Does culture confirmation of high-sensitivity rapid streptococcal tests make sense? A medical decision analysis

Evaluating efficiency and equity of prevention and control strategies for rheumatic fever and rheumatic heart disease in India: an extended cost-effectiveness analysis

BACKGROUND

There is a dearth of evidence on the cost-effectiveness of a combination of population-based primary, secondary, and tertiary prevention and control strategies for rheumatic fever and rheumatic heart disease. The present analysis evaluated the cost-effectiveness and distributional effect of primary, secondary, and tertiary interventions and their combinations for the prevention and control of rheumatic fever and rheumatic heart disease in India.

METHODS

A Markov model was constructed to estimate the lifetime costs and consequences among a hypothetical cohort of 5-year-old healthy children. Both health system costs and out-of-pocket expenditure (OOPE) were included. OOPE and health-related quality-of-life were assessed by interviewing 702 patients enrolled in a population-based rheumatic fever and rheumatic heart disease registry in India. Health consequences were measured in terms of life-years and quality-adjusted life-years (QALY) gained. Furthermore, an extended cost-effectiveness analysis was undertaken to assess the costs and outcomes across different wealth quartiles. All future costs and consequences were discounted at an annual rate of 3%.

FINDINGS

A combination of secondary and tertiary prevention strategies, which had an incremental cost of ₹23 051 (US$30) per QALY gained, was the most cost-effective strategy for the prevention and control of rheumatic fever and rheumatic heart disease in India. The number of rheumatic heart disease cases prevented among the population belonging to the poorest quartile (four cases per 1000) was four times higher than the richest quartile (one per 1000). Similarly, the reduction in OOPE after the intervention was higher among the poorest income group (29·8%) than among the richest income group (27·0%).

INTERPRETATION

The combined secondary and tertiary prevention and control strategy is the most cost-effective option for the management of rheumatic fever and rheumatic heart disease in India, and the benefits of public spending are likely to be accrued much more by those in the lowest income groups. The quantification of non-health gains provides strong evidence for informing policy decisions by efficient resource allocation on rheumatic fever and rheumatic heart disease prevention and control in India.

FUNDING

Department of Health Research, Ministry of Health and Family Welfare, New Delhi.

Existing cost-effectiveness analyses for diseases caused by Group A Streptococcus: A systematic review to guide future research

Background: Group A Streptococcus (Strep A) causes a broad spectrum of disease manifestations, ranging from benign symptoms including throat or skin infections, to fatal illness such as rheumatic heart disease, or chronic renal failure. Currently, there is no vaccine available against Strep A infections. Despite the high burden of Strep A-associated infections worldwide, little attention has been paid to the research of these diseases, including standardized surveillance programs, resulting in a lack of economic evaluations for prevention efforts. This study aims at identifying existing cost-effectiveness analyses (CEA) on any Strep A infections. Methods: A systematic literature review was conducted by searching the PubMed electronic database. Results: Of a total of 321, 44 articles met the criteria for inclusion. Overall, CEA studies on Strep A remain limited in number. In particular, a number of available CEA studies on Strep A are disproportionately lower in low-income countries than in high-income countries. Decision-analytic models were the most popular choice for CEA on Strep A. A majority of the models considered pharyngitis and acute rheumatic fever, but it was rare to observe a model which covered a wide range of disease manifestations. Conclusions: Future research is needed to address missing clinical outcomes, imbalance on study locations by income group, and the transmission dynamic of selected diseases.

Diagnostic Methods, Clinical Guidelines, and Antibiotic Treatment for Group A Streptococcal Pharyngitis: A Narrative Review

The most common bacterial cause of pharyngitis is infection by Group A β-hemolytic streptococcus (GABHS), commonly known as strep throat. 5-15% of adults and 15-35% of children in the United States with pharyngitis have a GABHS infection. The symptoms of GABHS overlap with non-GABHS and viral causes of acute pharyngitis, complicating the problem of diagnosis. A careful physical examination and patient history is the starting point for diagnosing GABHS. After a physical examination and patient history is completed, five types of diagnostic methods can be used to ascertain the presence of a GABHS infection: clinical scoring systems, rapid antigen detection tests, throat culture, nucleic acid amplification tests, and machine learning and artificial intelligence. Clinical guidelines developed by professional associations can help medical professionals choose among available techniques to diagnose strep throat. However, guidelines for diagnosing GABHS created by the American and European professional associations vary significantly, and there is substantial evidence that most physicians do not follow any published guidelines. Treatment for GABHS using analgesics, antipyretics, and antibiotics seeks to provide symptom relief, shorten the duration of illness, prevent nonsuppurative and suppurative complications, and decrease the risk of contagion, while minimizing the unnecessary use of antibiotics. There is broad agreement that antibiotics with narrow spectrums of activity are appropriate for treating strep throat. But whether and when patients should be treated with antibiotics for GABHS remains a controversial question. There is no clearly superior management strategy for strep throat, as significant controversy exists regarding the best methods to diagnose GABHS and under what conditions antibiotics should be prescribed.

Estimated burden of group a streptococcal pharyngitis among children in Beijing, China

BACKGROUND

Burden of Group A streptococcus (GAS) pharyngitis is scarce in developing countries, still unknown in China. The objective of this study was to determine the incidence of clinical cases of pharyngitis and GAS culture-positive pharyngitis, and their outpatient visits among children aged 0-14 years in Beijing, the capital of China.

METHODS

Multiplier model was used to estimate the numbers of pharyngitis cases, based on reported numbers of clinical cases and GAS culture-positive rates from GAS surveillances in Beijing, consultation rate, population coverage of GAS surveillances, sampling success rate, and test sensitivity of GAS culture from previous studies, surveys and surveillances.

RESULTS

An average of 29804.6 (95 % CI: 28333.2-31276.0) clinical cases of pharyngitis per 100,000 person-years occurred among children aged 0-14 years, resulting in correspondingly 19519.0 (95 % CI: 18516.7-20521.2) outpatient visits per 100,000 person-years from 2012 to 2014 in Beijing. On average, there were 2685.1 (95 % CI: 2039.6-3330.6) GAS culture-positive cases of pharyngitis and 1652.7 (95 % CI: 1256.5-2049.0) outpatient visits per 100,000 person-years during the same period. The estimated burden of GAS pharyngitis was significantly higher than that of scarlet fever. Children aged 5-14 years had a higher burden of GAS pharyngitis than those aged 0-4 years.

