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

Abstract

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 was 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 were 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% confidence interval [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 areas under the receiver operating characteristic curve 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).

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.

Keywords: Depression; Long-term care; Major neurocognitive disorder; Screening scale; Validity.