Pain adversely affects outcomes to a collaborative care intervention for anxiety in primary care

Abstract

Background: Primary care patients with Panic Disorder (PD) and Generalized Anxiety Disorder (GAD) experience poorer than expected clinical outcomes, despite the availability of efficacious pharmacologic and non-pharmacologic treatments. A barrier to recovery from PD/GAD may be the co-occurrence of pain.

Objective: To evaluate whether pain intensity interfered with treatment response for PD and/or GAD in primary care patients who had received collaborative care for anxiety disorders.

Design: A secondary data analysis of a randomized, controlled effectiveness trial comparing a telephone-delivered collaborative care intervention for primary care patients with severe PD and/or GAD to their doctor's "usual" care.

Participants: Patients had to have a diagnosis of PD and/or GAD and a severe level of anxiety symptoms. The 124 patients randomized at baseline to the collaborative care intervention were analyzed. Participants were divided into two pain intensity groups based on their response to the SF-36 Bodily Pain scale (none or mild pain vs. at least moderate pain).

Main measures: Pain was assessed using the Bodily Pain scale of the SF-36. Anxiety symptoms were measured with the Hamilton Anxiety Rating Scale (HRS-A), Panic Disorder Severity Scale (PDSS) and Generalized Anxiety Disorder Severity Scale (GADSS). Measures were collected over 12 months.

Key results: At baseline, patients with at least moderate pain were significantly more likely to endorse more anxiety symptoms on the HRS-A than patients with no pain or mild pain (P < .001). Among patients with severe anxiety symptoms, 65 % (80/124) endorsed experiencing at least moderate pain in the previous month. A significantly lesser number of patients achieved a 50 % improvement at 12 months on the HRS-A and GADSS if they had at least moderate pain as compared to patients with little or no pain (P = 0.01 and P = 0.04, respectively).

Conclusions: Coexisting pain was common in a sample of primary care patients with severe PD/GAD, and appeared to negatively affect response to anxiety treatment.

Figures

Figure 1.

Mean pain scores on the SF-36 Bodily Pain scale over 12 months. *Intervention patients with pain vs. intervention patients without pain, P < .0001. Bars indicate standard error. Higher scores indicate less pain. Controls for age, gender, race, marital status, working status, baseline PHQ-9 score, and comorbid conditions.

Figure 2.

Mean scores on mental health measures over 12 months. *Intervention patients with pain vs. intervention patients without pain, P < .05. Bars indicate standard error. Controls for age, gender, race, marital status, working status, baseline PHQ-9 score, and comorbid conditions. HRS-A = Hamilton Rating scale for Anxiety, lower scores better. PDSS = Panic Disorder Severity Scale, lower scores better. GADSS = Generalized Anxiety Disorder, lower scores better. SF-36 MCS = Short Form-36 Mental Component Summary, higher scores better.

Figure 3.

Effect sizes of change scores from baseline to 12 months between the intervention patients with pain and the intervention patients without pain. Controls for age, gender, race, marital status, working status, baseline PHQ-9 score, and comorbid conditions. Bars indicate standard error. HRS-A = Hamilton Rating scale for Anxiety; PDSS = Panic Disorder Severity Scale; GADSS = Generalized Anxiety Disorder; SF-36 MCS = Short Form-36 Mental Component Summary; PHQ-9 = Patient Health Questionnaire-9.