Lack of Association Between Barometric Pressure and Incidence of Colic in Equine Academic Ambulatory Practice

Anecdotal accounts correlate equine colic onset to changing weather conditions; however, atmospheric effects on colic have not been studied extensively. We hypothesized that changes in barometric pressure would increase the likelihood of a colic diagnosis compared with other noncolic sick events. Multivariable logistic regression analysis was used to look for associations between colic diagnosis and barometric pressure. The University of Pennsylvania Field Service electronic medical records were searched by identifiable examination type via billing procedure codes collecting 3,108 emergent and nonemergent medical events along with corresponding weather data from the National Weather Service from January 1, 2005, through January 1, 2017. Barometric pressure values and changes were not found to be statistically associated with a diagnosis of colic (P = .1). Horses that did not survive were almost 12 times more likely to have a diagnosis of colic (odds ratio [OR]: 11.97; P < .0001). Horses with disease recurrence were 30% more likely to have a diagnosis of colic (OR: 1.29; P = .006). The likelihood of colic diagnosis increased with increasing latitude (OR: 2.43; P = .04). Horses were more likely to be diagnosed with colic in the fall (OR: 1.72; P < .0001), spring (OR: 1.29; P = .04), and summer (OR: 1.85; P < .0001), compared with winter. Stallions were 48% less likely to colic compared with mares (OR: 0.52; P = .016) and Quarter Horses were 32% less likely to colic compared with Thoroughbreds and Arabians (OR: 0.68; P = .047). This study provided evidence that changes in barometric pressure were not a contributing risk factor for colic, although seasons with changing weather and latitude may play a role.