The Relationship between Scabies and Stroke: A Population-Based Nationwide Study

Background: Scabies is a commonly occurring infectious skin infestation that substantially impacts the quality of life, while stroke, which consists of a neurological deficit resulting from a lack of blood flow to the brain, carries sizable economic costs. The pathophysiologic mechanisms underlying both diseases involve inflammatory processes that are mediated by the immune system; however, no prior research has been conducted to explore the relationship between the two conditions. Methods: This population-based nationwide study utilized data from the National Health Insurance Research Database (NHIRD) of Taiwan for a total of 6628 scabies patients, who comprised a scabies group, and a randomly selected cohort of 26,509 matching patients, who served as a control group. More specifically, the medical records for the patients in both groups were checked for seven years to identify any new cases of stroke within that seven-year follow-up period. The hazard ratio (HR) of stroke for the follow-up period was then calculated using Cox proportional hazards regressions, while comorbidities and demographic characteristics were likewise analyzed. Results: During the follow-up period, 2892 patients, or 8.7%, of the overall total of 33,137 patients included in the study were newly diagnosed with a stroke. Of those newly diagnosed stroke patients, 833 were from the scabies group, and 2059 were from the control group, accounting for 12.6% and 7.8%, respectively, of the individuals in each group. With a crude hazard ratio of 1.67, the patients in the scabies group had a significantly higher risk of subsequent stroke than those in the control group, although the adjusted hazard ratio (aHR) for the scabies patients, which was determined by adjusting for covariates, was only 1.32 (95% confidence interval (CI): 1.21–1.43). Conclusions: The results of the study indicated an elevated risk of stroke among scabies patients, an association that might be contributed to by immunopathological factors. This information could serve as a reminder to clinicians to remain alert to any indications of neurological impairment in patients previously infected with scabies.