Revisiting nursing- and healthcare-associated pneumonia in Japan: Microbiology, multidrug resistance, and clinical outcomes compared with community-acquired pneumonia

BACKGROUND: In Japan, nursing- and healthcare-associated pneumonia (NHCAP) is used to describe pneumonia in patients with substantial exposure to healthcare and nursing care services. A systematic review and meta-analysis was conducted to re-evaluate their clinical significance. METHODS: Thirteen observational studies conducted in Japan directly comparing NHCAP with community-acquired pneumonia (CAP) were included. RESULTS: Patients with NHCAP were consistently older and had a higher burden of comorbidities than those with CAP. Thirty-day mortality was significantly higher in the NHCAP group than in the CAP group (12.7% vs. 5.0%), with a pooled odds ratio of 2.85 (95% confidence interval [CI], 2.25-3.61). In both groups, nearly half of the pneumonia cases had no identified etiological pathogen, with pooled proportions of 0.48 and 0.46 in the NHCAP and CAP groups, respectively. Streptococcus pneumoniae was the most frequently detected pathogen in both groups, and multidrug-resistant (MDR) pathogens were detected more frequently in NHCAP than in CAP (pooled odds ratio, 3.52; 95% CI, 2.02-6.14). However, despite this higher prevalence, the NHCAP classification showed limited discriminatory performance for MDR pathogens, with a pooled positive likelihood ratio of 1.48 and a negative likelihood ratio of 0.45, indicating a minimal impact on post-test probability. CONCLUSIONS: NHCAP identifies a clinically vulnerable population but has limited utility in predicting drug-resistant pathogens, supporting its use as a descriptive clinical framework rather than that used to determine empirical antimicrobial therapy.