Predicting the onset of bullous pemphigoid with co-morbidities: A survey based on a nationwide medical database

Bullous pemphigoid (BP) is an acute or chronic autoimmune skin disease. It has been reported that poor conditions of general health and increased mortality rates were observed in BP patients, while pathophysiologic reasons of these phenomena merit further investigation yet. In this paper we tried to investigate the co-morbid associations between bullous pemphigoid and various diseases, using a nationwide population-based medical database, NHIRD. 5,933 adult BP patients of ages >= 18 years were extracted from the NHIRD, accompanied with 17,712 age- and sex-matched control subjects. Thirty-one disorders were selected from the Charlson or Elixhauser index for which we tried to evaluate their respective associations with BP. The results obtained revealed that there existed co-morbid relationships between BP and various illnesses, especially for hemiplegia/paraplegia (odds ratio [OR] 8.71), dementia (OR 8.04), fluid electrolyte disorders (OR 6.6), cerebrovascular disease (OR 5.97), moderate/severe liver disease (OR 5.22), weight loss (OR 4.9), and psychoses (OR 4.64). Furthermore, using the study cohort as input data and the retrospective diagnosis records of the above-mentioned co-morbidities occurring within 24 months before onset of BP as features, we employed the algorithm of support vector machine (SVM) to generate the prediction model for onset of BP afterward. Subjects labeled as positive by the prediction model were about 9 times more likely than those as negative to actually develop BP. Accordingly, the prediction model created by SVM was valuable for physicians to screen patients with higher risk of BP.