Acute appendicitis is a frequently encountered surgical emergency characterized by sudden abdominal pain. Although its diagnosis has been extensively researched using a range of laboratory and radiological methods, clinical evaluation continues to be essential. Early identification and adequate management of appendicitis can result in a favorable outcome; however, a delayed diagnosis can increase the risk of morbidity as well as mortality. For the purpose of diagnosing acute appendicitis, several clinical scoring systems have been developed. The Alvarado scoring system and the Modified Alvarado scoring system (MASS) are the most often utilized scoring systems but exhibit limitations in certain populations. In 2008, the Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) score was created at Brunei Darussalam's RIPAS Hospital. It was created to improve the diagnostic accuracy of appendicitis in Asian and Middle Eastern populations because the sensitivity and specificity of the current Alvarado and MASS have been demonstrated to be insufficient in these areas. This research aims to assess and contrast the efficacy of MASS as well as RIPASA in patients who come with abdominal pain at Gauhati Medical College and Hospital. The objective is to determine which method is more efficient in promptly diagnosing acute appendicitis by assessing their sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy.

The research was conducted at Gauhati Medical College and Hospital in Guwahati over a period of one year, from January-December 2023 after obtaining approval from the Ethical Clearance Committee at GMCH. The study comprised of 120 patients who exhibited right iliac fossa pain and sought medical attention at the Surgery OPD as well as the Emergency Department, GMCH and it excluded those who fall under age group <5 & > 50 years, critically ill patients, known cases of tuberculosis and pregnant. Final diagnosis was confirmed either by CT scan, intra-operative finding, or post-operative histopathological examination report and was analysed against both RIPASA and MASS.

MODIFIED “ALVARADO SCORING SYSTEM (MASS)

              Score<5–unlikely to be appendicitis

          5-6–low-probability” to be appendicitis

          6-7–High-probability to be appendicitis

           >8–Definite appendicitis

RIPASA “SCORING SYSTEM :

       Score>5–unlikely to be appendicitis

          5-7.5-low-probability” to be appendicitis

          7.5-12–high-probability to be appendicitis

          >12–definite appendicitis

After scoring, patients in each group were classified into four categories based on their final scores.

Patient Management Procedures:

• Patients classified under the HP/D category were prioritized for immediate surgical intervention
• Patients categorized as LP underwent CT scanning for diagnostic purposes.
• Patients in the U category was evaluated for alternative causes of abdominal pain beyond appendicitis using imaging techniques and relevant laboratory tests.

All 120 patients suffering from pain in the right iliac fossa were evaluated employing the RIPASA along with MASS scoring system .

Analysis of RIPASA scoring        

All patients included in the research experienced discomfort in RIF, as it was a requirement for their inclusion. Out of the total, 98.3percent exhibited soreness in the RIF area, 45.8percent had a negative result in the urine, 69.2percent had a fever, and 64.2 percent had an elevated TC level. 29 percent of the patients had nausea/vomiting.

Table  showing various parameters of RIPASA score in our study

FIGURE showing Parameters of RIPASA score in this study

Patients were classified into four categories based on their total score. In this study, 0 patients scored above 12 and thus none were classified as category D. Forty-one patients  had scores ranging from 7.5 to 12, placing them in category HP. Seventy-three patients scored between 5 and 7.5, categorizing them as LP, while 6 patients with scores below 5 were assigned to category U.

Table  showing categories in RIPASA in our study

FIGURE showing The final score categories for RIPASA are as follows: D for Definite, HP for High-Probability, LP for Low-Probability, and U for Unlikely.

Analysis of MASS

Among the patients, 97.5% exhibited tenderness in the right iliac fossa (RIF), 69.2% had fever, 63.3% showed elevated total count (TC), and 29.2% experienced nausea or vomiting. Additionally, 39.2% reported migratory pain and anorexia, while 2.5% had rebound tenderness.

Table showing parameters in MASS in our study

FIGURE showing Parameters of MASS in the current research

The MASS scores categorized patients into four groups: 0.8% with scores above 8 were classified as D, 10% with scores between 6 and 7 were categorized as HP, 53.3% with scores from 5 to 6 fell into the LP category, and 35.8% with scores below 5 were classified as U.

Table showing categories in MASS score in our study

FIGURE showing Final score categories for MASS are: D for Definite, HP for High-Probability, LP for Low-Probability, and U for Unlikely

COMPARISON BETWEEN RIPASA AND MASS

SIGNIFICANCE

In this study, the specificity of RIPASA and MASS was found to be similar. However, RIPASA scoring demonstrated superior sensitivity, PPV, as well as diagnostic accuracy compared to MASS.

This research investigation assessed the effectiveness of both the RIPASA as well as MASS scoring systems by comparing them to the final diagnoses determined using CECT scans, intraoperative observations, and postoperative histopathological examination reports that included a total of 120 patients. The analysis revealed that while both RIPASA and MASS had equivalent specificity, RIPASA demonstrated greater sensitivity (40.00%) compared to MASS (13.00%). RIPASA also had a higher PPV(97.56%) than MASS (92.86%), and a superior NPV(24.05% versus 17.92%). Additionally, RIPASA showed better diagnostic accuracy (49.17%) compared to MASS (26.67%).

Given that RIPASA includes more parameters than MASS, it appeared to provide a more comprehensive assessment of the patient’s clinical status but may become difficult to calculate in certain circumstances. However in our study,  utilization of both RIPASA and MASS methods resulted in minimum time requirements & didn’t cause any notable disruptions in patient management.

