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Researchers propose new criteria for diagnosing acute rhinosinusitis in adults

Integrating signs, symptoms and C-reactive protein is one way to diagnose acute rhinosinusitis and acute bacterial rhinosinusitis in adults with “good accuracy,” according to research recently published in Annals of Family Medicine.

These findings could reduce inappropriate antibiotic prescribing for acute rhinosinusitis, which is the most common reason for antibiotics in the ambulatory setting, the researchers wrote. Antibiotics are prescribed for more than 70% of patients, according to the authors, but only about 30% of patients have a bacterial cause based on culture of sinus fluid.

“Practice guidelines recommend the use of antibiotics only for patients with prolonged, severe or worsening symptoms of acute rhinosinusitis, when the likelihood of a bacterial cause is thought to be higher,” Mark H. Ebell, MD, MS, department of epidemiology and biostatistics, University of Georgia, and Jens Georg Hansen, MD, DMSc, department of clinical epidemiology, Aarhus University Hospital, Denmark wrote. “It is common practice, however, for patients with a diagnosis of acute rhinosinusitis to be prescribed an antibiotic regardless of the duration of symptoms or their severity. One strategy to reduce inappropriate prescribing is to give physicians tools that can help them more confidently diagnose or rule out acute bacterial rhinosinusitis.”

Ebell and Hansen developed two clinical decision rules using multivariate analysis and classification and regression tree (CART). For the multivariate analysis, they developed three reference standards abnormal CT finding, abnormal antral puncture finding and positive bacterial culture and conducted logistic regression models to develop point scores for each reference standard using signs, symptoms and C-reactive protein as dependent variables. They also developed a diagnostic algorithm using a CART model for each of the reference standards. In each CART model and for the point scores, the researchers characterized low-, moderate- and high-risk groups.

The study included 175 patients aged 18 to 65 and living in Denmark who were seeking treatment for suspected acute rhinosinusitis. Researchers found that the point scores using univariate logistic regression analysis had an area under the receiver operating characteristic curve between 0.721 and 0.767. Using positive bacterial culture as the reference standard, low-risk groups had a 16% likelihood of acute bacterial rhinosinusitis, moderate-risk groups had a 49% likelihood and high-risk likelihood had a 73% likelihood.

In addition, the CART models had an area under the curve ranging from 0.783 to 0.827. Using positive bacterial culture as the reference standard, low-risk groups had a 6% likelihood of acute bacterial rhinosinusitis, moderate-risk groups had a 31% likelihood and high-risk patients had a 59% likelihood.

“This study is the first to systematically develop clinical decision rules for acute rhinosinusitis using different reference standards and statistical approaches,” Ebell and Hansen wrote. “Current practice is that 72% of patients with a clinical diagnosis of acute rhinosinusitis receive an antibiotic. Using our rule and assuming that all high-risk and one-half of intermediate-risk patients receive an antibiotic would reduce that practice to 34% of patients. This percentage is roughly consistent with the estimate that only 27% of episodes of sinusitis should be treated with an antibiotic. Even treating all patients who are at high or intermediate risk — 52% — would be an improvement over current practice.”

Researchers stated that the rule must now undergo prospective validation and an assessment of its effect on clinical and process outcomes. – by Janel Miller

Disclosure: The researchers report no relevant financial disclosures.