Background: Previous research using Latent Class Analysis (LCA) identified classes of patients with type 2 diabetes (T2D) and specific profiles of depression/anxiety1. Since LCA-defined anxious depression strongly predicts cardiovascular outcomes and mortality but cannot be applied to individual patients, we developed a validated combined depression-anxiety metric, the Diabetes Anxiety Depression Scale (DADS) for potential clinical application.
Objective: To determine whether DADS-defined anxious depression independently predicts all-cause mortality in people with T2D.
Methods: 1,337 participants with T2D from the Fremantle Diabetes Study Phase II underwent assessment including the Patient Health Questionnaire 9-item version (PHQ-9) and Generalised Anxiety Disorder Scale (GADS) to assess the presence of depression and anxiety symptoms. A single DADS score (0-39) was calculated by adding all PHQ-9 items plus four anxiety items used for the LCA and categorised into major anxious depression (≥18), minor anxious depression (8-17), subsyndromal anxiety (3-7), and no anxiety/depression (≤2). All-cause mortality to end-December 2016 was ascertained from WA health data linkage and active follow-up.
Results: At baseline, patients were 66±11 years old, 53% were male, with median diabetes duration 9 years. Based on DADS, 9% had major and 25% minor anxious depression, 33% had subsyndromal anxiety, and 33% had no anxiety/depression. During 9,099 patient-years’ follow-up, 199 died. In Cox regression with age as timeline, male sex, ethnicity, current smoking, HbA1c, pulse rate, aspirin use, eGFR<30 and ≥90 ml/min/1.73m2, and loge(N-terminal pro-brain natriuretic peptide) independently predicted all-cause mortality. After adjusting for these, total DADS score added significantly to the model (HR (95% CI): 1.02 (1.002-1.04)/unit. Categories of anxious depression showed a dose-response relationship with minor and major anxious depression reaching statistical significance (1.57 (1.07-2.30) and 1.76 (1.05-2.94), respectively) versus no anxiety/depression.
Conclusion: DADS combines depression and anxiety symptoms in a single score that enhances screening for both mental health and mortality risk in T2D.