Authors’ Disclosure Statement: The authors report no actual or potential conflict of interest in relation to this article.
Dr. Alvi is an Adult Joint Reconstruction Orthopedic Surgeon, Barrington Orthopedic Specialists, Schaumburg, Illinois. Dr. Thompson is Assistant Professor, Department of Orthopaedic Surgery, and Associate Director, Center for Cerebral Palsy, David Geffen School of Medicine, The University of California, Los Angeles, Los Angeles, California. Dr. Krishnan is a General Surgery Resident, Lenox Hill Hospital/Northwell Health, New York, New York. Dr. Kwasny is Professor of Preventive Medicine, Department of Preventive Medicine, Biostatistics Collaboration Center, Northwestern University, Chicago, Illinois. Dr. Beal is Associate Professor and Program Director; and Dr. Manning is Associate Professor and Vice Chairman Department of Orthopaedic Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
Address correspondence to: Hasham M. Alvi, MD, Barrington Orthopedic Specialists, 929 W. Higgins Road, Schaumburg, IL 60195 (tel, 847-285-4200; email, Halvi@barrringtonortho.com).
Hasham M. Alvi, MD Rachel M. Thompson, MD Varun Krishnan, MDMary J. Kwasny, ScD Matthew D. Beal, MD David W. Manning, MD . Time-to-Surgery for Definitive Fixation of Hip Fractures: A Look at Outcomes Based Upon Delay. Am J Orthop.
September 7, 2018
References
METHODS AND MATERIALS
This study used the data from the American College of Surgeon-National Surgical Quality Improvement Program (ACS-NSQIP) database. With over 258 participating hospitals, this database has been widely used to identify national trends in various surgical specialties.27-34 The database includes information from participants in 43 states with hospitals ranging from rural community hospitals to large academic centers. Each site employs surgical clinical reviewers who are rigorously trained to collect data through chart review and discussion with the treating surgeon and/or patient,35 allowing for the use of robust and quality data with proven inter-rater reliability.36,37
Using the 2011 to 2012 NSQIP database, we used primary Current Procedural Terminology codes to identify all patients who underwent percutaneous (27235) or open (27236) fixation of femoral neck fractures; and fixation with a screw and side plate (27244) or intramedullary fixation (27245) for peritrochanteric fractures. The sample was divided into 3 time-to-surgery groups (<24 hours from presentation to surgery, 24-48 hours, and >48 hours) which were matched for fracture type (femoral neck or peritrochanteric), sex, age (under 75 years or ≥75 years), and American Society of Anesthesiologists (ASA) class used as a surrogate for severity of medical infirmary. The subjects were randomly matched 1:1:1 to create 3 statistically equivalent time-to-surgery groups using Proc SurveySelect (SAS version 9.2, SAS Institute).
Generalized linear models using logit link function for binary variables and identity link function for normally distributed characteristics were used to compare the 3 time-to-surgery groups. Descriptive statistics are presented as counts and percentages or least-square means with standard deviations. Preoperative lab values that were not normally distributed were log transformed and presented in their original scales with median values and 25th to 75th percentiles. Outcomes were similarly modeled.
Total hospital stay was modeled with a negative binomial distribution. Proportional hazards models were used to model the time from operating room (OR) to discharge, censoring patients who died before discharge, with results presented as hazard ratios (HR) and 95% confidence intervals (CI) (Figure). The assumption of the proportional hazards was tested using a Wald test. Using this model, a HR of <1 denotes a longer postoperative hospital stay, as a longer hospital stay decreases the “risk” for discharge.
All models were adjusted for confounders, including race, body mass index (BMI), hypertension, chronic obstructive pulmonary disease, cancer, bleeding disorders, transfusion within 72 hours before surgery, preoperative levels of creatinine, platelet count, white blood cells (WBCs), hematocrit anesthesia type, and wound infection. These covariates were selected based upon their observed relationship to the studied outcomes and time-to-surgery groups, and were evaluated across the models for all outcomes for consistency and clarity. All statistical analyses were run at a type I error rate of 5% and performed in SAS version 9.2 software.
