Objective: The aims of this work were to characterize ambulatory patients in the United States presenting with primary or secondary insomnia complaints and resultant diagnoses, and to describe the characteristics of patients treated with medications commonly used for sleep complaints.
Methods: Data from the National Ambulatory Medical Care Survey for the years 1997 through 2002 were analyzed. Data were stratified by patient characteristics, physician specialty, resulting diagnosis, and medications prescribed or provided. The unit of analysis was the individual patient visit; statistical comparisons were made using the chi(2) test for categorical variables and the Rao-Scott design-adjusted chi(2) test for comparisons of patient age groups. P<0.05 was the criterion for statistical significance. Cells containing < 30 observations were not included in the statistical analysis.
Results: The data included 147,945 patient visit records; rates of physician response to the survey ranged from 62.9% in 1999 to 70.4% in 2002. Based on this sample, it was projected that 30 million office visits involved insomnia complaints over the 6-year period from 1997 to 2002 throughout the United States. With a total of 4.9 billion physician visits projected for that time period, 0.6% of visits were insomnia related. Women were 1.5 times more likely to have insomnia-related visits (P<0.001). Overall, the greatest proportion of insomnia patients of both sexes was between the ages of 18 and 64 years (P<0.001). Sleep difficulties were most frequently attributed to organic disorders, depression and/or anxiety, and primary insomnia (55.8%, 27.3%, and 9.8%, respectively; P<0.001). The most frequently prescribed or recommended medications were zaleplon/zolpidem and trazodone (28.5% and 32.0%, respectively; P<0.001). Zaleplon and zolpidem were most frequently used for patients with organic diagnoses and those aged < or =65 years (33.2% and 29.8%; P<0.001).
Conclusions: Demographics of patients with insomnia and their diagnoses from 1999 to 2002 remained stable, but the use of medications changed predictably as newer agents became available.