Etiology and Risk Factors for Mortality in an Adult Community-acquired Pneumonia Cohort in Malawi

Aston, Stephen J.; Ho, Antonia; Jary, Hannah; Huwa, Jacqueline; Mitchell, Tamara; Ibitoye, Sarah; Greenwood, Simon; Joekes, Elizabeth; Daire, Arthur; Mallewa, Jane; Everett, Dean; Nyirenda, Mulinda; Faragher, Brian; Mwandumba, Henry C.; Heyderman, Robert S.; Gordon, Stephen B.

Rationale: In the context of rapid antiretroviral therapy rollout and an increasing burden of noncommunicable diseases, there are few contemporary data describing the etiology and outcome of community-acquired pneumonia (CAP) in sub-Saharan Africa. Objectives: To describe the current etiology of CAP in Malawi and identify risk factors for mortality. Methods: We conducted a prospective observational study of adults hospitalized with CAP to a teaching hospital in Blantyre, Malawi. Etiology was defined by blood culture, Streptococcus pneumoniae urinary antigen detection, sputum mycobacterial culture and Xpert MTB/RIF, and nasopharyngeal aspirate multiplex PCR. Measurements and Main Results: In 459 patients (285 [62.1%] males; median age, 34.7 [interquartile range, 29.4–41.9] yr), 30-day mortality was 14.6% (64/439) and associated with male sex (adjusted odds ratio, 2.60 [95% confidence interval, 1.17–5.78]), symptom duration greater than 7 days (2.78 [1.40–5.54]), tachycardia (2.99 [1.48–6.06]), hypoxemia (4.40 [2.03–9.51]), and inability to stand (3.59 [1.72–7.50]). HIV was common (355/453; 78.4%), frequently newly diagnosed (124/355; 34.9%), but not associated with mortality. S. pneumoniae (98/458; 21.4%) and Mycobacterium tuberculosis (75/326; 23.0%) were the most frequently identified pathogens. Viral infection occurred in 32.6% (148/454) with influenza (40/454; 8.8%) most common. Bacterial–viral coinfection occurred in 9.1% (28/307). Detection of M. tuberculosis was associated with mortality (adjusted odds ratio, 2.44 [1.19–5.01]). Conclusions: In the antiretroviral therapy era, CAP in Malawi remains predominantly HIV associated, with a large proportion attributable to potentially vaccine-preventable pathogens. Strategies to increase early detection and treatment of tuberculosis and improve supportive care, in particular the correction of hypoxemia, should be evaluated in clinical trials to address CAP-associated mortality.