Ethnic differences in protein biomarkers of peripartum cardiomyopathy: a proteomic study on the EORP cohort

Aims The diagnosis of peripartum cardiomyopathy (PPCM) is often delayed due to the absence of disease‐specific biomarkers. Recently, serum proteins—QSOX1, adiponectin (ADIPOQ) and ITIH3—have shown potential for improving diagnostic accuracy, especially when used with NT‐proBNP. However, the influence of ethnicity on their expression remains unclear. We aimed to assess whether serum biomarker profiles differ among ethnic groups in a multinational PPCM cohort. Methods and results Eighty‐two PPCM patients from seven countries in the EURObservational Research Programme (EORP) provided demographic data and serum samples. Ethnicity was self‐reported. Proteomic profiling at diagnosis was performed using DIA‐based label‐free LC–MS, and data were analysed with Spectronaut v15. Ethnic variation was evaluated through principal component analysis (PCA). Participants had a mean age of 30.5 ± 6.7 years; 75% had no hypertension during pregnancy. Median LVEF was 35% (IQR 27.0–41.1), with no ethnic differences. Middle Eastern women showed more severe LV dilatation. PCA revealed no significant clustering by ethnicity; PC1 and PC2 explained 15.2% and 12.0% of variance, respectively. Conclusions QSOX1, ADIPOQ and ITIH3 exhibited consistent expressions across ethnic groups, supporting their use as universal PPCM biomarkers.