Evidence Report/Technology Assessment: Number 9
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Please Note: The evidence report this summary was derived from has been updated. For the updated report, go to http://www.ahrq.gov/clinic/tp/rhinouptp.htm.
Under its Evidence-based Practice Program, the Agency for Health Care Policy and Research (AHCPR) is developing scientific information for other agencies and organizations on which to base clinical guidelines, performance measures, and other quality improvement tools. Contractor institutions review all relevant scientific literature on assigned clinical care topics and produce evidence reports and technology assessments, conduct research on methodologies and the effectiveness of their implementation, and participate in technical assistance activities.
Overview / Reporting the Evidence / Methods / Decision Analysis and Cost-Effectiveness Analysis / Findings / Future Research / Availability of Full Report
Acute rhinosinusitis is one of the most common infections in the United States. Millions of cases occur each year, affecting all age groups and all segments of the population. Although only a small percentage of these cases come to the attention of a physician, this high prevalence translates into high costs for individual health, work time lost, and medical expenditures. In 1992, Americans spent $200 million on prescription medications for rhinosinusitis and more than $2 billion for over-the-counter medications.
In the majority of cases, inflammation of the paranasal sinuses (sinusitis) is accompanied by inflammation of the nasal passages (rhinitis); thus the clinical condition often referred to as sinusitis is, in fact, rhinosinusitis: inflammation of the sinuses with concomitant inflammation of the nasal passages. In clinical practice, the focus is on patients in whom this rhinosinusitis results in clinical symptoms.
Conditions that cause or predispose individuals to rhinosinusitis include:
- Infectious agents (bacteria, viruses, and fungi).
- Allergic conditions (allergic rhinitis).
- Anatomic abnormalities.
- Systemic diseases (endocrine, metabolic, genetic).
- Noxious chemicals.
The prevalence of rhinosinusitis resulting from each cause is unknown, although certain causes, such as viral infection, are more common. In some cases, the cause may be multifactorial (e.g., viral infection with bacterial superinfection).
Despite the common nature of rhinosinusitis, its management is controversial. Therapies are usually directed to alleviating or reducing symptoms, eradicating the underlying cause, or both. A major question is whether an antibiotic should be used and, if so, which one? Because the premise of treatment with antibiotics is that bacterial infection will be eliminated, patients with bacterial rhinosinusitis need to be identified. In addition, other disease and patient characteristics, such as age and duration and pattern of illness, may help in distinguishing patient subgroups for more specific types of treatment (e.g., antibiotics to eradicate specific bacteria).
Because bacterial infection of the sinuses is potentially serious, the use of antimicrobials to prevent complications is of interest. However, concern is increasing about the overuse or abuse of antibiotics, both for the individual≵in terms of potential side effects and cost≵as well as for society, in terms of cost and the development of antibiotic-resistant bacteria.
To address the need to identify and assess evidence on the diagnosis and treatment of acute bacterial rhinosinusitis, the Agency for Health Care Policy and Research awarded a contract to the New England Medical Center Evidence-based Practice Center (EPC) for a review of published reports and compilation of an evidence report. The EPC focused its efforts on the diagnosis and treatment of uncomplicated, community-acquired, acute bacterial rhinosinusitis in children and adults.
The EPC examined the prevalence of this illness in both general primary care and subspecialty clinic settings and analyzed the data from clinical studies that compared the performance of various diagnostic tests (including clinical examination criteria) for identifying patients with acute bacterial rhinosinusitis. Randomized controlled trials were assessed that compared the treatment effects of antibiotics with placebo and the effects of inexpensive antibiotics≵such as amoxicillin and folate inhibitors (e.g., trimethoprim/sulfamethoxazole)≵with newer, more expensive antibiotics (e.g., cephalosporins).
The EPC also collected evidence on ancillary therapies, such as decongestants, steroids, and sinus irrigation. Finally, the evidence was combined in a decision analysis and a cost-effectiveness analysis to compare clinical strategies for managing patients with acute bacterial rhinosinusitis and to help translate the evidence into practice. Although sinusitis can include acute, recurrent, and chronic forms, for this investigation the EPC focused on acute sinusitis and, more specifically, on community-acquired acute bacterial rhinosinusitis.
