Cardiovascular, thromboembolic and renal outcomes in IgA vasculitis (Henoch-Schönlein purpura): a retrospective cohort study using routinely collected primary care data

Background: IgA vasculitis (IgAV, Henoch-Schönlein purpura) is a small-vessel vasculitis most common in children but also occurring in adults. Case series have suggested that IgAV may be associated with cardiovascular disease and venous thromboembolism, but this has not been evaluated in population-based studies. Renal disease and hypertension are possible complications of the disease with unknown incidence.

Methods: Using a large United Kingdom primary care database, we conducted an open retrospective matched cohort study of cardiovascular, venous thrombotic and renal outcomes in adult-onset and childhood-onset IgAV. Control participants were selected at a 2:1 ratio, matched for age and sex.Adjusted hazard ratios (aHRs) were calculated using Cox proportional hazards models.

Results: 2,828 patients with adult-onset IgAV and 10,405 patients with childhood-onset IgAV were compared with age- and sex-matched controls. There was significantly increased risk of hypertension (adult-onset aHR 1.42, 95%CI 1.19-1.70, p<0.001; childhood-onset aHR 1.52, 95% CI1.22-1.89, p<0.001) and stage G3-G5 chronic kidney disease (adult-onset aHR 1.54, 95%CI 1.23-1.93,p<0.001; childhood-onset aHR 1.89, 95%CI 1.16-3.07, p=0.010). There was no evidence of association with ischaemic heart disease, cerebrovascular disease or venous thromboembolism. All cause mortality was increased in the adult-onset IgAV cohort compared to controls (aHR 1.27, 95%CI1.07-1.50, p=0.006).

Conclusions: Patients with IgAV are at increased risk of hypertension and CKD compared to individuals without IgAV; analysis restricted to adult-onset IgAV patients showed increased mortality. Appropriate surveillance and risk factor modification could improve long-term outcomes in these patients.