Preinfection systemic inflammatory markers and risk of hospitalization due to pneumonia.
BACKGROUND
Elevated proinflammatory cytokines are associated with severity of pneumonia, but the role of preinfection cytokine levels in the predisposition to pneumonia in humans is less clear.


OBJECTIVE
To ascertain role of preinfection inflammatory markers on susceptibility to community-acquired pneumonia (CAP).


METHODS
Longitudinal analysis over 6.5 yr of a cohort that consisted of 70- to 79-yr-old well-functioning elderly individuals.


METHODS
Association between preinfection tumor necrosis factor (TNF), interleukin 6 (IL-6), and C-reactive protein (CRP) levels and CAP requiring hospitalization.


RESULTS
Of the 3,075 participants, 161 (5.2%) developed at least one episode of CAP requiring hospitalization over a median duration of 3.3 yr. The highest tertiles of TNF (> 3.7 pg/ml) and IL-6 (> 2.4 pg/ml) were associated with increased risk of CAP, and the adjusted odds ratios were 1.6 (95% confidence interval [CI], 1.02-2.7) and 1.7 (95% CI, 1.1-2.8), respectively. The adjusted risk of CAP with at least one of these markers in the highest tertile was 1.6 (95% CI, 1.1-2.3). TNF and IL-6 levels in the highest tertile had a synergistic effect (p = 0.01 for interaction), and risk of CAP for both markers in the highest tertile was 2.8 (95% CI, 1.8-4.3). An FEV(1) of 50% or less of predicted was associated with the highest risk of CAP (adjusted odds ratio, 3.6; 95% CI, 2.3-5.6). Furthermore, TNF and IL-6 levels modified risk of CAP in participants with coexisting medical conditions and history of smoking.


CONCLUSIONS
In the well-functioning elderly subjects, preinfection systemic levels of TNF and IL-6 were associated with higher risk of CAP requiring hospitalization in smokers and those with coexisting medical conditions.
Yende
Sachin
S
Department of Critical Care Medicine, 3550 Terrace Street, Pittsburgh PA 15261, USA. yendes@upmc.edu
Tuomanen
Elaine I
EI
Wunderink
Richard
R
Kanaya
Alka
A
Newman
Anne B
AB
Harris
Tamara
T
de Rekeneire
Nathalie
N
Kritchevsky
Stephen B
SB
D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data / Q000639:trends; D006801:Humans; D007249:Inflammation / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D016017:Odds Ratio; D011014:Pneumonia / Q000097:blood* / Q000473:pathology; D011446:Prospective Studies; D012307:Risk Factors; D048069:Tumor Necrosis Factors / Q000097:blood*
D015415:Biomarkers; D015850:Interleukin-6; D048069:Tumor Necrosis Factors; D002097:C-Reactive Protein