Incidence patterns of nervous system diseases after carbon monoxide poisoning: a retrospective longitudinal study in South Korea from 2012 to 2018

OBJECTIVE: To analyze the incidence patterns of nervous system diseases in survivors of carbon monoxide (CO) poisoning using nationwide claims data from South Korea. METHODS: A national cohort was abstracted from a database that includes patients diagnosed with CO poisoning between January 2012 and December 2018. For all nervous system diseases, we investigated the frequency, pattern of incidence, effect of intensive care unit admission, and the standardized incidence ratios (SIRs) to estimate the risk of nervous system disease after CO poisoning. RESULTS: Of 26,778 patients, 18,720 (69.9%) were diagnosed with nervous system diseases after CO poisoning. The most common disease was disorders of sleep initiation and maintenance (n=701, 3.74%), followed by tension-type headache (n=477, 2.55%) and anoxic brain injury (n=406, 2.17%). Over half of the nervous system diseases occurred within the first year after CO poisoning. The cumulative hazard ratio for nervous system diseases in patients admitted to the intensive care unit was 2.25 (95% confidence interval [CI], 2.07–2.44). Among the frequent nervous system diseases after CO poisoning, patients had a higher risk of disorders of initiating and maintaining sleep (SIR, 1.61; 95% CI, 1.52–1.71), tension-type headache (SIR, 2.41; 95% CI, 2.23–2.61), anoxic brain injury (SIR, 58.76; 95% CI, 53.95–63.88), and post-zoster neuralgia (SIR, 1.94; 95% CI, 1.70–2.20). CONCLUSION: Patients who experience CO poisoning are at higher risk for several nervous system diseases. Therefore, monitoring for specific nervous system diseases is important after CO poisoning within the first year.