CONCLUSIONS

The present data suggests that GAS pharyngitis is very common in children in China. Further studies and surveillances are needed to monitor trends and the effectiveness of control measures.

The Effect of Rapid Antigen Detection Test on Antibiotic Prescription Decision of Clinicians and Reducing Antibiotic Costs in Children with Acute Pharyngitis

We aimed to investigate the effect of rapid antigen detection test (RADT) in the diagnosis of streptococcal pharyngitis, its impact on antibiotic prescription decision of pediatricians and influence on reduction of antibiotic treatment costs in children with pharyngitis. The study group consisted of 223 patients who were diagnosed with pharyngitis by pediatricians. The sensitivity and specificity of RADT were 92.1% (95% Cl: 78.6-98.3%) and 97.3% (95% Cl: 93.8-99.1%), respectively. In the first assessment, before performing RADT, pediatricians decided to prescribe antibiotics for 178 (79.8%) patients with pharyngitis. After learning RADT results, pediatricians finally decided to prescribe antibiotics for 83 (37.2%) patients with pharyngitis, and antibiotic prescription decreased by 42.6%. Antibiotic costs in non-Group A streptococcus pharyngitis, Group A streptococcus pharyngitis and all subjects groups decreased by 80.8%, 48%, and 76.4%, respectively. Performing RADT in children with pharyngitis has an important impact on treatment decision of clinicians, reduction of unnecessary antibiotic prescriptions and antibiotic costs.

Antibiotic Use in Sore Throat: Are We Judicious?

Introduction Sore throat (acute tonsillitis/pharyngitis) is one of the most common clinical diagnosis encountered in ENT practice. It is a common practice to advice antibiotics in patients of sore throat not only in otolaryngology practice but also in pediatricians, GP's and internists. This is now becoming a matter of concern for two reasons, for the side effects of antibiotics and bacterial drug resistance. Methods To analyse patients on their symptoms and rapid streptococcal test for group A Stretococcus and determine antibiotic use. A prospective study was done in 600 patients who were clinically diagnosed as acute tonsillitis or acute pharyngitis and results analysed. Discussion Results showed that 24 % patients needed antibiotics while the rest did well without antibiotics. Results Rapid streptococcal test is a useful test in determining whether the patient needs antibiotic and help is reducing irrational use of antibiotics.

Selective testing strategies for diagnosing group A streptococcal infection in children with pharyngitis: a systematic review and prospective multicentre external validation study

BACKGROUND

Several clinical prediction rules for diagnosing group A streptococcal infection in children with pharyngitis are available. We aimed to compare the diagnostic accuracy of rules-based selective testing strategies in a prospective cohort of children with pharyngitis.

METHODS

We identified clinical prediction rules through a systematic search of MEDLINE and Embase (1975-2014), which we then validated in a prospective cohort involving French children who presented with pharyngitis during a 1-year period (2010-2011). We diagnosed infection with group A streptococcus using two throat swabs: one obtained for a rapid antigen detection test (StreptAtest, Dectrapharm) and one obtained for culture (reference standard). We validated rules-based selective testing strategies as follows: low risk of group A streptococcal infection, no further testing or antibiotic therapy needed; intermediate risk of infection, rapid antigen detection for all patients and antibiotic therapy for those with a positive test result; and high risk of infection, empiric antibiotic treatment.

RESULTS

We identified 8 clinical prediction rules, 6 of which could be prospectively validated. Sensitivity and specificity of rules-based selective testing strategies ranged from 66% (95% confidence interval [CI] 61-72) to 94% (95% CI 92-97) and from 40% (95% CI 35-45) to 88% (95% CI 85-91), respectively. Use of rapid antigen detection testing following the clinical prediction rule ranged from 24% (95% CI 21-27) to 86% (95% CI 84-89). None of the rules-based selective testing strategies achieved our diagnostic accuracy target (sensitivity and specificity>85%).

INTERPRETATION

Rules-based selective testing strategies did not show sufficient diagnostic accuracy in this study population. The relevance of clinical prediction rules for determining which children with pharyngitis should undergo a rapid antigen detection test remains questionable.

PRImary care Streptococcal Management (PRISM) study: in vitro study, diagnostic cohorts and a pragmatic adaptive randomised controlled trial with nested qualitative study and cost-effectiveness study

BACKGROUND

Antibiotics are still prescribed to most patients attending primary care with acute sore throat, despite evidence that there is modest benefit overall from antibiotics. Targeting antibiotics using either clinical scoring methods or rapid antigen detection tests (RADTs) could help. However, there is debate about which groups of streptococci are important (particularly Lancefield groups C and G), and uncertainty about the variables that most clearly predict the presence of streptococci.

OBJECTIVE

This study aimed to compare clinical scores or RADTs with delayed antibiotic prescribing.

DESIGN

The study comprised a RADT in vitro study; two diagnostic cohorts to develop streptococcal scores (score 1; score 2); and, finally, an open pragmatic randomised controlled trial with nested qualitative and cost-effectiveness studies.

SETTING

The setting was UK primary care general practices.

PARTICIPANTS

Participants were patients aged ≥ 3 years with acute sore throat.

INTERVENTIONS

An internet program randomised patients to targeted antibiotic use according to (1) delayed antibiotics (control group), (2) clinical score or (3) RADT used according to clinical score.

MAIN OUTCOME MEASURES

The main outcome measures were self-reported antibiotic use and symptom duration and severity on seven-point Likert scales (primary outcome: mean sore throat/difficulty swallowing score in the first 2-4 days).

