Peritonitis is a severe, life-threatening condition characterized by inflammation of the peritoneum, the serous membrane lining the abdominal cavity. It is usually caused by bacterial infection, which can either arise from within the abdominal cavity or spread via the bloodstream. Peritonitis can be classified into primary, secondary, or tertiary, depending on its cause. Primary peritonitis occurs without a direct gastrointestinal or genitourinary origin, commonly affecting patients with chronic liver disease or nephrotic syndrome who have ascites. Secondary peritonitis, the most common form, results from the rupture or perforation of an abdominal organ, releasing contents such as food, bile, or fecal material into the sterile peritoneal cavity. This contamination causes widespread inflammation. Tertiary peritonitis is a recurrent infection following either primary or secondary peritonitis, often due to inadequate treatment or antimicrobial-resistant pathogens [1-3].

Secondary peritonitis, especially resulting from hollow viscus perforation, requires urgent surgical intervention. It is a critical medical emergency that can lead to septic shock, organ failure, and death. The perforation usually occurs due to conditions such as peptic ulcer disease, appendicitis, diverticulitis, or Crohn's disease. When gastrointestinal contents spill into the peritoneal cavity, they trigger a systemic inflammatory response, progressing to sepsis and tissue damage. Peptic ulcer disease, a common cause of perforation peritonitis, remains prevalent, particularly in developing countries, where factors like Helicobacter pylori infection, NSAID use, and delayed medical care contribute to its high incidence. Although treatment options are available, such as proton pump inhibitors and H. pylori eradication therapies, perforation still remains a critical complication requiring immediate surgical attention [4-6].

Clinically, perforation peritonitis presents with severe abdominal pain, tenderness, fever, tachycardia, and hypotension. Patients may show signs of septic shock, including hypotension unresponsive to fluid resuscitation, altered mental status, and organ dysfunction. Early diagnosis and prompt surgical intervention are vital for improving survival. Standard treatment involves emergency surgery to repair the perforation, wash out the peritoneal cavity, and administer broad-spectrum antibiotics to control infection. Post-surgical drainage of the peritoneal cavity may also be necessary to prevent the buildup of infected material. Despite advancements in surgical techniques, ICU care, and antimicrobial therapies, the mortality and morbidity associated with perforation peritonitis remain high. The mortality rate can range from 10% to 40%, influenced by factors like delayed surgery, age, chronic NSAID or steroid use, and comorbid conditions such as diabetes or renal failure. Postoperative complications, such as wound infection, pneumonia, paralytic ileus, and septic shock, contribute to high morbidity and further complicate recovery, affecting overall survival rates [7,8].

Given the complexity of managing perforation peritonitis, early risk assessment is crucial to guide treatment decisions. Various scoring systems have been developed to predict mortality and morbidity, helping clinicians stratify patients and tailor interventions. Two widely recognized systems are the Mannheim Peritonitis Index (MPI) and the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM). The MPI is specifically designed to assess the severity of peritonitis and predict outcomes, especially in perforation cases. It incorporates parameters such as age, organ failure severity, extent of peritoneal contamination, and biochemical markers like white blood cell count and serum creatinine levels. A higher MPI score correlates with a higher risk of poor outcomes, including sepsis and multiorgan failure. It is a reliable, easy-to-use tool for clinicians, particularly in cases of perforated gastrointestinal ulcers [9,10].

The POSSUM scoring system, on the other hand, is a more comprehensive tool initially developed to assess surgical mortality and morbidity. It considers a broad range of physiological variables, such as cardiovascular and respiratory function, and operative factors like the type of surgery and degree of contamination. The final POSSUM score combines these values to predict patient outcomes. Although widely used in various surgical conditions, its application in perforation peritonitis is still an area of ongoing research [11,12].

The objective of this study is to compare the predictive accuracy and clinical relevance of the MPI and POSSUM scoring systems in patients with perforation peritonitis. By evaluating their effectiveness in predicting mortality and morbidity, the study aims to determine which scoring system provides the most reliable guidance for clinical decision-making. A more accurate scoring system would help identify high-risk patients early, allowing for more targeted interventions and better resource allocation. The results could also help refine existing treatment protocols, improve management strategies, and enhance survival rates for patients with perforation peritonitis [13].

Ultimately, perforation peritonitis remains a major cause of morbidity and mortality in emergency surgery, and reliable predictive tools are essential for improving patient outcomes. This study seeks to provide valuable insights into which scoring system—MPI or POSSUM—offers the best prognostic value for this challenging and critical condition. The findings may help optimize management strategies and improve survival rates by enabling earlier identification and intervention for high-risk patients [14].

