"Caseness" for depression and anxiety in a depressed outpatient population: symptomatic outcome as a function of baseline diagnostic categories

Abstract

Objective: To examine the diagnostic status of patients enrolled in the Factors Influencing Depression Endpoints Research (FINDER) study and symptomatic outcomes and baseline characteristics associated with remission 6 months after commencing antidepressant therapy.

Method: Status of clinically diagnosed depressed patients was based on self-rated Hospital Anxiety and Depression Scale (HADS) scores. Five diagnostic categories were defined: noncaseness, mixed anxiety-depression (subthreshold depressive and anxious symptomatology), caseness for depression, caseness for anxiety, and caseness for comorbid anxiety-depression. Assessments included the Somatic Symptom Inventory and health-related quality of life (HRQoL) using the Medical Outcomes Study 36-item Short-Form Health Survey. Remission rates (based on HADS noncaseness for both depression and anxiety) and their associations with baseline characteristics were investigated. Patients were enrolled between May 2004 and September 2005.

Results: Of the 3,353 patients enrolled, 66.4% met the HADS criteria for probable depressive disorder and 74.1% met the HADS criteria for probable anxiety disorder. Somatic symptom severity (painful and nonpainful) was highest and HRQoL was lowest in the comorbid anxiety-depression group. After 6 months, remission rates were 50.2% for caseness for depression, 40.4% for caseness for anxiety, and 40.6% for caseness for comorbid anxiety-depression. A lower number of previous depressive episodes, shorter current episode duration, lower painful and nonpainful somatic symptom scores, being married, a higher educational level, and working for pay were most consistently associated with higher remission rates.

Conclusions: Physicians do not always differentiate between anxiety and depressive symptoms when making a clinical diagnosis of depression. At baseline, most enrolled patients had significant emotional depressive and anxious symptoms, as well as significant nonpainful and painful somatic symptomatology, and these factors were associated with outcome.

Figure 1

Baseline Characteristics Associated With Categorical Status at 6 Months' Follow-Up^{a,b a}An OR < 1 indicates decreased odds of remission. ^bCountry not statistically significant (P = .252) but included in the model. Data from Norway were pooled with those from Sweden and Ireland with the United Kingdom to avoid problems of quasi separation during the modeling. ^cOther includes divorced, legally separated, widowed, partner (living separately), and no relationship. ^dOther includes retired, student, voluntary work, and keeping house (full-time). ^eOther also significantly different from unemployed (OR = 2.58; 95% CI = 1.00 to 6.62). Abbreviations: OR = odds ratio, VAS = visual analog scale.

Figure 2

Baseline Characteristics Associated With Categorical Status at 6 Months' Follow-Up^{a,b a}An OR < 1 indicates decreased odds of remission. ^bCountry not statistically significant (P = .211) but included in the model. ^cEducation includes further, university, and postgraduate education. Abbreviations: MDD = major depressive disorder, OR = odds ratio, SSI = Somatic Symptom Inventory.

Figure 3

Baseline Characteristics Associated With Categorical Status at 6 Months' Follow-Up^{a,b a}An OR < 1 indicates decreased odds of remission. ^bCountry was statistically significant (P < .001). ^cOther includes retired, student, voluntary work, and keeping house (full-time). Abbreviations: HADS-A = Hospital Anxiety and Depression Scale-Anxiety, OR = odds ratio, VAS = visual analog scale.