Dynamic changes in FGF-21 and their association with inflammation and pulmonary function in ESRD patients undergoing...

End-stage renal disease (ESRD) is frequently accompanied by systemic inflammation and pulmonary dysfunction. Fibroblast growth factor-21 (FGF-21), an emerging metabolic and inflammatory biomarker, may be involved in these pathological processes. This study aimed to evaluate dynamic changes in FGF-21 and their association with inflammatory markers-including C-reactive protein (CRP) and interleukin-6 (IL-6)-as well as pulmonary function in ESRD patients receiving peritoneal dialysis (PD).

In this prospective cohort study, 150 ESRD patients initiating PD were enrolled. Serum FGF-21, CRP, and IL-6 levels were measured at baseline and at 1, 3, and 6 months after PD initiation. Pulmonary function parameters, including forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), diffusing capacity for carbon monoxide (DL_CO) and maximal voluntary ventilation (MVV), were assessed at baseline and 6 months. Longitudinal changes in FGF-21, CRP, and IL-6 were analyzed using linear mixed-effects models and correlation analyses were used to examine associations among FGF-21, inflammatory markers, and lung function.

Over 6 months of PD, FGF-21, CRP, and IL-6 levels significantly decreased (p < 0.01). Mixed-effects linear time models demonstrated a significant decline in FGF-21 (Estimate =  - 0.0457, p < 0.001), which remained significant after adjusting for residual renal function, dialysis adequacy (Kt/V), BMI, and smoking status (p < 0.001). Pulmonary function improved, with FEV₁ increasing by 0.098 L (p < 0.001), FVC by 0.101 L (p < 0.001), and DL_CO by 0.47 mL/min/mmHg (p < 0.001). However, MVV did not show a significant change (p = 0.320). However, correlations between FGF-21 and pulmonary function and inflammatory factors were weak and non-significant (all p > 0.05). Subgroup analyses showed that age and baseline CRP did not significantly affect FEV₁ improvement, but patients with lower baseline FGF-21 showed slightly better recovery.

FGF-21 demonstrates consistent associations with inflammatory markers including CRP and IL-6, and inversely relates to pulmonary function in ESRD patients undergoing PD. These findings support the potential role of FGF-21 as an integrative biomarker for systemic inflammation, renal impairment, and respiratory dysfunction in this population.