Clinical and economic burden of hospitalizations with registration of penicillin allergy.

Background: Penicillin allergy is commonly reported, but only a minority of claimants has a confirmed diagnosis. Nevertheless, patients labeled as having penicillin allergy are treated with second-line antibiotics, which are more expensive and less effective, possibly increasing the risk of drug-resistant infections.

Objective: To compare hospitalizations with and without registration of penicillin allergy concerning their morbidity and hospital resource use.

Methods: We analyzed a national administrative database containing a registration of all Portuguese hospitalizations from 2000 to 2014. All episodes occurring in adults with a penicillin allergy registration were compared with an equal number of hospitalizations without such registration and matched for inpatients' age, sex, and main diagnosis. We compared those episodes concerning their length of stay, hospital price charges, comorbidities, and frequency of drug-resistant infections. Differences between medical and surgical hospitalizations were explored.

Results: Hospitalizations with registration of penicillin allergy (n = 102,872) had a longer average length of stay than the remainder episodes (8 vs 7 days; P < .001) and higher hospital charges (3,809.0 vs 3,490.0 USD; P < .001). Inpatients with penicillin allergy registration also had a higher mean Charlson Comorbidity Index (0.91 vs 0.76; P < .001) and a significantly higher frequency of infections by several agents, including methicillin-resistant Staphylococcus aureus, Enterococcus species, and Escherichia coli. Among surgical episodes, septicemia was 1.2-fold more frequent among penicillin allergy cases.

Conclusion: Hospitalizations with registration of penicillin allergy are associated with increased economic costs and frequency of infections by drug-resistant agents, reinforcing the need to establish a correct diagnosis of penicillin allergy.