Utility of Red Cell Distribution Width (RDW) as a Noninvasive Biomarker for the Diagnosis of Acute Appendicitis: A Systematic Review and Meta-Analysis of 5222 Cases

Diagnostic value of laboratory parameters for complicated appendicitis: A two‑center study

There are two types of treatment for acute appendicitis (AA): surgery and antibiotic therapy. Some patients with complex appendicitis are treated with surgery; however, for uncomplex appendicitis, most could be treated effectively with antibiotics instead. How to distinguish complex appendicitis from uncomplex appendicitis before surgery is currently unknown. The present study aimed to assess the efficacy of the laboratory parameters to diagnose complicated appendicitis. Data from 1,514 cases with acute appendicitis who were admitted to Beijing Tsinghua Changgung Hospital and Beijing Aerospace General Hospital (both Beijing, China) from January 2016 to September 2021 were retrospectively analyzed. All cases were divided into uncomplicated and complicated appendicitis. Independent variables were analyzed by uni- and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curve analysis was used to identify significant parameters in the multivariate logistic regression analysis. Cut-off values, sensitivity, specificity and accuracy with area under the curve (AUC)>0.600 were considered significant parameters. Significant differences were found in age (P<0.001), body temperature (P<0.001), white blood cell (WBC) count (P<0.001), C-reactive protein (CRP; P<0.001), neutrophil count (P<0.001), neutrophil-to-lymphocyte ratio (NLR, P=0.019), platelet-to-lymphocyte ratio (PLR, P<0.001), platelet count (P<0.001), coefficient of variation (CV) and standard deviation (SD) of red blood cell distribution width (RDW); both P<0.001), mean platelet volume (MPV, P<0.001) and total (P<0.001) and direct bilirubin (P<0.001) between the two groups. CRP, neutrophil count, NLR, PLR, platelet count, RDW-CV, RDW-SD, MPV and direct bilirubin levels were found as the independent variables to diagnose complicated appendicitis. In patients with acute appendicitis, CRP >22.95 mg/l, NLR >5.7, serum direct bilirubin >6.1 mmol/l and RDW-SD>17.7 fl were significantly associated with complicated appendicitis.

Association of mean RDW values and changes in RDW with in-hospital mortality in ventilator-associated pneumonia (VAP): Evidence from MIMIC-IV database

INTRODUCTION

Ventilator-associated pneumonia (VAP) is a hospital-acquired infection with high mortality, and remains a challenge for clinical treatment. Red blood cell distribution width (RDW) was associated with worse outcomes in several diseases. The purpose of this study was to investigate the relationship between mean RDW values, changes in RDW (delta RDW), and in-hospital mortality among patients with VAP.

METHODS

In the present study, we enrolled 1266 VAP patients from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. All patients were categorized into low group, medium group, and high group according to tertiles of mean RDW values. The primary outcome was all-cause in-hospital mortality. Univariate logistic regression analysis, multivariate logistic regression analysis, and restricted cubic spline (RCS) curve were performed to determine the association between mean RDW values and in-hospital mortality in VAP. Moreover, RCS curve was plotted to explore the dose-response relationship between delta RDW and in-hospital mortality in VAP.

RESULTS

Among the VAP patients included in the study, the in-hospital mortality was 20.85% with 264 non-survivors and 1002 survivors. The non-survivors exhibited significantly higher mean RDW values and delta RDW values compared to survivors. Multivariate logistic regression analysis indicated that mean RDW values were positively associated with in-hospital mortality in VAP after adjusting for relevant covariates. The RCS curve demonstrated a dose-response relationship between mean RDW and the mortality in VAP. Moreover, a linear relationship was observed between delta RDW and in-hospital mortality in VAP.

CONCLUSION

Higher mean RDW values were significantly associated with an increased risk of in-hospital mortality in VAP. Additionally, a linear relationship was found between delta RDW values and in-hospital mortality. These findings suggest that RDW can be used to identify high-risk patients with poorer outcomes in VAP.

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.

Diagnostic Utility of Serum Leucine-Rich α-2-Glycoprotein 1 for Acute Appendicitis in Children

PURPOSE

The aim of this study is to assess the diagnostic utility of serum leucine-rich α-2-glycoprotein 1 (LRG1) in pediatric patients with acute abdominal pain, admitted to the emergency surgical unit, in order to make a prompt and accurate diagnosis of acute appendicitis.

