A comparative evaluation of different scores in predicting severity and outcome in acute pancreatitis

Introduction

The pancreas is a unique endocrine & exocrine organ. The exocrine glands discharges enzymes into the digestive system, while the endocrine glands secrete hormones into the circulatory system.¹ According to Claude Bernard's theory from 1856, acute pancreatitis was brought on by bile reflux into the common pancreatic duct. However, the controversy did not begin to be settled until 1901, when Eugene Opie proposed that gallstone immigration into the common bile duct was the major cause of acute pancreatitis.² When intracellular defences that stop trypsinogen activation or lessen trypsin activity are overpowered, AP results. Pancreatic enzyme activation causes the gland to digest itself & causes localised inflammation.³ Necrotizing pancreatitis & interstitial oedematous pancreatitis are two types of acute pancreatitis. Inflammation & edema are present in the peripancreatic tissues and pancreatic parenchyma in interstitial edematous pancreatitis. Necrotizing pancreatitis appears when this condition deteriorates to the point of peripancreatic or pancreatic tissue death.⁴ Most patients have localised inflammation, but about one-fifth of them go on to develop multiple organ dysfunction syndrome (MODS), which is linked to a significant increase in mortality. A diagnosis of acute pancreatitis requires abdominal pain, high pancreatic amylase and/or lipase values that are at least three times above normal, & imaging studies that show anomalies unique to acute pancreatitis. The Atlanta Classification has been used to gauge the severity of acute pancreatitis ever since its establishment in 1992.⁵ The original classification's boundaries given by Atlanta, notably the definition of severity is unclear. In 2012, the Atlanta classification was revised to include chronic organ failure.⁶ Early diagnosis of acute pancreatitis is crucial for lowering morbidity & mortality caused by the condition. To determine the severity of AP, many biochemical, radiological & clinical scores had been devised in the past. Ranson's score, the CT-severity index (CTSI), the bedside index of severity in acute pancreatitis (BISAP), the Modified Glasgow Score, & APACHE-II are some of them.⁷ Acute pancreatitis severity can now be determined with the use of these forecasting methods. Though complex & difficult to use in clinical settings, it has been shown that these multi-factorial scoring systems work with a high negative predictive value but a meagre overall sensitivity.⁸ In this study, we aim to determine which scoring method best predicted acute pancreatitis severity. Its secondary aim was to determine which scoring method best predicted the outcome of AP.

Methods

This observational and prospective research work was conducted for two years at a tertiary care centre in the rural area of Wardha district. Patients with significant abdominal pain, elevated serum amylase and serum lipase levels more than three times the upper limit of the normal range and abdominal ultrasonography findings suggestive of acute pancreatitis were included in the study. 110 subjects were studied. The Atlanta Criteria was used for the diagnosis of acute pancreatitis. The study was approved by Institutional Ethical Committee, Datta Meghe Institute of Medical Science (Deemed to be University) with Ref.No. DMIMS (DU)/IEC/2020-21/9284.

The enrolment of the subjects was started after approval from the ethics committee. The study included subjects over the age of 18 who provided written consent. The study excluded all subjects with chronic pancreatitis and those who received outside treatment prior to coming to the emergency room.

All subjects admitted for acute pancreatitis had their prospectively gathered demographic, clinical, biochemical, & radiological data. One can determine if they have acute pancreatitis if they meet two out of the following three criteria: (i) AP-specific abdominal pain, (ii) Serum amylase and serum lipase levels that are at least three times above normal (iii) Radiological abnormalities on abdominal ultrasonography and/or computerized tomography (CT) scan characteristic of acute pancreatitis. Patients with features of chronic pancreatitis, such as dilated pancreatic ducts, pancreatic calcifications, pseudocysts & areas of atrophy, discovered during radiological examinations performed while they were hospitalised or who had chronic pancreatitis based on their prior hospital records were excluded from the research.

After a thorough history & physical examination, several clinical & biochemical factors were assessed. All subjects underwent abdominal ultrasonography at the time of admission. Subjects with mild AP did not experience any local consequences or organ failure, however those with severity did. The local sequelae included pseudocyst, pancreatic necrosis, walled off necrosis, & acute fluid collections. MGS, BISAP, APACHE II score, Ranson score on admission & 48 hrs after were the grading systems used for assessment of all the subjects. Subjects were followed until they were discharged or died.

