OBJECTIVES: To determine the global clinical burden of pneumonia among adults aged 50 and older.

METHODS: We exhaustively searched MEDLINE, EMBASE, Web of Science and Cochrane Library for primary observational studies published from January 2010 to December 2020, which investigated the clinical burden of CAP in aged adults. Data were extracted and descriptively summarized. Risk of bias were assessed.

RESULTS: Thirty-eight studies were included from 5562 searched citations. Thirty-two of them reported evidence from industrialized countries while the other reported evidence from less industrialized regions. The included studies were mainly cohort studies and surveillance studies.

The reported incidences of all-cause pneumonia varied from 600 to 2000 (per 100,000 person-years) and increased rapidly with age. The case fatality ratios (1% to 40%) and mortality rate (0.02% to 10.8%) for inpatients varied a lot across studies. The most frequently reported pathogen was Streptococcus pneumonia, with 3, 12F, 19A as the three most prevalent serotypes, which were covered by the 13-valent pneumococcal conjugate vaccine.

CONCLUSIONS: Comparing with the findings of previous systematic reviews on pneumonia burden from 1990 to 2009 in European and North American adults, the clinical burden from 2010 to 2020 in global aged adults reported by our review did not change significantly, although immunization programs and treatment guidelines were widely recommended. Better understanding of pneumonia clinical burden in industrialized countries was established partially on the matured national surveillance systems. The scarcity of evidence from less industrialized regions hindered our understandings of their pneumonia clinical burdens. An increase of Pneumonia burden globally was expected given the aging population worldwide. In the future, potential interventions, for example expanding current immunization program, scaling up antimicrobial stewardship projects, and introducing next generation vaccines, need be considered to resolve the burden of Pneumonia in aged adults.