Longitudinal changes in peak urinary flow rates in a community based cohort

Purpose: We describe longitudinal changes in peak urinary flow rates in com munity dwelling men in Olmsted County, Minnesota. Materials and Methods: A cohort of 2,115 men 40 years old or older was rand omly selected from the Olmsted County, Minnesota population. Peak urinary f low rates and the American Urological Association symptom index were assess ed in all men at baseline and biennially, and in a 25% random subsample pro state volume was determined by transrectal ultrasonography. The annualized percentage change in peak urinary flow rate (slope) was assessed for 492 me n in the subsample during 6 years of followup. Results: Median peak urinary flow rate slope was -2.1% per year (25th perce ntile -4.0, 75th percentile -0.6). Peak urinary flow rate declined more rap idly with decreasing baseline rate, and increasing baseline age, prostate v olume and symptom severity (all p = 0.001). When the variables were simulta neously adjusted for each other, a rapid decline (negative slope 4.5% or gr eater per year) was more likely in men 70 years old or older (odds ratio 46 .4, 95% confidence intervals 16.8, 127.7) and those with a rate less than 1 0 ml, per second (42.0, 14.1, 125.3) at baseline compared to those 40 to 49 years old and those with a rate of 15 ml. or greater, respectively. Prosta te volume and symptom severity were not statistically significant predictor s of a rapid decline in peak urinary flow rate when variables were consider ed simultaneously. Conclusions: Despite variability in measurement of peak urinary flow rate, a consistent decline was observed when measured longitudinally in a communi ty based cohort, Furthermore, this decline was associated with impairments in other physiological and anatomical measures of lower urinary tract funct ion in an unselected cohort of men.