Chronic sinusitis less common than reported

Chronic sinusitis, usually believed to affect 14% to 16% of the population, may have a much lower prevalence, according to a paper in the March Archives of Otolaryngology -- Head and Neck Surgery.

Mayo Clinic researchers analyzed medical records of Olmstead County, Minn., residents attending their facility and the neighboring Olmsted Medical Center in search of the actual diagnosis rate. They found that chronic sinusitis was more common in women than men. Most diagnoses were made by primary care physicians rather than specialists. And, the average age at diagnosis was 39.

They also found that the prevalence was only 2%.

"It was much lower than we expected," said Ron Shashy, MD, lead author and chief resident in otolaryngology at Mayo.

The study drew praise for attempting to get a handle on a condition that can be difficult to diagnose because its symptoms tend to be nonspecific and mimic several other common complaints. Some experts also said the findings point to the need for a better definition of chronic sinusitis in order to more accurately diagnose and treat it.

"Many of the things that get called chronic sinusitis are most likely something else," said Robert Flaherty, MD, a family physician and staff doctor at the student health service of Montana State University. "The criteria are so vague as to not be helpful at all. Sinus disease exists, but we don't really have very good diagnostic criteria."

But critics said researchers may be comparing apples with oranges. The studies that found the higher prevalence were based on patient self-reporting that may reflect whether they ever believed or were told that they had the disease, not necessarily whether they have it at the moment. This new research looked at the rate of diagnosis by a physician in a specific one-year period.

"What they have determined is the point prevalence," said Neil Bhattacharyya, MD, an otolaryngologist at Brigham and Women's Hospital in Boston. "The studies the authors are comparing to actually get more to a lifetime prevalence."

Most suspect the true prevalence may be somewhere in the middle.

"It's one of the most overdiagnosed and also one of the most underdiagnosed conditions there are out there," said Michael Blaiss, MD, president of the American College of Allergy, Asthma and Immunology. "And patients think there's a lot more out there than there really is."

No matter what the prevalence, the burden of chronic sinusitis remains significant in terms of money spent on medications as well as work time and productivity lost. The costs are particularly high because of the difficulty in diagnosing the disease.

"There's a lot of money that's being thrown at this per year," said Bradley Marple, MD, associate professor and vice chair of the department of otolaryngology at the University of Texas Southwestern Medical Center at Dallas. "The impact is great whether you say the prevalence is 2% or 16%, but the number is not as important as establishing an accurate diagnosis."

Researchers have just finished analyzing the records of those with a diagnosis to determine if they fit the accepted definitions of the disease and expect to publish a study in the future that states that the prevalence estimates are even lower.