Pneumonia mortality, comorbidities matter?

Pneumonia remains one of the most important causes of mortality. In Portugal, it is the first cause of respiratory death, excluding lung cancer. This is a retrospective cohort study designed to seek for explanations, identifying the characteristics of patients and measure the impact of each one of them on the risk of dying from pneumonia. We analyzed demographic and clinical data of all patients (pts) with 18 years or older with pneumonia requiring hospitalization registered on the national health service registry of mainland Portugal over 2015. A total of 36366 patients corresponding to 40696 pneumonia hospital admissions in 2015 were analyzed. Most of the patients were very old (median age 80 years). Hospital mortality for pneumonia was higher among older (30,3% pts>75 years). Pneumococcus is the more frequent bacterial isolate, reaching 41.2% of the isolates of total pneumonia cases. The frequency of pneumococcus decreases with aging; conversely, gram-negative bacteria and staphylococcus increase. Pneumococcus is more frequently identified in the winter, closely related to influenza outbreaks. Gram-negative bacteria are more prevalent during the summer months. Diabetes, obesity, COPD, and tobacco smoking are not associated with an increased risk of dying from pneumonia. Patients older than 75 years; living in a senior house; or with chronic renal disease, lung cancer, metastatic disease, mobility impairment, cachexia, dementia, cerebrovascular disease, and ischemic heart disease are at greater risk of dying from pneumonia. Comorbidities contribute decisively to the risk of dying from pneumonia in the hospital, regardless of their type or origin.