The aim of this study is to conduct a comparative analysis between the Mannheim Peritonitis Index and the POSSUM scoring system in predicting mortality and morbidity in cases of perforation peritonitis. The objectives are to determine which scoring system is most accurate in predicting morbidity and mortality in perforation peritonitis and to identify the postoperative complications in different cases of perforation peritonitis.

This is hospital based prospective and observational study was conducted at the Department of surgery, S.N, Medical College Agra from 2023 to 2025 for 2 years. Ethical approval has been obtained from the Ethical Approval Committee of S.N, Medical College Agra.

Study Population

Patients undergoing emergency surgery and admitted to the emergency room of the Department of Surgery at S.N. Medical College, Agra, will be enrolled based on the inclusion and exclusion criteria. Inclusion criteria include patients aged 18-60 years with traumatic, infective, or iatrogenic etiology, or cases of perforation peritonitis diagnosed on X-ray. Exclusion criteria include cases of primary and tertiary peritonitis, pediatric patients, and those in septic shock.

Data Analysis

After patient admission, a detailed history will be taken, including general condition, abdominal pain, distension, vomiting, altered bowel habits, fever, duration of symptoms, co-morbidities like diabetes and hypertension, and any significant past history. Physical examination will assess pulse, BP, CVP, temperature, GCS, pupils, respiratory rate, and abdominal findings such as tenderness, guarding, and palpable masses. Investigations will include blood counts, KFT, LFT, ABG, serum electrolytes, PT-INR, chest X-ray, abdomen X-ray, USG, and ECG. Surgical procedures may involve primary closure of perforation or resection and anastomosis with proximal diverting stomas. Intraoperative details like blood loss, perforation site, and peritoneal contamination will be recorded. Post-operative care will focus on wound soakage, bowel sound appearance, chest infections, post-operative shock, and duration of hospital stay. The Mannheim Peritonitis Index and POSSUM scoring system will be used to assess patient severity and risk factors, including age, sex, organ failure, malignancy, sepsis origin, and operative details like blood loss and peritoneal soiling.

The study population comprised 52 males (52%) and 48 females (48%), reflecting a nearly equal gender distribution with a male-to-female ratio of approximately 1:1. The age of participants ranged from 15 to 60 years, with the mean age being 41 ± 13.24 years. Most subjects were in the 51–60-year age group (30%). Gender-wise age distribution showed that the highest number of male patients were in the 15–30 age group (n=17), while the highest number of female patients were in the 51–60 age group (n=16); however, the difference was not statistically significant (p=0.1949). Regarding outcomes, 86 patients (86%) were discharged, and 14 patients (14%) died. Mortality distribution between males (n=8) and females (n=6) was nearly equal, with no significant gender-based difference (p=0.7771). Similarly, analysis of outcomes by age group revealed no statistically significant association between age and mortality (p=0.08778), although a higher number of deaths occurred in the 51–60 age group.

Table 1: Distribution of study subjects as per the Mannheim Peritoneal Index

Among the study subjects, 52% were low-risk (MPI <21), 28% intermediate-risk (MPI 21–29), and 20% high-risk (MPI >29), with a mean Mannheim Peritoneal Index score of 21 ± 8.43.

Analysis of the Mannheim Peritoneal Index (MPI) revealed a statistically significant association with both gender and age. Among males, the majority (n=34) fell into the low-risk category (<21), while females were more represented in the intermediate-risk group (n=17), with a p-value of 0.0459 indicating significance. Regarding age, younger patients (particularly those aged 15–30 years) predominantly fell into the low-risk group (n=22), whereas the highest-risk category (>29) was most common among patients aged 51–60 years (n=18). The association between MPI and age groups was also statistically significant (p=0.004).

Table 2: Distribution of MPI Score based on outcome

Low MPI scores (<21) were significantly associated with discharge, whereas higher MPI scores (>29) showed a significant association with mortality (χ² = 14.04, p = 0.0008).

Table 3: Distribution of study subjects as per the Physiological Score

The mean physiological score was 29.96 ± 6.58, with the majority of subjects (33%) scoring between 26–30, showing a statistically significant distribution (p = 0.009).

Table 4: Distribution of study subjects as per the Operative Score

The mean operative score was 12.39 ± 4.39, with the highest proportion of subjects (47%) scoring between 11–15, indicating a statistically significant distribution (p = 0.0444).

Table 5:  Comparison of the predictive ability of MPI and POSSUM Scores for Perforative Peritonitis

Both MPI and POSSUM scores demonstrated high predictive accuracy for morbidity and mortality in perforative peritonitis, with POSSUM showing a slightly higher AUC (0.944 vs. 0.94).

