Acute appendicitis is one of the most common surgical emergencies worldwide, with an estimated lifetime risk of 7–10% and a peak incidence in the second and third decades of life [1]. Globally, appendicitis accounts for a significant proportion of emergency abdominal surgeries, and delayed diagnosis remains a major contributor to complications such as perforation, peritonitis, and abscess formation, which substantially increase morbidity and healthcare costs [2]. Despite advancements in imaging and laboratory diagnostics, predicting the intra-operative severity and postoperative outcomes in acute appendicitis remains challenging. In India, acute appendicitis represents a major burden on both urban and rural healthcare systems. Studies suggest that the incidence in Indian populations mirrors global trends, with a significant number of patients presenting late due to limited access to healthcare, lack of awareness, and delayed referral [3]. Complicated appendicitis, including gangrenous and perforated cases, is reported more frequently in India than in many high-income countries, highlighting the need for reliable preoperative markers to guide clinical decision-making and resource allocation. Systemic inflammatory markers have gained attention as simple, cost-effective tools for predicting disease severity. The neutrophil-to-lymphocyte ratio (NLR), calculated from a routine complete blood count, reflects the balance between innate and adaptive immunity and correlates with systemic inflammation [4]. Elevated NLR has been associated with complicated appendicitis, increased operative difficulty, and higher rates of postoperative complications such as wound infection, prolonged hospital stay, and intra-abdominal abscess formation [5]. This makes NLR an attractive biomarker in both developed and resource-limited healthcare settings. The utility of NLR in predicting surgical outcomes has been investigated in several global studies, demonstrating its potential as a reliable, inexpensive, and widely available tool for risk stratification in acute appendicitis [6]. In the Indian context, where advanced imaging and laboratory facilities may not always be accessible, NLR offers a practical approach to identifying high-risk patients who may benefit from early surgical intervention or more intensive perioperative care [3,7]. Despite promising evidence, there remains a need for prospective studies validating the correlation of preoperative NLR with intra-operative severity and postoperative outcomes, particularly in diverse populations. The present study was therefore undertaken to evaluate the predictive value of preoperative NLR in acute appendicitis and its association with intra-operative findings, postoperative recovery, and complications, with the goal of improving risk stratification and guiding surgical management in both global and Indian clinical practice. AIM To evaluate the correlation of preoperative neutrophil-to-lymphocyte ratio (NLR) with intra-operative severity and postoperative outcomes in patients with acute appendicitis. OBJECTIVES 1. To assess the relationship between preoperative NLR and intra-operative severity of appendicitis. 2. To evaluate the association of preoperative NLR with postoperative complications. 3. To determine if NLR can serve as a simple predictor for high-risk appendicitis cases.

Study Design and Setting This was a prospective observational study conducted in the Department of General Surgery at a tertiary care teaching hospital. Study Population All patients presenting with clinically suspected acute appendicitis and planned for emergency appendicectomy during the study period were evaluated for inclusion. Sample Size A total of 120 patients were included in the study. The sample size was determined based on Convenience sampling method, evaluating the role of neutrophil-to-lymphocyte ratio (NLR) in predicting appendicitis severity, a confidence level of 95% and power of 80%, and accounting for possible dropouts. Inclusion Criteria • Patients aged ≥18 years • Clinically diagnosed cases of acute appendicitis • Patients undergoing open or laparoscopic appendicectomy • Availability of complete preoperative blood investigations Exclusion Criteria • Patients with appendicular mass or abscess managed conservatively • Patients with chronic inflammatory diseases, malignancy, or autoimmune disorders • Patients on steroids, immunosuppressive drugs, or chemotherapy • Pregnant women • Patients with hematological disorders affecting white blood cell counts Preoperative Assessment All patients underwent detailed clinical evaluation, including history, physical examination, and routine laboratory investigations. Preoperative blood samples were collected at admission for complete blood count (CBC). The neutrophil-to-lymphocyte ratio (NLR) was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count obtained from the CBC. Surgical Procedure and Intra-operative Assessment Patients underwent open or laparoscopic appendicectomy as per standard institutional protocols. Intra-operative findings were documented by the operating surgeon and classified based on severity as: • Uncomplicated appendicitis (inflamed or suppurative appendix) • Complicated appendicitis (gangrenous, perforated appendix or presence of pus/abscess) Postoperative Assessment and Outcomes Patients were followed up during the postoperative period for assessment of outcomes, including: • Surgical site infection • Intra-abdominal abscess • Duration of hospital stay • Need for intensive care or re-intervention Postoperative outcomes were categorized as uneventful or complicated based on the presence of any postoperative morbidity. Statistical Analysis Data were entered into Microsoft Excel and analyzed using SPSS. Continuous variables were expressed as mean ± standard deviation, while categorical variables were expressed as frequencies and percentages. The association between preoperative NLR and intra-operative severity was assessed using the student’s t-test or Mann–Whitney U test as appropriate. The relationship between NLR and postoperative outcomes was evaluated using the Chi-square test. A p-value <0.05 was considered statistically significant.