RESULTS

The IMI TestPack Plus Strep A (Inverness Medical, Bedford, UK) was sensitive, specific and easy to use. Lancefield group A/C/G streptococci were found in 40% of cohort 2 and 34% of cohort 1. A five-point score predicting the presence of A/C/G streptococci [FeverPAIN: Fever; Purulence; Attend rapidly (≤ 3 days); severe Inflammation; and No cough or coryza] had moderate predictive value (bootstrapped estimates of area under receiver operating characteristic curve: 0.73 cohort 1, 0.71 cohort 2) and identified a substantial number of participants at low risk of streptococcal infection. In total, 38% of cohort 1 and 36% of cohort 2 scored ≤ 1 for FeverPAIN, associated with streptococcal percentages of 13% and 18%, respectively. In an adaptive trial design, the preliminary score (score 1; n = 1129) was replaced by FeverPAIN (n = 631). For score 1, there were no significant differences between groups. For FeverPAIN, symptom severity was documented in 80% of patients, and was lower in the clinical score group than in the delayed prescribing group (-0.33; 95% confidence interval -0.64 to -0.02; p = 0.039; equivalent to one in three rating sore throat a slight rather than moderately bad problem), and a similar reduction was observed for the RADT group (-0.30; -0.61 to 0.00; p = 0.053). Moderately bad or worse symptoms resolved significantly faster (30%) in the clinical score group (hazard ratio 1.30; 1.03 to 1.63) but not the RADT group (1.11; 0.88 to 1.40). In the delayed group, 75/164 (46%) used antibiotics, and 29% fewer used antibiotics in the clinical score group (risk ratio 0.71; 0.50 to 0.95; p = 0.018) and 27% fewer in the RADT group (0.73; 0.52 to 0.98; p = 0.033). No significant differences in complications or reconsultations were found. The clinical score group dominated both other groups for both the cost/quality-adjusted life-years and cost/change in symptom severity analyses, being both less costly and more effective, and cost-effectiveness acceptability curves indicated the clinical score to be the most likely to be cost-effective from an NHS perspective. Patients were positive about RADTs. Health professionals' concerns about test validity, the time the test took and medicalising self-limiting illness lessened after using the tests. For both RADTs and clinical scores, there were tensions with established clinical experience.

CONCLUSIONS

Targeting antibiotics using a clinical score (FeverPAIN) efficiently improves symptoms and reduces antibiotic use. RADTs used in combination with FeverPAIN provide no clear advantages over FeverPAIN alone, and RADTs are unlikely to be incorporated into practice until health professionals' concerns are met and they have experience of using them. Clinical scores also face barriers related to clinicians' perceptions of their utility in the face of experience. This study has demonstrated the limitation of using one data set to develop a clinical score. FeverPAIN, derived from two data sets, appears to be valid and its use improves outcomes, but diagnostic studies to confirm the validity of FeverPAIN in other data sets and settings are needed. Experienced clinicians need to identify barriers to the use of clinical scoring methods. Implementation studies that address perceived barriers in the use of FeverPAIN are needed.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN32027234.

SOURCE OF FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 6. See the NIHR Journals Library website for further project information.

Impact of the rapid antigen detection test in diagnosis and treatment of acute pharyngotonsillitis in a pediatric emergency room

OBJECTIVE

To evaluate the impact of the routine use of rapid antigen detection test in the diagnosis and treatment of acute pharyngotonsillitis in children.

METHODS

This is a prospective and observational study, with a protocol compliance design established at the Emergency Unit of the University Hospital of Universidade de São Paulo for the care of children and adolescents diagnosed with acute pharyngitis.

RESULTS

650 children and adolescents were enrolled. Based on clinical findings, antibiotics would be prescribed for 389 patients (59.8%); using the rapid antigen detection test, they were prescribed for 286 patients (44.0%). Among the 261 children who would not have received antibiotics based on the clinical evaluation, 111 (42.5%) had positive rapid antigen detection test. The diagnosis based only on clinical evaluation showed 61.1% sensitivity, 47.7% specificity, 44.9% positive predictive value, and 57.5% negative predictive value.

CONCLUSIONS

The clinical diagnosis of streptococcal pharyngotonsillitis had low sensitivity and specificity. The routine use of rapid antigen detection test led to the reduction of antibiotic use and the identification of a risk group for complications of streptococcal infection, since 42.5% positive rapid antigen detection test patients would not have received antibiotics based only on clinical diagnosis.

Primary Prevention of Acute Rheumatic Fever and Rheumatic Heart Disease With Penicillin in South African Children With Pharyngitis

Background—

Acute rheumatic fever and subsequent rheumatic heart disease remain significant in developing countries. We describe a cost-effective analysis of 7 strategies for the primary prevention of acute rheumatic fever and rheumatic heart disease in children presenting with pharyngitis in urban primary care clinics in South Africa.

Methods and Results—

We used a Markov model to assess the cost-effectiveness of treatment with intramuscular penicillin using each of the following strategies: (1) empirical (treat all); (2) positive throat culture (culture all); (3) clinical decision rule (CDR) score ≥2 (CDR 2+); (4) CDR score ≥3 (CDR 3+); (5) treating those with a CDR score ≥2 plus those with CDR score <2 and positive cultures (CDR 2+, culture CDR negatives); (6) treating those with a CDR score ≥3 plus those with CDR score <3 and positive cultures (CDR 3+, culture CDR negatives); and (7) treat none. The strategies ranked in order from lowest cost were treat all ($11.19 per child), CDR 2+ ($11.20); the CDR 3+ ($13.00); CDR 2+, culture CDR negatives ($16.42); CDR 3+, culture CDR negatives ($23.89); and culture all ($27.21). The CDR 2+ is the preferred strategy at less than $150/quality-adjusted life year compared with the treat all strategy. A strategy of culturing all children compared with the CDR 2+ strategy costs more than $125 000/quality-adjusted life year gained.

Conclusions—

Treating all children presenting with pharyngitis in urban primary care clinics in South Africa with intramuscular penicillin is the least costly. A strategy of using a clinical decision rule without culturing is overall the preferred strategy. A strategy of culturing all children may be prohibitively expensive.

