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Risk Factors Associated With 30-day Readmissions After Instrumented Spine Surgery in 14,939 Patients: 30-day readmissions after instrumented spine surgery

Akins, Paul T., MD, PhD*; Harris, Jessica, MS, RD; Alvarez, Julie L., MPH; Chen, Yuexin, BS; Paxton, Elizabeth W., MA; Bernbeck, Johannes, MD*,†; Guppy, Kern H., MD, PhD*

doi: 10.1097/BRS.0000000000000916
Health Services Research

Study Design. A retrospective review of instrumented spine registry from an integrated US healthcare system.

Objective. Investigate the 30-day readmission rate and risk factors after instrumented spine surgery.

Summary of Background Data. Published readmission rates range from 2% to over 20%. We were interested in learning which patients were at greatest risk, when did readmissions occur, and why.

Method. 30-day readmission rates were determined for 14,939 patients after an index spine procedure between 1/2009 and 3/2013. Data were analyzed with descriptive statistics, univariate, and multivariate logistic regression analysis.

Result. The average age of the cohort was 59 (SD = 13.4) and 52% were female. The 30-day readmission rate was 5.5% (821/14,939). The temporal pattern for readmission was: 17% (140) at week 1, 48% (394) at week 2, 72% (591) at week 3, and 100% (821) at week 4. The leading causes were wound complications (infection, hematoma, dehiscence, seroma), sepsis, pain management, pneumonia, and pulmonary emboli/deep venous thrombosis. In a multivariate model, readmission risk factors were: malignancy (OR 2.99, 95% CI: 1.56, 5.73), operative time more than 400 minutes (OR 2.59, 95% CI: 1.66, 4.02), operative time 300–399 minutes (OR 2.33, 95% CI: 1.54–3.52), hospital stay 6–10 days (OR 2.03, 95% CI: 1.31–3.14), hospital stay more than 10 days (OR 1.85, 95% CI: 1.1, −3.08), surgical complications (OR 1.67, 95% CI: 1.18, 2.36), operative time 200–299 (OR 1.52, 95% CI: 1.04, 2.22), depression (OR 1.48, 95% CI: 1.14, 1.93), rheumatoid arthritis (OR 1.45, 95% CI: 1.05, 2.01), deficiency anemia (OR 1.30, 95% CI: 1.05, 1.61), and hypothyroidism (OR 1.29, 95% CI: 1.01, 1.64).

Conclusion. Surgical complications (dural tear, deep infections, superficial infections, epidural hematoma), malignancy, lengthy operative times, and lengthy initial hospitalizations are all risk factors for 30-day readmission. These findings should be considered during preoperative assessment and surgical planning.

Level of Evidence: 3

30-day readmissions were determined for 14,939 patients after spine surgery. Surgical complications (dural tear, deep and superficial infections, epidural hematoma), malignancy, lengthy operative times, and long hospitalizations are all risk factors. The timing for readmission was: 17% at week 1, 48% at week 2, 72% at week 3, and 100% at week 4.

*Kaiser Permanente Neurosurgery, 2025 Morse Avenue, Sacramento, CA95825; and

Kaiser Permanente Spine Implant Registry, San Diego, CA.

Address correspondence and reprint requests to Paul T. Akins, MD, PhD, Kaiser Neurosurgery, 2025 Morse Ave, Sacramento, CA 95825; E-mail:

Acknowledgment date: November 24, 2014. First revision date: February 2, 2015. Acceptance date: March 15, 2015.

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

Relevant financial activities outside the submitted work: grants.

Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.