Patient and Parent-Reported Signs and Symptoms for Group A Streptococcal Pharyngitis

Systematic review and meta-analysis of the accuracy of McIsaac and Centor score in patients presenting to secondary care with pharyngitis

BACKGROUND

Centor and McIsaac scores are clinical prediction rules for diagnosing group A streptococcus (GAS) infection in patients with pharyngitis. Their recommended thresholds vary between guidelines.

OBJECTIVES

To estimate the sensitivity and specificity of the McIsaac and Centor scores to diagnose GAS pharyngitis and evaluate their impact on antibiotic prescribing at each threshold in patients presenting to secondary care.

DATA SOURCES

MEDLINE, Embase, and Web of Science were searched from inception to September 2022.

STUDY ELIGIBILITY CRITERIA

Studies of patients presenting with acute pharyngitis to emergency or outpatient clinics that estimated the accuracy of McIsaac or Centor scores against throat cultures and/or rapid antigen detection tests (RADT) as reference standards.

TESTS

Centor or McIsaac score.

REFERENCE STANDARD

Throat cultures and/or RADT.

ASSESSMENT OF RISK OF BIAS

Quality Assessment of Diagnostic Accuracy Studies.

METHODS OF DATA SYNTHESIS

The sensitivities and specificities of the McIsaac and Centor scores were pooled at each threshold using bivariate random effects meta-analysis.

RESULTS

Fourteen studies were included (eight McIsaac and six Centor scores). Eight studies had unclear and six had a high risk of bias. The McIsaac score had higher estimated sensitivity and lower specificity relative to Centor scores at equivalent thresholds but with wide and overlapping confidence regions. Using either score as a triage to RADT to decide antibiotic treatment would reduce antibiotic prescription to patients with non-GAS pharyngitis relative to RADT test for everyone, but also reduce antibiotic prescription to patients with GAS.

DISCUSSION

Centor and McIsaac scores are equally ineffective at triaging patients who need antibiotics presenting with pharyngitis at hospitals. At high thresholds, too many true positive cases are missed, whereas at low thresholds, too many false positives are treated, leading to the over prescription of antibiotics. The former may be compensated by adequate safety netting by clinicians, ensuring that patients can seek help if symptoms worsen.

Diagnostic performance of clinical prediction rules to detect group A beta-haemolytic streptococci in people with acute pharyngitis: a systematic review

OBJECTIVE

To assess and compare the diagnostic performance of Clinical Prediction Rules (CPRs) developed to detect group A Beta-haemolytic streptococci in people with acute pharyngitis (or sore throat).

STUDY DESIGN

A systematic review.

METHODS

We searched PubMed, Embase and Web of Science (inception-September 2022) for studies deriving and/or validating CPRs comprised of ≥2 predictors from an individual's history or physical examination. Two authors independently screened articles, extracted data and assessed risk of bias in included studies. A meta-analysis was not possible due to heterogeneity. Instead we compared the performance of CPRs when they were validated in the same study population (head-to-head comparisons). We used a modified grading of recommendations, assessment, development, and evaluations (GRADE) approach to assess certainty of the evidence.

RESULTS

We included 63 studies, all judged at high risk of bias. Of 24 derived CPRs, 7 were externally validated (in 46 external validations). Five validation studies provided data for head-to-head comparison of four pairs of CPRs. Very low certainty evidence favoured the Centor CPR over the McIsaac (2 studies) and FeverPain CPRs (1 study) and found the Centor CPR was equivalent to the Walsh CPR (1 study). The AbuReesh and Steinhoff 2005 CPRs had a similar poor discriminative ability (1 study). Within and between study comparisons suggested the performance of the Centor CPR may be better in adults (>18 years).

CONCLUSION

Very low certainty evidence suggests a better performance of the Centor CPR. When deciding about antibiotic prescribing for pharyngitis patients, involving patients in a shared decision making discussion about the likely benefits and harms, including antibiotic resistance, is recommended. Further research of higher rigour, which compares CPRs across multiple settings, is needed.

Internet Tool to Support Self-Assessment and Self-Swabbing of Sore Throat: Development and Feasibility Study

BACKGROUND

Sore throat is a common problem and a common reason for the overuse of antibiotics. A web-based tool that helps people assess their sore throat, through the use of clinical prediction rules, taking throat swabs or saliva samples, and taking throat photographs, has the potential to improve self-management and help identify those who are the most and least likely to benefit from antibiotics.

OBJECTIVE

We aimed to develop a web-based tool to help patients and parents or carers self-assess sore throat symptoms and take throat photographs, swabs, and saliva samples for diagnostic testing. We then explored the acceptability and feasibility of using the tool in adults and children with sore throats.

