Incidence and risk factors for recurrent Henoch-Schönlein purpura in children from a 16-year nationwide database

The recurrence rate of Henoch-Schönlein purpura (HSP) is 2.7%-30%, with varied average intervals between the first and second episodes. Few studies have explored the incidence and risk factors for recurrent HSP. We used a 16-year nationwide database to analyze the incidence of recurrent HSP. Patients with HSP were identified, and risk factors for recurrent HSP were explored. Kaplan-Meier and Cox regression model analyses were performed, and covariates were adjusted in the multivariate model. From January 1, 1997 to December 31, 2012, among 2,886,836 individuals in the National Health Insurance Research Database, 1002 HSP patients aged