Diagnostic performance of calprotectin and APPY-1 test in pediatric acute appendicitis: a systematic review and a meta-analysis

Utility of Ischemia-Modified Albumin as a Biomarker for Acute Appendicitis: A Systematic Review and Meta-Analysis

BACKGROUND

Acute appendicitis is a frequently encountered surgical emergency. Despite several scoring systems, the possibility of delayed diagnosis persists. In addition, a delayed diagnosis leads to an increased risk of complicated appendicitis. Hence, there is a need to identify biological markers to help clinicians rapidly and accurately diagnose and prognosticate acute appendicitis with a high sensitivity and specificity. Although several markers have been evaluated, the pressing concern is still the low specificity of these markers. One such marker is serum ischemia-modified albumin (IMA), which can be a novel biomarker for accurately diagnosing and prognosticating acute appendicitis.

METHODS

The authors conducted a systematic search of the PubMed, EMBASE, Web of Science, and Scopus databases through February 2023 as per the PRISMA guidelines. The difference in the levels of IMA between patients with acute appendicitis vs. healthy controls, and the difference in the levels of IMA between patients with complicated vs. non-complicated acute appendicitis were taken as the outcome measures. Statistical analysis was performed using a random effects model and mean difference (MD) was calculated. The methodological quality of the studies was assessed by utilizing the Newcastle-Ottawa scale.

RESULTS

A total of six prospective comparative studies were included in the meta-analysis. The analysis revealed that the mean level of serum IMA was significantly raised in the acute appendicitis group (MD 0.21, 95% CI 0.05 to 0.37, p = 0.01). Similarly, the mean serum IMA levels were also raised in the complicated appendicitis group compared to the non-complicated appendicitis group (MD 0.05, 95% CI 0.01 to 0.10, p = 0.02). Three of the studies included were, however, of poor methodological quality.

CONCLUSIONS

Serum IMA is a viable potential marker for diagnosing and prognosticating acute appendicitis. However, due to the limited methodological quality of available studies, further prospectively designed and adequately powered studies are needed.

The BIDIAP index: a clinical, analytical and ultrasonographic score for the diagnosis of acute appendicitis in children

BACKGROUND

Pediatric acute appendicitis (PAA) continues to be a diagnostic challenge today. The diagnostic performance of classical indices is only moderate, especially in pediatric population. This study aimed to define a clinical, radiological and analytical index for the diagnosis of PAA.

MATERIALS AND METHODS

This prospective study included 151 patients divided into two groups: (1) 53 patients with non-surgical abdominal pain (NSAP) and (2) 98 patients with a confirmed PAA. Sociodemographic and clinical characteristics were compared between groups using the Mann-Whitney U test and the Fisher exact test. To identify the predictors of PAA, we performed a multivariable logistic regression using a forward stepwise analysis and we assigned multiples of integer values to the selected variables. The diagnostic performance of the index was assessed by calculating the area under the receiver operating characteristic curve. Intra-cohort calibration was assessed with the Hosmer-Lemeshow test.

RESULTS

We developed the BIDIAP index (BIomarkers for the DIagnosis of Appendicitis in Pediatrics), which included three variables that independently predicted higher odds of PAA: appendiceal caliber (≥ 6.9 mm), systemic immune-inflammation index (≥ 890) and peritoneal irritation, which scored 4, 3 and 2 points, respectively. Mean (SD) score of the participants was 2.38 (2.06) in group 1 and 7.89 (1.50) in group 2. The area under the ROC was 0.97 (95% CI 0.95-0.99). The cut-off point was established at 4 points, resulting in a sensitivity of 98.98% and a specificity of 77.78%.

CONCLUSIONS

The BIDIAP index has an exceptional diagnostic performance in PAA. The importance of these results lies in its novelty and in the simplicity of the index. Although external validation will be necessary, initial results look promising.

Alterations and diagnostic performance of capillary ketonemia in pediatric acute appendicitis: a pilot study

INTRODUCTION

The diagnostic performance of capillary ketonemia (CK) has been previously evaluated in context of pediatric acute gastroenteritis. To our knowledge, there is no literature on its performance in the setting of pediatric acute appendicitis (PAA).

