WASHINGTON – A nine-item questionnaire of self-reported symptoms was more reliable and efficient than the widely used Geriatric Depression Scale and the Minimum Data Set 2.0 scale at assessing mood disorders in nursing home patients, according to a study in 71 facilities across eight states.
Accurate detection of mood disorders in the long-term care population remains a constant challenge, said Dr. Debra Saliba, who is a geriatrician at the University of California, Los Angeles, and the director of the Borun Center for Gerontological Research there. She reported the results at the annual meeting of the American Geriatrics Society.
Identifying depression in nursing home patients is important, she emphasized, because the condition is associated with poor functional status; increased perception of pain; stress; suicide; and increased need for medical services. “In fact, a disproportionate number of successful suicides occur in people over the age of 65,” said Dr. Saliba.
Treating depression can be effective in reducing poor outcomes in long-term care residents, but depression often goes unnoticed in this population. There are several screening tools for mood disorders in use, but they have not been compared with one another or to any validated psychiatric-assessment tool, Dr. Saliba explained.
The new study compared the effectiveness of the nine-item Patient Health Questionnaire (PHQ-9), the Geriatric Depression Scale (GDS), Minimum Data Set version 2.0 (MDS 2.0) assessment by staff, and one of two validated tools for identifying mood disorders in a long-term care population.
The GDS was designed for older adults and has become a geriatric standard–this study used the newer version of the test, which is made up of 15 yes/no questions–but other studies have suggested that the test may be overly influenced by somatic symptoms when individuals answer questions such as, “Have you stopped many of your activities and interests?” without being able to elaborate.
By contrast, PHQ-9 questions prompt open-ended responses to topics including sleep problems, feeling bad about oneself, and having trouble concentrating. The tool may be administered either as a self-reported survey or as part of an interview. The MDS 2.0 observer-rated scale avoids an interview or self-report.
“Some people have said that the PHQ-9 is too symptom driven or too complicated,” Dr. Saliba said, leading to questions of the survey's validity for assessing mood disorders in frail old people.
She and her associates selected 418 nursing home residents who were scheduled to receive mandatory MDS 2.0 assessments. Nearly half of the study participants were older than 85 years.
In addition to the MDS 2.0 assessment for each resident, one nurse administered the PHQ-9 and GDS, and a second nurse administered either the modified Schedule for Affective Disorders and Schizophrenia (mSADS) or the Cornell Scale for Depression.
The Cornell tool was used for residents whose cognition was too low to allow assessment by mSADS, but both of these tests are validated, standard tools, said Dr. Saliba.
About 80% of study participants were assessed by at least one of the screening tools as well as one of the validated tools. Overall, the GDS screen found 41% of residents with probable depression, PHQ-9 found 42%, and MDS 2.0 found 17%.
When the investigators used a measure of agreement adjusted for chance (kappa scores), the PHQ-9 had significantly higher agreement with the validated standard than either the GDS or the MDS 2.0 did. In fact, the MDS 2.0 assessment was less accurate than if the results had happened by chance, Dr. Saliba said.
“Contrary to the expectations of many, the PHQ-9 did not lead to more classification with depression,” Dr. Saliba said.
Not only was the PHQ-9 tool more accurate than the GDS screen, but it also took less time to complete: 4.9 minutes for the PHQ-9 vs. 11.4 minutes for the GDS.
Most of the residents, including the large number with cognitive impairment, could complete the PHQ-9, said Dr. Saliba.
The findings suggest that standardized mood assessment of older adults could be performed more effectively with the PHQ-9 than with the GDS or MDS 2.0, although more research is needed to confirm the results.
“We hadn't expected it to be quite so favorable for PHQ-9,” she said. “But it is often difficult for older adults to reduce their life experiences to yes or no questions.”