Do risk factors for acute whiplash injury also predict non-recovery? a case-control study

Study Design Case-control study of persons having suffered whiplash injury. Objective Toassess the degree to which three putative risk factors—gender, age, and collision vector—can influence recovery after whiplash injury. Summary of Background Data While the extant literature is consistent with a 2:1 acute whiplash injury ratio between females and males, it is inconsistent in terms of whether adifferential risk exists between females and males for non-recovery (i.e., chronicity). It is also ambiguous in terms of the risk potential for aging and collision vector. Methods Binary multivariate logistic regression analysis was used to determine the effect of three predictor variables (sex, age, and collision vector) upon the binary outcome variable of recovery/non-recovery in 123 subjects previously suffering whiplash injuries. Subjects were recruited from 12 private clinics in the U.S. The sample comprised 55% females and 45% males aged 18-68 years of age. The 64% who had not recovered and the 36% who had recovered comprised the cases and controls, respectively. Results No statistically significant predictive regression model could be developed, nor were there any statistically significant correlations despite adequate statistical power. Varying levels of evidence exist indicating that female gender, increasing age, and rear impact vector predict acute injury risk, but, on the basis of this study, they do not appear to predict non-recovery. Conclusions: One earlier study demonstrated that females are injured acutely at approximately double the rate of males. But apart from their higher risk threshold, once injured, males have a roughly equivalent risk for non-recovery. The current study supports this finding and suggests, a fortiori, the same unidirectional relationship for age and crash vector: increasing age and a rear impact vector probably do increase the risk for acute injury, but, once an injury has occurred, these factors do not predict non-recovery.