Objective: The potential contribution of asymmetric dimethylarginine (ADMA) and high-sensitivity C reactive protein (hsCRP) to endothelial dysfunction in APS patients has not been studied in detail, until now. The study involved 105 APS patients (59 diagnosed with primary APS (PAPS) and 46 APS associated with systemic lupus erythematosus (SAPS)) who were compared to 40 controls. Endothelial dysfunction was assessed by measurement of flow-mediated dilatation (FMD) and glyceryl trinitrate dilatation (NMD) of the brachial artery. ADMA (micromol/L) was analyzed by ELISA. Results: FMD in patients with APS was significantly lower than that of the controls (p < 0.001), with no difference between the PAPS and the SAPS groups. ADMA and hsCRP concentrations were significantly higher in the patient cohort than in the control group (p < 0.001, p = 0.006, respectively), as was the case with the SAPS group as compared to the PAPS group (p < 0.001, p = 0.022, respectively). FMD impairment correlated to ADMA (ρ 0.472, p < 0.001) and to hsCRP (ρ 0.181, p = 0.033). In the regression model, the ADMA concentration confirmed the strength of its association (B 0.518, SE 0.183, Wald 8.041, p = 0.005, Exp(B) 1.679, 95% CI 1.174–2.402) to FMD impairment. The synergistic probability model of ADMA and hsCRP caused FMD impairment when the positivity of β2GPIIgG was added. ADMA may be used as a simple and low-cost tool for verifying the presence of endothelial dysfunction in APS patients. According to the results of the study, we could presume that hsCRP, together with aPL, has a preparatory effect on the endothelium in causing endothelial dysfunction.

Background: Anemia is common among patients with antiphospholipid syndrome (APS). It can persist alone (primary APS—pAPS) or with another associated disease (secondary APS—sAPS), predominantly systemic lupus erythematosus (SLE). There are no systematic reviews addressing the type of anemia (iron deficiency without anemia—IDWA, iron deficiency—IDA, and anemia of chronic disease—ACD) in these patients. Objectives: This study aimed to assess the type of anemia and to compare the usefulness of common diagnostic anemia parameters and their mutual relations. Methods: A cross-sectional study involving 163 patients was conducted at the University Clinical Center Bezanijska kosa from June 2022 to June 2024, including 79 patients with pAPS, 47 with sAPS and 37 patients diagnosed with SLE. We compared the usefulness of iron metabolism markers (serum iron—Fe; total iron-binding capacity—TIBC; ferritin; hepcidin) in the presence of inflammatory markers such as high-sensitivity (hsCRP) and IL6 in determining the type of anemia. Results: The most common types were IDA (61.9%) and IDWA (64.3%) in pAPS patients. In contrast, ACD was equally distributed across the three groups, with prevalences of 32%, 32%, and 36% (pAPS, sAPS, and SLE, respectively). A higher frequency of thrombosis was significantly associated with a high ferritin level ≥100 (p = 0.017) and high IL6 levels (p = 0.033) as well as fetal losses (p = 0.034 and p = 0.019, respectively). The logistic regression model identified ferritin as the only significant predictor of IDA (p = 0.023). For IDWA, both ferritin (p = 0.017) and hepcidin (p = 0.038) were significant predictors of this type of iron depletion. IL-6 levels were significantly correlated with ferritin and hsCRP levels (p = 0.004 and p = 0.007, respectively). In contrast, hepcidin did not show a statistically significant correlation with inflammatory markers. A total of 40% of patients with IDA had hepcidin levels below 10, and 48% of those with ACD had hepcidin levels above 10 (p = 0.036). Conclusions: It was found that iron deficiency anemia was the most common form in pAPS, while anemia of chronic disease was equally present across all patient groups. Ferritin emerged as an independent marker for identifying iron deficiency anemia in APS patients. Although hepcidin reflects a low-inflammatory state in APS, it proved to be a more valuable tool than ferritin in distinguishing the type of anemia, especially when ferritin levels were inconclusive. Clinical manifestations in APS patients correlated with inflammatory markers. Liver function or any drug used alone or in combination had no impact on anemia type.