The local reliability of the 15-item version of the Geriatric Depression Scale: An item response theory (IRT) study

Adapting the multilevel model for estimation of the reliable change index (RCI) with multiple timepoints and multiple sources of error

OBJECTIVE

One of the primary tools in the assessment of individual-level patient outcomes is Jacobson and Truax, (1991's) Reliable Change Index (RCI). Recent efforts to optimize the RCI have revolved around three issues: (a) extending the RCI beyond two timepoints, (b) estimating the RCI using scale scores from item response theory or factor analysis and (c) estimation of person- and time-specific standard errors of measurement.

METHOD

We present an adaptation of a two-stage procedure, a measurement error-corrected multilevel model, as a tool for RCI estimation (with accompanying Statistical Analysis System syntax). Using DASS-21 data from a community-based mental health center (N = 379), we illustrate the potential for the model as unifying framework for simultaneously addressing all three limitations in modeling individual-level RCI estimates.

RESULTS

Compared to the optimal-fitting RCI model (moderated nonlinear factor analysis scoring with measurement error correction), an RCI model that uses DASS-21 total scores produced errors in RCI inferences in 50.8% of patients; this was largely driven by overestimation of the proportion of patients with statistically significant improvement.

CONCLUSION

Estimation of the RCI can now be enhanced by the use of latent variables, person- and time-specific measurement errors, and multiple timepoints.

Design and methodology for an integrative data analysis of coping power: Direct and indirect effects on adolescent suicidality

As suicide rates have risen in the last decade, there has been greater emphasis on targeting early risk conditions for suicidality among youth and adolescents as a form of suicide "inoculation". Two particular needs that have been raised in this nascent literature are a) the dearth of examination of early intervention effects on distal suicide risk that target externalizing behaviors and b) the need to harmonize multiple existing intervention datasets for greater precision in modeling intervention effects on low base rate outcomes such as suicidal behaviors. This project, entitled "Integrative Data Analysis of Coping Power (CP): Effects on Adolescent Suicidality", funded by the National Institute of Mental Health (NIMH), will harmonize and analyze data from 11 randomized controlled trials of CP (total individual-level N = 3183, total school-level N = 189). CP is an empirically-supported, child- and family-focused preventive intervention that focuses on reducing externalizing more broadly among youth who exhibit early aggression, which makes it ideally suited to targeting externalizing pathways to suicidality. The project utilizes three measurement and data analysis frameworks that have emerged across multiple independent disciplines: integrative data analysis (IDA), random treatment effects multilevel modeling (RTE-MLM), and propensity score weighting (PSW). If successful, the project will a) provide initial evidence that CP would have gender-specific indirect effects on suicidality through reductions in externalizing for boys and reductions in internalizing for girls and b) identify optimal conditions under which CP is delivered (e.g., groups, individuals, online) across participants on reductions in suicidality and other key intermediate endpoints.

A clinically feasible short version of the 15-item geriatric depression scale extracted using item response theory in a sample of adults aged 85 years and older

OBJECTIVES

To extract the items most suitable for a short version of the 15-item Geriatric Depression Scale (GDS-15) in a sample of adults aged ≥ 85 years using item response theory (IRT).

METHOD

This population-based cross-sectional study included 651 individuals aged ≥ 85 years from the Umeå 85+/GErontological Regional DAtabase (GERDA) study. Participants were either community dwelling (approximately 70%) or resided in institutional care (approximately 30%) in northern Sweden and western Finland in 2000-2002 and 2005-2007. The psychometric properties of GDS-15 items were investigated using an IRT-based approach to find items most closely corresponding to the GDS-15 cut off value of ≥5 points. Receiver operating characteristic curves were used to compare the performance of the proposed short version with that of previously proposed short GDS versions.

RESULTS

GDS-15 items 3, 8, 12, and 13 best differentiated respondents' levels of depressive symptoms corresponding to the GDS-15 cut off value of ≥5, regardless of age or sex, and thus comprise the proposed short version of the scale (GDS-4 GERDA). For the identification of individuals with depression (total GDS-15 score ≥ 5), the GDS-4 GERDA with a cut-off score of ≥2 had 92.9% sensitivity and 85.0% specificity.