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Reporting the Evidence
The EPC worked in collaboration with a panel of technical experts, including representatives from four professional organizations≵the American Academy of Family Physicians, the American Academy of Otolaryngology-Head and Neck Surgery, the American Academy of Pediatrics, and the American College of Physicians≵to formulate the following questions:
- What is the prevalence of bacterial infection among patients presenting with acute rhinosinusitis in primary care and specialty settings?
- What is the diagnostic value of clinical features and imaging technologies for identifying acute rhinosinusitis and acute bacterial rhinosinusitis?
- Given a (clinical) diagnosis of acute bacterial rhinosinusitis, are antibiotics effective in resolving symptoms and preventing complications or recurrence?
- In treating acute bacterial rhinosinusitis, what is the efficacy of antibiotics compared with placebo, and among the various antibiotics, what is their comparative efficacy? What evidence do these comparative studies provide regarding side effects?
- Are there data to support the use of other types of treatments for acute rhinosinusitis and acute bacterial rhinosinusitis≵specifically, decongestants, steroids, antihistamines, and drainage and irrigation? What is the efficacy of antibiotics compared with other types of treatment? What evidence do any comparative studies provide regarding side effects of these treatments?
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The EPC systematically reviewed the literature for evidence addressing these questions. Prospective studies that compared two or more diagnostic tests were used to assess diagnostic test performance, and randomized controlled trials were used to assess treatment efficacy. The review included English-language articles indexed in the Medline database between 1966 and May 1998; several sensitive search strategies were used to identify studies on sinusitis. The titles, MeSH headings, and abstracts of the retrieved citations were manually screened to identify articles for retrieval. Technical experts were consulted, and bibliographies of retrieved primary studies, review articles, and published and unpublished meta-analyses on the diagnosis or treatment of acute rhinosinusitis were examined for additional references.
A separate Medline search for potentially useful foreign-language articles was also conducted to assess the magnitude of the bias caused by excluding foreign-language articles from the primary search strategy. Several studies published in other languages were included in the EPC's analyses.
Data from primary clinical studies that met inclusion criteria were extracted to develop evidence tables pertaining to the specified questions. A summary receiver operating characteristics (ROC) curve was constructed from a meta-analysis to assess the performance of clinical criteria and various imaging technologies commonly used to diagnose acute bacterial rhinosinusitis. Meta-analyses were also performed to pool the clinical outcomes of patients treated with and without antibiotics and to compare different individual and classes of antibiotics. Several subgroup analyses were performed to identify factors that may be related to treatment variations.
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Decision Analysis and Cost-Effectiveness Analysis
A decision analysis was performed from the patient's perspective to evaluate several diagnostic tests and treatment strategies for managing acute bacterial rhinosinusitis. A cost-effectiveness analysis was performed from the payer's perspective to estimate the cost-effectiveness of several common treatment strategies. Both a single-time-point decision tree and a Markov process were used to model the clinical decisions, possible events, and clinical outcomes. The models used estimates drawn from the meta-analyses, primary studies, review articles, expert opinions, and consensus.
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The overall methodological quality and reporting of both diagnostic and treatment studies on this topic are poor. Few studies were conducted in North America. So few studies met strict diagnostic criteria (sinus puncture with bacterial culture) that it was necessary to relax the selection criteria to have enough studies for meta-analyses (the investigators' diagnoses were accepted). Still, only 14 of 48 diagnostic test comparison studies and only 30 of the 74 randomized controlled trials on antibiotics met the revised criteria.
For studies of children, only one diagnostic test study and two antibiotic treatment studies met the revised criteria for their respective meta-analysis. Although there is a pathophysiologic basis for differentially treating children and adults, the lack of evidence for children precluded making distinctions in diagnosis and treatment in these populations beyond inspection of the individual studies.
Prevalence rates were obtained from the studies reviewed, although estimates from additional observational studies are also described.
1. What is the prevalence of bacterial infection among patients presenting with acute rhinosinusitis in primary care and specialty settings?
- Prevalence data for acute bacterial rhinosinusitis in the general population are sparse. The 1994 National Health Interview Survey report on chronic sinusitis estimated 35 million people affected per year in the United States.