A total of 120 patients with acute appendicitis were included in the study. The mean age of patients was 32.6 ± 11.4 years, with a male predominance. Table 1. Demographic Profile of Study Population (n = 120) Variable Number (%) Age (years), mean ± SD 32.6 ± 11.4 Male 72 (60.0) Female 48 (40.0) Open appendicectomy 68 (56.7) Laparoscopic appendicectomy 52 (43.3) A total of 120 patients diagnosed with acute appendicitis were included in the study. The mean age of the study population was 32.6 ± 11.4 years, with 72 (60%) males and 48 (40%) females. Open appendicectomy was performed in 68 (56.7%) patients, while 52 (43.3%) underwent laparoscopic appendicectomy (Table 1). Table 2. Distribution of Intra-operative Severity Intra-operative finding Number (%) Uncomplicated appendicitis 74 (61.7) Complicated appendicitis 46 (38.3) – Gangrenous 26 (21.7) – Perforated / pus 20 (16.6) Based on intra-operative findings, 74 (61.7%) patients had uncomplicated appendicitis, whereas 46 (38.3%) patients were found to have complicated appendicitis. Among the complicated cases, 26 (21.7%) had gangrenous appendicitis and 20 (16.6%) had perforation or presence of pus (Table 2). Table 3. Preoperative NLR in Relation to Intra-operative Severity Severity Mean NLR ± SD p-value Uncomplicated appendicitis 4.2 ± 1.3 Complicated appendicitis 8.1 ± 2.4 <0.001 Patients with complicated appendicitis had significantly higher preoperative NLR. The mean preoperative neutrophil-to-lymphocyte ratio (NLR) was significantly higher in patients with complicated appendicitis (8.1 ± 2.4) compared to those with uncomplicated appendicitis (4.2 ± 1.3), and this difference was statistically significant (p < 0.001) (Table 3). Table 4. Postoperative Outcomes Outcome Number (%) Uneventful recovery 92 (76.7) Postoperative complications 28 (23.3) – Surgical site infection 16 (13.3) – Intra-abdominal abscess 7 (5.8) – Prolonged hospital stay (>5 days) 5 (4.2) Postoperative recovery was uneventful in 92 (76.7%) patients, while 28 (23.3%) patients developed postoperative complications. The most common complication observed was surgical site infection in 16 (13.3%) patients, followed by intra-abdominal abscess in 7 (5.8%) patients and prolonged hospital stay (>5 days) in 5 (4.2%) patients (Table 4). Table 5. Association of Preoperative NLR with Postoperative Outcomes Outcome Mean NLR ± SD p-value Uneventful recovery 4.6 ± 1.5 Complicated recovery 8.5 ± 2.6 <0.001 Patients who developed postoperative complications had a significantly higher mean preoperative NLR (8.5 ± 2.6) compared to those with an uneventful postoperative course (4.6 ± 1.5), with the difference being statistically significant (p < 0.001) (Table 5). Table 6. NLR Cut-off and Risk Stratification NLR value Patients (n) Complicated appendicitis (%) ≤5 68 10 (14.7) >5 52 36 (69.2) A preoperative NLR >5 was strongly associated with complicated appendicitis. When patients were stratified based on preoperative NLR values, 68 patients had an NLR of ≤5, and 52 patients had an NLR of >5. Among patients with NLR ≤5, 10 (14.7%) developed complicated appendicitis, whereas 36 (69.2%) patients with NLR >5 had complicated appendicitis (Table 6).

In the present prospective study, preoperative neutrophil-to-lymphocyte ratio (NLR) showed a strong and statistically significant correlation with both intra-operative severity and postoperative outcomes in patients with acute appendicitis. Patients with complicated appendicitis had a markedly higher mean preoperative NLR (8.1 ± 2.4) compared to those with uncomplicated appendicitis (4.2 ± 1.3), highlighting the usefulness of NLR as a predictor of disease severity [8]. The biological basis for this association lies in the systemic inflammatory response seen in advanced appendiceal inflammation. Neutrophilia reflects acute inflammatory activation, while relative lymphopenia represents physiological stress, making NLR a sensitive composite marker of inflammation [9]. Similar findings were reported by Tsapras et al., who demonstrated significantly higher NLR values in perforated and gangrenous appendicitis compared to uncomplicated cases [10]. Keskin et al. also observed that elevated NLR was strongly associated with complicated appendicitis, supporting the findings of the present study [11]. In this study, postoperative complications were observed in 23.3% of patients, with surgical site infection being the most common. Patients who developed postoperative complications had a significantly higher mean preoperative NLR (8.5 ± 2.6) compared to those with an uneventful recovery (4.6 ± 1.5). This association suggests that NLR may serve as a useful marker not only for predicting intra-operative severity but also for anticipating postoperative morbidity [12]. Risk stratification based on NLR cut-off values further strengthened its predictive role. When an NLR cut-off of >5 was applied, 69.2% of patients in this group were found to have complicated appendicitis, compared to only 14.7% among patients with NLR ≤5. This finding is consistent with previous studies that identified elevated NLR as a reliable indicator of perforation and advanced disease [13]. The clinical relevance of these findings is particularly significant in the Indian healthcare setting, where delayed presentation and limited access to advanced imaging often result in higher rates of complicated appendicitis. As NLR is derived from a routine complete blood count, it represents a cost-effective and readily available tool for early risk stratification and surgical decision-making in emergency settings [13,14]. Despite its strengths, this study has limitations, including its single-centre design and lack of comparison with other inflammatory markers such as C-reactive protein. Larger, multicentric prospective studies incorporating multiple biomarkers may further enhance the predictive accuracy of NLR in acute appendicitis. Overall, the present study demonstrates that preoperative NLR is a simple, inexpensive, and reliable marker that correlates well with intra-operative severity and postoperative outcomes in acute appendicitis, and it can be effectively incorporated into routine clinical assessment.

Preoperative neutrophil-to-lymphocyte ratio is a simple, inexpensive, and reliable marker for predicting intra-operative severity and postoperative outcomes in acute appendicitis. Elevated NLR is significantly associated with complicated appendicitis and increased postoperative morbidity. Routine use of NLR may aid in early risk stratification and improved surgical decision-making.

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