Regression to the mean occurs in measuring peak urinary flow

Area of Science:

• Urology
• Andrology
• Medical Diagnostics

Background:

• Benign prostatic hyperplasia (BPH) is a common condition affecting aging men.
• Accurate diagnostic methods are crucial for effective BPH management.
• Maximum urinary flow rate (Qmax) is a key urodynamic parameter.

Purpose of the Study:

• To investigate the phenomenon of increased maximum urinary flow rates (Qmax) observed in men referred to a prostate diagnostic clinic.
• To understand the underlying causes of these anomalous Qmax increases.

Main Methods:

• A cohort of 1994 men aged 40-79 with suspected BPH underwent urodynamic assessments.
• Assessments were conducted at community health centers, upon referral to a diagnostic clinic, and at a one-year follow-up.
• Men were referred based on Qmax (< 15 mL/s) and/or urinary symptoms.

Main Results:

• Men referred to the clinic showed a statistically significant mean increase in Qmax at the clinic and one-year follow-up.
• No significant Qmax changes were observed in men referred without pre-selection based on low Qmax.
• These findings suggest a regression to the mean effect.

Conclusions:

• Patient selection based on low maximum flow rate (Qmax) can lead to regression to the mean.
• Isolated low Qmax values should not be solely relied upon for diagnosing BPH.
• Clinical interpretation of Qmax requires consideration of potential regression to the mean biases.