Anxiety Prevalence High in Primary Care

INDIANAPOLIS, March 13 -- Anxiety disorders are as prevalent as depression among patients in primary-care practices, but often go untreated, investigators here have found.

Nearly one in five patients in 15 primary-care practices had signs of anxiety, as determined by a self-administered seven-item questionnaire, but only 61% of those with a possible anxiety disorder were being treated for it, reported Kurt Kroenke, M.D., of Indiana University and the Regenstrief Institute.

Answers to just two of the seven questions would have been sufficient to alert clinicians to the need for further screening and treatment of patients for anxiety, the investigators wrote in the March 6 issue of the Annals of Internal Medicine.

Dr. Kroenke pointed out that symptoms of anxiety can be easily missed in a busy primary-care practice. "The seven-question [instrument] and remarkably even the two-question 'ultra brief' version gives the physician a tool to quantify the patient's symptoms--sort of a lab test for anxiety."

Dr. Kroenke and colleagues found that 19.5% of the patients surveyed in the study had one or more of the four most common anxiety disorders: post-traumatic stress disorders, generalized anxiety disorder, panic disorder, or social anxiety disorder.

In an accompanying editorial, Wayne Katon, M.D., and Peter Roy-Byrne, M.D., of the University of Washington in Seattle said that "accurate recognition of anxiety disorders in primary care is the first step in providing effective treatment and potentially preventing development of major depression and social and vocational impairment."

"Kroenke and colleagues have developed and validated a brief anxiety questionnaire that efficiently screens for the most common anxiety disorders," they continued. "Hopefully, this contribution will help stimulate the continued development of effective primary care-based models to treat these highly prevalent disorders."

To determine the prevalence of anxiety disorders in primary care settings and evaluate the seven-item generalized anxiety disorder scale (GAD-7) they devised, the authors looked at 965 patients from 15 U.S. primary care clinics.

The patients completed the GAD-7 questionnaire in the clinic, and agreed to a follow-up telephone interview, consisting of a structured psychiatric interview administered by a mental health professional who was blinded to the questionnaire results.

The outcomes included patient functional status as measured by the Medical Outcomes Study Short Form-20, depressive and somatic symptoms, self-reported disability days, and physician visits.

They found that nearly one-fifth of the 965 patients (19.5%, 95% confidence interval 17.0% to 22.1%) had at least one anxiety disorder. The disorders included post-traumatic stress disorder in 8.6% (95% CI, 6.9% to 10.6%), generalized anxiety disorder in 7.6% (95% CI, 5.9% to 9.4%) panic disorder in 6.8% (95% CI, 5.3% to 8.6%) and social anxiety disorder in 6.2% (95% CI, 4.7% to 7.9%).

The investigators also found that each anxiety disorder was strongly associated with impaired functioning on all six domains of the Medical Outcomes Study Short Form-20 (SF-20) scale.

"Differences among patients with each anxiety disorder and those with no anxiety disorder were most marked for the SF-20 domains that previous studies have shown are most strongly related to mental disorders -- that is, mental health, followed by social, overall general health, and role functioning, with a lesser relationship to pain and physical functioning," they wrote.

Impairment associated with each disorder increased significantly as the number of anxiety disorders increased (P

When they evaluated the GAD-7 screening instrument, the authors found that it had high sensitivity and good specificity for detecting the four anxiety disorders.

"The comorbidity that anxiety disorders share with one another, as well as with depressive and somatic symptoms, is noteworthy," Dr. Kroenke and colleagues wrote. "This three-way relationship among anxiety, depression, and somatic symptoms is well established. Anxiety disorders also frequently occur in patients with chronic medical disorders and increase the disability of such patients. Recognizing the potentially treatable anxiety or depressive disorders that are highly concurrent with somatic symptoms or medical comorbid conditions is therefore important."

In their editorial, Dr. Katon and Dr. Roy-Byrne praised the study, but noted that "the authors did not make statistical adjustments to control for the higher prevalence of comorbid major depression and medical disorders in patients with anxiety disorders versus those without. However, other researchers have found that anxiety disorders are associated with statistically significant decrements in function after statistically controlling for depression and medical comorbidity."

They also pointed out, as did Dr. Kroneke and colleagues, that the patients in the sample were recruited rather than randomly selected, which could lead to overrepresentation of patients with anxiety disorders, working under the assumption that such patients might be more likely to attend clinic frequently.