Streptococcal pharyngitis in children: a meta-analysis of clinical decision rules and their clinical variables

OBJECTIVE

To identify the best clinical decision rules (CDRs) for diagnosing group A streptococcal (GAS) pharyngitis in children. A combination of symptoms could help clinicians exclude GAS infection in children with pharyngitis.

DESIGN

Systematic review and meta-analysis of original articles involving CDRs in children. The Pubmed, OVID, Institute for Scientific and Technical Information and Cochrane databases from 1975 to 2010 were screened for articles that derived or validated a CDR on a paediatric population: 171 references were identified.

SETTING

Any reference including primary care for children with pharyngitis.

DATA EXTRACTION

The methodological quality of the articles selected was analysed according to published quality standards. A meta-analysis was performed to assess the statistical performance of the CDRs and their variables for the diagnosis of GAS pharyngitis.

PRIMARY OUTCOME MEASURE

The main criterion was a false-negative rate in the whole population not any worse than that of a rapid diagnostic test strategy for all patients (high sensitivity and low negative likelihood ratio).

RESULTS

4 derived and 12 validated CDRs for this diagnosis in children. These articles involved 10 523 children (mean age, 7 years; mean prevalence of GAS pharyngitis, 34%). No single variable was sufficient for diagnosis. Among the CDRs, that of Joachim et al had a negative likelihood ratio of 0.3 (95% CI 0.2 to 0.5), resulting in a post-test probability of 13%, which leads to 3.6% false-negative rate among low-risk patients and 10.8% overall, equivalent to rapid diagnostic tests in some studies.

CONCLUSIONS

The rule of Joachim et al could be useful for clinicians who do not use rapid diagnostic tests and should allow avoiding antibiotic treatment for the 35% of children identified by the rule as not having GAS pharyngitis. Owing to its poor specificity, such CDR should be used to focus rapid diagnostic tests to children with high risk of GAS pharyngitis to reduce the antibiotic consumption.

[Diagnostic strategies for acute tonsillitis in France: a cost-effectiveness study]

CONTEXT

Inability to identify clinically group A streptococcal (GAS) tonsillitis has resulted for a long time in treating all tonsillitis with antibiotics in France. The use of the rapid detection tests (RDT) for GAS is currently recommended, in order to keep antibiotics only for GAS tonsillitis. Our objective was to carry out a cost-effectiveness analysis, comparing various strategies for the management of acute tonsillitis in France.

METHODS

We used a decision analysis model, including seven strategies (S) for tonsillitis management, specifically in children and in adults: S1: observation only (reference strategy); S2: clinical scoring; S3: RDT testing; S4: throat culture; S5: clinical scoring combined with RDT testing; S6: RDT testing combined with throat culture; S7: systematic antibiotic therapy. The criterion for effectiveness was the absence of locoregional suppurative complications.

RESULTS

The use of the RDT alone had the best cost-effectiveness ratio in both adults and children. For this strategy, we estimated the cost per suppurative complication avoided at 970€ in children and at 903€ in adults. For the strategy associating a confirmative throat culture to the RDT, the extra cost per suppurative complication avoided was estimated at 106,666€ in children and at 228,000€ in adults. Sensitivity analysis showed the stability of the model while making the main parameters vary.

CONCLUSION

In acute tonsillitis, in both adults and children, RDT testing by practitioners is the more efficient strategy to identify and treat patients with GAS tonsillitis. Combining RDT testing with throat culture can provide additional effectiveness, but at the cost of a significant extra charge for the community.

Diagnosis and management of acute pharyngitis in a paediatric population: a cost-effectiveness analysis

Acute pharyngitis is one of the most frequent causes of primary care physician visits; however, there is no agreement about which is the best strategy to diagnose and manage acute pharyngitis in children. The aim of the current study was to evaluate the cost-effectiveness of the recommended strategies to diagnose and manage acute pharyngitis in a paediatric population. A decision tree analysis was performed to compare the following six strategies: "treat all", "clinical scoring", "rapid test", "culture", "rapid test + culture" and "clinical scoring + rapid test". The cost data came from the Spanish National Health Service sources. Cost-effectiveness was calculated from the payer's perspective. Effectiveness was measured as the proportion of patients cured without complications from the disease and did not have any reaction to penicillin therapy; a sensitivity analysis was performed. The findings revealed that the "clinical scoring + rapid test" strategy is the most cost-effective, with a cost-effectiveness ratio of 50.72 <euro>. This strategy dominated all others except "culture", which was the most effective but also the most costly. The sensitivity analysis showed that "rapid test" became the most cost-effective strategy when the clinical scoring sensitivity was <91% and its specificity was ≤9%. In conclusion, the use of a clinical scoring system to triage the diagnoses and performing a rapid antigen test for those with a high score is the most cost-effective strategy for the diagnosis and management of acute pharyngitis in children. When the clinical scoring system has a low diagnostic accuracy, testing all patients with rapid test becomes the most cost-effective strategy.

The patient with sore throat

Sore throat is a common medical complaint seen by the emergency practitioner, internist, pediatrician, and otolaryngologist. The differential for sore throat is vast. However, with a directed history this can often be narrowed down to 2 to 3 possible diagnoses. By paying particular attention to the associated symptoms and duration of symptoms, common self-limited etiologies like viral pharyngitis and nonstreptococcal tonsillitis can be distinguished from those that require more investigation, such as supraglottitis and tonsillar cancer. A sore throat is most commonly caused by an infectious, inflammatory, or neoplastic etiologic factor.

Group A streptococcal pharyngitis and immune-mediated complications: from diagnosis to management

Group A streptococcal pharyngitis remains the most important bacterial pharyngitis because of its frequency and potential complications. Group A streptococcal pharyngitis is most common in children 5-11 years of age in winter-spring, and a rapid test or culture is necessary for accurate diagnosis. We propose a management strategy for those geographic areas with very low acute rheumatic fever rates, emphasizing selective testing that avoids testing those patients with viral-like features (e.g., rhinorrhea and cough). Acute rheumatic fever is the most important immune-mediated sequela and has become rare in most areas of the USA and Western Europe, most probably due to decreased circulation of highly rheumatogenic group A streptococcal strains.