- The prevalence of acute sinusitis appears to be increasing, according to data from the National Ambulatory Medical Care Survey (from 0.2 percent of diagnoses at office visits in 1990 to 0.4 percent of diagnoses at office visits in 1995).
- Up to 38 percent of patients with symptoms of sinusitis in adult general medicine clinics may have acute bacterial rhinosinusitis. In otolaryngology practices, the prevalence was higher (50 to 80 percent). Between 6 to 18 percent of children in the primary care setting presenting with upper respiratory infections may have acute bacterial sinusitis.
2. What is the diagnostic value of clinical features and imaging technologies for identifying acute rhinosinusitis and acute bacterial rhinosinusitis?
- Bacterial rhinosinusitis has been diagnosed from clinical criteria, sinus puncture with culture of the aspirate, sinus radiography, ultrasonography, and computed tomography.
- Although sinus puncture with culture is the diagnostic reference standard, it is rarely used because it is invasive and costly; it is not a practical routine procedure.
- A meta-analysis of six studies shows that sinus radiography has moderate sensitivity (76 percent) and specificity (79 percent) compared with sinus puncture in the diagnosis of acute bacterial rhinosinusitis.
- Studies comparing sinus ultrasonography with puncture or sinus radiography were inconclusive in determining how well ultrasonography identifies patients with acute bacterial rhinosinusitis. The results of ultrasonography varied substantially, possibly because of differences in patient populations, ultrasonography techniques, or medical personnel involved in diagnostic testing.
- Limited evidence suggests that clinical criteria (i.e., the presence of three or four of the following symptoms: purulent rhinorrhea with unilateral predominance, local pain with unilateral predominance, bilateral purulent rhinorrhea, and the presence of pus in the nasal cavity) may have a diagnostic accuracy similar to that of sinus radiography.
- No studies comparing magnetic resonance imaging or endoscopy with either radiography or sinus puncture were found. The one randomized trial comparing computed tomography with sinus radiography was inadequately reported.
3. Given a (clinical) diagnosis of acute bacterial rhinosinusitis, are antibiotics effective in resolving symptoms and in preventing complications or a recurrence?
- More patients were cured, and cured earlier, when treated with antibiotics rather than placebo.
- About two-thirds of the patients receiving placebo recovered without antibiotics.
- Serious complications of rhinosinusitis, such as meningitis, brain abscess, and periorbital cellulitis are rare, and none were reported in the clinical trials examined for this study.
- Most clinical trials have only short-term followup and report no data on relapse.
4a. In treating acute bacterial rhinosinusitis, what is the efficacy of antibiotics compared with placebo, and among the various antibiotics, what is their comparative efficacy?
- Antibiotics are significantly more effective than placebo for treating acute bacterial rhinosinusitis, reducing the clinical failure rate by one-half. Patients are cured more quickly and more often when treated with antibiotics compared with no treatment.
- Amoxicillin or folate inhibitors are as efficacious as the newer and more expensive antibiotics. The current evidence does not justify the use of the newer antibiotics for treating uncomplicated, community-acquired acute bacterial rhinosinusitis.
4b. What evidence do these comparative studies provide regarding side effects?
- About 4 percent of the patients in the amoxicillin arms of the clinical trials withdrew as a result of side effects, but this withdrawal rate did not differ statistically among those treated with other antibiotics. The data for folate inhibitors are more limited but similar.
5a. Are there data to support the use of other types of treatments for acute rhinosinusitis and acute bacterial rhinosinusitis, specifically: decongestants, steroids, antihistamines, and drainage and irrigation?
- Ten randomized controlled trials evaluated ancillary treatment for rhinosinusitis. Meta-analysis was not possible due to different treatments compared, diagnosis criteria, and outcomes measures, as well as inconsistent concurrent use of antibiotics.
5b. What is the efficacy of antibiotics compared with other types of treatment?
- Many studies of antibiotic treatment also included ancillary therapies. However, these therapies were seldom standardized, which prevented an analysis of their benefits.
5c. What evidence do any comparative studies provide regarding side effects of these treatments?
- Data from randomized controlled trials are insufficient to answer this question.
