Peroral endoscopic myotomy (POEM) is now considered one of the reference treatments for achalasia. However, predictive factors for unfavorable postoperative outcomes remain insufficiently defined.C-reactive protein (CRP), a simple, rapid, and accessible inflammatory biomarker, could help early identify patients at increased risk of complications.The objective of this preliminary study is to assess the association between the CRP level measured on day 1 after POEM, the occurrence of postoperative complications, and the length of hospitalization.

This is a prospective, descriptive, and analytical study conducted over 2 years and 10 months, from January 2023, including 52 patients who underwent POEM.We evaluated demographic data (age, sex), the type of achalasia, the Eckardt score, previous treatments (dilation or myotomy), the CRP level at day 1 post-POEM, and postoperative outcomes (complications and length of hospital stay). A prolonged hospitalization was defined as a stay longer than 4 days.Statistical analyses used Welch’s t-test for continuous variables and χ² or Fisher’s exact test for categorical variables. A ROC curve was constructed to determine the optimal CRP threshold predictive of complications.

The mean age of the patients was 43.7 years, with a male predominance

(53.8 %).11.5 % of patients had previously undergone treatment. Type II achalasia was predominant, representing 52.1 % of cases.Patients with postoperative complications had significantly higher CRP levels than those without complications (82.6 mg/L vs. 52.5 mg/L; p = 0.003).

Using a CRP threshold of 50 mg/L, the sensitivity was 27.8 % and the specificity 88.9 %. The positive predictive value (PPV) was 83.3 %, while the negative predictive value (NPV) was 38.1 %. The area under the curve (AUC) for this threshold was 0.293, indicating limited discriminative ability.

These results suggest that, although this threshold identifies at-risk patients with good precision (high PPV), its low sensitivity and limited AUC show that it cannot detect all cases of complications by itself. However, it could serve as a clinical alert marker, to be combined with other risk factors to optimize postoperative surveillance.

The overall rate of immediate postoperative complications was 17.3 %, including:

• -Mucosal breach: 3.85 %
• -Pneumoperitoneum: 5.77 %
• -Subcutaneous emphysema: 7.69 %
• -Pneumomediastinum: 1.92 %
• -Death: 1.92 %

Moreover, a post-POEM CRP > 50 mg/L was strongly associated with a prolonged hospital stay (χ² = 4.98, p = 0.026; Fisher’s exact test p = 0.042), with an odds ratio of 10.1 (95 % CI: 1.04–98).

Our preliminary study demonstrates that CRP at day 1 post-POEM is a significant predictive factor for postoperative complications (p = 0.003).A CRP level above 50 mg/L is also associated with an increased risk of prolonged hospitalization, making CRP a simple and potentially valuable tool to enhance postoperative monitoring