Supplementary Material for: The External Validation of the Nursing Homes Short Depression Inventory in Older Adults with Major Neurocognitive Disorders in Long-Term Care Centers

Introduction: Depression is often difficult to detect in long-term care (LTC) patients with major neurocognitive disorders (MNCD) and an observer-rated screening scale could facilitate assessments. This study aimed to establish the external validity and reliability of the Nursing Homes Short Depression Inventory (NH-SDI) in LTC patients with MNCD and to compare its estimates to the Cornell Scale for Depression in Dementia (CSDD), the most used scale for depression in MNCD. Methods: A focus discussion group of experts assessed the content validity of the NH-SDI. Then, a convenience sample of 93 LTC patients with MNCD were observer-rated by trained nurses with the NH-SDI and CSDD. For 57 patients, a medical assessment of depression was obtained, and screening accuracy estimates generated. Results: The prevalence of depression was 8.8% as per reference standard. NH-SDI's content validity was judged acceptable with minor item wording modifications and specifications. The NH-SDI (cut-off > 3) achieved 100% (95%CI: 46-100%) sensitivity, 83% (95%CI: 69-91%) specificity and 36% (95%CI: 14-64%) positive predictive value (PPV). The CSDD (cut-off > 3) achieved 100% (95%CI: 46-100%) sensitivity, 75% (95%CI: 61-86%) specificity and 28% (95%CI: 11-54%) PPV. No significant differences in AUCs were found between scales. The NH-SDI and CSDD were highly correlated (rs = 0.913; p < 0.001) and reliable (ICC = 0.77, p < 0.001). Discussion/Conclusion: The NH-SDI appears valid and reliable in LTC patients with MNCD and quicker than the CSDD to rule-out depression in a busy or short-staffed setting.