Abstract
BACKGROUND: This study aimed to describe the incidence rate, patient characteristics, treatments, and outcomes of adults hospitalized with Mycoplasma pneumoniae pneumonia. METHODS: This retrospective cohort study included adults diagnosed with M pneumoniae pneumonia and admitted to emergency care hospitals in Stockholm County, Sweden, from 2013 to 2017. Patients were identified through positive M pneumoniae polymerase chain reaction and ICD-10 code J15.7 (M pneumoniae pneumonia). Medical records were reviewed manually, and population data were extracted from statistical databases. Incidence rates were calculated, and treatment outcomes were analyzed using regression models. RESULTS: A total of 747 adults with a median age of 42 (interquartile range [IQR], 33-55) years, of whom 55% (385/747) were male, were hospitalized with M pneumoniae pneumonia. The incidence rate was 8.5 cases per 100 000 person-years, peaking at 14.1 in 2016. Cough (95%) and fever (92%) were the most common symptoms, and 71% were hypoxemic at admission. Patients with severe disease had longer symptom duration at admission. In-hospital mortality was 0.4%, and 6% required intensive care unit admission. Median length of stay (4 [IQR, 2-6] days) was longer in patients treated with macrolides (+1.0 [IQR, 0.9-1.2] days; P < .001) and fluoroquinolones (+0.8 [IQR, 0.1-1.4] days; P = .03) compared to those treated with tetracyclines. The median fever duration was significantly longer (+0.3 [IQR, 0.1-0.6] days; P = .02) in patients treated with fluoroquinolones compared to those treated with tetracyclines. CONCLUSIONS: The study highlights the importance of timely and accurate treatment of M pneumoniae pneumonia. Tetracycline treatment was associated with better outcomes, suggesting they may be an effective first-line treatment option.