790. Risk Stacking of Pneumococcal Vaccination Indications Increases Mortality in Unvaccinated Adults with Streptococcus pneumoniae Infections
Session: Poster Abstract Session: Vaccines: Pneumococcal
Thursday, October 27, 2016
Room: Poster Hall
Background: Serious pneumococcal infections (pneumonia, bacteremia, and meningitis) contribute significantly to morbidity and mortality, particularly in the setting of chronic disease states. However, risk of mortality according to increasing numbers of chronic disease states has not been quantified. We sought to determine the impact of concomitant, multiple risk factors (risk stacking) on 30-day mortality in unvaccinated adults.

Methods: This was a national nested case-control study of older Veterans (≥50 years of age) unvaccinated within the past 5 years with positive S. pneumoniaeblood, cerebrospinal fluid, or respiratory cultures admitted to Veterans Affairs facilities between January 1, 2002 and December 31, 2011. Using logistic regression, we quantified 30-day mortality (cases: not alive 30 days after culture; controls: alive at 30 days) by comparing individual pneumococcal disease risk factors present within one year prior to culture (age ≥65, alcoholism, diabetes mellitus, heart disease, immunodeficiency, liver disease, respiratory disease, smoking) and all possible combinations of risk factors to those without risk factors.

Results: We identified 9,730 serious pneumococcal infections (1,764 cases and 7,966 controls) in 9,468 unvaccinated individuals, with a 30-day mortality of 18.6%. Primary infection types included pneumonia (62%), bacteremia (26%), and bacteremic pneumonia (11%). In addition to the 8 individual risk factors, there were 247 unique combinations of risk factors, with 85% (n=1,496) and 74% (n=5,898) of cases and controls having at least two risk factors, respectively. Beginning with two risk factors, risk of mortality increased with each addition of a risk factor up to a total of 6 risk factors (two: OR 2.01, CI 1.47-2.75; three: OR 2.71, CI 1.99-3.69; four: OR 3.27, CI 2.39-4.47; five: OR 3.63, CI 2.60-5.07; six: OR 4.23, CI 2.69-6.65). The addition of each risk factor increased risk of mortality by an average of 56%.

Conclusion: Among older adults with serious pneumococcal disease, risk of 30-day mortality more than doubled from 2 to 6 disease states present. Pneumococcal disease prevention is therefore essential to minimize the deleterious effects of acute infection in the setting of multiple disease states.

Jacob Morton, PharmD, MBA, BCPS1,2, Haley Morrill, PharmD1,2, Kerry Laplante, Pharm.D., FCCP1,2,3 and Aisling Caffrey, PhD, MS1,2, (1)Providence Veterans Affairs Medical Center, Providence, RI, (2)University of Rhode Island, Kingston, RI, (3)Brown University, Providence, RI

Disclosures:

J. Morton, None

H. Morrill, Pfizer: Grant Investigator , Research grant

K. Laplante, Merck (Cubist): Consultant and Scientific Advisor , Research support
Pfizer: Consultant and Scientific Advisor , Research support
Allergan (Forest): Consultant and Scientific Advisor , Research support
The Medicines Company: Consultant and Scientific Advisor , Research support
Melinta: Consultant and Scientific Advisor , Research support

A. Caffrey, Pfizer: Research , Research grant
Merck (Cubist): Research , Research grant

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