RIPASA versus Alvarado score in the assessment of suspected appendicitis in children: a prospective study

Diagnosis of acute appendicitis remains a problem in children with right lower quadrant pain. Challenging diagnosis and fears of missing an inflamed appendix may lead to a negative appendectomy. Many scoring systems have been developed to reduce ambiguities in the diagnosis of appendicitis. Alvarado is one of the most commonly used scoring methods in pediatric patients. The RIPASA score is considered to be a better diagnostic scoring method in adults compared to Alvarado. The present study aims to compare RIPASA and Alvarado scoring systems in determining the possibility of acute appendicitis in children with right lower quadrant pain. This study included 179 consecutive pediatric patients who were referred to pediatric surgery with suspicion of acute appendicitis. The cut-off value was >7.5 for the RIPASA score vs. ≥7 for the Alvarado score. The possibility of appendicitis was divided into three groups for the Alvarado score and four groups for the RIPASA score. In this study, 158 of 179 patients were operated on. In 140 of the operated patients, the diagnosis of appendicitis was confirmed by histopathology. The negative appendectomy rate was 11.4%. Specificity and negative predictive value of RIPASA score were higher than those of Alvarado (p<0.001). No difference was found between the two scores concerning sensitivity, positive predictive value, and the area under the receiver operator characteristics curve (p>0.05). The RIPASA scoring system can be used as an alternative to the Alvarado scoring system in the management of patients with right lower quadrant pain in emergency services and pediatric outpatient clinics. With the use of the RIPASA score, more patients with a low likelihood of appendicitis can be detected and further contributed to the reduction of the negative appendectomy rate.


Background
Acute appendicitis is the most common emergency surgical pathology in children. It is not easy to diagnose, especially in children younger than 5 years of age which may lead to an increased rate of perforation [1]. Diagnosis is usually established with history, physical examination and non-specific laboratory investigations such as white blood count (WBC), Neutrophil percentage (NP), C-reactive protein (CRP), and imaging methods. Ultrasonography (USG) is the first and the most preferred imaging method due to its quick practicality and nonradiation exposure. It has disadvantages, such as failure to visualize the retrocecal appendix, as well as its dependency on the performer [2,3]. In patients in whom USG fails to visualize the appendix, it is recommended that the patient be monitored instead of utilizing methods, such as contrast tomography (CT) or magnetic resonance imaging (MRI) or diagnostic laparoscopy [4].
Complications such as abscess, perforation, peritonitis, and rarely sepsis may develop during monitoring [5]. Emergency operations performed in patients with suspected acute appendicitis may result in a negative appendectomy [1,6,7]. Many scoring systems have been developed to reduce ambiguities in the diagnosis of appendicitis. Alvarado is one of the most commonly used scoring methods in pediatric patients [2]. The RIPASA includes some parameters not included in the Alvarado score, such as age, gender, symptom duration, and urinalysis, which are not found [7,8]. To our knowledge, in the current literature, there is no study comparing RIPASA and Alvarado scoring systems in the evaluation of the possibility of acute appendicitis in children with right lower quadrant pain.
This study aims to compare RIPASA and Alvarado scoring systems in assessing the possibility of acute appendicitis in pediatric patients with right lower quadrant pain.

Methods
This prospective study included 179 consecutive patients who had been referred to our pediatric surgery clinic with suspected acute appendicitis between July 2018 and December 2019. The Institutional Ethics Committee approved this study. Written informed consent to participate in this study was obtained from patients' parents /legal guardians. During the study period, patients with right lower quadrant pain managed conservatively or by appendectomy were included in this study. Patients younger than 5 years of age who were unable to cooperate in the physical examination were excluded from this study.
The decision to operate was made by surgeons independently other than those who conducted this study based on history, examination, laboratory, and radiological imaging. Patients were evaluated by the physicians who performed this study before the operation. Patients' age, gender, duration of symptoms, nausea, vomiting, tenderness in the right lower quadrant, migration of pain to the right lower quadrant, defensive, rebound, Rovsing's sign, fever, WBC, NP, CRP, urinalysis, and radiology reports were recorded in the pre-prepared scoring form.
RIPASA and Alvarado scores were calculated prospectively for only this study. RIPASA and Alvarado Scores are presented in Table 1.
The possibility of appendicitis was divided into three groups for the Alvarado score and four groups for the RIPASA score. RIPASA score was considered very high at ≥12, high at 7.5-11.5, moderate at 5-7, and low probability at <5; Alvarado score was considered high at ≥7, moderate at 5-6, and of low probability at 0-4 [1,11].
The accuracy rate, sensitivity, specificity, negative predictive values (NPV), positive predictive values (PPV), and receiver operator characteristics curve (ROC) analysis were performed for RIPASA and Alvarado scoring systems.

Statistical methods
Data obtained in this study were statistically analyzed using SPSS Statistics for Windows, Version 22.0. (IBM Corp. Released 2013. Armonk, NY). Categorical variables were expressed as numbers (n) and percentages (%) and the Kolmogorov-Smirnov test was used to examine the normal distribution of continuous data. Numerical variables with normal distribution were shown as mean ± standard deviation. Normally distributed numerical variables were compared by Student's t-test. The cut-off value was >7.5 for the RIPASA score vs. ≥7 for the Alvarado score [12]. Pearson's chi-square test was used to determine whether there was a difference between RIPASA and Alvarado scores concerning accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under the ROC curve (AUC). In all data, p <0.05 was considered statistically significant.

