Aetiology and Risk Factors for Mortality in an Adult Community-Acquired Pneumonia Cohort in Malawi.

RATIONALE

In the context of rapid antiretroviral therapy (ART) rollout and an increasing burden of non-communicable diseases, there are few contemporary data describing the aetiology and outcome of community-acquired pneumonia (CAP) in sub-Saharan Africa.

OBJECTIVES

To describe the current aetiology of CAP in Malawi and identify risk factors for mortality.

METHODS

We conducted a prospective observational study of adults hospitalised with CAP to a teaching hospital in Blantyre, Malawi. Aetiology 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 [IQR: 29.4-41.9] years), 30-day mortality was 14.6% (64/439) and associated with male sex (adjusted odds ratio 2.60 [95% CI: 1.17-5.78]), symptom duration >7 days (2.78 [1.40-5.54]), tachycardia (2.99 [1.48-6.06]), hypoxaemia (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 co-infection occurred in 9.1% (28/307). Detection of M. tuberculosis was associated with mortality (aOR 2.44 [1.19-5.01]).

CONCLUSIONS

In the ART 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 hypoxaemia, should be evaluated in clinical trials to address CAP-associated mortality.