Perforation peritonitis is a severe condition resulting from the perforation of an abdominal organ, releasing gastrointestinal contents into the peritoneal cavity, leading to widespread inflammation and infection. This medical emergency necessitates immediate surgical intervention, and the outcomes are heavily influenced by factors such as the infection's severity, the timing of surgery, the patient's health status, and any existing comorbidities. Predicting mortality and morbidity in these patients is crucial for effective clinical decision-making and risk stratification, helping guide interventions and post-operative care. The development of accurate prognostic tools is key to evaluating the severity of the condition, providing preoperative counseling, and determining the most effective treatment strategies [15].

Two prominent scoring systems used to assess the prognosis of patients with perforation peritonitis are the Mannheim Peritonitis Index (MPI) and the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM). Both tools are widely employed in clinical practice to evaluate outcomes in peritonitis cases, although their accuracy and applicability are still debated. The MPI, specifically designed for peritonitis, considers factors such as age, comorbidities, the degree of contamination, the organ involved, and the patient's physiological state. The score ranges from 0 to 42, with higher scores indicating a higher risk of morbidity and mortality. Conversely, the POSSUM scoring system, which was originally developed for evaluating surgical outcomes across various types of procedures, incorporates both physiological parameters (e.g., blood pressure, heart rate, temperature) and operative severity factors. Although POSSUM was not initially tailored for peritonitis, its broad application in surgical settings has led to interest in its use for perforation peritonitis [16,17].

The MPI offers the advantage of being more focused on the specific pathophysiology of intra-abdominal infections, directly relating to the key factors influencing outcomes in perforation peritonitis, such as contamination and the patient's general condition. However, its limitations include subjectivity and the lack of some modern physiological parameters that could improve its prognostic accuracy. On the other hand, POSSUM’s broad applicability and standardized approach make it a useful tool for evaluating surgical patients, though it may not fully capture the unique nuances of peritonitis-related outcomes. Studies comparing the predictive accuracy of these two systems suggest that MPI is more sensitive to the risks associated with peritonitis, but POSSUM’s comprehensive nature may also provide reliable predictions. Some researchers advocate for a combined approach using elements from both scoring systems to improve the accuracy of prognosis in these critically ill patients [18].

A recent study on the gender distribution of patients with perforation peritonitis revealed that 52% were male and 48% female, showing a nearly equal gender representation. This finding aligns with the results of other studies, where male patients slightly outnumber females in such cases, although the difference is not significant. Regarding age, the study showed that the highest proportion of patients (30%) were in the 51-60 age group, followed by 26% in the 15-30 age group. This pattern is consistent with findings from other studies that indicate a higher prevalence of perforation peritonitis in middle-aged and older individuals [19].

Further analysis of gender and age groups revealed no significant gender-based differences across various age categories, with similar distributions of male and female patients in each group. This contrasts with other studies where male patients, particularly in younger age groups, are more frequently affected. In terms of mortality, the study found that 14% of patients died, while 86% were discharged after treatment, which reflects the generally low mortality associated with early diagnosis and intervention. This is consistent with findings from other studies, where mortality rates are typically low, owing to advances in surgical and critical care management [20].

The study also examined the association between gender and mortality, finding no statistically significant differences. Both male and female patients exhibited similar mortality rates. Age, however, did appear to influence mortality, with older age groups showing higher mortality rates. This aligns with other studies that have observed increased mortality in older patients with perforation peritonitis. The study further analyzed the use of the Mannheim Peritonitis Index (MPI) for risk stratification and found that 52% of patients were classified as low-risk (MPI <21), 28% as intermediate-risk (MPI 21-29), and 20% as high-risk (MPI >29). This distribution reflects the general trend observed in other studies, where the majority of patients fall into the low-risk category, though a significant proportion are also classified as high-risk [21].

The correlation between MPI scores and mortality was significant in the study, with higher MPI scores associated with increased mortality. Among patients classified as low-risk, 4 died, while 8 died in the high-risk category, further supporting the utility of MPI in predicting outcomes. These results align with other research that has demonstrated a strong relationship between higher MPI scores and worse prognoses, highlighting the importance of using MPI to guide clinical decisions in perforation peritonitis cases [22].

The findings of this study indicate that both the MPI and POSSUM scoring systems are effective in predicting mortality and morbidity in cases of perforation peritonitis, with POSSUM showing slightly higher predictive accuracy. Elevated MPI and POSSUM scores were significantly associated with increased mortality, emphasizing the importance of these scoring systems in clinical practice for early risk assessment and personalized patient management. Given their predictive value, the use of these systems in emergency settings can improve clinical decision-making, prioritize high-risk patients, and optimize resource allocation to enhance patient outcomes.

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