The sensitivity and the specifity of rapid antigen test in streptococcal upper respiratory tract infections

BACKGROUND

It is aimed to detect the sensitivity and specificity of rapid antigen detection of group A beta hemolytic streptococci from throat specimen compared with throat culture. The other goal of the study is to help in giving clinical decisions in upper respiratory tract infections according to the age group, by detection of sensitivity and positive predictive values of the rapid tests and throat cultures.

MATERIALS AND METHODS

Rapid antigen detection and throat culture results for group A beta hemolytic streptococci from outpatients attending to our university hospital between the first of November 2005 and 31st of December 2008 were evaluated retrospectively. Throat samples were obtained by swabs from the throat and transported in the Stuart medium and Quickvue Strep A [Quidel, San Diego, USA] cassette test was applied and for culture, specimen was inoculated on 5% blood sheep agar and identified according to bacitracin and trimethoprim-sulphametaxazole susceptibility from beta hemolytic colonies.

RESULTS

During the dates between the first of November 2005 and 31st of December 2008, from 453 patients both rapid antigen detection and throat culture were evaluated. Rapid antigen detection sensitivity and specificity were found to be 64.6% and 96.79%, respectively. The positive predictive value was 80.95% whereas negative predictive value was 92.82%. Kappa index was 0.91. When the results were evaluated according to the age groups, the sensitivity and the positive predictive value of rapid antigen detection in children were 70%, 90.3% and in adults 59.4%, 70.4%.

DISCUSSION

When bacterial infection is concerned to prevent unnecessary antibiotic use, rapid streptococcal antigen test (RSAT) is a reliable method to begin immediate treatment. To get the maximum sensitivity of RSAT, the specimen collection technique used and education of the health care workers is important. While giving clinical decision, it must be taken into consideration that the sensitivity and the positive predictive value of the RSAT is quite lower in adult age group than in pediatric age group.

Upper Respiratory Infections and Acute Bronchitis

Upper respiratory infections include the following: uncomplicated upper respiratory infections also known as the “common cold,” acute otitis media, pharyngitis/tonsillitis, and acute sinusitis. These conditions, along with acute bronchitis, are very common illnesses that are commonly seen in outpatient settings and are widely treated with antibiotics. In fact, these conditions are the primary indications for outpatient antibiotic prescriptions. These conditions tend to have overlapping clinical characteristics yet evidence regarding the utility of antimicrobial treatments varies across conditions.

Prevention of rheumatic fever and diagnosis and treatment of acute Streptococcal pharyngitis: a scientific statement from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee of the Council on Cardiovascular Disease in the Young, the Interdisciplinary Council on Functional Genomics and Translational Biology, and the Interdisciplinary Council on Quality of Care and Outcomes Research: endorsed by the American Academy of Pediatrics

Primary prevention of acute rheumatic fever is accomplished by proper identification and adequate antibiotic treatment of group A beta-hemolytic streptococcal (GAS) tonsillopharyngitis. Diagnosis of GAS pharyngitis is best accomplished by combining clinical judgment with diagnostic test results, the criterion standard of which is the throat culture. Penicillin (either oral penicillin V or injectable benzathine penicillin) is the treatment of choice, because it is cost-effective, has a narrow spectrum of activity, and has long-standing proven efficacy, and GAS resistant to penicillin have not been documented. For penicillin-allergic individuals, acceptable alternatives include a narrow-spectrum oral cephalosporin, oral clindamycin, or various oral macrolides or azalides. The individual who has had an attack of rheumatic fever is at very high risk of developing recurrences after subsequent GAS pharyngitis and needs continuous antimicrobial prophylaxis to prevent such recurrences (secondary prevention). The recommended duration of prophylaxis depends on the number of previous attacks, the time elapsed since the last attack, the risk of exposure to GAS infections, the age of the patient, and the presence or absence of cardiac involvement. Penicillin is again the agent of choice for secondary prophylaxis, but sulfadiazine or a macrolide or azalide are acceptable alternatives in penicillin-allergic individuals. This report updates the 1995 statement by the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee. It includes new recommendations for the diagnosis and treatment of GAS pharyngitis, as well as for the secondary prevention of rheumatic fever, and classifies the strength of the recommendations and level of evidence supporting them.

[Streptococcal pharyngitis in the pediatric emergency department: value and impact of rapid antigen detection test]

The French Health Agency (Afssaps) recommands the resort to the streptocoque rapid test strip for a better targetting of antibiotics prescription.

OBJECTIVES

To evaluate the systematic use of the test in a pediatric emergengy department.

METHODS

Comparison of results of the test to the laboratory cultures. Our study took place between January and December 2004. Two thousand one hundred (and) forty-four children with acute pharyngitis have been included (mean age: 4.8+/-3.6 years).

RESULTS

Group A streptococcus was involved in 57 pharyngitis (26%). Mean age of children with positive culture was 7+/-3 years versus 4+/-3 years if culture was negative (p>0.05). The test sensitivity was 77% (CI 95%: 65-86) and its specificity 82% (CI 95%: 75-87), the positive predictive value was 60% (CI 95%: 49-71) and the negative predictive value 91% (CI 95%: 85-95). Antibiotic prescriptions have diminished: no prescription for 70% of pharyngitis and for 93% if cultures were negative.

CONCLUSION

The rapid test strip wide use has a strong repercussion on the antibiotics prescription. This test is realist in pediatric emergency unit.

Throat culture is necessary after negative rapid antigen detection tests

This study was conducted to determine if culture confirmation is needed for a negative rapid antigen detection test. Data on 18,509 tests done in patients younger than 18 years old were reviewed. Of the 14,167 (76.5%) that were negative, 968 (6.8%) were associated with positive cultures. No significant seasonal variation was noted. Significant differences were found between hospital and pediatric practices in the percentage of patients with a negative rapid antigen detection test who actually had group A beta-hemolytic streptococcus (3.5% to 9.8%). This study supports the recommendation of culture confirmation of a negative rapid antigen detection test and validation of results within an individual practice if confirmatory cultures are not being performed. This study showed a high false-negative rate of the negative rapid antigen detection test and variation among hospital and pediatric practices for rates of positive culture after a negative rapid antigen detection test.

