Abstract: www.nature.com/scientificreports OPEN Non‑steroidal anti‑inflammatory agent use may not be associated with mortality of coronavirus disease 19 Jungchan Park1, Seung‑Hwa Lee2,6*, Seng Chan You3, Jinseob Kim4 & Kwangmo Yang5,6* Non-steroidal anti-inflammatory drugs (NSAIDs) have been widely used in patients with respiratory infection, but their safety in coronavirus disease 19 (Covid-19) patients has not been fully investigated. We evaluated an association between NSAID use and outcomes of Covid-19. This study was a retrospective observational cohort study based on insurance benefit claims sent to the Health Insurance Review and Assessment Service of Korea by May 15, 2020. These claims comprised all Covid-19-tested cases and history of medical service use for the past 3 years in these patients. The primary outcome was all-cause mortality, and the secondary outcome was need for ventilator care. Among 7590 patients diagnosed with Covid-19, two distinct cohorts were generated based on NSAID or acetaminophen prescription within 2 weeks before Covid-19 diagnosis. A total of 398 patients was prescribed NSAIDs, and 2365 patients were prescribed acetaminophen. After propensity score matching, 397 pairs of data set were generated, and all-cause mortality of the NSAIDs group showed no significant difference compared with the acetaminophen group (4.0% vs. 3.0%; hazard ratio [HR], 1.33; 95% confidence interval [CI], 0.63–2.88; P = 0.46). The rate of ventilator care also did not show significantly different results between the two groups (2.0% vs. 1.3%; HR, 1.60; 95% CI 0.53–5.30; P = 0.42). Use of NSAIDs was not associated with mortality or ventilator care in Covid-19 patients. NSAIDs may be safely used to relieve symptoms in patients with suspicion of Covid-19. In December 2019, a major outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) in Wuhan City, China, was first reported. It was later characterized as coronavirus disease 19 (Covid-19) and has become a global threatening disease with more than 6,000,000 confirmed cases worldwide as of June ­20201. By then, more than 11,629 cases of Covid-19 had been diagnosed, and 273 deaths had been reported throughout Korea. Based on this, the government of Korea decided to share the world’s first de-identified Covid-19 nationwide patient data collected from the Korean National Health Insurance System for the purpose of investigation. The primary site of infection in Covid-19 is the respiratory system. However, epidemiologic reports indicated that mortality of Covid-19 was much higher in patients with cardiovascular ­disease2, and the most serious complications of Covid-19 are those involving cardiovascular and respiratory systems, as well as s­ epsis3,4. Non-steroidal anti-inflammatory drugs (NSAIDs) have long been widely used for symptomatic relief of infected patients by controlling pain, fever, and inflammation, although safety concerns remain regarding harmful effects on the cardiovascular ­system5. Moreover, NSAID treatment was associated with pulmonary complication in patients with ­pneumonia6. The association between NSAID use and adverse outcome of Covid-19 has been previously evaluated, but limited data have been ­reported7–9. In this study, we used de-identified Covid-19 nationwide data from Korea to investigate the association between NSAID use to relieve symptoms before confirmed diagnosis 1 Department of Anesthesiology and Pain Medicine, Samsung Medical Center,..