The July effect and cardiac surgery: the effect of the beginning of the academic cycle on outcomes

Background: The effect of the time of the academic year on cardiac surgical outcomes is unknown. Methods: Using prospectively collected data, we identified all (n = 1,673) cardiac surgical procedures performed at our institution between October 1997 and April 2007. Morbidity and mortality rates were compared between 2 periods of the academic year, one early (July 1-August 31, n = 242) and one later in the year (September 1-June 30, n = 1,431). A prediction model was constructed by using stepwise logistic regression modeling. Results: Morbidity rates did not differ significantly between the early (12.8%) and later periods (15.4%) (odds ratio [OR], 0.83; 95% confidence interval [CI], 0.54-1.28; P = 0.3). Additionally, there was no significant difference in operative mortality between the early (1.2%) and later periods (3.5%) (OR, 0.28; 95% CI, 0.07-1.19; P = 0.06). Conclusions: The early and later parts of the academic year were associated with similar risk-adjusted outcomes. Further studies are needed to determine whether our findings are applicable to other academic cardiac centers.