Surgical site infection in spinal surgery: description of surgical and patient-based risk factors for postoperative infection using administrative claims data.
METHODS
Retrospective analysis.


OBJECTIVE
The objective of this study was to investigate the accuracy of using an automated approach to administrative claims data to assess the rate and risk factors for surgical site infection (SSI) in spinal procedures.


BACKGROUND
SSI is a major indicator of health care quality. A wide range of SSI rates have been proposed in the literature depending on clinical setting and procedure type.


METHODS
All spinal surgeries performed at a university-affiliated tertiary-care center from July 2005 to December 2010 were identified using diagnosis-related group, current procedural terminology, and International Classification of Diseases, Ninth Revision (ICD-9) codes and were validated through chart review. Rates of SSI and associated risk factors were calculated using univariate regression analysis. Odds ratios were calculated through multivariate logistic regression.


RESULTS
A total of 6628 hospital visits were identified. The cumulative incidence of SSI was 2.9%. Procedural risk factors associated with a statistically significant increase in rates of infection were the following: sacral involvement (9.6%), fusions greater than 7 levels (7.8%), fusions greater than 12 levels (10.4%), cases with an osteotomy (6.5%), operative time longer than 5 hours (5.1%), transfusions of red blood cells (5.0%), serum (7.4%), and autologous blood (4.1%). Patient-based risk factors included anemia (4.3%), diabetes mellitus (4.2%), coronary artery disease (4.7%), diagnosis of coagulopathy (7.8%), and bone or connective tissue neoplasm (5.0%).


CONCLUSIONS
Used individually, diagnosis-related group, current procedural terminology, and ICD-9 codes cannot completely capture a patient population. Using an algorithm combining all 3 coding systems to generate both inclusion and exclusion criteria, we were able to analyze a specific population of spinal surgery patients within a high-volume medical center. Within that group, risk factors found to increase infection rates were isolated and can serve to focus hospital-wide efforts to decrease surgery-related morbidity and improve patient outcomes.
Department of Orthopaedic Surgery, University of California, San Francisco, CA 94143, USA. amir.abdul-jabbar@ucsf.edu
Amir
A
Abdul-Jabbar
Steven
S
Takemoto
Michael H
MH
Weber
Serena S
SS
Hu
Praveen V
PV
Mummaneni
Vedat
V
Deviren
Christopher P
CP
Ames
Dean
D
Chou
Philip R
PR
Weinstein
Shane
S
Burch
Sigurd H
SH
Berven
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002140:California / Q000453:epidemiology; D039702:Current Procedural Terminology; D016208:Databases, Factual / Q000706:statistics & numerical data; D003953:Diagnosis-Related Groups / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D038801:International Classification of Diseases; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000379:methods; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000706:statistics & numerical data; D012307:Risk Factors; D013131:Spine / Q000601:surgery*; D013530:Surgical Wound Infection / Q000453:epidemiology / Q000209:etiology*; D055815:Young Adult