Platelet Count within the Normal Range at Hospital Admission is Associated with Mortality in Patients with Community-Acquired Pneumonia

Abstract

Background

Apart from their hemostatic role, platelets are immune cells that play a role in fighting infections. The presence of thrombocytopenia and thrombocytosis at hospital admission are predictors of mortality in community-acquired pneumonia patients. We hypothesized that variations in platelet counts within the normal range also may be associated with mortality in these patients.

Methods

The study included all adults in the North and Central Denmark Regions with a first acute hospital admission for community-acquired pneumonia during 2006–2012. We assessed the association between the first platelet count within ± 24 hours of admission (within the normal range of 150 to 400 x 10⁹/L) and 30-day mortality using Cox models. Analyses were adjusted for age, sex, Charlson Comorbidity Index score, hemoglobin level, leukocyte count, and creatinine level at admission.

Results

Among the 12,905 study patients, 30-day mortality was 12.4%. The mean platelet count upon admission was 250 × 10⁹/L. Compared with the 250–275 × 10⁹/L category, platelet counts of 151–175 were associated with a lower 30-day mortality (adjusted hazard ratio [aHR]: 0.79, 95% confidence interval [CI]: 0.63–0.99), while higher platelet counts were associated with a higher 30-day mortality (351–375 × 10⁹/L, aHR: 1.34, 95% CI: 1.07–1.68; 376–400× 10⁹/L, aHR: 1.21, 95% CI: 0.94–1.56).

Conclusion

Platelet counts, even within the normal range, are associated with mortality in adult patients hospitalized for community-acquired pneumonia.

Keywords:

• platelet count
• thrombocytopenia
• thrombocytosis
• community-acquired pneumonia
• mortality

Abbreviations

CAP, community-acquired pneumonia; CCI, Charlson Comorbidity Index; DNPR, Danish National Patient Registry; ICD-10, International Classification of Diseases, Tenth Revision; ICU, intensive care unit.

Author Contributions

All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

Dr Guillaume Moulis reports grants from CSL Behring, Institut Servier, Grifols, and Novartis, and meeting attendance from Novartis and Amgen, outside the submitted work. The authors report no other possible conflicts of interest related to this study.

The abstract of this paper was presented in the abstract book of the 24th European Hematology Association meeting with interim findings. The poster’s abstract was published in HemaSphere 2019;3:916; doi: 10.1097/01.HS9.0000566600.64159.d7.

Additional information

Funding

To conduct this study, GM received grants from the Foundation for the Development of Internal Medicine in Europe (FDIME, linked to the European Federation of Internal Medicine), from the Institut Servier, and from Toulouse University Hospital (CHU de Toulouse). The sponsors had no role in the study.