We conclude from our data that1
: (1) the PRIME-MD can be used to screen and diagnose primary care patients for PD and GAD within a variety of busy primary care settings2
; (2) patients diagnosed by the PRIME-MD Anxiety Module as having either PD, GAD, or both endorse anxiety symptoms of wide-ranging severity; and3
(3) PCPs rapidly agree with the finding of an anxiety disorder on the PRIME-MD independent of their patients' level of anxiety symptomatology. These findings suggest that health care delivery organizations interested in identifying primary care patients with PD and/or GAD can use the PRIME-MD as a part of a broader strategy to improve quality of care for individuals with these conditions.
We are unaware of other clinical trials that utilized the PRIME-MD to identify patients with an anxiety disorder. However, an entirely self-administered version of the PRIME-MD—the Patient Health Questionnaire (PHQ)—was developed and validated in a large cross-sectional study of primary care patients.26
Still, compared with the PRIME-MD, the PHQ is only capable of making a precise diagnosis of panic disorder and not GAD. Furthermore, the skip-out design of the PHQ's anxiety module does not facilitate its use as an anxiety severity and outcome measure, in contrast to the PHQ's 9-item depression module.32,33
Therefore, when targeting anxiety disorders, the PRIME-MD has some diagnostic advantages over the newer PHQ.
Because PD and GAD are 2 of the most prevalent and treatable anxiety disorders seen in primary care, it is of great interest that PCPs rapidly agreed with the vast majority of PD and GAD cases thus identified by the PRIME-MD, and regardless of the type of anxiety disorder or episode severity. We did not ask PCPs to justify their decision making or otherwise impose any additional burden on them when they disagreed with the PRIME-MD. Therefore, PCPs' agreement with the PD and GAD diagnoses at similar rates and regardless of their patients' actual level of anxiety symptoms possibly suggests that PCPs were either unfamiliar at recognizing these anxiety disorders and/or relied on the PRIME-MD and the clinical investigators to inform them of the diagnosis. This finding is in contrast to our earlier work where PCPs disagreed with the finding of major depression on the PRIME-MD for 23% of patients when presented to them in a similar electronic fashion as in our current trial.34
A substantial minority of patients detected by the PRIME-MD as experiencing PD and GAD had relatively mild levels of anxiety symptoms and it is presently unclear what, if any, treatment is required for these individuals. Additionally, the inclusion of substantial numbers of patients with diagnosable but mild levels of anxiety into a clinical trial or a quality improvement program could adversely affect sample size calculations. Thus, large numbers of patients would need to be enrolled to demonstrate statistically significant, let alone clinically meaningful, symptom improvements. Therefore, we favor administration of a time-efficient case-finding instrument such as the PRIME-MD followed by a measure of distress such as the SIGH-A or PDSS to determine whether a patient's condition is sufficiently severe to warrant active treatment.28,35,36
As is the case for primary care patients with major depression, those treated for PD and GAD in the primary care sector tend to experience poorer than expected clinical outcomes for these conditions despite the availability of efficacious pharmacologic and non-pharmacologic treatments that PCPs can readily provide.35–41
Possible explanations include PCPs' inadequate recognition of anxiety disorders, PCP and/or patient resistance to a psychiatric diagnosis and its associated stigma, and competing demands on PCP's time by patient concerns within the limit of the typical 15-minute clinical encounter.42–44
While tempting to speculate that systematic screening for the presence of an anxiety disorder could help overcome these barriers and improve clinical outcomes, reports from the depression literature suggest otherwise.27,41,45–47
Nevertheless, recognition of the anxiety disorder is a necessary first step. A variety of “collaborative care” strategies48
for treating depressed primary care patients that include a case-finding component and systematic follow-up by a care manager who follows an evidence-based protocol in concert with patients' PCPs have been proven effective.49
Initial studies suggest that these strategies can be clinically effective35,50
and cost-effective 51
at treating anxiety disorders.
This study has several limitations potentially affecting the generalizability of our conclusions. First, our findings may only apply to whites given that they constituted 95% of the study sample (). This racial pattern reflects the fact that 85% of the subjects were recruited from 3 practices located in suburban-rural Westmoreland County, PA, where, according to the 2000 U.S. Census, only 3.4% of the population was nonwhite. Second, we relied on dedicated patient recruiters stationed in our study practices' reception rooms to administer, score, and collect the PRIME-MD. While this strategy is feasible within the context of research which requires that investigators obtain subjects' signed informed consent, such case identification procedures may not be applicable to routine practice. Nevertheless, administration of the PRIME-MD by nonclinical practice staff has been found to generate significant increases in new psychiatric diagnoses and subsequent PCP interventions at support levels achievable in most clinical settings.52
Third, we did not verify our PRIME-MD diagnoses with a “gold-standard” clinical interview administered by a mental health professional, the procedure utilized to validate the PRIME-MD.10
Fourth, we excluded the majority (58%) of PQ+ patients from the PRIME-MD Anxiety Module interview and a number of patients with PD and/or GAD from our telephone assessment of anxiety severity. Still, this strategy is acceptable for maintaining internal validity within the context of a clinical trial as we did not aim to establish the prevalence of PD and GAD in primary care.
In summary, the PRIME-MD can be used by non-PCP personnel to efficiently screen primary care patients for PD and GAD within a variety of busy primary care settings. Furthermore, patients thus identified by the PRIME-MD as having PD and GAD endorse a wide range of anxiety symptom severity, and PCPs rapidly agree with these diagnoses when presented to them electronically regardless of the severity of their patients' symptomatology. Our findings have important implications for use of the PRIME-MD as a case-finding tool for anxiety disorders within the context of a clinical trial and as part of a quality improvement program.