Results

According to the classification given by Atlanta, 110 subjects displayed symptoms of acute pancreatitis. Out of them, 60 (54.54%) had mild and 50 (45.46%) had severe acute pancreatitis. nine (0.08%) of them died while being treated in the hospital (Tables 1 and 2; Figures 1 and 2; Table 3).

Figure 1. ROC curve representing diagnostic performance of various scoring systems in predicting severity in AP.

Figure 2. ROC curve analysis showing diagnostic performance of scoring methods in predicting outcome in AP.

Discussion

Acute pancreatitis is pancreatic inflammation which can range from mild to severe. The majority of patients suffer with mild condition with low morbidity, while the others have severe acute pancreatitis, which has a mortality rate of 10% to 20%.⁹ In present study mean age of the subjects was 40.49±12.12 years and maximum i.e. 38 (34.5%) of the participants were in the age group of 31-40 years. 72 individuals, evaluated by Ajay K. Khanna et al., had mean age of 40.5 years, similar to our study.⁹ Similarly, in a study by Anubhav Kumar et al., 50 patients with acute pancreatitis had the mean age of 48.42 years.¹⁰ In our study there were 100 (90.9%) males and 10 (9.1%) of the subjects were females. Similar findings were reported by Lankisch PG et al., as they found, out of 274 patients 172 were males and 102 were females.¹¹ We found that the mean value of Serum Amylase was 399.82±104.82 U/L and 680.06±157.54 U/L in Mild and Severe acute pancreatitis groups, respectively. Kiat et al, also found in their study that the mean serum amylase was 1151.1±753.5 U/L and 1484.6±736.5 U/L in Mild and Severe acute pancreatitis groups, respectively.¹² In the present study, out of 110 subjects, 41 (37.3%) had APACHE II Score of <8 and 69 (62.7%) had APACHE II Score of ≥8. In their analysis of 161 Acute Pancreatitis patients, Cho J H et al., also observed that 52 (32.2%) of Severe Acute Pancreatitis patients had APACHE II score of <8 and 109 (67.8%) of Severe Acute Pancreatitis had APACHE II score of ≥8.¹³ In our study, 42 (38.2%) subjects had BISAP Score of <2 and 68 (61.8%) subjects had BISAP Score of ≥2. Cho et al., studied 161 subjects and found that 109 (67.70%) participants had BISAP Score of <2 and 52 (32.30%) participants had BISAP Score ≥2, which was in contrast to our study.¹³ In the present study, 62 (56.4%) subjects had Ranson score of <3 at admission and 48 (43.6%) subjects had Ranson score of ≥3 at admission. Similarly, Khanna et al. in their study of 72 participants showed that 37 (51.4%) participants had Ranson score of <3 and 35 (48.6%) participants had Ranson of ≥ 3.⁹ In our study, 61 (55.5%) subjects had Modified Glasgow Score of <3 and 49 (44.5%) subjects had Modified Glasgow Score of ≥3. Similar results were reported by by Kiat TT et al. in their study of 669 participants which showed that 425 (63.52%) participants had Modified Glasgow Score of <3 and 244 (36.48%) participants had Modified Glasgow Score ≥3.¹²

Conclusion

We conclude that the best scoring system for predicting the severity of Acute Pancreatitis is Ranson Score after 48 Hours with area under the curve, 0.900 (0.841 – 0.960), at 95% CI with p value <0.001 which was found to have the highest sensitivity and specificity of 87% and 86%, respectively. That was followed by Ranson score at admission with area under the curve 0.885, sensitivity of 85%, specificity of 75%. Then Modified glasgow scale with area under the curve 0.812, sensitivity of 77%, specificity of 72% then APACHE II score with area under the curve 0.812, sensitivity of 75%, specificity of 72% and lastly BISAP score with area under the curve 0.751, sensitivity of 73%, specificity of 67%.

We also conclude that BISAP Score was best with area under the curve, 0.841 (0.724 – 0.958) at 95% CI, with p<0.001 was found to have the highest sensitivity and specificity of 83% and 94%, respectively for predicting the outcome of Acute Pancreatitis as compared to Ranson score at admission with area under the curve 0.824, sensitivity of 70%, specificity of 73%, Modified glasgow scale with area under the curve 0.819, sensitivity of 66%, specificity of 75%, APACHE II with area under the curve 0.812, sensitivity of 75%, specificity of 60% and Ranson score after 48 hours with area under the curve 0.736, sensitivity of 70%, specificity of 80%.