The Diagnostic Performance of Various Clinical Specimens for the Detection of COVID-19: A Meta-Analysis of RT-PCR Studies

BACKGROUND

The diagnostic performance of numerous clinical specimens to diagnose COVID-19 through RT-PCR techniques is very important, and the test result outcome is still unclear. This review aimed to analyze the diagnostic performance of clinical samples for COVID-19 detection by RT-PCR through a systematic literature review process.

METHODOLOGY

A compressive literature search was performed in PubMed/Medline, Scopus, Embase, and Cochrane Library from inception to November 2022. A snowball search on Google, Google Scholar, Research Gate, and MedRxiv, as well as bibliographic research, was performed to identify any other relevant articles. Observational studies that assessed the clinical usefulness of the RT-PCR technique in different human samples for the detection or screening of COVID-19 among patients or patient samples were considered for this review. The primary outcomes considered were sensitivity and specificity, while parameters such as positive predictive value (PPV), negative predictive value (NPV), and kappa coefficient were considered secondary outcomes.

RESULTS

A total of 85 studies out of 10,213 non-duplicate records were included for the systematic review, of which 69 articles were considered for the meta-analysis. The meta-analysis indicated better pooled sensitivity with the nasopharyngeal swab (NPS) than saliva (91.06% vs. 76.70%) and was comparable with the combined NPS/oropharyngeal swab (OPS; 92%). Nevertheless, specificity was observed to be better with saliva (98.27%) than the combined NPS/OPS (98.08%) and NPS (95.57%). The other parameters were comparable among different samples. The respiratory samples and throat samples showed a promising result relative to other specimens. The sensitivity and specificity of samples such as nasopharyngeal swabs, saliva, combined nasopharyngeal/oropharyngeal, respiratory, sputum, broncho aspirate, throat swab, gargle, serum, and the mixed sample were found to be 91.06%, 76.70%, 92.00%, 99.44%, 86%, 96%, 94.4%, 95.3%, 73.63%, and above 98; and 95.57%, 98.27%, 98.08%, 100%, 37%, 100%, 100%, 97.6%, and above 97, respectively.

CONCLUSIONS

NPS was observed to have relatively better sensitivity, but not specificity when compared with other clinical specimens. Head-to-head comparisons between the different samples and the time of sample collection are warranted to strengthen this evidence.

Recent Advances in Locoregional Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is responsible for 90% of primary hepatic cancer cases, and its incidence with associated morbidity and mortality is growing worldwide. In recent decades, there has been a revolution in HCC treatment. There are three main types of locoregional therapy: radiofrequency ablation, transarterial chemoembolisation, and transarterial radioembolisation. This article summarises recent advances in locoregional methods.

Comparison of the safety and immunogenicity of the BNT-162b2 vaccine and the ChAdOx1 vaccine for solid organ transplant recipients: a prospective study

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and its resulting disease, coronavirus disease 2019 (COVID-19), has spread to millions of people worldwide. Preliminary data from organ transplant recipients have shown reduced seroconversion rates after the administration of different SARS-CoV-2 vaccination platforms. However, it is unknown whether different vaccination platforms provide different levels of protection against SARS-CoV-2. To answer this question, we prospectively studied 431 kidney and liver transplant recipients (kidney: n = 230; liver: n = 201) who received either the ChAdOx1 vaccine (n = 148) or the BNT-162b2 vaccine (n = 283) and underwent an assessment of immunoglobulin M/immunoglobulin G spike antibody levels. The primary objective of the study is to directly compare the efficacy of two different vaccine platforms in solid organ transplant recipients by measuring of immunoglobulin G (IgG) antibodies against the RBD of the spike protein (anti-RBD) two weeks after first and second doses. Our secondary endpoints were solicited specific local or systemic adverse events within 7 days after the receipt of each dose of the vaccine. There was no difference in the primary outcome between the two vaccine platforms in patients who received two vaccine doses. Unresponsiveness was mainly linked to diabetes. The rate of response after the first dose among younger older patients was significantly larger; however, after the second dose this difference did not persist (p = 0.079). Side effects were similar to those that were observed during the pivotal trials.