Diagnosis and management of pharyngitis in a pediatric population based on cost-effectiveness and projected health outcomes

BACKGROUND

Pharyngitis is a common childhood complaint. Current management for children and adolescents includes 1 of 6 strategies, ie, (1) observe without testing or treatment, (2) treat all suspected cases with an antibiotic, (3) treat those with positive throat cultures, (4) treat those with positive rapid tests, (5) treat those with positive rapid tests and those with positive throat cultures after negative rapid tests, or (6) use a clinical scoring measure to determine the diagnosis/treatment strategy. The sequelae of untreated group A hemolytic streptococcal (GAS) pharyngitis are rare, whereas antibiotic treatment may result in side effects ranging from rash to death. The cost-utility of these strategies for children has not been reported previously.

METHODS

A decision tree analysis incorporating the total cost and health impact of each management strategy was used to determine cost per quality-adjusted life-year ratios. Sensitivity analyses and Monte Carlo simulations assessed the accuracy of the estimates.

RESULTS

From a societal perspective with current Medicaid reimbursements for testing, performing a throat culture for all patients had the best cost-utility. For private insurance reimbursements, rapid antigen testing had the best cost-utility. Observing without testing or treatment had the lowest morbidity rate and highest cost from a societal perspective but the lowest cost from a payer perspective. The model was most sensitive to the incidence of acute rheumatic fever and peritonsillar abscess after untreated GAS pharyngitis. Monte Carlo simulations demonstrated considerable overlap among all of the options except for treating all patients and observing all patients.

CONCLUSIONS

Observing patients with pharyngitis had the lowest morbidity rate. The costs of this option were primarily from parental time lost from work. Before recommending observation rather than treatment of GAS pharyngitis, accurate estimates of the risk of developing acute rheumatic fever and peritonsillar abscess after GAS pharyngitis are needed.

Efficacy and safety of Sultamicillin (Ampicillin/Sulbactan) and Amoxicillin/Clavulanic Acid in the treatment of upper respiratory tract infections in adults - an open-label, multicentric, randomized trial

Upper respiratory tract infections are the most common causes of medical visits in children and adults, demanding massive use of antibiotics. Bacterial resistance caused by beta-lactamase is one of the most serious problems in this matter. Sultamicillin, a double pro-drug of Ampicillin/Sulbactan, is a potent beta-lactamase inhibitor which can face this challenge.

Aim

evaluate efficacy, safety and tolerability of Ampicillin/Sulbactan compared to Amoxicillin/Clavulanate in upper respiratory tract infections in adults.

Methods

102 patients were enrolled and randomized to receive Ampicillin/Sulbactan or Amoxicillin/Clavulanate during 10 days. They were evaluated 10 and 30 days after treatment to learn about the therapeutic response.

Results

There were no differences between the two groups respecting cure at the end of treatment (visit 2) or at the end of the study (visit 3). Cure ratio was 61.7% and 93.2% (visits 2 and 3) in the Amoxicillin/Clavulanate group compared to 64.4% and 97.4%, respectively, in Ampicillin/Sulbactan group. The adverse events ratio for the two groups was the same (p=0.940). The number of patients with diarrhea was greater in the group of patients receiving Amoxicillin/Clavulanate (70.6%) than in the group receiving Ampicillin/Sulbactan (29.4%) (p=0.0164).

Conclusions

Ampicillin/Sulbactan is as safe and efficient as Amoxicillin/Clavulanate in the empiric treatment of upper respiratory infections in adults. The low occurrence of diarrhea in the group receiving Ampicillin/Sulbactan needs confirmation in other studies.

Relationship between the clinical likelihood of group a streptococcal pharyngitis and the sensitivity of a rapid antigen-detection test in a pediatric practice

OBJECTIVE

The sensitivity of a rapid antigen-detection test (RADT) for group A streptococcal (GAS) pharyngitis is critical to whether the test is cost-effective and to whether a confirmatory throat culture is needed. We evaluated a second-generation RADT to determine if its sensitivity varies across the broad clinical spectrum of patients tested for GAS in pediatric outpatient practice.

METHODS

We used laboratory logbooks from a single pediatric clinic to identify 1184 consecutive patient visits at which an RADT was performed. In a blinded chart review, we calculated McIsaac scores to separately estimate the pretest clinical likelihood of GAS pharyngitis for visits at which the RADT result was positive (n = 384) and for visits at which the result proved to be false-negative (n = 65). Positive RADT results were assumed to be true positives, and test sensitivity was estimated by dividing the number of positive results by the sum of positives and false-negatives.

RESULTS

As the clinical likelihood of GAS increased, there were stepwise increases in RADT sensitivity (from 0.67 to 0.88). Sensitivity was low (0.73; 95% confidence interval [CI]: 0.62-0.86) in patients clinically unlikely to have GAS (McIsaac score < or =2) and high (0.94; 95% CI: 0.89-0.99) in patients <15 years old who had tonsillar exudate and no cough. False-negative RADT results were associated with lighter growth of GAS than found on specimens obtained from a random sample of clinic patients who had only primary throat cultures ordered.

CONCLUSIONS

For pediatric patients who are clinically unlikely to have GAS pharyngitis, as indicated by a McIsaac score < or =2, the sensitivity of a second-generation RADT may drop below thresholds reported for cost-effectiveness. For children who have tonsillar exudate and no cough, the test may be sensitive enough to meet current pediatric practice guidelines for stand-alone testing.

Rapid diagnosis of pharyngitis caused by group A streptococci

Although commercial rapid antigen detection tests (RADTs) are more expensive than blood agar plate (BAP) cultures, the advantage they offer is the speed with which they provide results. Rapid identification and consequent prompt treatment of patients with pharyngitis due to group A beta-hemolytic streptococci (GABHS) can reduce the risk of spread of GABHS, can allow patients to return to school or work sooner, and may reduce the acute morbidity of this illness. In most studies, RADTs have been compared with BAP cultures as the criterion standard. However, these comparisons are complicated by the fact that there is no universally accepted procedure for performing a BAP culture. The great majority of the RADTs that are currently available have a high specificity (i.e., 95% or greater) and a sensitivity of between 70 and 90% compared with BAP cultures. Few published studies have compared the performance of various RADTs to each other or examined the performance of various RADTs in the office setting. There is also relatively little published information about how physicians in practice actually use RADTs, but the available information suggests that many physicians do not follow recommended guidelines. While the development of easy-to-perform RADTs for the diagnosis of GABHS pharyngitis has altered clinical practice substantially, only limited data about cost-effectiveness are currently available.

