Comparison of Long-Term Pneumonia Risk between Spleen Injury and Non-Spleen Injury after Total Splenectomy-A Population-Based Study.

Patients who undergo splenectomy are at a high risk of infection. We aimed to investigate the rate of pneumonia in patients who underwent splenectomy, specifically comparing those who had splenectomy due to spleen injury and those who had it for other reasons. A population-based cohort study was conducted. Overall, 17,498 patients who underwent splenectomy between 2000 and 2015 were enrolled, including 11,817 patients with a history of spleen injury and 5681 controls without spleen injury. The incidence of pneumonia was calculated at the end of 2016. A multivariable Cox proportional hazards regression model was used to compare the hazard ratio with 95% CI for pneumonia associated with the spleen injury-caused splenectomy and splenectomy due to other causes. The crude HR for patients with splenectomy due to spleen injury to develop pneumonia was 1.649. After adjusting for covariates, the adjusted hazard ratio was 1.567. There were statistically significant differences in all subgroups, except for the group with a tracking duration >10 years. We found an increase in pneumonia risk in the 'spleen injury' group when comparing it to that of the 'other causes' group, regardless of age, sex, and area of residence.