Psychometric Properties of the Generalized Anxiety Disorder Scale (GAD-7) in Older Adults With Advanced Cancer

Over half of new cancer diagnoses occur in patients aged 65 or older, with up to 40% experiencing anxiety. The American Society of Clinical Oncology recommends using the Generalized Anxiety Disorder Scale (GAD-7) for anxiety screening, but the GAD-7 psychometric properties in this population are unknown. This study examined the GAD-7's reliability, validity, and item parameters, comparing its utility with the GAD-2 in older adults with cancer.

This cross-sectional secondary analysis of a nationwide multi-site two-arm cluster randomized trial in older adults (≥ 70) with advanced cancer. The GAD-7 was administered at baseline. Properties were evaluated with Cronbach's α, Pearson correlation coefficients, and a 2-parameter logistic model. Logistic regression models compared the GAD-2 and GAD-7.

The sample included 718 participants (Mean age = 77, SD = 5) with mild anxiety (M = 3.74, SD = 4.74). Internal consistency was strong (Cronbach's alpha = 0.89) and item-total correlations ranged 0.53 to 0.78. Item 2 (Not being able to stop or control worrying) was the most discriminating and item 5 (Being so restless that it is hard to sit still) was least discriminating. Area Under the Curve (AUC) analyses demonstrated the GAD-2 had a 0.93-0.96 AUC.

Establishing the psychometric properties of anxiety screening measures is crucial in the older adults with cancer to maximize referral efficiency and accuracy. This study indicates that the GAD-7 is reliable and valid for older adults with cancer. Analyses suggest the GAD-2 may be as sufficient as the GAD-7 in identifying anxiety in older adults with cancer, thereby reducing assessment burden.