BACKGROUND: COVID-19 is one of the most pressing public health issues worldwide. The sequelae of COVID-19 however remains unclear. We performed a systematic assessment of sequelae across all body systems, focusing on whether COVID-19 is associated with increased risk of hospitalization for various diseases. METHODS: In this cohort study, we examined 135 disorders in UK biobank (UKBB) (N = 412,096
age: 50-87). We also conducted analysis for new-onset and recurrent cases, and employed the prior event rate adjustment (PERR) approach to minimize effects of unmeasured confounders. Time-dependent effects were also tested. RESULTS: Compared to individuals with no known COVID-19 history, those with severe COVID-19 (hospitalized) exhibited increased hazards of hospitalization due to multiple disorders (median follow-up = 261 days), including disorders of respiratory, cardiovascular, neurological, gastrointestinal, genitourinary, musculoskeletal systems, as well as injuries, infections and non-specific symptoms. Notably, severe COVID-19 was associated with increased hospitalization risks in 77 out of the 107 disease categories with ≥ 5 events in both groups. These results remained largely consistent in sensitivity analyses. Mild (non-hospitalized) COVID-19 was associated with increased risk of hospitalization for several disorders: aspiration pneumonitis, musculoskeletal pain and other general signs/symptoms. The risk of hospitalizations following infection was generally higher during the pre-vaccination era. CONCLUSION: This study revealed increased risk of hospitalization from a wide variety of pulmonary and extra-pulmonary diseases after COVID-19, especially for severe infections. The findings may have important clinical implications, such as the need for closer monitoring and risk assessment of relevant sequelae, and allocating more resources toward prevention and treatment of such sequelae.