Overactive Bladder Patients With and Without Urgency Incontinence: A Spectrum of One Condition or Different Phenotypes?

Importance: The importance of this study is to explore potential differences in pathophysiologies of OAB-wet and OAB-dry.
Objectives: The aim of this study was to define fundamental and unique presenting features of patients exhibiting storage lower urinary tract symptoms (LUTS) with urgency incontinence (OAB-wet) and patients without urgency incontinence (OAB-dry).
Study Design: This was a secondary analysis of cross-sectional data from the National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Diseases-sponsored Symptoms of Lower Urinary Tract Dysfunction Research Network. Demographic, physical examination, and questionnaire responses were analyzed for women seeking care for LUTS at 6 U.S. centers. Differences between OAB-wet and OAB-dry patients were compared using the Fisher exact test and Mann-Whitney U test. Differences in questionnaire data were assessed using a Benjamini-Hochberg false discovery rate correction.
Results: Fifty-six, 84, and 67 women were included in the OAB-dry, wet, and control cohorts, respectively. There was no difference in demographic and physical examination characteristics of the 2 groups. OAB-wet patients reported more urgency incontinence symptoms (LUTS 16a, P < 0.001). OAB-dry reported more bladder pain, feeling of incomplete bladder emptying (LUTS 4, P < 0.001), and a need to strain to urinate (AUA-SI 7, P = 0.003). Sensation of incomplete emptying and straining with urination did not correlate with elevated postvoid residual volumes. Although degrees of symptomatic bother were similar, bother in OAB-dry patients was most closely related to pelvic floor tenderness severity, whereas bother in OAB-wet patients was most related to urgency severity.
Conclusions: Women with OAB-dry have distinct presenting features of straining with urination, bladder pain, and a feeling of incomplete emptying. These suggest a unique pathophysiology driving OAB-dry symptoms, which we hypothesize is pelvic floor myofascial dysfunction.
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