PATIENTS AND METHODS

Pediatric patients older than 5 years of age who presented to the emergency department from 15 October 2021 to 30 June 2022 with acute abdominal pain and suspected acute appendicitis were prospectively recruited in the study. Demographic and clinical data, as well as operative and postoperative data, were recorded. A total of 92 patients were equally distributed into two groups: children with acute appendicitis who underwent laparoscopic appendectomy and non-appendicitis patients, presenting with non-specific abdominal pain. LRG1 levels were determined using a commercially available LRG1 enzyme-linked immunosorbent assay (ELISA) kit. Serum LRG1 levels, as well as other inflammatory markers (white blood cell count (WBC), C-reactive protein (CRP) and absolute neutrophil count) were compared between groups.

RESULTS

The median level of LRG1 in serum was significantly higher in the group of children with pathohistologically confirmed acute appendicitis than in the control group, at 350.3 µg/mL (interquartile range (IQR) 165.2-560.3) and 25.7 µg/mL (IQR 14.7-36.8) (p < 0.001), respectively. Receiver operating characteristic area under the curve for LRG1 from serum was 1.0 (95% CI 0.96-1.00; p < 0.001) and the value of >69.1 µg/mL was found to perfectly separate acute appendicitis cases from controls. Additionally, as expected, each of the examined laboratory inflammatory markers provided a significantly higher values in the acute appendicitis group compared to the control group: WBC 14.6 × 10⁹/L (IQR 12.7, 18.7) vs. 7.0 × 10⁹/L (IQR 5.4, 9.0) (p < 0.001), CRP 16.3 mg/dL (IQR 6.9, 50.4) vs. 2.2 mg/dL (IQR 2, 2) (p < 0.001) and absolute neutrophil count 84.6% (IQR 79.5, 89.0) vs. 59.5% (IQR 51.5, 68.6) (p < 0.001).

CONCLUSIONS

LRG1 in the serum was found to be a promising novel biomarker, with excellent differentiation of acute appendicitis from non-appendicitis cases in children presenting with non-specific abdominal pain.

The Management of Pediatric Acute Appendicitis-Survey among Pediatric Surgeons in Romania

Background and Objectives: To assess the current practice pattern in the management of pediatric acute appendicitis in Romania. Materials and Methods: A questionnaire was emailed to all the members of the Romanian Society of Pediatric Surgery between June-July 2022. Results: 118 answers were received, 79.7% responses being from permanent staff members. In the diagnosis of appendicitis, complete blood count, C-reactive protein and abdominal ultrasound are the most commonly used diagnostic tools, while appendicitis scores are not widely used (25% of surgeons). In the case of simple appendicitis, 49.2% of surgeons prefer the conservative approach-oral/intravenous antibiotics. Those who choose the operative approach begin preoperative antibiotics in 56.7% of patients. In case of a stable patient, only 16.7% of surgeons will operate during the night. Laparoscopic approach is chosen by 51.7% of surgeons. In the case of a complicated appendicitis, 92.4% of surgeons will perform the appendectomy, prescribing preoperative antibiotics in 94% of the cases and continuing the therapy postoperatively in 98.2%. Laparoscopic approach is used by 28.8% of surgeons in case of complicated appendicitis. In presence of appendicular mass, 80% prefer a conservative approach with a delayed appendectomy within 6 months. Appendicular abscesses are managed operatively in 82.2% of the cases. The appendix is sent for histological analysis by 95.8% of surgeons. If the peritoneal cavity is contaminated, 95% of the respondents will take a sample for microbiological analysis, 71% will always place a drainage and 44% will always irrigate (71.9%-saline). Conclusions: Clearly, there seems to be a lack of consensus regarding several aspects of the management of acute appendicitis in children. In addition, minimally invasive surgery is not as widely used as reported, despite literature support.

Diagnostic value of RDW for the prediction of mortality in adult sepsis patients: A systematic review and meta-analysis

Background

Red blood cell distribution width (RDW) is a common biomarker of bacterial infections, and it can be easily obtained from a routine blood test. We investigate the diagnostic value of RDW for the prediction of mortality in adult sepsis patients through a review and meta-analysis. We registered this review in PROSPERO (Registration Number: CRD42022357712), and the details of the registration are included in Appendix 1.

