Abstract 19964: Effect of Clopidogrel Treatment on the Incidence and Severity of Community Acquired Pneumonia: Results of a Five-Year Cohort Study
Introduction: While the role of platelets in hemostasis is well-established, their function in inflammation and immune response has not been fully characterized. Platelet activation results in the release and upregulation of mediators responsible for inflammatory/immune cell activation and recruitment. Experimental models suggest platelet activation may be beneficial or detrimental in infectious disease states such as pneumonia and sepsis.
Hypothesis: The study hypothesis was that clopidogrel treatment would alter the incidence and severity of community-acquired pneumonia (CAP).
Methods: A five-year retrospective cohort of patients enrolled in Kentucky Medicaid (2001–2005) was used, comparing patients receiving clopidogrel treatment (defined as >/=6 consecutive prescriptions during the study period, n=14,947) to patients who did not receive clopidogrel (n = 391,503). The primary study objectives were to determine the effects of clopidogrel on CAP incidence and severity, as measured by the initial site of care (inpatient vs. outpatient). Secondary endpoints included additional markers of pneumonia severity, including: mortality, need for ICU care or mechanical ventilation, or diagnoses of sepsis, acute respiratory distress syndrome (ARDS), or acute lung injury (ALI).
Results: A total of 406,450 patients were identified in the database and included in the study. Clopidogrel therapy was associated with an increased incidence of CAP compared to the overall population (34.6% vs. 13.5%, adjusted OR 1.478, 95% CI 1.41–1.55, p<0.0001). Patients receiving clopidogrel were less likely to be treated as outpatients (43.7% vs. 60.3%, adjusted OR 1.00, 95% CI 0.94–1.07, p=0.88). However, in patients receiving clopidogrel, a trend towards lower mortality rates was observed (0.5% vs. 0.8%, adjusted OR 0.71, 95% CI 0.41–1.25). Other secondary markers of severity were not significant.
Conclusions: Patients receiving clopidogrel appear more likely to develop CAP. The effects of clopidogrel on the severity of CAP were not significant overall, although a trend towards a reduction in mortality was observed in patients hospitalized for CAP. Further analysis of the effects of clopidogrel on inflammatory disease processes is warranted.
- © 2010 by American Heart Association, Inc.