Results
Of the 179 patients included in the present study, 33.5% were girls and 66.5% were boys and the mean age was 11.6 ± 3.2 years (5-17 years The distribution of scores was as follows. RIPASA was very high in 5.6%, high in 67.1%, moderate in 26.8% and low in 0.5% whereas Alvarado was high in 57%, moderate in 27.8%, and low in 15.2% (Table 3). Conservative management was applied to 21 of the patients, while 158 of them received surgical treatment (Table 4).
In our study, the sensitivity and specificity of RIPASA score were 76.9% and 87.1 %, while those of Alvarado score were 84.6% and 55.4%, respectively. This demonstrated statistically significant superiority of the RIPASA score in terms of specificity (P<0.001).
PPV and NPV were 93.1% and 61.2% in RIPASA score vs. 95.1% and 44.2% in the Alvarado score, respectively. The NPV was significantly higher for the RIPASA score compared to the Alvarado score (p < 0.001).
The accuracy rate was 84.4% in the RIPASA score vs. 73.2% in the Alvarado score. With ROC curve analysis applied, AUC was 0.827 (0.75-0.90) in the RIPASA score vs. 0.826 (0.74-0.90) in the Alvarado score. The AUC accuracy rate of RIPASA and Alvarado scores were not different (p = 0.97) ( Table 5).
Since the number of foreign patients (n = 5) was very low in our study, there was no significant change as a result of the inclusion of these patients.

Discussion
Diagnosis of acute appendicitis remains a problem in children with right lower quadrant pain. In laboratory tests, the increase in WBC count, NP, and CRP can be interpreted in favor of appendicitis, but the diagnostic value of these tests is low [3,13]. Although ultrasonography is usually performed for diagnosis in patients with suspected appendicitis, the detection rate of the appendix vermiformis by ultrasonography varies between 2 and 82% [5]. Challenging diagnosis and fears of missing an inflamed appendix may lead to the negative appendectomy at a rate of 15-27% [1,6,7]. Since only patients with right lower quadrant pain referred to pediatric surgery were evaluated in our study, the rate of negative appendectomy (11.4%) was relatively low compared to previous studies. Currently, there is a tendency for patients with suspected appendicitis to be observed rather than operated and to perform surgery in patients who do not respond to medical treatment and observation. Using scoring systems, identifying patients with a low probability of appendicitis may contribute to the reduction of negative appendectomies.
While some studies have reported that the RIPASA score is more valuable in adult patients [11,14,15], other studies have reported higher accuracy and sensitivity but lower specificity for the RIPASA score compared to the Alvarado scoring system [16,17]. In a study conducted by Díaz-Barrientos et al., the findings showed that the RIPASA score had no advantage over the Alvarado score [18]. Another study was reported that no significant difference was found in ROC analysis between RIPASA and Alvarado scores concerning the area under the curve [19]. In our study, the specificity of the RIPASA scoring system was higher than Alvarado in children with right lower quadrant pain. The results of our study support that more parameters in the RIPASA score increase the specificity. Our study suggests that the RIPASA score may be more useful than Alvarado in identifying patients with a low probability of appendicitis in the differential diagnosis of patients with suspected appendicitis.
Various studies have reported the NPV value of the RIPASA score in the range of 10.1-97.6% [11, 14, 16-18, 20, 21], while the NPV value in the Alvarado score has been reported as 64-87.8% [1,13]. It has been stated that the Alvarado score does not have sufficient PPV and NPV to determine the need for surgery [1,3]. In our study, the NPV value was higher in the RIPASA score (60%) than the Alvarado score (45.3%). Our results suggest that the NPV value of the RIPASA score is higher due to the patient's history, duration of symptoms, pain in the right lower quadrant, guarding, Rovsing's sign, and urine test. In addition, it was concluded that history and repeated examinations have an important role in the differential diagnosis of patients with right lower quadrant pain.
RIPASA and Alvarado scoring systems can be used in the management of patients with right lower quadrant pain. It has been reported that acute appendicitis can be excluded in patients with low scores in both scoring systems [1,6,11]. In our study, appendicitis was not detected in patients with low RIPASA scores. However, contrary to the literature, appendicitis was detected in 5.1% of the patients who were evaluated with low Alvarado scores. Therefore, we think that the RIPASA scoring system is more useful in identifying patients with a low probability of appendicitis and who do not need emergency surgery in children with abdominal pain. In patients with moderate Alvarado scores and moderate or high RIPASA scores monitoring and score repetition or US were recommended [1,6,11]. In our study, the rate of negative appendectomy was similar in patients with moderate Alvarado scores and moderate and high RIPASA scores. In patients with high Alvarado scores and very high RIPASA scores, surgery is recommended [1,6,11]. In our study, negative appendectomy was not detected in patients who were evaluated with a very high RIPASA scores, but negative appendectomy was detected at a rate of 2.8% in patients who were evaluated with high Alvarado scores. According to the results of our study, pediatric patients with right lower quadrant pain and low RIPASA scores can be discharged.

Limitations of the study
This study was conducted in a single center; the number of patients was small and only patients with abdominal pain referred to pediatric surgery were evaluated.

Conclusions
The RIPASA scoring system can be used as an alternative to the Alvarado scoring system in the management of patients with right lower quadrant pain in emergency services and pediatric outpatient clinics. With the use of the RIPASA score, more patients with a low likelihood of appendicitis can be detected and further contributed to the reduction of the negative appendectomy rate. Thus, hospital costs can be reduced, and time and labor loss can be prevented. Further studies with more patients and multi-center studies are required to strengthen the results of this study.