METHODS

We used the Person-Based Approach to develop a web-based tool and then recruited adults and children with sore throats who participated in this study by attending general practices or through social media advertising. Participants self-assessed the presence of FeverPAIN and Centor score criteria and attempted to photograph their throat and take throat swabs and saliva tests. Study processes were observed via video call, and participants were interviewed about their views on using the web-based tool. Self-assessed throat inflammation and pus were compared to clinician evaluation of patients' throat photographs.

RESULTS

A total of 45 participants (33 adults and 12 children) were recruited. Of these, 35 (78%) and 32 (71%) participants completed all scoring elements for FeverPAIN and Centor scores, respectively, and most (30/45, 67%) of them reported finding self-assessment relatively easy. No valid response was provided for swollen lymph nodes, throat inflammation, and pus on the throat by 11 (24%), 9 (20%), and 13 (29%) participants respectively. A total of 18 (40%) participants provided a throat photograph of adequate quality for clinical assessment. Patient assessment of inflammation had a sensitivity of 100% (3/3) and specificity of 47% (7/15) compared with the clinician-assessed photographs. For pus on the throat, the sensitivity was 100% (3/3) and the specificity was 71% (10/14). A total of 89% (40/45), 93% (42/45), 89% (40/45), and 80% (30/45) of participants provided analyzable bacterial swabs, viral swabs, saliva sponges, and saliva drool samples, respectively. Participants were generally happy and confident in providing samples, with saliva samples rated as slightly more acceptable than swab samples.

CONCLUSIONS

Most adult and parent participants were able to use a web-based intervention to assess the clinical features of throat infections and generate scores using clinical prediction rules. However, some had difficulties assessing clinical signs, such as lymph nodes, throat pus, and inflammation, and scores were assessed as sensitive but not specific. Many participants had problems taking photographs of adequate quality, but most were able to take throat swabs and saliva samples.

Use of the McIsaac Score to Predict Group A Streptococcal Pharyngitis in Outpatient Nurse Phone Triage and Electronic Visits Compared With In-Person Visits: Retrospective Observational Study

Background

The McIsaac criteria are a validated scoring system used to determine the likelihood of an acute sore throat being caused by group A streptococcus (GAS) to stratify patients who need strep testing.

Objective

We aim to compare McIsaac criteria obtained during face-to-face (f2f) and non-f2f encounters.

Methods

This retrospective study compared the percentage of positive GAS tests by McIsaac score for scores calculated during nurse protocol phone encounters, e-visits (electronic visits), and in person f2f clinic visits.

Results

There was no difference in percentages of positive strep tests between encounter types for any of the McIsaac scores. There were significantly more phone and e-visit encounters with any missing score components compared with f2f visits. For individual score components, there were significantly fewer e-visits missing fever and cough information compared with phone encounters and f2f encounters. F2f encounters were significantly less likely to be missing descriptions of tonsils and lymphadenopathy compared with phone and e-visit encounters. McIsaac scores of 4 had positive GAS rates of 55% to 68% across encounter types. There were 4 encounters not missing any score components with a McIsaac score of 0. None of these 4 encounters had a positive GAS test.

Conclusions

McIsaac scores of 4 collected during non-f2f care could be used to consider empiric treatment for GAS without testing if significant barriers to testing exist such as the COVID-19 pandemic or geographic barriers. Future studies should evaluate further whether non-f2f encounters with McIsaac scores of 0 can be safely excluded from GAS testing.

Positive Rate of Tests for Group a Streptococcus and Viral Features in Children with Acute Pharyngitis

Group A streptococcus (GAS) is an important cause of acute pharyngitis. We investigated the positive rate of GAS tests and clinical viral features in children with acute pharyngitis. A retrospective review was conducted for patients <15 years old with both rapid antigen detection test (RADT) and throat culture results. Patients were excluded if they were diagnosed with influenza or had received antibiotics within two weeks before these tests. A total of 377 patients were eligible. The median age of patients was 3.5 years, and 45.4% of total patients were <3 years old. Among all patients, 68.7% had at least one viral feature, and 39% had more than two. The overall positiv rate for GAS was 11.4%. The GAS positive rate was significantly lower in patients <3 years old than in older patients (1.8% vs. 19.4%, p < 0.0001). The overall sensitivity and specificity of RADT were 75.0% (95% CI: 57.8-87.9) and 97.9% (95% CI: 95.8-99.2), respectively. The GAS positive rate was not significantly different between patients with and without viral features (12.4% vs. 9.3%, p = 0.4854). In patients aged 3-14 years, the GAS positive rate was not associated with the modified Centor score or the frequency of clinical viral features. Despite a low prevalence of GAS pharyngitis, testing for GAS was frequently performed in children <3 years old in this study. Appropriate use of laboratory testing for GAS pharyngitis and judicious prescription of antibiotics were imperative.