After RIPASA was developed, Chong et al. prospectively enrolled 200 adults and children to compare the results with the AS in order to further test it. They discovered that while the AS displayed a sensitivity of 68%, an NPV of 71%, and an accuracy of 87%, RIPASA had a sensitivity of 98%, an NPV of 97%, as well as an accuracy of 92%. There were similarities in the two scoring systems' specificity & PPV.

When N.N. Mohammed et al. compared the RIPASA and Alvarado scores, they discovered that the RIPASA was more practical, precise, and targeted. In contrast to the Alvarado score, which had a sensitivity of 58% & a specificity of 85%, RIPASA had a sensitivity of 96% & a specificity of 90%.

When Erdem et al. evaluated the sensitivity rates of 4 clinical scoring systems—Alvarado, Eskelinen, Ohmann, and RIPASA—they discovered that they were, respectively, 81%, 80.5%, 83.1%, as well as 83%. They discovered that the most specific methods for identifying acute appendicitis employed the Ohmann and RIPASA scores.

In a 2018 meta-analysis, Maximos Frountzas et al. reviewed 12 studies with 2,161 patients, comparing the Alvarado and RIPASA scores for acute appendicitis diagnosis from 2004 to 2017. According to their report, RIPASA had a 94% sensitivity, 55% specificity, 0.9431 area under the curve, giving a diagnostic odds ratio of 24.66. RIPASA has been demonstrated to be more sensitive than the Alvarado score, with the latter having a diagnostic odds ratio of 7.99, an area under the curve of 0.7944, a specificity of 77%, along a sensitivity of 69%.

Syed Shams Ud Din et al. examined the Alvarado and RIPASA scores for diagnosing acute appendicitis in a cross-sectional prospective study conducted in 2023 with 400 patients. The results suggested that RIPASA had a 97.67percent diagnostic accuracy, a 98.88percent PPV, a 97.67percent NPV, a sensitivity of 95.8percent, as well as a specificity of 87.9percent. As an illustration, the Alvarado score displayed the following values: 71.1percent sensitivity, 75.1percent specificity, 96.84percent PPV, 21.82percent NPV, and 69.33percent diagnostic accuracy. According to this study, the RIPASA score has higher accuracy, sensitivity, and specificity than the Alvarado score.

 In a 2023 prospective cross-sectional study, 100 patients diagnosed with acute appendicitis at Shahid Sadoughi and Shahid Rahnemoon hospitals had appendectomy; the RIPASA and AS had been compared. The results showed that the RIPASA score had an AUC of 0.87, sensitivity of 86.6 percent, specificity of 66.7 percent, PPV of 92.2percent NPV of 52.2 percent, as well as diagnostic accuracy of 83 percent. In comparison, the AS had a sensitivity 67.1 percent, specificity 72.2 percent, PPV 91.7 percent, NPV 32.5 percent, diagnostic accuracy of 68%, and an AUC of 0.77. In comparison to the Alvarado score, the RIPASA score showed higher sensitivity, positive predictive value, negative predictive value, and accuracy.

 Similar evaluations were conducted by Hummaz Mehbub et al. and Suhas Devananthan et al. in 2023, comparing RIPASA with the MASS for diagnosing acute appendicitis.

In our investigation, RIPASA's sensitivity for identifying acute appendicitis had been 40 percent, 89.83% in Hummaz Mehbub et al., and 94.11% in Suhas Devananthan et al. Meanwhile, MASS had sensitivities of 13%, 64.41%, and 70.53% in these studies, respectively.

In our research, the specificity of RIPASA for diagnosing acute appendicitis was 95%. This was compared to 59.38% in the study by Hummaz Mehbub et al. and 93.75% in the study by Suhas Devananthan et al. Conversely, the specificity of MASS was 95% in our study, 53.12% in Hummaz Mehbub et al., and 68.75% in Suhas Devananthan et al.

In our research, the PPV of RIPASA for diagnosing acute appendicitis was 97.56%. This compared to 89.08% in the study by Hummaz Mehbub et al. and 96.96% in Suhas Devananthan et al. In contrast, the PPV for MASS was 92.86% in our study, 83.52% in Hummaz Mehbub et al., and 82.75% in Suhas Devananthan et al.

In our study, the NPV of RIPASA for diagnosing acute appendicitis was 24.05%. This was compared to 61.29% in Hummaz Mehbub et al. and 88.23% in Suhas Devananthan et al. In contrast, the NPV for MASS was 17.92% in our study, 28.81% in Hummaz Mehbub et al., and 52.38% in Suhas Devananthan et al.

In the present investigation, RIPASA had a diagnosis accuracy of 49.17 percent for acute appendicitis, compared to 83.33 percent in the research of Hummaz Mehbub et al. and 83 percent in the research of Naeimeh Heiranizadeh et al. In comparison, the diagnostic accuracy of MASS was 26.67% in our study, 62% in Hummaz Mehbub et al., and 68% in Naeimeh Heiranizadeh et al.

Therefore, this study suggests that RIPASA is more effective than MASS for diagnosing acute appendicitis.   

This study being conducted at a single centre, may limit the generability of the findings. It is recommended that more studies to be carried out with large sample size and in multiple centers

The present study concludes that , in the diagnosis of acute appendicitis, RIPASA score is more sensitive than Modified Alvarado score , and also has a higher positive predictive value and diagnostic accuracy. For the clinician, it gives a clearer categorisation of management of patients with right iliac fossa pain suggesting that in most cases , patients in HP/D category can straight away be taken up for surgery without any extra imaging modality, patients in LP category would benefit the maximum from CT imaging and those patients in U category can be worked up for non- appendiceal diagnosis. RIPASA also reduces the number of missed appendicitis cases . Hence  RIPASA is clinically and statistically a better scoring system for the diagnosis of acute appendicitis, as compared to MASS.

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