Methods
We conducted a multicenter point prevalence survey of hospitalised patients. Between 4th of April 2019 and 14th of June 2021, a total of 1486 hospital inpatients were surveyed at five government-funded hospitals and two privately-funded hospitals in Cape Town South Africa. The government-funded hospitals included Groote Schuur Hospital (GSH, tertiary level), Red Cross Memorial Children’s Hospital (RXH, paediatric tertiary level), and three secondary level Hospitals - Victoria Wynberg Hospital (VWH), New Somerset Hospital (NSH), and Mitchells Plain Hospital. The two privately-funded hospitals were Christiaan Barnard Memorial Hospital (CBH) and University of Cape Town Academic Hospital (UCTPAH) (Figure 1, Table 1, see Appendix for descriptions of hospitals) .
This study was approved by the Human Ethics Research Counsel of the University of Cape Town (UCT) (HREC: 417/2019) and the Netcare Research Operations Committee. The delay in conducting the final surveys was due to the COVID-19 pandemic, as six of the surveys were performed in between the second and third COVID-19 waves in South Africa.
Point prevalence surveys were conducted after-hours to ensure that all inpatient prescription chart were available for review. All hospital inpatients on the day of the survey had basic demographic information (date of birth and gender) captured via electronic case record form (eCRF) but detailed medical information was only captured for patients who reported a BLA or non-beta-lactam (BL) antibiotic allergy. Medical information included documentation of antibiotic allergies in the patients notes and prescription charts, description of the allergic event, and review of information on the antibiotic prescription chart. Classification of patients with a self-reported BLA was completed by an allergist after completion of all surveys using the PEN-FAST tool. The PEN-FAST BLA phenotype clinical decision tool (developed by Trubiano et al(15)) has a high negative predictive value of 96.3% (95% CI 94.1-97.8%) (15, 17). The major criteria for the PEN-FAST tool are: the allergy event occurring within the preceding five years (2 points); anaphylaxis, angioedema or severe cutaneous delayed reactions (2 points). A single minor criterion of whether the allergic reaction required treatment scores 1 point. The PEN-FAST tool has a validated area under the curve of 0.805 (for a cut-off of 3 points chosen to classify as low risk of penicillin allergy) (15). The novel PEN-FAST BLA clinical decision mobile app was used by investigators to classify patients as low risk (1-5%), moderate risk (20%), or high risk (50%) of a positive penicillin allergy test.
Descriptive statistics were performed using counts and proportions for categorical data, and medians and interquartile ranges for continuous variables. All statistical analyses were conducted using STATA version 14 (STATA Corp., College Station, TX, USA).