Do weather conditions influence the onset of renal colic? A novel approach to analysis.

BACKGROUND/AIM To investigate the seasonal variations of the incidence of renal colic by a computerized analysis of cyclic climatic features. METHODS 1,163 consecutive patients with acute renal colic were studied. Eigendecomposition and signal reconstruction of district temperature and humidity were performed to establish any cyclic variation. Average temperatures and humidity values were calculated at time periods of 15, 30, 45 and 60 days preceding each renal colic. RESULTS Patients were allocated to groups every 30 days, since eigendeanalysis suggested that intervals of this duration have homogeneous climatic features. With an average time period of 15 days preceding each renal colic, a positive correlation coefficient of temperature (r = +0.75 with CI 0.31-0.93, p < 0.005) and a cubic relationship at the regression analysis (R = 82.4%, p = 0.015) were found with the onset of colics. We observed a negative correlation between humidity and renal colic (rho = -0.70 with CI -0.92 to -0.21, p < 0.01), with an inverse relation as regression model (R = 57.9%, p < 0.05). CONCLUSIONS We demonstrated an association between the onset of renal colics and exposure to hot and dry weather, particularly when temperatures rose above 27 degrees C and relative humidity fell below 45%.