MATERIALS AND METHODS

In this study, 151 patients were prospectively included and divided into two groups: (1) patients with non-surgical abdominal pain in whom the diagnosis of PAA was excluded (n = 53) and (2) patients with a confirmed diagnosis of PAA (n = 98). In 80 patients (Group 1, n = 23 and group 2, n = 57) a CK was measured at the time of diagnosis. The PAA group was further classified into complicated (n = 18) and uncomplicated PAA (n = 39). Quantitative variables were compared between groups using the Mann-Whitney U test. Diagnostic performance of CK was evaluated with ROC curves.

RESULTS

CK values were 0.3 [0.1-0.9] mmol/L in group 1 and 0.7 [0.4-1.4] mmol/L in group 2 (p = 0.01). Regarding the type of PAA, CK values were 0.6 [0.4-0.9] mmol/L in uncomplicated PAA and 1.2 [0.8-1.4] mmol/L in complicated PAA (p = 0.02). The AUC for the discrimination between groups 1 and 2 was 0.68 (95% IC 0.53-0.82) (p = 0.24) and the AUC for the discrimination between uncomplicated PAA and complicated PAA was 0.69 (95% IC 0.54-0.85) (p = 0.04). The best cut-off point (group 1 vs group 2) resulted in 0.4 mmol/L, with a sensitivity of 80.7% and a specificity of 52.2%. The best cut-off point (non-complicated vs complicated PAA) resulted in 1.1 mmol/L, with a sensitivity of 61.1% and a specificity of 76.9%.

CONCLUSIONS

This study found significantly higher levels of CK in patients with PAA than in those with NSAP. Similarly, significantly higher levels were observed in patients with complicated than in those with uncomplicated PAA. Nevertheless, the diagnostic performance of CK was only moderate in the two settings analyzed. The potential usefulness of CK determination as a tool to guide the preoperative rehydration regimen of patients with PAA to prevent postoperative hyporexia and vomiting is a promising line of research and should be evaluated in future studies.

Diagnostic performance of serum pentraxin-3 in pediatric acute appendicitis: a prospective diagnostic validation study

INTRODUCTION

Pediatric acute appendicitis (PAA) is a pathology with a high rate of diagnostic error. The search for new diagnostic tools is justified by the high morbidity and healthcare costs associated with diagnostic error.

METHODS

We designed a prospective study to validate serum pentraxin-3 (PTX3) as a diagnostic tool in PAA. Participants were divided into three groups: (1) patients with no underlying pathology (2) patients with non-surgical abdominal pain and (3) patients with a confirmed diagnosis of PAA. For further analyses, patients in group 3 were divided into complicated or uncomplicated PAA. Quantitative variables were expressed as medians and interquartile ranges and categorical variables as percentages. Quantitative variables were compared using the Kruskal-Wallis test and the Mann-Whitney U test. Diagnostic performance was evaluated with ROC curves.

RESULTS

This study included 215 patients divided into group 1 (n = 63), group 2 (n = 53) and group 3 (n = 99). Median serum PTX3 values were 2.54 (1.70-2.95) ng/mL, 3.29 (2.19-7.64) ng/mL and 8.94 (6.16-14.05) in groups 1, 2 and 3, respectively (p = 0.001). Patients with complicated PAA showed significantly higher values than patients with uncomplicated PAA (p = 0.04). The AUC (group 2 vs. 3) was 0.77 (95% CI 0.69-0.85) and the best cut-off point was at 7.28 ng/mL, with a sensitivity of 61.3% and a specificity of 73.1%. The AUC (complicated vs. uncomplicated PAA) was 0.65 (95% CI 0.54-0.77) and the best cut-off point was 12.33 ng/mL, with a sensitivity of 51.72% and a specificity of 72.73%.

CONCLUSIONS

The diagnostic ability of serum PTX3 in PAA is only moderate and therefore it cannot be considered a definitive diagnostic test. The discriminatory ability of PTX3 between complicated and uncomplicated PAA is poor. These findings, which contrast with those reported to date, should be validated with future properly designed prospective studies.

