Dynamic changes in FGF-21 and their association with inflammation and pulmonary function in ESRD patients undergoing peritoneal dialysis: a prospective cohort study.

BACKGROUND

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).

METHODS

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 (DLCO) 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.

RESULTS

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 DLCO 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.

CONCLUSION

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.