Association of NOS Gene Polymorphisms with Sepsis-Related Complications in Secondary Peritonitis

Secondary peritonitis (SP) remains a major clinical challenge due to its high complication rates and it often results in sepsis and multi-organ dysfunction. This study investigated the association between four nitric oxide synthase (NOS) single-nucleotide polymorphisms (SNPs)-<i>NOS3</i> c.-786T>C (rs2070744), <i>NOS3</i> c.894G>T (rs1799983), <i>NOS3</i> 27 bp variable number tandem repeat (VNTR) (rs61722009), and <i>NOS2</i> (rs2297518)-and sepsis-related complications in 202 patients with SP. Demographic and baseline clinical characteristics, Acute Physiology and Chronic Health Evaluation (APACHE) II scores, Mannheim Peritonitis Index, and complications (multiple organ dysfunction syndrome (MODS), multiple organ failure (MOF), acute respiratory distress syndrome (ARDS), and sepsis) were analyzed for associations with the <i>NOS</i> gene variants. Haplotype analysis was also performed. No SNP showed an association with in-hospital mortality. However, the <i>NOS3</i> c.-786T>C TT genotype was significantly associated with an increased risk of MOF (<i>p</i> = 0.008), and remained independently associated after multivariate adjustment (<i>p</i>_MOF = 0.006). The T4bG haplotype was significantly more frequent among patients with MODS (<i>p</i> = 0.026), MOF (<i>p</i> = 0.048), and sepsis (<i>p</i> = 0.018). These findings suggest that <i>NOS</i> gene variants, particularly <i>NOS3</i> c.-786T>C and the T4bG haplotype, may potentially serve as biomarkers for risk stratification in critically ill patients.