hypothesized that cases have higher Peezy failure rates than controls. Our secondary aim was to identify clinical characteristics associated with Peezy failure.

Methods: We conducted a prospective cohort study between 6/1/23-7/30/23. Cases were >50 years-old with a history of Stage III/IV pelvic organ prolapse, prior sling, or documented urinary retention. Controls were 18-30 years-old, nulliparous, and without lower urinary tract symptoms. Baseline UDI-6 and demographics, urine flow rate (ml/s) and Peezy failure rate (inability to void or voided volume < 30ml) were collected. Logistic regression was used to analyze flow rate and collection failure. Univariate and multivariate was used to analyze remaining demographic variables.

Results: We enrolled 84 participants (42 cases and 42 controls). Eight cases were unable to void with Peezy, while all controls were able to void. Compared to controls, cases were older (median age 70.5 vs 25.5), had slower flow rates (median 2.0ml/s vs 11.6ml/s), and higher UDI-6 scores (median 18.8 vs 0). Among cases, every 1 ml/s increase in the flow rate decreased the odds of failure by 31.5% (OR = 0.69, 95% CI: 0.47 to 1.01; p = .06). For controls, every 1 ml/s increase in the flow rate decreased the odds of failure decreased by about 11% (OR = 0.89, 95% CI: 0.80 – 0.99; p = .04). (Figure 1). There was no significant difference between these two odds ratios (interaction p = .20). For cases, the vaginal birth rate was associated with Peezy failure (OR = 1.95, 95% CI: 1.01 – 4.40; p = .04), and they were also significantly more likely than controls to experience Peezy failure (OR = 8.2, 95% CI: 3.1 – 21.9; p < .001). However, this conclusion attenuated after adjusting for UDI and void volume (OR = 1.2, 95% CI: 0.3 – 5.1; p = .12). In fact, after adjusting for cohort status and UDI score, the odds of a Peezy failure declined by only about 4% for every 5-ml increase in the voided volume (OR = 0.96, 95% CI: 0.94 – 0.98; p = .001).

Conclusions: Flow rate was not sufficient to explain the chance of Peezy failure, however, increasing parity and decreasing voided volume were associated with higher probability of Peezy failure. Targeting patients with fuller bladder and lower parity may be ideal for Peezy use.