title: Diagnostic and prognostic value of thrombocytosis in admitted medical patients.
abstract: BACKGROUND
  Whether secondary thrombocytosis is a distinguishing clinical biomarker of various diseases, and whether it is an independent predictor of short-term outcome of admitted medical patients is unknown and has never been examined.
  
  
  METHODS
  A cohort of all 138 patients with secondary thrombocytosis (platelets count ≥ 5 x 105/μL) admitted to the department of medicine during the last 2 years was analyzed. Epidemiological and clinical data, and the final diagnosis and outcome were recorded and compared with a cohort of 684 consecutive admitted patients without thrombocytosis.
  
  
  RESULTS
  Thrombocytosis was not a non-specific marker of inflammation, because uncomplicated infections and most admission causes were not associated with thrombocytosis, except for inflammatory rheumatic diseases (6% versus 1%), along with anemia (9.4% versus 2.5%) and tumor comorbidity (25% versus 14%). In contrast, thrombocytosis was a distinguishing biomarker for severe pyogenic infections, especially empyema (5% vs. 0%), any abscesses (14% versus 3%), and soft tissue infections (7% versus 3%). Moreover, the thrombocytosis group had significantly more admission days, infections (45% versus 33%), sepsis (21% versus 6%), in-hospital major complications (15% versus 3%) and mortality (19% versus 5%). Finally, thrombocytosis was found to be an independent predictor of mortality, in a multivariate regression analysis.
  
  
  CONCLUSIONS
  Thrombocytosis is not a simple marker of inflammation. Its presence warrants thorough investigation for the presence of severe underlying disease, mostly complicated pyogenic infections, inflammatory rheumatic diseases and malignancy. Moreover, thrombocytosis is a marker for major complications and is an independent predictor of mortality in admitted medical patients.
authors.affiliation: Department of Medicine B, Tel-Aviv Souraski Medical Center, Tel-Aviv, Israel.
authors.forename: Joseph Zvi
authors.initials: JZ
authors.lastname: Tchebiner
authors.forename: Amir
authors.initials: A
authors.lastname: Nutman
authors.forename: Ben
authors.initials: B
authors.lastname: Boursi
authors.forename: Amir
authors.initials: A
authors.lastname: Shlomai
authors.forename: Tal
authors.initials: T
authors.lastname: Sella
authors.forename: Assaf
authors.initials: A
authors.lastname: Wasserman
authors.forename: Hanan
authors.initials: H
authors.lastname: Guzner-Gur
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006760:Hospitalization; D006801:Humans; D007249:Inflammation / Q000150:complications* / Q000175:diagnosis*; D007557:Israel; D008297:Male; D008875:Middle Aged; D010343:Patient Admission; D011379:Prognosis; D013922:Thrombocytosis / Q000175:diagnosis* / Q000209:etiology*
chemical_list: D015415:Biomarkers