Effect of COVID-19 on liver abnormalities: a systematic review and meta-analysis

Emerging evidence suggest association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with the development of many liver abnormalities. The overarching aim of this study was therefore to assess the available evidence on the clinical effects of SARS-CoV-2 on the profiles of liver chemistries and coagulation in COVID-19 diagnosed patients. We considered all study designs including epidemiological and observational that reported liver function test abnormalities in patients confirmed with SARS-CoV-2 infection. Medline, Embase databases and Google Scholar as well as relevant reviews were searched to identify appropriate studies from inception to 31st of August 2020. We calculated the pooled mean with 95% confidence intervals (95% CI) through a random-effect model meta-analysis. A total of 35 studies with 10,692 participants were considered for the review from which 23 studies with sufficient quantitative data were included in the meta-analysis. The pooled mean for liver enzymes and coagulation parameters did not significantly change in patients diagnosed with COVID-19 and remained within normal range. Notwithstanding potential bias from confounding factors in interpretation of data in this review, findings from the observational studies and case reports suggest that COVID-19 does not appear to have a significant impact on the transaminases or total bilirubin levels of patients with confirmed SARS-CoV-2 infection. Further controlled studies and larger sample size observational studies are needed with adequate reporting of other liver function parameters are warranted.

Validating controlled attenuation parameter in the assessment of hepatic steatosis in living liver donors

INTRODUCTION

Hepatic steatosis (HS) negatively impacts transplant outcomes in living liver donors. To date, liver biopsy is preferred for HS evaluation. This study aims to evaluate the measurement of controlled attenuation parameter (CAP) as a diagnostic tool of HS in living liver donors.

METHODS

Candidates recruited to this study, conducted from April 2016 to February 2020, were potential donors who had undergone transient elastography using Fibroscan® and CAP measurements at liver segments VI and VII, followed by liver biopsy. The HS grades from liver biopsy were classified as S0 (<5%), S1 (5-33%), S2 (33-66%), and S3 (>66%). For CAP, they were S0 (≤218dB/m), S1 (218-249dB/m)), S2 (250-305dB/m)), and S3 (>305dB/m)). The CAP measurements were compared with the liver biopsy results.

RESULTS

Of the 150 potential donors [male, 73.3%; mean age, 30.0±7.0 years; body mass index (BMI), 24.7±3.5kg/m2], 92 (61.3%) had no or mild HS, while 58 (38.7%) and 10% had moderate to severe HS based on CAP and liver biopsy, respectively. Subjects with moderate to severe HS per CAP were mostly males (0.014), and had higher BMI (p = .006), alanine aminotransferase (ALT) (.001), gamma-glutamyl transferase (.026), and high-density lipoprotein (.008). On multivariate analysis, high ALT (OR, 1.051; 95% CI, 1.016-1.087; p = .004) was a predictor of significant HS. The sensitivity, specificity, positive and negative predictive values of CAP to detect significant HS were 93.3%, 67.4, 24.1%, and 98.9%, respectively.

CONCLUSION

The high sensitivity and negative predictive values of CAP make it a good screening test to exclude significant HS in potential living liver donors which, in turn, can help avoid unnecessary liver biopsies.

Living donor liver transplantation in septuagenarians: Better late than never

BACKGROUND

The coupling of increased life expectancy and improvements in both quality and access to chronic liver disease care, is culminating in an expanding population of septuagenarians (≥70 years) in need of liver transplantation (LT). The objective of this study is to partially alleviate this knowledge deficit and to add clarity to the current status and role of LDLT in this recipient population.

METHODS

Of 295 adult patients underwent LDLT between January 1, 2011 and December 31, 2016. Twelve (4%) of these patients were septuagenarians and this group was compared to younger cohort (n = 283).

RESULTS

Comorbidity profiles between the two groups were similar and no statistically significant differences were noted in warm/cold ischemia times, operative duration, or blood product utilization. ICU and total hospital stays were comparable. Septuagenarian 1-and 5-year graft and patient survivals were identical at 91.7%. Their younger counterparts had 1-and 5-year patient survivals of 91.1% and 84.0 % accompanied by 1-and 5-year graft survivals of 89.8% and 82.7%, respectively.

