Prevalence of Antibiotic Allergy at a Spinal Cord Injury Center
Background: Infectious diseases are the most common reason for rehospitalization in patients with spinal cord injury (SCI). Persons with SCI are at high risk for antibiotic overuse and hospital-acquired infection due to chronic bacteriuria, frequent health care exposure, implanted medical devices, and other factors. We aimed to record the percentage of subjects from the local SCI registry with an antibiotic allergy, the most common antibiotic classes responsible for the allergy, and allergic reactions.
Methods: We conducted a retrospective study at the James A. Haley Veterans’ Hospital in Tampa, Florida, of patients in the SCI registry between October 1, 2015, and September 30, 2017. We collected patient demographics and SCI descriptors. The outcomes included antibiotic allergy and adverse drug reactions.
Results: Of 1866 patients, 1659 met inclusion criteria; 29.8% of the subjects had a recorded allergy to antibiotics. Penicillin (13.1%), sulfa drugs (9.6%), and fluoroquinolone (4.5%) were the most common allergens. However, only 11.9% of patients with a penicillin allergy had severe reactions.
Conclusions: Almost 30% of patients with SCI had a recorded allergy to an antibiotic. There are opportunities to examine whether approaches to confirm true reactions, such as skin testing, would help mitigate unnecessary avoidance of certain antibiotic classes due to mild adverse effects, rather than a true allergy, in the SCI population. Differentiating true allergy is the only clear way to deter unnecessary avoidance of first-line therapies for antibiotic treatment and avoid promotion of antibiotic resistance.
Methods
We performed a retrospective chart review of patients included in the local SCI registry between October 1, 2015, and September 30, 2017. We collected data on patient demographics (age, sex, race and ethnicity) and a description of patients’ injuries (International Standards for Neurological Classification of Spinal Cord Injury [ISNCSCI] and etiology of injury [traumatic vs atraumatic]). The outcomes included antibiotic allergy and ADRs.
In the EHR, allergies can be listed toward an antibiotic class or a specific antibiotic. An allergy to each specific antibiotic would be recorded separately; however, overlap among antibiotic classes was not duplicated. For example, if a subject has a listed antibiotic allergy to ceftriaxone and cefepime with listed reactions, we would record allergies to each of these antibiotics but would only report a single allergy to the cephalosporin subclass.
Since we did not differentiate hypersensitivity reactions (HSRs) from other ADRs, the reported reactions were grouped by signs and symptoms. There is a variety of terms used to report similar reactions, and best efforts were made to record the data as accurately as possible. Patient-reported history for risk stratification is a tool we used to group these historical reactions into high- vs low-risk for severe reactions. High-risk signs are those listed as anaphylaxis; anaphylactic reactions; angioedema presenting as swelling of mouth, eyes, lips, or tongue; blisters or ulcers involving the lips, mouth, eyes, urethra, vagina, or peeling skin; respiratory changes; shortness of breath; dyspnea; hypotension; or organ involvement (kidneys, lungs, liver).6
Inclusion criteria were all veterans who were diagnosed with tetraplegia or paraplegia and received annual evaluation between October 1, 2015, and September 30, 2017. We chose this period because it was the beginning of a financial year at the JAHVH SCI department using the SCI registry. The SCI annual evaluation is a routine practitioner encounter with the veteran, along with appropriate laboratory testing and imaging to follow up potential chronic health issues specific to patients with SCI. Annual evaluations provide an opportunity to maintain routine health screening and preventive care. Patients who had significant portions of data missing or missing elements of primary outcomes were excluded from analysis. The study was reviewed and approved by the University of South Florida Institutional Review Board (VA IRBNet #1573370-4 on September 9, 2019).
Results
Of 1866 patients reviewed, 207 (11.1%) were excluded due to missing data, resulting in 1659 records that were analyzed. Mean age was 64 years, and male to female ratio was about 10 to 1. Most of the SCI or diseases were classified as incomplete (n = 1249) per ISNCSCI (absence of sensory and motor function in the lowest sacral segments) compared with 373 classified as complete. 
Of the 1659 patients, 494 (29.8%) had a recorded allergy to antibiotics. The most frequently recorded were 217 penicillin (13.1%), 159 sulfa drugs (9.6%), 75 fluoroquinolone (4.5%), 66 cephalosporin (4.0%), and 44 vancomycin (2.7%) allergies. 