McIsaac score for group A streptococcal infection: Comparison of electronic visits versus face-to-face visits

INTRODUCTION

Acute sore throat is a common complaint traditionally completed with an in-person visit. However, non-face-to-face telemedicine visits offer greater access at reduced cost. We evaluated patient/caregiver asynchronous text-based electronic visits (eVisits) for acute sore throat and whether there was concordance for individual components and total McIsaac score compared to a clinician's assessment. eVisits were completed by patients and/or their caregivers via a secure patient portal.

METHODS

In this retrospective study, we manually reviewed charts between February 2017 and July 2019 of patients who had an eVisit, in-person visit and group A streptococcal (GAS) test performed on the same day for an acute sore throat. We calculated a McIsaac score for eVisits and in-person visits, and compared each component and total score using Cohen's kappa agreement statistic.

RESULTS

There were 320 instances of patients who had an eVisit, in-person visit and GAS testing done on the same day. Approximately a third of eVisits were missing at least one McIsaac component, with the physical examination elements missing most commonly. Individual score congruence was moderate for cough (0.41), fair for fever (0.34) and slight for tonsillar swelling/exudate and lymphadenopathy (0.17 and 0.08, respectively), with total congruence being slight to fair (0.09-0.37). A McIsaac score of ≤1 showed moderate agreement (0.44). Visits with complete individual score components demonstrated improved congruence: substantial for cough (0.64), moderate for fever (0.57), fair for tonsillar swelling (0.3) and slight for lymphadenopathy (0.13).

DISCUSSION

Overall agreement for individual score components was better for symptoms than it was for examination components, and was improved when data were complete. A McIsaac score of 1 or 0 had moderate agreement and thus could reasonably be safely used to exclude patients from GAS testing.

Impact of viral symptoms on the performance of the modified centor score to predict pediatric group A streptococcal pharyngitis

BACKGROUND

Clinicians use the Modified Centor Score (MCS) to estimate the risk of group A streptococcal (GAS) pharyngitis in children with sore throat. The Infectious Diseases Society of America (IDSA) recommends neither testing nor treating patients with specific viral symptoms. The goal of this study is to measure the impact of those symptoms on the yield of GAS testing predicted by the MCS.

METHODS

Retrospective cohort study of all patients aged 3-21 years presenting with sore throat and tested for GAS in a pediatric emergency department (ED) in 2016. After identifying all patients tested for GAS, we used natural language processing (NLP) to identify the subgroup complaining of sore throat. We abstracted all MCS variables as well as symptoms suggestive of a viral etiology per the IDSA guideline (conjunctivitis, coryza, cough, diarrhea, hoarseness, ulcerative oral lesions, viral exanthema). We calculated the proportion of patients who tested positive for GAS by MCS with and without viral symptoms.

RESULTS

Of the 1574 patients included, 372 patients (24%) tested GAS positive. Patients with at least one viral symptom had a reduced GAS risk compared to those without any of the viral symptoms 91/547 (17% GAS positive) vs. 281/1027 (27%), odds ratio 0.53 (95% CI 0.41-0.69).

CONCLUSIONS

The presence of viral symptoms specified by the IDSA alters the predicted yield of testing by traditional MCS. Clinicians may consider adjusting interpretation of a patient's MCS based on the presence of viral symptoms, but viral symptoms may not always fully obviate the need for GAS testing.

A Fungal Immunotherapeutic Vaccine (NDV-3A) for Treatment of Recurrent Vulvovaginal Candidiasis-A Phase 2 Randomized, Double-Blind, Placebo-Controlled Trial

Background

Recurrent vulvovaginal candidiasis (RVVC) is a problematic form of mucosal Candida infection, characterized by repeated episodes per year. Candida albicans is the most common cause of RVVC. Currently, there are no immunotherapeutic treatments for RVVC.

Methods

This exploratory randomized, double-blind, placebo-controlled trial evaluated an immunotherapeutic vaccine (NDV-3A) containing a recombinant C. albicans adhesin/invasin protein for prevention of RVVC.

Results

The study in 188 women with RVVC (n = 178 evaluable) showed that 1 intramuscular dose of NDV-3A was safe and generated rapid and robust B- and T-cell immune responses. Post hoc exploratory analyses revealed a statistically significant increase in the percentage of symptom-free patients at 12 months after vaccination (42% vaccinated vs 22% placebo; P = .03) and a doubling in median time to first symptomatic episode (210 days vaccinated vs 105 days placebo) for the subset of patients aged <40 years (n = 137). The analysis of evaluable patients, which combined patients aged <40 years (77%) and ≥40 years (23%), trended toward a positive impact of NDV-3A versus placebo (P = .099).

Conclusions

In this unprecedented study of the effectiveness of a fungal vaccine in humans, NDV-3A administered to women with RVVC was safe and highly immunogenic and reduced the frequency of symptomatic episodes of vulvovaginal candidiasis for up to 12 months in women aged <40 years. These results support further development of NDV-3A vaccine and provide guidance for meaningful clinical endpoints for immunotherapeutic management of RVVC.

Clinical Trials Registration

NCT01926028.