Exploring the presence of long COVID-like symptoms in patients with chronic pain: a large-scale internet-based cross-sectional study in Japan

Individuals with chronic pain not only endure the direct burden of pain but also experience various symptoms, including sleep disturbances and fatigue, which deteriorate their quality of life. Notably, these symptoms closely resemble those observed in "long COVID," a prolonged health complication that can arise after coronavirus disease 2019 (COVID-19) infection. Because the similarities between chronic pain and long COVID remain unexplored, this study aimed to investigate their relationship using Japanese epidemiological data. Using the Japan COVID-19 and Society Internet Survey in 2022, which included 32,000 participants, we analyzed data on the presence of chronic pain, history of COVID-19 infection, and presence of 17 long COVID-like symptoms, including gastrointestinal upset, back pain, limb/joint pain, headache, chest pain, shortness of breath, dizziness, sleep disorder, hearing disorder, taste disorder, smell disorder, memory impairment, poor concentration, hair loss, decreased libido, fatigue, and cough. Individuals with history of COVID-19 experienced a significantly greater number of long COVID-like symptoms (median: 5) compared with those with neither COVID-19 nor chronic pain (median: 4, P < 0.001). Individuals with chronic pain alone and those with both COVID-19 and chronic pain exhibited an even greater number of symptoms (median: 8 and 9, respectively). In addition, individuals with chronic pain exhibited greater prevalence odds for 15 of the 17 symptoms than those with neither COVID-19 nor chronic pain ( P < 0.001). Our findings indicate that long COVID-like symptoms are not specifically associated with COVID-19. Instead, the data suggest that chronic pain contributes as an independent risk factor for these symptoms.