Evaluation of diseases complicating long COVID: A retrospective chart review

Evidence for the pathogenesis and treatment of postacute coronavirus disease 2019 (COVID‐19) (long COVID) is lacking. As long COVID symptoms are predicted to have an impact on the global economy, clarification of the pathogenesis is urgently needed. Our experiences indicated that some symptoms were complicated by diseases established before the COVID‐19 pandemic.Using a retrospective, cross‐sectional study, we aimed to evaluate the diseases complicating long COVID. Using the medical records of patients with confirmed COVID‐19 exhibiting residual symptoms lasting ≥60 days postinfection who visited our clinic in January 2021–February 2023, we investigated the symptoms and diseases observed. We identified diseases that occurred after COVID‐19 and excluded those that were exacerbations of existing diseases.During the first visit, the most common symptoms reported in a total of 798 patients were fatigue (523 patients), anxiety (349 patients), and lack of motivation (344 patients). Complicating diseases were observed in 452 patients (57%). There were 115, 65, and 60 patients with postural tachycardia syndrome, postural syndrome without tachycardia, and mood disorders, respectively. Some diseases requiring immediate treatment included pulmonary thromboembolism, purulent shoulder arthritis, cerebellopontine angle tumors, myasthenia gravis, and cervical myelopathy.Not all symptoms that occur after COVID‐19 should be treated as long COVID. Similar to normal medical treatment, a list of differential diagnoses should be maintained based on symptoms to obtain definitive diagnoses.