Seasonal variation in the occurrence of acute urinary retention

Objective: To determine whether acute urinary retention shows a seasonal variation. Methods: All acute urinary retentions observed in the emergency room of St. Anna Hospital, Ferrara, along an eight-year period (1991-1998) were considered. Diagnosis was made on the basis of history, physical examination, and bladder drainer by insertion of a catheter with registration of the retained urinary volume. The main determining cause of the acute urinary retention event was tentatively determined. Month and day of each event were categorized both by seasons and monthly intervals. For statistical analysis chi-square test for goodness of fit and partial Fourier series were used. Results: 1,133 acute urinary retention events were observed in 929 different subjects (871 males, 58 females). In 738 cases it was possible to define the main determining cause of the event. The seasonal distribution showed a higher frequency peak of events in summer and autumn both for total population and males subgroup. Analysis by determining cause of the event demonstrated a greater frequency of events in summer only in patients with prostatic hypertrophy. Chronobiologic evaluation showed a circannual pattern for acute urinary retention, both for total sample and male subgroup, with a significant peak in late summer (August-September). Analysis by main determining cause revealed a similar circannual pattern only for cases of acute urinary retention determined by prostatic hypertrophy. Conclusions: The present study shows that acute urinary retention exhibits a circannual distribution in its occurrence, particularly when caused by prostatic hypertrophy.