biostudies-literaturePark JMinistry of Food and Drug SafetyKorea Health Industry Development Institute19528https://www.ebi.ac.uk/biostudies/studies/S-EPMC10636038biostudies-literatureUnknown13(1)Studies on the trends in the prevalence of rheumatoid arthritis (RA) and osteoarthritis (OA) are limited, particularly during the COVID-19 pandemic. This study aimed to analyze the temporal trend of RA and OA in South Korean adults from 1998 to 2021, including the COVID-19 pandemic period. The Korea National Health and Nutrition Examination Survey (KNHANES) data on adults aged ≥ 19 years were analyzed to investigate the prevalence of RA and OA from 1998 to 2021. The prevalence trends were compared by the years, and β_diff (β difference) was calculated. Odds ratios (ORs) were computed for each disease to examine changes in disease prevalence before and during the pandemic in order to determine the impact of the pandemic on disease prevalence. Among 163,221 Korean adults, the prevaScientific reportsNational trends in rheumatoid arthritis and osteoarthritis prevalence in South Korea, 1998-2021.PMC10636038HV22C023321153MFDS601Yang HKwon RYon DKKim MSPark JRhee SYKim HJLee MElena DLee HSmith LKim SJacob LLopez Sanchez GFShin JIYoo MCKoyanagi ALee SWRahmati MfalseNational trends in rheumatoid arthritis and osteoarthritis prevalence in South Korea, 1998-2021.Studies on the trends in the prevalence of rheumatoid arthritis (RA) and osteoarthritis (OA) are limited, particularly during the COVID-19 pandemic. This study aimed to analyze the temporal trend of RA and OA in South Korean adults from 1998 to 2021, including the COVID-19 pandemic period. The Korea National Health and Nutrition Examination Survey (KNHANES) data on adults aged ≥ 19 years were analyzed to investigate the prevalence of RA and OA from 1998 to 2021. The prevalence trends were compared by the years, and β_diff (β difference) was calculated. Odds ratios (ORs) were computed for each disease to examine changes in disease prevalence before and during the pandemic in order to determine the impact of the pandemic on disease prevalence. Among 163,221 Korean adults, the preva2023-01-01T00:00:00Z2023 Nov2025-04-18T17:22:32.715Z2025-02-18T23:30:47.217ZS-EPMC106360383794563310.1038/s41598-023-46279-6