Spectrum bias of a rapid antigen detection test for group A beta-hemolytic streptococcal pharyngitis in a pediatric population

BACKGROUND

Rapid antigen detection testing (RADT) is often performed for diagnosis of group A beta-hemolytic streptococcal (GABHS) pharyngitis among children. Among adults, the sensitivity of this test varies on the basis of disease severity (spectrum bias). A similar phenomenon may occur when this test is used in a pediatric population, which may affect the need for culture confirmation of all negative RADT results.

OBJECTIVES

To assess the performance of a clinical scoring system and to determine whether RADT spectrum bias is present among children who are evaluated for GABHS pharyngitis.

METHODS

Laboratory and clinical records for a consecutive series of pediatric patients who underwent RADT at the Marshfield Clinic between January 2002 and March 2002 were reviewed retrospectively. Patients were stratified according to the number of clinical features present by using modified Centor criteria, ie, history of fever, absence of cough, presence of pharyngeal exudates, and cervical lymphadenopathy. The sensitivity of the RADT was defined as the number of patients with positive RADT results divided by the number of patients with either positive RADT results or negative RADT results but positive throat culture results.

RESULTS

RADT results were positive for 117 of 561 children (21%), and culture results were positive for 35 of 444 children (8%) with negative RADT results. The overall prevalence of GABHS pharyngitis was 27% (95% confidence interval: 23-31%). The prevalence of GABHS pharyngitis was 18% among patients with 0 Centor criteria, 16% among those with 1 criterion, 32% among those with 2 criteria, and 50% among those with 3 or 4 criteria. Spectrum bias was present, inasmuch as RADT sensitivity increased with Centor scores, ie, 47% sensitivity among children with 0 Centor criteria, 65% among those with 1 criterion, 82% among those with 2 criteria, and 90% among those with 3 or 4 criteria.

CONCLUSIONS

The sensitivity of RADT for GABHS pharyngitis is not a fixed value but varies with the severity of disease. However, even among pediatric patients with > or =3 Centor criteria for GABHS pharyngitis, the sensitivity of RADT is still too low to support the use of RADT without culture confirmation of negative results.

Rapid Detection and Diagnosis of Group A Streptococcal Pharyngitis

This article reviews techniques of rapid testing and the effective diagnosis of streptococcal pharyngitis. Despite 50 years' study of streptococcal pharyngitis and 20 years' experience with rapid tests for its diagnosis, the subject continues to evolve. Rapid diagnostic tests have become more sensitive. Experts now consider not if but when they may replace throat cultures. Highly accurate rapid tests will still challenge clinicians to screen the right patients. The improvement of clinical diagnosis will require an understanding of the clinical spectrum of pharyngitis and questions relating to disease prevalence, test performance, and medical decision making. Implications for diagnostic strategies are discussed.

[Reliability and general practice value of 2 rapid Streptococcus A tests]

Rapid streptococcal-A-antigen detection assays have good specificity (over 90 percent) but moderate sensitivity (between 80 and 90 percent), when the tests are compared with a standard throat culture. Contradictory results have been found for one of the more recent tests, the optical immune assay Strep A OIA MAX, while for 6 years, we have been using the immune assay Strep A Plus. Results of the optical immunoassay and the conventional immune assay Strep A Plus were compared in 65 patients with acute pharyngitis. A standard culture was used as reference and confirmed by enhanced broth culturing and nucleic acid hybridization assay (Gen-Probe) when the two detection assays produced contradictory results. While both assays were equally sensitive (78.3%), Strep A OIA MAX and Strep A Plus had a similar specificity of 95.2% and 100%, respectively. Four and nine steps were required for Strep A Plus and for Strep A OIA MAX test procedures, respectively with results being available in 4-5 min and in 9-10 min, respectively. We conclude that both rapid immunoassays have a similar reliability while the handling of the Strep A Plus is much simpler than the handling of the Strep A OIA MAX. Neither rapid immunoassays are sensitive enough to eliminate the need for backup cultures.

Cost-effective workup for tonsillitis. Testing, treatment, and potential complications

Despite increased strictness in surgical criteria, tonsillectomy continues to be one of the most common outpatient surgical procedures performed in the United States. The primary care physician is integrally involved in the diagnosis and treatment of tonsillitis, the chief reason for tonsillectomy. This article gives guidelines for diagnosis and management of tonsillitis and provides an overview of its potential complications.

Cost-effectiveness of treatment options for prevention of rheumatic heart disease from Group A streptococcal pharyngitis in a pediatric population

BACKGROUND

We set out to examine which treatment option available in the United States was most cost-effective in treating children with endemic group A streptococcal pharyngitis to prevent rheumatic heart disease.

METHODS

Cost-effectiveness was calculated from the societal perspective and expressed in cases of rheumatic heart disease prevented annually in the U.S. pediatric population aged 5 to 17 based on U.S. Census data. We used a decision-analysis model to assess the cost-effectiveness of five treatment options for patients with pharyngitis: (1) "treat all," (2) "treat none," (3) "rapid test," where only patients with a positive rapid antigen test are treated, (4) "culture," where only patients with a positive throat culture are treated, and (5) "rapid test with culture" or (RTCX), where confirmatory cultures are used on patients with negative rapid tests. Cost data were gathered from existing empirical data or estimated. We performed sensitivity analyses of the antigen test sensitivity and antibiotic effectiveness and examined whether changes in these variables would alter our outcome.