CONCLUSION

Our study highlights a recognition that LDLT can afford highly-selected elderly patients to access to transplant with equivalent outcomes to those realized by younger recipients.

Hepatocellular carcinoma and the Fontan circulation: Clinical presentation and outcomes

BACKGROUND

Fontan-associated liver disease (FALD) is universal in patients with a Fontan circulation. Hepatocellular carcinoma (HCC) is one of its severe expressions, and, though rare, frequently fatal. The purpose of this study was to describe the clinical presentation, risk factors, and outcomes of HCC in patients with a Fontan circulation.

METHODS

A multicenter case series of Fontan patients with a diagnosis of HCC formed the basis of this study. The case series was extended by published cases and case reports. Clinical presentation, tumor characteristics, laboratory and hemodynamic findings as well as treatment types and outcomes, were described.

RESULTS

Fifty-four Fontan patients (50% female) with a diagnosis of HCC were included. Mean age at HCC diagnosis was 30 ± 9.4 years and mean duration from Fontan surgery to HCC diagnosis was 21.6 ± 7.4 years. Median HCC size at the time of diagnosis was 4 cm with a range of 1 to 22 cm. The tumor was located in the right hepatic lobe in 65% of the patients. Fifty-one percent had liver cirrhosis at the time of HCC diagnosis. Fifty percent of the patients had no symptoms related to HCC and alpha-fetoprotein was normal in 26% of the cases. Twenty-six patients (48%) died during a median follow-up duration of 10.6 (range 1-50) months.

CONCLUSIONS

HCC in Fontan patients occurs at a young age with a 1-year survival rate of only 50%. Meticulous liver surveillance is crucial to detect small tumors in the early stage.

Takayasu's arteritis and liver transplantation: Association and implications

We present a 37-year-old lady who had liver transplantation for hepatitis B cirrhosis and was on immune suppressive treatment consisting of mycophenolate mofetil (MMF) and tacrolimus. She presented with undue fatigue and recurring pain in both arms. The diagnosis of Takayasu's arteritis was made, supported by angiographic findings of significant stenosis of the left subclavian and both renal arteries. She was managed by adjusting the immune suppressive medications and underwent a successful percutaneous transluminal balloon angioplasty (PTBA).

HCV genotypes among 1013 Saudi nationals: a multicenter study

BACKGROUND AND OBJECTIVES

Hepatitis C virus (HCV) genotype (G) knowledge is essential for determining type, duration and rate of response to antiviral therapy, possible route of HCV transmission, and future vaccine development. Our aim was to study HCV genotypes and to provide precise data on genotype distribution in both genders and different age groups amongst Saudi patients.

DESIGN AND SETTING

Genotype data from molecular laboratories at four different tertiary care hospitals in Riyadh from January 2006 until December 2010 were collected and analyzed.

PATIENTS AND METHODS

Consecutive data on genotype, sex and age was collected from 1013 Saudi patients. Genotyping was done by selective hybridization of amplicons to HCV genotype-specific oligonucleotides.

RESULTS

We found G1 in 262 patients (25.9%), G2 in 44 (4.4 %), G3 in 29 (2.9 %), G4 in 608 (60%), and 3 patients (0.3%) each of G5 and G6. In addition, 64 (6.3%) patients had mixed genotypes, mostly G4 and G1. On subtyping in 191 G1 patients, 67 (35.1%) were G1a, and 124 (64.9 %) G1b. Age distribution showed that 18 (1.7%) were 0-20 years, 173 (17.1 %) 21-40 years, 521 (51.4%) 41-60 years and 301(29.7%) > 60 years. There was no significant difference in frequency of G1, G3 and G4 among the two genders.

CONCLUSION

G1 and G4 are the predominant genotypes in Saudi patients infected with HCV (85.9%), with a similar distribution among the two sexes and no significant changes in genotype distribution over the past decade.