CONCLUSION

The GDS-4 GERDA could be used as an optimized short version of the GDS-15 to screen for depression among adults aged ≥ 85 years.

Identification of Central Symptoms in Depression of Older Adults With the Geriatric Depression Scale Using Network Analysis and Item Response Theory

OBJECTIVE

This study aimed to identify the central symptoms of late-life depression using network analysis and the item response theory.

METHODS

A total of 3,472 older adults were enrolled and the Geriatric Depression Scale-15 (GDS-15) was used to evaluate the depressive symptoms. To identify the central symptoms and the network structures among the individual symptoms, the analyses of symptom network structures and item response theory were performed.

RESULTS

Among items on the GDS-15, "Happy," "Hopeless," "Empty," "Bored," "Worthless," and "Good spirits" showed significantly higher strength centrality than the other symptoms. Among all the edges, the edge between "Empty" and "Bored" was the strongest; however, these two symptoms were not connected strongly to other symptoms. In the analysis of item response theory, "Empty," "Bored," "Hopeless," "Worthless," "Happy," "Helpless," and "Satisfied" presented a very high value on the discrimination parameter.

CONCLUSION

Our study identified the central symptoms and the network structures among symptoms listed on the GDS-15. Most of central symptoms identified by network analysis and item response theory coincided. Our results suggest that these central symptoms need to be prioritized as highly comorbid symptoms and can contribute to the development of a brief screening tool for the elderly.

The Geriatric Depression Scale (GDS-15): Validation in Mexico and Disorder in the State of Knowledge

The objective of this study was to evaluate the reliability and validity of the Geriatric Depression Scale in its 15-item version (GDS-15) in Mexican older adults. Participants included 1178 older adults between the ages of 60 and 94 (M = 69.16, SD = 7.69); 53.9% were women and 55.8% were married or with a partner. They completed the GDS-15, a subjective well-being scale, and a quality-of-life questionnaire. A Kuder-Richardson coefficient of .80 was obtained, which indicates an acceptable internal consistency of the GDS-15, as well as evidence of divergent validity with significant correlations of -.783 with subjective well-being and -.569 with quality of life, in addition to concurrent validity when discriminating between participants with low scores from those with high scores of depressive symptoms. The need for a simple screening tool such as the GDS-15 that helps in the identification of depressive symptoms in Mexican older adults is underlined.

Putting the Patient Back in Clinical Significance: Moderated Nonlinear Factor Analysis for Estimating Clinically Significant Change in Treatment for Posttraumatic Stress Disorder

The present study introduced a modernized approach to Jacobson and Truax's (1991) methods of estimating treatment effects on individual-level (a) movement from the clinical to the normative range and (b) reliable change on posttraumatic stress disorder (PTSD) severity. Participants were 450 trauma-exposed women (M age = 39.2 years, SD = 8.9, range: 18-65 years) who presented to seven geographically diverse community mental health and substance use treatment centers. Data from 53 of these women, none of whom met the criteria for full or subthreshold PTSD, were used to establish the normative range. Using moderated nonlinear factor analysis (MNLFA) scale scoring, which weights symptoms by their clinical relevance, a significantly larger proportion of participants moved into the normative range for PTSD severity scores and/or exhibited reliable changes after treatment compared to the same individuals' movement when using symptom counts. Further, approximately 24% of the participants showed discrepant judgments on reliable change indices (RCI) between MNLFA scores and symptom counts, likely due to the false assumption that the standard error of measurement is equal for all levels of underlying PTSD severity when estimating RCIs with symptom counts. An MNLFA approach to estimating underlying PTSD severity can provide clinically meaningful information about individual-level change without the de facto assumption that PTSD symptoms have equivalent weight. Study implications are discussed with regard to a joint emphasis on (a) measurement models that highlight differential symptom weighting and (b) treatment-arm differences in individual-level outcomes rather than the current overemphasis of treatment-arm differences on group-averaged trajectories.

