Association of Hemoglobin Level and Diagnostic Delay with Left Atrial Volume Index in Patients with Familial Mediterranean Fever: A Cross-Sectional Observational Study

Background/Objectives: Subclinical cardiac involvement may occur in familial Mediterranean fever, even outside acute attacks. However, the factors associated with variation in left atrial volume index (LAVI), particularly the roles of hemoglobin levels and diagnostic delay, remain poorly understood. This study aimed to evaluate the association between hemoglobin levels, diagnostic delay, and LAVI in patients with FMF. Methods: This cross-sectional observational study included 98 FMF patients with preserved left ventricular ejection fraction (LVEF ≥ 50%). Demographic, clinical, laboratory, and echocardiographic parameters were assessed. The relationships between LAVI, hemoglobin levels, and diagnostic delay were investigated using correlation analyses and multivariable linear regression. Results: Patients were 35.3 ± 12.4 years old on average, and 45.9% were men. The mean hemoglobin level, diagnostic delay, and LAVI were 13.51 ± 1.63 g/dL, 8.90 ± 9.94 years, and 18.32 ± 4.67 mL/m2, respectively. LAVI was inversely correlated with hemoglobin (r = −0.454, p < 0.001) and positively correlated with diagnostic delay (r = 0.262, p = 0.009). In the final multivariable model, hemoglobin (β = −0.333, p < 0.001), LVEF (β = 0.244, p = 0.006), and LVMI (β = 0.265, p = 0.002) were independently associated with LAVI, whereas diagnostic delay (β = 0.212, p = 0.017) and lateral a′ (β = 0.215, p = 0.014) were considered exploratory associations. Conclusions: In FMF patients, lower hemoglobin levels were independently associated with higher LAVI values, whereas diagnostic delay showed an exploratory association. These findings are hypothesis-generating and require confirmation in longitudinal studies.