Patient comorbidities and complications after spinal surgery: a societal-based cost analysis.

STUDY DESIGN: Prospective observational study. OBJECTIVE: To determine how patient comorbidities and perioperative complications after spinal surgery affect the health care costs to society. SUMMARY OF BACKGROUND DATA: Despite efforts to reduce adverse events related to spinal surgery, complications are common and significantly increased by patient comorbidities. METHODS: Patients who underwent spinal surgery at a tertiary academic center during a 6-month period (May 2008 to December 2008) were prospectively followed. All demographic data, comorbidities, procedural information, and complications to 30-day follow-up were recorded. Diagnosis-Related Group codes and Current Procedural Terminology codes were captured for each patient. Direct costs were estimated from a societal perspective, using 2008 Medicare rates of reimbursement. A multivariable analysis was performed to assess the impact of specific patient comorbidities and complications on total health care costs. RESULTS: A total of 226 cases were analyzed. The mean cost of care for cases with complications was greater than that for cases without complications ($13,518.35 [95% confidence interval (CI), $9378.80-$17,657.90]; P < 0.0001). These results were consistent across degenerative, traumatic, and tumor/infection preoperative diagnoses. Cases with major complications were more costly than those with minor complications ($13,714.88 [CI, $6353.02-$21,076.74]; P = 0.0001). Systemic malignancy and preoperative neurological comorbidity were each associated with an increase in the cost of care ($7919 [CI, $2073-$15,225]; P = 0.006] and $5508 [CI, $814-$11,198; P = 0.02]), respectively, when compared with a baseline cost of care derived from all cases in the database. The cost of care was increased by pulmonary complications ($7233 [CI, $3982.53-$11,152.88]; P < 0.0001), instrumentation malposition ($6968 [CI, $1705.90-$14,277.16]; P = 0.0062), new neurological deficit ($4537 [CI, $863.95-$9274.30]; P = 0.013), and by wound infection ($4067 [CI, $1682.79-$6872.39]; P = 0.0004), after adjustment for covariates. CONCLUSION: Both minor and major complications were found to increase the cost of care in a prospective assessment of spine surgery complications. Specific patient comorbidities and perioperative complications are associated with significant increases in the total cost of care to society.