Impact of coronavirus disease on the incidence rate of methicillin-resistant Staphylococcus aureus among hospitalized patients with lung cancer: a nationwide retrospective cohort study in Japan.

BACKGROUND: Patients with lung cancer are at increased risk for methicillin-resistant Staphylococcus aureus (MRSA) infection, which prolongs treatment and worsens prognosis. Therefore, preventing MRSA infection is critically important in this population. We aimed to investigate whether the incidence rate of MRSA among patients with lung cancer declined after the coronavirus disease (COVID-19) pandemic, owing to the widespread reinforcement of hand-rub use. METHODS: We conducted a nationwide, retrospective, interrupted time-series analysis using a claims database in Japan Medical Data Vision. Hospitalized patients diagnosed with lung cancer between December 2016 and August 2022 were followed for 6 months. MRSA was identified using International Classification of Diseases, 10th Revision, codes in combination with a same-month prescription for an anti-MRSA agent. The incidence rate of MRSA among patients with lung cancer was compared between the pre-COVID (December 2016-April 2020) and post-COVID (April 2020-August 2022) periods using segmented Poisson regression with Newey-West errors and seasonal adjustment. RESULTS: Among 93,508 eligible patients, 364 developed MRSA. The pre-COVID slope for the incidence rate of MRSA among patients with lung cancer was flat (0.20 per 1,000 person-years/year), whereas the post-COVID slope declined to -8.97 per 1,000 person-years/year. The slope difference (-9.17 per 1,000 person-years/year) indicates a sustained decline in the incidence rate of MRSA among this population after April 2020. CONCLUSIONS: The incidence rate of MRSA among hospitalized patients with lung cancer decreased steadily after the COVID-19 pandemic. These findings suggest that routine hospital-wide infection control measures implemented during the pandemic may yield lasting benefits even in the absence of targeted interventions.