Long-term mortality after IPD and bacteremic versus non-bacteremic pneumococcal pneumonia

Abstract

Background: Short-term mortality after invasive pneumococcal disease (IPD) and pneumococcal pneumonia is high but data on long-term mortality (including the comparison between bacteremic and non-invasive/non-bacteremic pneumococcal pneumonia) within the first years after diagnosis are scarce.

Methods: Adult patients with 'non-pneumonia' IPD and 'invasive pneumonia' (from 2004 to 2012) and with 'bacteremic' vs 'non-invasive/non-bacteremic (NI/NB)' pneumococcal pneumonia (from 2008 to 2012) diagnosed by negative blood culture but a positive urinary antigen test (UAT) were identified in a Dutch hospital. Mortality of patients up to 10years after diagnosis was compared with age- and sex-matched life-expectancy data of the general population. Multivariable Cox regression analysis was used to study predictors for mortality in invasive pneumonia patients and to adjust for confounders comparing mortality between bacteremic and NI/NB/UAT-positive pneumonia patients.

Results: Of 228 invasive pneumonia patients 17% died within 30days and in 30-day survivors cumulative long-term mortality at 1 and 5years were 16% and 39% as compared with 3% and 15% in age- and sex-matched persons. High mortality was largely dependent on pre-existent comorbidities. In invasive pneumonia patients who survived the first 30days, age, male gender, chronic cardiovascular disease, malignancy and PCV7 serotype disease were independent predictors for higher long-term mortality. For bacteremic pneumonia patients (n=128) 30-day mortality was 16% and almost similar to 14% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=170). In 30-day survivors of bacteremic pneumonia (n=108, median age 66years), cumulative mortality at 1 and 3years were 13% and 29% as compared with 18% and 40% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=146, median age 67years) without a significant difference in mortality.

Conclusions: Approximately 40% of all patients, who survived the first 30days after presentation with non-pneumonia IPD and pneumococcal pneumonia died within the following 5years. High long-term mortality was largely dependent on pre-existent comorbidity.

Keywords: Invasive pneumococcal disease; Long-term mortality; Pneumococcal pneumonia; Serotypes; Streptococcus pneumonia.