Abstract: Objective To investigate the relationship between fibroblast growth factor-21 (FGF-21), protein kinase R-like endoplasmic reticulum kinase (PERK) and acute physiology and chronic health system Ⅱ (APACHE Ⅱ) score in patients with mild acute pancreatitis (MAP), and to analyze the value of the two in evaluating the risk of disease progression after conservative treatment. 
Methods A total of 169 patients with MAP were selected and divided into a progression group (n=32) and a non-progression group (n=137) according to whether they progressed to moderately severe AP (MSAP) or severe AP (SAP) within 24 h after admission.The serum FGF-21 and PERK levels were detected at admission and 24 h after admission, and the APACHE II score was evaluated. The relationship between serum FGF-21 and PERK levels and APACHE Ⅱ score and their effects on disease progression were analyzed. Receiver operating characteristic curve (ROC) and decision curve analysis (DCA) were used to evaluate the value of serum FGF-21 and PERK in the progression of MAP patients. 
Results The levels of serum FGF-21 ［(2.37±0.33) vs. (2.05±0.31),(2.57±0.36) vs. (1.89±0.32)ng/L］, PERK［(24.68±4.35) vs. (20.43±4.08), (27.19±4.54) vs. (17.81±4.03)μg/L］ and APACHE Ⅱ score ［(12.54±2.62) vs. (9.87±2.58), (13.94±2.54) vs. (8.45±2.29)］ in the progression group at admission and 24 h after admission were higher than those in the non-progression group (t=5.194， 10.566， 5.239， 11.569， 5.256，  11.958， P＜0.001). The levels of serum FGF-21, PERK and APACHE Ⅱ score in the progression group at 24 h after admission were higher than those at admission, while these indicators in the non-progression group were lower than those at admission (P＜0.05). The serum FGF-21 (r=0.872, 0.445, P＜0.001) and PERK (r=0.852,0.372, P＜0.001) levels were positively correlated with the APACHE Ⅱ score at admission and 24 h after admission (P＜0.05). Logistic regression analysis model showed that FGF-21 and PERK were independent risk factors for disease progression (P＜0.05). The area under the ROC curve (AUC) value of the combined assessment of FGF-21 and PERK for disease progression was 0.872, which was greater than that of FGF-21 （χ2=2.746, P=0.006） and PERK alone (χ2=2.784, P=0.005). Within the threshold range of 0.10 to 0.88, the net benefit rate of FGF-21 and PERK in combination to assess disease progression was superior to that of single detection. 
Conclusion The changes of serum FGF-21 and PERK levels in MAP patients are closely related to the APACHE Ⅱ score, and they are independent risk factors for the progression of MAP. They can provide a reference for clinical assessment of the risk of MAP progression.

Key words: pancreatitis, fibroblast growth factors 21, protein kinases