Mortality risk in splenectomised patients: a Danish population-based cohort study.

Background: The extent and magnitude of mortality risk among patients splenectomised for a variety of indications is not well-described in the literature. We assessed mortality risk among splenectomised patients compared to the general population and to un-splenectomised patients with similar underlying medical conditions.

Methods: We conducted a historical population-based cohort study in Denmark between January 1, 1996 and December 31, 2005. Mortality risk was evaluated within 90 days, 91-365 days, and >365 days post-splenectomy, controlling for age, sex, and comorbid conditions using Cox proportional hazards models for a splenectomised cohort compared to the general Danish population and a matched indication cohort.

Results: We identified a total of 3812 splenectomised patients, 38,120 population comparisons, and 8310 matched indication comparisons. Within 90 days post-splenectomy, the adjusted relative risk (RR) for death, regardless of indication, was highly elevated compared to the general population: RR 33.6 [95% confidence interval (CI): 6.9, 35.0]. This risk declined substantially after 90 days post-splenectomy but remained higher 365 days post-splenectomy for all indications compared to the general population. When compared to the matched indication cohort, short- and long-term mortality risk with splenectomy was not increased.

Conclusion: Regardless of indication, the adjusted short- and long-term risk of death for splenectomised patients was higher than the general population. Most of this risk seems to be due to the underlying splenectomy indication and not to splenectomy alone.