Results of Decision- and Cost-Effectiveness Analyses
The EPC conducted a cost-effectiveness analysis to compare four treatment strategies:
- A sinus radiography-directed strategy.
- The use of clinical criteria to guide treatment.
- Initial symptomatic (ancillary) treatment.
- Routine empirical use of antibiotics, with either amoxicillin or a folate inhibitor.
The result is essentially a "toss-up" in terms of symptom days for empirical, radiography-guided, and clinical-guided treatments.
Symptomatic treatment alone provided fewer symptom-free days at all but the very lowest prevalence of acute bacterial rhinosinusitis. In terms of cost, the use of clinical criteria and initial symptomatic treatment is a toss-up at any prevalence. Empirical treatment is more costly at all but the highest range of prevalence. Radiography is considerably more costly at any prevalence. Initial symptomatic treatment is the most cost-effective strategy at prevalence of up to 25 percent, the use of clinical criteria is most cost effective for a prevalence between 25 and 83 percent, and empirical antibiotic treatment with amoxicillin or a folate inhibitor is cost effective only at prevalence greater than 83 percent. Sinus radiography is never a cost-effective strategy at any prevalence. The prevalence thresholds for various strategies are moderately sensitive to the severity of sinus symptoms as reflected in the utilities for computing quality-of-life adjustments.
At the prevalence of acute bacterial rhinosinusitis likely to be encountered in most primary care settings, the evidence indicates that a strategy of either initial symptomatic treatment or the use of clinical criteria to guide treatment would be an effective and cost-effective approach for uncomplicated patients. According to the evidence, a 7- to 10-day course of watchful waiting before prescribing antibiotics would be reasonable, since most patients' symptoms resolve without antibiotic treatment, and serious complications are rare. Finally, the evidence supports the use of amoxicillin or a folate inhibitor as the initial antibiotic therapy. The severity of the patient's symptoms affected the utilities used in the EPC's decision models and thus may need to be considered when assessing this evidence.
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- Many patients with acute rhinosinusitis are not seen by health care providers. The prevalence of this condition needs to be known to help distinguish those people requiring treatment with antibiotics from those not requiring antibiotics or further evaluation.
- Because of the anatomical differences in children and adults, diagnostic and treatment studies should be conducted on pediatric populations.
- Future studies also are needed involving patients with comorbidities (e.g., allergies, asthma, HIV infection) that may influence the development, progression, and response to treatment of acute bacterial rhinosinusitis.
- Involvement of sinuses other than maxillary sinuses should be studied.
- The diagnostic reference standard of sinus puncture with culture of aspirate is infeasible in routine practice, and most trials based diagnosis on other criteria. Alternative less invasive reference standard methods for diagnosing acute rhinosinusitis are needed.
- Future studies of clinical criteria (including risk scores), ultrasonography, and endoscopy with middle meatal sampling, ideally comparing them with sinus puncture in a variety of research and clinical settings, are needed to establish their diagnostic utility.
- Better designs are needed for future studies. In particular, definitions of the populations to be treated, the test methods, and the criteria for diagnosis should be more precise, and investigators should be masked.
- The role of antibiotic resistance in individual clinical decisionmaking needs to be clarified. More data are needed on patients with resistant organisms and their responses to therapies and on the association between laboratory and clinical resistance.
- Outcome measures need to be reassessed. In particular, assessing outcomes at different time points may better represent the differential effects of therapies.
- In addition to better understanding of the connection between treatment and time to resolution of symptoms, there is a need for increased knowledge regarding treatments and relapse rates or the potential development of recurrent sinusitis.
- Standardization and focused evaluations of ancillary treatments are needed.
- The influence of several factors on patient-assigned utilities (patient-physician interactions, availability of "time for sickness," and variability of severity of episodes) need to be better understood when applying evidence to clinical practice.
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Availability of the Full Report
The full evidence report from which this summary was taken was prepared for the Agency for Health Care Policy and Research by the New England Medical Center, Boston, MA, under contract 290-97-0019. The Evidence Report is available online at the National Library of Medicine Bookshelf. Print copies are no longer available.
AHCPR Publication No. 99-E015
Current as of March 1999