Community-acquired pneumonia in younger patients is an entity on its own.

Community-acquired pneumonia (CAP) is now most frequent in elderly patients. CAP in the younger patient has attracted much less attention. Therefore, we compared patients with CAP aged 18 to <65 yrs with those aged ≥ 65 yrs. Data from the prospective multicentre Competence Network for Community Acquired Pneumonia Study Group (CAPNETZ) database were analysed for potential differences in baseline characteristics, comorbidities, clinical presentation, microbial investigations, aetiologies, antimicrobial treatment and outcomes. Overall, 7,803 patients were studied. The proportion of younger patients (aged <65 yrs) was 52.3% (18 to <30 yrs 6.4%; <40 yrs 17.1%; <50 yrs 29.4%). Comorbidity was present in only half of the younger patients (46.6% versus 88.2%). Fever and chest pain were more common. Most younger patients presented with mild CAP (74.0% had a CRB-65 [corrected] score of 0 (confusion of new onset, [corrected] respiratory rate of ≥ 30 breaths · min(-1), blood pressure <90 mmHg or diastolic blood pressure ≤ 60 mmHg, age ≥ 65 yrs)). Overall, Streptococcus pneumoniae and Mycoplasma pneumoniae were the most frequent pathogens in the younger patients. Short-term mortality was very low (1.7% versus 8.2%) and even lower in patients without comorbidity (0.3% versus 2.4%). Long-term mortality was 3.2% versus 15.9%, also lower in patients without comorbidity (0.8% versus 6.1%). Most of the differences found clearly arise after the fifth or within the middle of the sixth decade. CAP in the younger patient is a clinically distinct entity.