Serum neutrophil gelatinase-associated lipocalin (NGAL) as a diagnostic tool in pediatric acute appendicitis: a prospective validation study

INTRODUCTION

NGAL has recently been studied as a biomarker in the diagnostic context of pediatric acute appendicitis (PAA), although existing series are scarce and have limited sample sizes.

MATERIALS AND METHODS

A prospective observational study was designed to validate serum NGAL as a diagnostic tool in PAA. This study included 215 patients, divided into 3 groups: (1) patients undergoing major outpatient surgery (n = 63), (2) patients with non-surgical abdominal pain in whom a diagnosis of PAA was excluded (n = 53) and (3) patients with a confirmed diagnosis of PAA (n = 99). Patients in group 3 were divided into complicated or uncomplicated appendicitis. In 201 patients, a serum sample was obtained at the time of diagnosis and NGAL concentration was determined by ELISA. The Kolmogorov-Smirnov test was used to assess normality. Comparative statistical analyses were performed using the Mann-Whitney U test, the Kruskal-Wallis test and the Fisher's exact test. To calculate the discriminative ability of the molecule, the area under the receiver-operating characteristic curves (AUC) was calculated. A p value < 0.05 established statistical significance.

RESULTS

Median (interquartile range) of serum NGAL values were 38.88 (27.15-48.04) ng/mL (group 1), 51.84 (37.33-69.80) ng/mL (group 2) and 65.06 (50.50-86.60) ng/mL (group 3). The AUC (group 2 vs 3) was 0.642 (95% CI 0.542-0.741) (p < 0.001) and the best cutoff point was found to be at 40.97 ng/mL, with a sensitivity of 89% and a specificity of 34.6%. No statistically significant differences in serum NGAL values were found between patients with uncomplicated PAA and those with complicated PAA.

CONCLUSIONS

This prospective validation study with a large sample size confirms that the diagnostic yield of NGAL in the context of PAA is only moderate, and therefore, it should not be used as a unique diagnostic tool. Furthermore, NGAL is not a valid biomarker to discern between uncomplicated and complicated PAA.

Discriminatory capacity of serum interleukin-6 between complicated and uncomplicated acute appendicitis in children: a prospective validation study

BACKGROUND

Serum interleukin-6 (IL-6) has a moderate diagnostic performance in pediatric acute appendicitis (PAA). The evidence regarding its capacity to discern between complicated and uncomplicated PAA is scarce.

METHODS

We designed a prospective observational study to validate serum IL-6 as a marker for diagnostic classification between complicated and uncomplicated PAA. This study included 205 patients divided into three groups: (1) patients who underwent major outpatient surgery (n = 57); (2) patients with non-surgical abdominal pain (NSAP) in whom the diagnosis of PAA was excluded (n = 53), and (3) patients with a confirmed diagnosis of PAA (n = 95). The PAA patients were further classified as uncomplicated or complicated PAA. IL-6 concentration was determined in all patients at diagnosis. Comparative statistical analysis was performed using the Mann-Whitney U test, the Fisher exact test and the Kruskall Wallis test. The area under the receiver operating characteristic curves (AUC) were calculated.

RESULTS

Median (interquartile range, IQR) serum IL-6 values were 2 pg/mL (2.0-3.4) in group 1, 3.9 pg/mL (2.4-11.9) in group 2, and 23.9 pg/mL (11.1-61.0) in group 3 (P < 0.001). Among the participants in group 3, those with uncomplicated PAA had median (IQR) serum IL-6 values of 17.2 pg/mL (8.5-36.8), and those with complicated PAA had 60.25 pg/mL (27.1-169) serum IL-6 (P < 0.001). At the cut-off point of 19.55 pg/mL, the AUC for the discrimination between patients in group 2 vs. 3 was 0.83 [95% confidence interval (CI) 0.76-0.90], with a sensitivity of 61.3% and a specificity of 86.8. The AUC for the discrimination between patients with uncomplicated and complicated PAA was 0.77 (95% CI 0.68-0.86) and the cut-off point was 25.90 pg/mL, with a sensitivity and specificity of 84.6% and 65.6%, respectively.

CONCLUSIONS

Serum IL-6 has a good performance in discerning between complicated and uncomplicated PAA. A score including clinical and radiological variables may increase the diagnostic performance of this molecule.