High dietary acid load predicts severity of autoimmune skin disease: a cross-sectional study

No previous study has examined the association of an acid-base imbalanced diet to autoimmune bullous disease. The present study aimed to investigate the association between dietary acid load (DAL) as either potential renal acid load (PRAL) and net endogenous acid production (NEAP) intake on the odds of high-severity Pemphigus Vulgaris (PV) disease in adult Iranian patients to fill this gap. A cross-sectional study was conducted on 138 patients, aged 18-65 years with confirmed diagnoses of PV in a referral university center for autoimmune bullous diseases. The dietary intakes of all patients during the last year before enrollment in the study were assessed using a 168-item semi-quantitative food frequency questionnaire. Dietary acid load was calculated based on the PRAL and NEAP scores. To assess PV severity, the pemphigus disease area index (PDAI) score was used. Logistic regression was used to evaluate the association between DAL and PDAI. A positive association was observed between PRAL and PDAI score in the crude (adjusted R² = 0.088, B = 6.88, P < 0.0001) and all other adjusted models, as well as the crude model for NEAP (adjusted R² = 0.037, B = 4.72, P = 0.013). In terms of adherence to NEAP and PRAL, those in the top tertile of PRAL and NEAP had a higher vulnerability for severe PV in unadjusted (OR = 5.18, 95% (CI) 2.19-12.25) and (OR = 2.48, 95% (CI)  1.08-5.68) respectively. In the present study, we found a significant direct association between DAL and severity of disease in PV patients. Further studies are required to confirm these findings.