Psychometric evaluation of the Hospital Anxiety and Depression Scale 3 months after acute lung injury

Abstract

Purpose: To conduct a psychometric evaluation of the Hospital Anxiety and Depression Scale (HADS) and to evaluate associations of 2 measures of psychological distress with the HADS Anxiety (HADS-A) and HADS Depression (HADS-D) subscales in acute lung injury (ALI) survivors.

Materials and methods: We used 3-month post-ALI follow-up data from 151 participants in a multisite prospective cohort study to evaluate the internal consistency and structure of the HADS subscales and items, respectively. We used Spearman ρ correlations and other statistics to relate the 3-level version of the EuroQol-5D (EQ-5D-3L) anxiety/depression item and Medical Outcomes Study Short Form-36 (SF-36) "mental health"-related domains to the HADS subscales.

Results: Internal consistency was good for each of the HADS subscales (α ≥ .70). Exploratory factor analysis revealed a 2-factor structure (anxiety and depression). The EQ-5D-3L item and the SF-36 mental health-related domain scores were associated with HADS-A (ρ = 0.54 and -0.48 to -0.70, respectively) and HADS-D (ρ = 0.41 and -0.48 to -0.52, respectively) scores (all P < .01). The relationship between the SF-36 mental health domain score and the HADS-A subscale score was particularly strong (ρ = -0.70, P < .01).

Conclusions: When evaluated in ALI survivors, the HADS has good internal consistency and a 2-factor structure. The HADS subscales were substantially correlated with the EQ-5D-3L anxiety/depression item and SF-36 mental health-related domain scores, suggesting convergent validity for these measures of psychological distress in ALI survivors.

Keywords: Acute lung injury; Anxiety; Critical care; Depression; Intensive care unit; Psychometrics.

fig. 1

Flow diagram of study participants.

fig. 2

Hospital Anxiety and Depression Scale factor structure.^a,b Large ovals represent latent variables; straight lines represent hypothesized direct effects; rectangles represent measured variables; small ovals represent error terms; and numbers represent standardized parameter estimates. Large ovals represent latent variables; straight lines represent hypothesized direct effects; rectangles represent measured variables; small ovals represent error terms; and numbers represent standardized parameter estimates.^a There were no significant cross loadings (i.e. ≥0.4).^b Hospital Anxiety and Depression Scale Items: Q1=I feel tense or wound up; Q2=I still enjoy things I used to enjoy; Q3=I get sort of a frightened feeling as if something awful is about to happen; Q4=I can laugh and see the funny side of things; Q5=Worrying thoughts go through my mind; Q6=I feel cheerful; Q7=I can sit at ease and feel relaxed; Q8=I feel as if I am slowed down; Q9=I get sort of a frightened feeling like butterflies in the stomach; Q10=I have lost interest in my appearance (this item did not load onto either of the factors); Q11=I feel restless, as if I have to be on the move; Q12=I look forward with enjoyment to things; Q13=I get sudden feelings of panic; Q14=I can enjoy a good book or radio or TV program.