Insurance status, geography, race, and ethnicity as predictors of anterior cervical spine surgery rates and in-hospital mortality: An examination of United States trends from 1992 to 2005

STUDY DESIGN. Retrospective cross-sectional study. OBJECTIVE. To determine the role of race, insurance status, and geographic location on US anterior cervical spine surgery rates and in-hospital mortality between 1992 and 2005. SUMMARY OF BACKGROUND DATA. Previous investigation indicates that anterior cervical spine surgery has been increasingly used in the management of degenerative cervical spine disease throughout the 1990s. Significant predictors of health outcomes, including race, ethnicity, geography, and insurance coverage have yet to be investigated in detail for these procedures. METHODS. Cases of anterior cervical spine surgery were identified from the Nationwide Inpatient Sample. The US population counts were taken from the Current Population Survey. Multivariate regression models were employed to describe national rates of anterior cervical spine surgery and model the odds of death among admissions for anterior cervical spine surgery. All models incorporated adjustment for hospital sample clustering, age, and comorbidity status. RESULTS. Based on an analysis of a total 100,286,482 hospital discharge records, an estimated 965,600 anterior cervical spine procedures were performed between 1992 and 2005 in the United States. During this period, rates of surgery increased by 289%. Though adjusted rates of surgery were lowest among minority populations, disparities decreased with time. The mean age of patients, as well as the average preoperative comorbidity status, increased with time. The odds of mortality did not significantly increase between 1992 and 2005. Odds of in-hospital death were greatest in among black patients (P < 0.001) and lowest in Southern states (P < 0.001) and patients with private insurance (P < 0.001). CONCLUSION. With the recent rise of anterior cervical spine procedures in the United States, substantial variation in the delivery of surgical care exists along a number of demographic factors. A detailed investigation of variation in surgical decision-making algorithms among spine specialists, as well as a determination of differences among patient populations in attitudes toward surgery, may help elucidate the trends observed in this study.