Nephrology & Urology Xagena

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Patients with lower urinary tract symptoms / benign prostatic hyperplasia and small prostate volume: urodynamic features and significant predictors of bladder outlet obstruction

A study has investigated the clinical and urodynamic features of patients with lower urinary tract symptoms/benign prostatic hyperplasia ( LUTS/BPH ) according to their prostate size.

Researchers analyzed 2,039 LUTS/BPH patients who underwent urodynamic study between October 2004 and August 2013. the The patients were divided into three groups according to their prostate size: small ( less than or equal to 30 mL ), moderately enlarged ( 30-80 mL ), and large prostate ( greater than or equal to 80 mL ) groups.

The groups were compared regarding age, International Prostatic Symptom Score ( IPSS ), maximal flow rate ( Qmax ), post-void residual ( PVR ), serum prostate-specific antigen, prostate volume measured by ultrasonography, and urodynamic findings.

Patients with a small prostate had better urodynamic outcomes than those with larger prostates in overall population. Although the total prostate volume significantly correlated with the bladder outlet obstruction ( BOO ) index ( r = 0.51 ), BOO patients with a small prostate had similar Qmax, higher PVR and lower voiding efficiency, compared to those with larger prostates.

Moreover, urodynamic parameters indicating bladder abnormalities, including low compliance and involuntary detrusor contraction positivity, were similar among the groups in BOO patients.

A higher proportion of detrusor underactivity was also observed in the small prostate group in BOO patients.

Finally, when adjusting for potential confounding variables, researchers identified serum prostate-specific antigen levels ( odds ratio, 1.34 ) and Qmax ( odds ratio, 0.77 ) as significant predictors for bladder outlet obstruction in LUTS/BPH patients with a small prostate.

In conclusion, BOO patients with a small prostate showed higher PVR and poor voiding efficiency, as well as similar urodynamic bladder abnormalities, compared to those with moderately enlarged and large prostates. ( Xagena )

Kang M et al, Urology 2015; Epub ahead of print