[Analysis of relevant risk factors to Henoch-Schönlein purpura in Tibetan children]

To analyze probable risk factors to Henoch-Schönlein purpura (HSP) in Tibetan children so as to bring evidences for correct identification of high-risk children in plateau areas.

140 high-altitude Tibetan children with HSP admitted to Shannan People's Hospital of Tibet Autonomous Region from October 2015 to October 2018 were enrolled, and 140 high-altitude Tibetan healthy children and 140 plain area HSP children were selected as the control. Gender, age, family history, allergy, past history (rheumatic disease, autoimmune disease, asthma), clinical phenotype, biochemical markers (antibody positive rate, platelet count and hemoglobin), clinical efficacy and recurrence were retrospective analyzed. The risk factors of HSP in the high-altitude Tibetan children were analyzed by univariate and multivariate Logistic regression analysis.

It was shown by univariate analysis that the proportion of allergic history and past history of high-altitude HSP children was higher than those of high-altitude healthy children (allergic history: 35.7% vs. 11.4%, past history: 21.4% vs. 5.7%, both P < 0.05). Compared with plain area HSP children, the age of high-altitude HSP children was increased (years old: 6.5±2.3 vs. 5.3±2.2), the clinical phenotype was more complex (37.9% vs. 57.1% for simple skin and limb type, 21.4% vs. 14.3% for abdominal type, 28.6% vs. 21.4% for renal type, 7.1% vs. 5.0% for brain or lung type, 5.0% vs. 2.2% for complex type), the positive rate of antibody was increased (64.3% vs. 50.0%), platelet count was decreased (×10⁹/L: 116.2±12.3 vs. 176.8±35.4), hemoglobin level was increased (g/L: 125.6±15.7 vs. 113.8±10.9), recurrence rate was lower (4.3% vs. 10.7%), and the difference was statistically significant (all P < 0.05). It was shown by multivariate Logistic regression analysis that age, allergic history and past history were independent risk factors for HSP in high-altitude Tibetan children [age: odds ratio (OR) = 1.263, 95% confidence interval (95%CI) = 1.063-1.968; allergic history: OR = 1.765, 95%CI = 1.326-2.452, past history: OR = 1.421, 95%CI = 1.102-2.232, all P < 0.05]. Clinical phenotypic and biochemical indexes were important risk factors affecting the clinical efficacy of high-altitude Tibetan HSP children (non-simple skin and limb type: OR = 2.123, 95%CI = 1.623-2.869; antibody positive: OR = 1.865, 95%CI = 1.502-2.768; both P < 0.05).

It is different of HSP occurrence in Tibetan children from plateau and plain areas. Attention should be paid to screening age, allergy history, past history, clinical phenotype, antibody positive and other high risk children. Early and effective intervention can improve clinical curative effect and reduce recurrence.