Effects of age and comorbidities on inflammatory markers in community-acquired pneumonia

Abstract Background: Studies have suggested that an inappropriate inflammatory response is a major cause of treatment failure and mortality in patients with community-acquired pneumonia (CAP). We aimed to determine the effect of comorbidities and age on serum inflammatory markers in CAP.Methods: We performed a prospective cohort study of adults hospitalized with CAP. For the purposes of this study, we compared patients according to comorbidities and age. Inflammatory markers were measured at hospital admission, focusing on acute phase proteins, cytokines, and monocyte human leukocyte antigen DR (mHLA-DR) expression.Results: In patients with chronic pulmonary disease (COPD), serum cytokines had significantly decreased levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and mHLA-DR expression, as well as the C-reactive protein (CRP), compared with patients who had no comorbidities. Similarly, patients with chronic heart disease had a significantly reduced CRP levels and mHLA-DR expression, whereas patients with chronic kidney disease had significantly higher serum levels of procalcitonin and TNF-α. Lower procalcitonin, IL-6, and IL-10 levels, as well as mHLA-DR expression, were documented in older patients, but with no significant differences compared to younger patients. Multimorbidity in older patients was associated with significant lower levels of CRP and mHLA-DR expression.Conclusions: The circulating inflammatory markers to CAP have profiles that differ with age and underlying comorbidities. Multimorbidity in the elderly is also associated with lower serum levels of some inflammatory markers. These findings suggest that age and comorbidities have much more of an impact than to simply reduce physiological reserve and can cause variations in the inflammatory response in CAP.