Methods

We searched PubMed, Cochrane Library, Springer, and Embase between Jan. 1, 2000, and May 30, 2022, for primary studies about this research. We collected articles that investigated RDW for varying degrees of sepsis patients—those who suffered from sepsis, severe sepsis, or sepsis shock. Studies of healthy people and sepsis of children and neonates were excluded from our research. The definition of study characteristics and data extraction were finished by two independent researchers and discrepancies resolved by consensus. The combined sensitivities and specificities were calculated by meta-analysis using STATA14.0. The sensitivity of the included studies was analyzed by excluding studies that had potential heterogeneity. A summary operating characteristic curve was made to evaluate the diagnostic value for the prediction of mortality in adult sepsis patients. The Fagan test was used to explore likelihood ratios and posttest probabilities. Finally, we investigated the source of heterogeneity using meta-regression.

Results

Twenty-four studies, including 40,763 cases altogether, were included in this analysis. Bivariate analysis indicated a combined sensitivity of 0.81 (95% CI 0.73–0.86) and specificity of 0.65 (95% CI 0.54–0.75). The area under the summary receiver operating characteristic curve was 0.81 (95% CI 0.77–0.84). Substantial heterogeneity resided in the studies (I^{2 =}96.68, 95% CI 95.95–97.4). Meta-regression showed that the reference description, prospective design, and blinded interpretation of the included studies could be responsible for the heterogeneity.

Conclusions

RWD is an available and valuable biomarker for prediction of mortality in adult sepsis patients.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022357712.

Diagnostic Value of IGFBP-2 in Predicting Preeclampsia before 20 Weeks of Pregnancy: A Prospective Nested Case-Control Study

Purpose

To identify novel biomarker insulin-like growth factor binding protein-2 (IGFBP-2) associated with preeclampsia (PE) before 20 weeks of gestation and to explore the predictive value of plasma IGFBP-2 in PE.

Methods

A prospective nested case-control investigation involving 122 PE patients and 122 normal controls (NC) that were matched 1 : 1 in terms of age and week of pregnancy was carried out in Guangzhou Women and Children's Medical Center (Guangzhou, China, 2018030306) from April 2016 to December 2019. At 8 to 20 weeks, blood samples from the mother were taken. To calculate the correlations, univariate conditional logistic regression was employed.

Results

Herein, 12 clinical indices were significantly different between the PE and NC groups (uric acid (UA), cystatin C (Cys C), aspartate aminotransferase (AST), glutamyl transpeptidase (γ-GT), total bilirubin (TB), prothrombin time (PT), red blood cell (RBC), hematocrit (HCT), red cell distribution width (RDW), platelets (PLT), mean platelet volume (MPV), and thrombocytocrit (PCT)). Compared with the NC group (36.79 ± 19.91 pg/mL), the expression level of IGFBP2 in the PE group (19.76 ± 19.40 pg/mL) before 20 weeks of pregnancy was significantly decreased (P < 0.01). Two high-risk factors were found to be significantly associated with PE independently of confounders: anemia 4.35 (2.20-8.45) (P < 0.01) and cesarean section history 8.25 (2.67-26.67) (P < 0.01). As a result of the univariate logistic regression analysis, the following three variables were included in the final logistic regression model.: Y = −18.841 − 0.085 × (IGFBP‐2) + 0.630 × (RDW) + 0.165 × (AST) + 0.863 × (MPV). In comparison to IGFBP-2 alone as an independent predictor of PE (AUC = 0.897, 95% CI 0.830–0.964), the model's discriminatory power was considerably higher (AUC = 0.953, 95% CI 0.911–0.995).

Conclusion

Plasma IGFBP-2 before 20 weeks of pregnancy combined with high-risk factors and routine blood indexes has a high early predictive value for PE.

IL-6 Serum Levels Can Enhance the Diagnostic Power of Standard Blood Tests for Acute Appendicitis

