Splenectomy and the Risk of Sepsis A Population-Based Cohort Study

Objective: We sought to estimate the long-term risk of sepsis in patients who underwent splenectomy before, during, and after implementation of vaccination. Background: Because patients who have undergone splenectomy are considered at increased risk of bacterial sepsis, they typically receive vaccination, education, and occasionally antibiotic prophylaxis. However, the extent to which these interventions have actually reduced the risk of sepsis remains unclear. Methods: Retrospective cohort study encompassing all patients in the Swedish national inpatient register, who underwent splenectomy in 1970-2009. Patients were followed for hospitalization for or death from sepsis, as identified using national inpatient and cause of death registers. Relative risks, comparing patients to the background population were expressed as standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs). Results: Altogether, 20,132 splenectomized patients were included. The overall SIR for hospitalization for sepsis was 5.7 [95% confidence interval (CI), 5.6-6.0]. However, risks depended on the indication for splenectomy, with SIRs varying from 3.4 (95% CI, 3.0-3.8) for trauma patients to 18 (95% CI, 16-19) for patients with hematologic malignancies. SMRs ranged from 3.1 (95% CI, 2.1-4.3) for trauma to 8.7 (95% CI, 6.8-11) for hematologic disease. In regression analyses adjusting for age at splenectomy, follow-up time, sex, and calendar year of splenectomy, there were no significant risk decreases after implementation of routine vaccination, except for in patients with malignant and non-malignant hematologic disease. Conclusions: The risk of hospitalization or death from sepsis is high in patients who previously underwent splenectomy and depends on the indication for splenectomy. The effectiveness of current vaccination practices warrants further evaluation.