Complete blood counts and their derived inflammatory markers with anal fistulas in male children: A retrospective case-control study.

BACKGROUND: Perianal abscesses (PA) and pediatric fistula-in-ano (PFIA) are stages of the same perianal infectious disease, with PFIA often developing from PA. In children, PFIA predominantly affects male infants under one year, mostly involving low-level fistulas. The pathogenesis remains unclear, though infection and inflammation play central roles. Novel inflammatory markers, such as systemic inflammatory response index (SIRI), systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR), provide valuable insights into immune-inflammatory status. However, the relationship between complete blood count (CBC) derived markers and PFIA has not been investigated. This study evaluates CBC and its derivatives in PFIA to inform diagnosis, prognosis, and prevention strategies. AIM: To analyze changes in CBC and inflammatory markers in male infants and toddlers with PFIA. METHODS: Among 974 male infants and toddlers under six years of age, the case and control groups comprised 681 patients with PFIA and 293 healthy individuals, respectively. The CBC results and derived inflammatory markers, including the SIRI, SII, NLR, PLR, and MLR, were analyzed. The associations between PFIA and CBC-related inflammatory markers were also investigated. Finally, the predictive values of these markers were evaluated. RESULTS: PFIA was significantly associated with CBC-derived inflammatory markers. Compared with healthy controls, patients with PFIA demonstrated higher lymphocyte and lower MLR and SIRI levels, which remained robust after adjusting for patient age. Lymphocyte count, MLR, and SIRI had high predictive values. Additionally, lymphocyte count, MLR, and SIRI showed high clinical utility across a wide range of threshold probabilities, thus enhancing early detection and prognostic prediction. Finally, the number of fistula tracts in patients was significantly correlated with lymphocyte, MLR, and SIRI levels. CONCLUSION: Lymphocyte count may be an inflammatory biomarker in the evaluation of PFIA among male infants and toddlers. Closer clinical observation and timely preventive or diagnostic measures will be beneficial.