Introduction: The aim of this study was to investigate the effect of three major environmental variables (temperature, humidity, air pressure) on the probability of onset of renal colic (RC) in a large cohort of patients in Rome.
Methods: The records of 2682 patients discharged by the Emergency Department (ED) of the University Hospital of Tor Vergata, Rome, from January 2007 to November 2009 with the main diagnosis of reno-ureteric colic associated with a proven calculus, were retrospectively evaluated. The climatic parameters (average humidity, average air pressure and daily minimum, medium and maximum temperature) were recorded in a second, independent database. RC events were grouped by weeks and months and analysed for a total period of 35 months and 153 weeks.
Results: Two thousand five hundred and fourteen patients out of 2682 had a proven urolithiasis. RC events were observed more likely in the warmer months, from the second half of June to the first half of September, compared with the colder months. Although the weekly model showed a positive correlation (R2 = 0.134) between the average increase of environmental temperature and RC incidence, the monthly model was much more convincing (R2 = 0.373). We found no statistically significant correlation between humidity and air pressure and the incidence of RC.
Conclusions: This study demonstrates that an increase in average environmental temperature is associated with a significant increase in the number of episodes of RC seen in the ED at both weekly and monthly time intervals. The average humidity and air pressure were not found to be associated with an increased incidence of RC.