Prevalence of the chronic sinusitis diagnosis in Olmsted County, Minnesota.

BACKGROUND: Commonly cited estimates from the National Health Interview Survey rank chronic sinusitis as one of the most prevalent chronic diseases in the United States. These data rely on patient self-reporting of the disease. However, chronic sinusitis is difficult to diagnose because its symptoms overlap those of many other disease processes. As such, these prevalence data may be unreliable.

OBJECTIVE: To provide an estimate of the prevalence of chronic sinusitis based on assigned International Classification of Diseases, Ninth Revision (ICD-9) codes for the year 2000 in a population-based sample. This study establishes the individual patient as the unit of measure vs previous ICD-9-based estimates that measured physician encounters.

DESIGN: Using existing databases, we identified all residents of Olmsted County, Minnesota, who were assigned an ICD-9 diagnosis code for chronic sinusitis (473.x) in the year 2000.

SETTING: Primary care and referral center serving the general community.

PARTICIPANTS: All residents of Olmsted County who provided research authorization were eligible.

MAIN OUTCOME MEASURE: Age- and sex-specific prevalence of chronic sinusitis based on assigned ICD-9 diagnosis codes.

RESULTS: In the year 2000, 2405 residents of Olmsted County were given an ICD-9 diagnosis code for chronic sinusitis. Among these, 1627 (67.7%) were female and 778 (32.3%) were male. The overall age- and sex-adjusted prevalence per 100,000 was 1955 (1.96%). The mean (SD) age at the time of diagnosis was 39.4 (17.6) years (age range, 4.2 months to 94 years). Eighty-seven percent were diagnosed at Mayo Clinic, and the balance were from the Olmsted Medical Center. At Mayo, family practitioners and internists diagnosed most of the cases (70%); only 8% were diagnosed by the Department of Otolaryngology. The diagnosis code 473.9 for unspecified chronic sinusitis made up 95% of cases.

CONCLUSIONS: Current prevalence estimates of chronic sinusitis may be exaggerated. Chronic sinusitis has been reported to affect 14% to 16% of the US population according to a National Health Interview Survey. In Olmsted County, we found a much lower prevalence (1.96%) of chronic sinusitis using ICD-9 codes as an identifier.