RESULTS

The "rapid test" was the most cost-effective option. Using "rapid tests" prevented 85 cases of rheumatic heart disease annually and cost society $727,000 per case prevented. Performing throat cultures instead of "rapid tests" would pick up an additional 11 cases of rheumatic heart disease but would cost $13.7 million for each of these additional cases prevented. The current standard of using throat cultures as a confirmatory test on patients with a negative "rapid" test would detect an additional 21 cases of rheumatic heart disease but cost society an additional $8 million per case prevented.

CONCLUSIONS

To reduce the incidence of rheumatic heart disease cost-effectively, the management of pediatric pharyngitis may best be accomplished by using antigen testing. The added costs associated with the remaining treatment options may not be justified, especially, as the sensitivity of the antigen tests continues to improve and closely approaches the sensitivity of the practice standard, throat culture.

Rapid direct antibiotic susceptibility testing in endophthalmitis

OBJECTIVE

To compare a new rapid antibiotic susceptibility test (RAST) to the conventional method in patients with endophthalmitis.

DESIGN

Prospective nonrandomized comparative trial.

PARTICIPANTS

Intraocular aspirates from 24 consecutive patients with endophthalmitis were tested.

METHODS

Approximately 0.25 ml of vitreous or anterior chamber aspirate was obtained and tested for antibiotic sensitivity using the Kirby-Bauer agar disk diffusion method. Using this conventional testing method, the aspirates were cultured for bacterial growth before antibiotic susceptibility testing (AST). In contrast, for direct RAST, the aspirates were inoculated directly onto agar plates with antibiotic disks without first culturing for bacterial growth.

RESULTS

Of the 24 endophthalmitis aspirates studied, 4 (17%) could not be tested by direct RAST because either more than one bacterial species was present or no bacteria were cultured. The remaining 20 cases provided 467 antibiotic-microorganism combinations. The two methods yielded identical susceptibility results in 409 (88%) of the 467 tests. In 42 tests (9%), a minor discrepancy occurred between the conventional method and RAST, in which one resulted in intermediate susceptibility, whereas the other was either resistant or sensitive. Significant discrepancy, defined as a bacterial sample reported as sensitive in one method yet resistant in the other, occurred with 16 samples (3%). Results of the RAST were available within 6 to 10 hours compared with more than 24 hours for the conventional method. Of clinical significance, the results of the RAST revealed that in 11 cases of epidemic Stenotrophomonas maltophilia endophthalmitis, the bacteria were resistant to the antibiotics prescribed, and change of antibiotic therapy was made on the basis of the RAST results.

CONCLUSIONS

RAST provided accurate antibiotic susceptibility results in a much shorter time than did the conventional method. We suggest that conventional AST be performed for confirmation of the RAST results, but initial antibiotic therapy can quite reliably be based on the results of RAST.

Critical evaluation of a CLIA-waived streptococcal antigen detection test in the emergency department

STUDY OBJECTIVE

We compare the performance of a Clinical Laboratory Improvement Amendments (CLIA)-waived antigen detection test (ADT) analyzed in the emergency department and a CLIA moderately complex ADT performed in the hospital microbiology laboratory.

METHODS

Samples from throat swabs were obtained using a double-headed Culturette II (Becton Dickinson Medical Systems, Sparks, MD) from a consecutive sample of 322 patients 3 years or older who presented to the ED of a university-affiliated pediatric referral hospital with the complaint of sore throat during 1998. One swab was transported to the microbiology laboratory and analyzed using a CLIA moderately complex ADT; negative results were confirmed using sheep blood agar culture. The second swab remained in the ED where a nurse conducted a CLIA-waived ADT. The accepted standard for documentation of group A beta-hemolytic streptococcal (GABHS) infection was either a positive moderately complex ADT or culture result. The time of specimen collection, as well as the time the ED results and microbiology laboratory results were available to treating physicians, were recorded. Main outcome measures were concordance (kappa statistic), sensitivity, and turnaround time (Mann-Whitney U test).

RESULTS

Three hundred twenty-two patients (mean age 7.5 years) had both ADTs performed. One hundred one (31%) patients had documented GABHS in the microbiology laboratory; 83 (82%) had a positive ADT result in the microbiology laboratory, and 18 (18%) had a positive culture result after a negative moderately complex ADT result. In 299 patients or 93% (95% confidence interval [CI] 90.8%, 95.8%) of patients, the waived ADT and the moderately complex ADT results were concordant (kappa 0.82; 95% CI 0.78, 0.86; P <.001). The sensitivity of the waived ADT was 80%; the sensitivity of the moderately complex ADT approximated 82% (difference of 2%; 95%CI -3%, 7%). The median times from swab specimen collection to availability of ADT results were 10 minutes (range 3 to 37 minutes) for the waived ADT and 35 minutes (range 5 to 162 minutes) for the moderately complex ADT (P <.001) with a difference of 25 minutes (95% CI 22.4, 27.6 minutes).

CONCLUSION

In this study, an ED CLIA-waived rapid streptococcal throat test performed as well as its equivalent CLIA-regulated laboratory test. Further, the ED test provided results more rapidly than the laboratory test. Our results also validate previous work that negative rapid throat test results in pediatric patients in the ED should be confirmed by standard throat culture.

Acute pharyngitis

The primary care physician needs to identify those patients with acute pharyngitis who require specific antimicrobial therapy and to avoid unnecessary and potentially deleterious treatment in the large majority of patients who have a benign, self-limited infection that is usually viral. In most cases, differentiating between these two types of infection can be accomplished easily if the physician considers the epidemiologic setting, the history, and the physical findings, plus the results of a few readily available laboratory tests. When antimicrobial therapy is required, the safest, narrowest-spectrum, and most cost-effective drugs should be used. Despite agreement on these principles by expert advisory committees, data from national surveys of ambulatory care indicate that antimicrobial agents continue to be prescribed indiscriminately for upper respiratory infections.

Causes, diagnosis and treatment of pharyngitis

Pharyngitis is the only respiratory tract infection in which microbiologic diagnosis has immediate influence on the treatment decision. Microbiologic diagnosis should always precede antibiotic treatment of pharyngitis to ensure optimal treatment. Penicillin administered for 10 days is still the drug of choice.