Eosinophilic gastroenteritis causing stenosis of bulbo-duodenal junction: medical and endoscopic management

Eosinophilic gastroenteritis is a rare disease characterised by tissue eosinophilia that can involve any layer or part of the gut from the oesophagus to the rectum. In Saudi Arabia, the disease has not been reported in the literature before. We report the disease entity as an unusual cause of gastric outlet obstruction. A 50-year-old man was admitted through the gastrointestinal clinic with complaints of epigastric pain associated with dyspepsia for 1 month, and weight loss of 4 kg in 2 months. Examination revealed only the epigastric tenderness on deep palpation. Laboratory investigations including full blood count, liver function tests and renal function tests were normal. Gastroscopy disclosed stenosis of the second and third part of the duodenum. Biopsies were taken and the patient underwent endoscopic dilatation of the pylorus and duodenal bulb. Histopathology showed chronic active eosinophilic inflammation. The patient was successfully treated with a tapering course of steroids and had a complete recovery post-endoscopic dilatation.

Corrosive gastritis: an extreme outcome

Caustic substances, whether acid or alkali, cause a wide range of injuries to the digestive tract, from mild hyperaemia to extensive necrosis and perforation. We report the case of 40-year-old woman who presented 6 weeks after intentional ingestion of hydrochloric acid with abdominal pain and haematemesis. Gastroscopy showed a necrosed and ulcerated stomach with pyloric stricture. The third attempt at dilatation of the stricture caused perforation of the lesser curvature of the stomach requiring laparoscopic gastroduodenostomy. The approach to corrosive ingestion and its subsequent management is discussed.

Biliary complications after hydatid liver surgery: incidence and risk factors

The aims of this study were to determine the incidence and risk factors of biliary leakage and biliary fistulae after hydatid liver surgery and to suggest preventive precautions. From January 1999 to June 2000, 70 cysts were examined from 54 patients who were operated on for hydatid liver disease. Age, sex, primary or recurrent disease, liver function tests, number, location, content, radiological type, and diameter and cavity management techniques were examined with univariate and multivariate analyses for biliary complications. Biliary leakage occurred in 14 cysts (26%) from the patients. Purulent and/or bilious cyst content (61.9% vs. 2.0%; P = 0.022), male gender (40.9% vs. 10.4%; P = 0.038), and pre-operative raised alkaline phosphatase and gamma glutamyl transferase levels (34.6% vs. 11.4%; P = 0.047) were found as independent risk factors for post-operative biliary leakage. Nine instances of biliary leakage (16.7%) closed spontaneously within seven days. The remaining five instances of biliary leakage (9.3%) persisted for more than 10 days and were accepted as biliary fistulae. Stepwise logistic regression identified cyst content was the only risk factor for biliary fistulae (19% vs. 2%; P = 0.036). Described risk factors for post-operative biliary complications after hydatid liver surgery may be the guidelines for additional pre-operative or intra-operative radiological interventions of the biliary tract and for preventive procedures such as surgical biliary drainage.

Benzodiazepine receptor antagonism improves reaction time in latent hepatic encephalopathy

Endogenous benzodiazepine-like substances are thought to play a role in the development of hepatic encephalopathy (HE). Ten patients with sub-clinical or latent hepatic encephalopathy (LHE) and ten normal controls were cognitively assessed pre- and post-infusion of 0.2 mg of the benzodiazepine (BZ) antagonist flumazenil in a placebo-controlled, cross-over, double-blind design. Flumazenil infusion resulted in a significant improvement in simple reaction time in patients, but not in controls. Saline infusion had no effect on any of the cognitive measures in either group. Flumazenil appeared to have a particular enhancing effect on the cognitive, as opposed to the motor, component of the reaction time task. This finding supports the view that the benzodiazepine/GABA system is implicated in the bradyphrenia that is characteristic of chronic liver disease, even before hepatic encephalopathy is apparent. We conclude that benzodiazepine receptor antagonism may improve cognitive function, particularly speed of information processing, in patients with latent hepatic encephalopathy.