Thomas J Marrie1, Gregory J Tyrrell2, Sumit R Majumdar3, Dean T Eurich4. 1. Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada. 2. Division of Diagnostic and Applied Microbiology, Department of Laboratory Medicine and Pathology, University of Alberta, and The Provincial Laboratory for Public Health, Edmonton, Alberta, Canada. 3. Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada. 4. School of Public Health, University of Alberta, 2-040 Li Ka Shing HRIF, Edmonton, Alberta, T6G 2E1, Canada. Electronic address: deurich@ualberta.ca.
Abstract
OBJECTIVES: Most are aware of pneumococcal infection as a complication of splenectomy and the increased risk of severe invasive pneumococcal disease (IPD) in asplenic patients. However little is known of the current status of this entity in a population with an active pneumococcal conjugate vaccine program for children. METHODS: All IPD cases reported from 2000 to 2014 in Northern Alberta, Canada were collected prospectively. Socio-demographic variables, clinical characteristics, and IPD-related outcomes were compared between patients with and without a spleen using the Student t-test, Chi-square test, or Fisher's exact test, as appropriate. RESULTS: Thirty-seven of 2435 patients with IPD (1.5%) were asplenic. Asplenic patients were significantly more likely to require mechanical ventilation or admission to the intensive care unit and had more complications (e.g., acute kidney injury). However, in-hospital mortality rates were similar in those with and without a spleen (19% vs. 16%, p=0.58). Pneumococcal serotype 22B was 33-fold higher in asplenic patients compared to those with a spleen. CONCLUSIONS: In patients with IPD, those who are asplenic have a more severe infection than those with a spleen; however, the mortality rate is not significantly different. The reason for the predominance of serotype 22B requires further investigation and if replicated may warrant attention to current vaccination strategies.
OBJECTIVES: Most are aware of pneumococcal infection as a complication of splenectomy and the increased risk of severe invasive pneumococcal disease (IPD) in asplenic patients. However little is known of the current status of this entity in a population with an active pneumococcal conjugate vaccine program for children. METHODS: All IPD cases reported from 2000 to 2014 in Northern Alberta, Canada were collected prospectively. Socio-demographic variables, clinical characteristics, and IPD-related outcomes were compared between patients with and without a spleen using the Student t-test, Chi-square test, or Fisher's exact test, as appropriate. RESULTS: Thirty-seven of 2435 patients with IPD (1.5%) were asplenic. Asplenic patients were significantly more likely to require mechanical ventilation or admission to the intensive care unit and had more complications (e.g., acute kidney injury). However, in-hospital mortality rates were similar in those with and without a spleen (19% vs. 16%, p=0.58). Pneumococcal serotype 22B was 33-fold higher in asplenic patients compared to those with a spleen. CONCLUSIONS: In patients with IPD, those who are asplenic have a more severe infection than those with a spleen; however, the mortality rate is not significantly different. The reason for the predominance of serotype 22B requires further investigation and if replicated may warrant attention to current vaccination strategies.