Background: The diagnosis of acute appendicitis (AA) remains challenging, especially in pediatrics, because early symptoms are not specific, and the younger the patient the more difficult their interpretation is. There is a large degree of agreement between pediatric surgeons on the importance of an early diagnosis to avoid complicated acute appendicitis (CAA) and its consequences. The aim of this study is to assess if Interleukin 6 (IL-6) could enhance the sensitivity (Sn) and specificity (Sp) of the currently available and routinely performed diagnostic tools in case of suspected AA in pediatric patients. Materials and Methods: A prospective observational study was conducted including patients who underwent appendectomy between November 2020 and March 2022. We divided patients into three groups: not inflamed appendix (group NA), not complicated AA (group NCAA), and complicated AA (group CAA). We compared the mean values of white blood cells (WBC), neutrophils, fibrinogen, ferritin, aPTT, INR, C-reactive protein (CRP), IL-6, and CRP between the three groups. Then we evaluated Sn, Sp, and odds ratio (OR) of IL-6 and CRP alone and combined. Results: We enrolled 107 patients operated on for AA (22 in Group NA, 63 in Group NCAA, and 21 in group CAA). CRP levels resulted in a significant increase when comparing CAA with NA (p = 0.01) and CAA with NCAA (p = 0.01), whereas no significance was found between NA and NCAA (p = 0.38). A statistically significant increase in average IL-6 levels was found when comparing NCAA with NA (p = 0.04), CAA with NA (p = 0.04), and CAA with NCAA (p = 0.02). Considering CRP alone, its Sn, Sp, and OR in distinguishing NA from AA (both NCAA and CAA together) are 86%, 35%, and 33,17, respectively. Similarly, Sn, Sp, and OR of IL-6 alone are 82%, 54%, and 56, respectively. Combining CRP and IL-6 serum levels together, the Sn increases drastically to 100% with an Sp of 40% and OR of 77. Conclusions: Our study may suggest an important role of IL-6 in the detection of AA in its early stage, especially when coupled with CRP.

Hyponatremia-A New Diagnostic Marker for Complicated Acute Appendicitis in Children: A Systematic Review and Meta-Analysis

Background: Acute appendicitis in the pediatric population remains a diagnostic challenge for clinicians. Despite many biochemical markers, imaging modalities and scoring systems, initial misdiagnosis and complication rates are high in children. This suggests the need for investigations directed towards new diagnostic tools to aid in the diagnosis. Recent studies have shown a correlation between serum sodium levels and complicated appendicitis. Although the exact reasons for hyponatremia in patients with complicated appendicitis are not known, there is persuasive data to support the role of pro-inflammatory cytokines such as IL-6 in the non-osmotic release of antidiuretic hormone. This meta-analysis aims to investigate all available data on hyponatremia as a diagnostic marker of complicated appendicitis in the pediatric population. Methods: The literature search was conducted by two independent investigators according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The scientific databases (PubMed, EMBASE, Web of Science, and Scopus) were systematically searched for relevant studies using the keywords (hyponatremia) AND (appendicitis) AND (children). The methodological quality was assessed using a validated scale, and RevMan 5.4 software was utilized for pooled analysis. Results: Seven studies were included in the final meta-analysis, five of which were retrospective. A total of 1615 and 2808 cases were distributed into two groups: group A with complicated appendicitis and group B with uncomplicated acute appendicitis, respectively. The studies compared serum sodium levels of patients among the groups. Pooling the data demonstrated significantly lower serum sodium levels in children with complicated appendicitis vs. the non-complicated appendicitis (WMD: −3.29, 95% CI = −4.52 to −2.07, p < 0.00001). The estimated heterogeneity among the included studies was substantial and statistically significant (I2 = 98%, p < 0.00001). Conclusion: The results of the present meta-analysis indicate that hyponatremia has potential to be utilized as a biochemical marker in the diagnosis of complicated appendicitis in the pediatric population. However, well designed prospective diagnostic efficiency studies are essential to consolidate the association between hyponatremia and complicated acute appendicitis.

Mean Platelet Volume in the Diagnosis of Acute Appendicitis in the Pediatric Population: A Systematic Review and Meta-Analysis

Background: Mean Platelet Volume (MPV) has been suggested as a biomarker for acute appendicitis (AA) in the adult population. The utility of MPV in pediatric AA remains vague. This systematic review and meta-analysis aimed to systematically summarize and compare all relevant data on MPV as a diagnostic biomarker for AA in children. Methods: Databases were systematically searched using keywords ((mean platelet volume) OR mpv) AND (appendicitis). The inclusion criteria were all comparative studies of MPV in children aged less than 18 years and diagnosed with AA. Two authors independently assessed the methodological quality using the Downs and Black scale. Results: We included fourteen studies in the final meta-analysis; most were retrospective. Eight studies compared the MPV values between AA and non-AA; four studies compared the same between AA and healthy controls; two studies compared the MPV values among all three groups. The estimated heterogeneity among the studies for all outcomes was high and statistically significant. The pooling the data showed no statistically significant difference in MPV (weighted mean difference (WMD) = −0.42, 95% CI = (−1.04, 0.20), p = 0.19) between AA and healthy controls or AA and non-AA cases (WMD = 0.01, 95% CI = (−0.15, 0.17), p = 0.90). Conclusion: While MPV levels seem to have some utility in adult AA diagnosis, MPV levels should not dictate treatment options in pediatric AA.