Risk Factors for Depression in Long-term Care: A Prospective Observational Cohort Study

Objectives: Depression among older adults in long-term care remains a problem, despite the uptake of antidepressants and the development of intervention programs. A better understanding of the risk factors for depression is much needed. Guided by a systematic assessment of the evidence, this prospective observational cohort study sought to clarify existing evidence, identify modifiable risk factors and explore novel variables. Methods: Adults aged ≥65 (T1 n=147, T2 n= 81) were recruited from 15 long-term-care facilities in Melbourne, Australia. Cognitive impairment, functional impairment, pain, sleep disturbance, social support, and person-environment fit were investigated as risk factors. Outcomes were depressive symptoms and indicated Major Depressive Episode. Results: Generalized Estimating Equations (GEE) identified that changes in pain (b= 0.06, p<.05), sleep disturbance (b= 0.02, p< .001), social support (b= -0.02, p< .001) and person-environment fit (b= -0.02, p= <.01) were significantly associated with changes in depression score. Conclusions: Pain, sleep disturbance, social support, and person-environment fit are modifiable risk factors, making them strongly positioned to strategically inform prevention and intervention strategies. Clinical Implications: Individuals with clinically significant symptoms on these risk factors for depression should be selected for interventions that target these risk factors. For depressed individuals, psychotherapy should prioritize the potential role of these risk factors. Finally, these risk factors should be used as screening and monitoring variables: clinically significant changes in symptoms warrant investigation.

Assessment of Geriatric Depression Scale's Applicability in Longevous Persons based on Classical Test and Item Response Theory

BACKGROUND

The 15-item short form Geriatric Depression Scale (GDS-15) has been widely used for depression screening in multiple settings. However, few studies have specifically investigated the applicability of GDS-15 in longevous population. The aim of this study is to evaluate the psychometric property and item characteristic of the scale in Chinese community-dwelling longevous persons.

MATERIALS AND METHODS

A total of 838 longevous people participated in this study. The reliability and validity of GDS-15 were analyzed with classical test theory, and the characteristics of each item were analyzed with item response theory using a three-parameters logistic model.

RESULTS

The Cronbach's α coefficient of the scale was 0.776. Spearman correlation coefficients between the GDS-15 score and each item were between 0.274 and 0.667 (P<0.01); the summed GDS-15 score was negatively associated with physical function, self-report health status and subjective well-being. Factors extracted using exploratory factor analysis accounted for 52.63% of the variance and the item loadings were between 0.513 and 0.828. The discrimination of each item ranged from 1.045 to 3.777; the difficulty ranged from -0.972 to 2.006, and the guessing parameter ranged from 0.000 to 0.499. The total information of GDS-15 was 13.645 when the subject's latent trait located at 1.131.

LIMITATION

The sample used is representative of the longevous in rural communities, thus extrapolation to other populations requires further validation.

CONCLUSION

The GDS-15 has good applicability in depression detecting among Chinese longevous persons, especially for the individuals with moderate symptoms. Suggestions were provided on further improving its measurement precision.

Risk indicators for depression in aged care: The contribution of a meaningful life, mastery and environmental fit

OBJECTIVES

Depression is a pernicious, growing problem in the aged care population. Knowledge about the risk factors for depression focuses on unchangeable, medical factors; therefore, a deeper, systematic understanding of modifiable psychological risk indicators is needed.

METHODS

This secondary analysis used data from an observational cohort study (T1, n = 147; T2, n = 81) of adults aged ≥65 years recruited from 15 aged care facilities in Melbourne, Australia. Meaningful existence, mastery, social support and person-environment fit were investigated as risk indicators.

RESULTS

Generalised estimating equation analysis identified that changes in meaningful existence (b = -0.06, P < .05), mastery (b = -0.05, P < .05) and person-environment fit (b = -0.02, P < .05) were significantly associated with change in depression score. These remained significant controlling for socio-demographic variables, cognitive impairment and functional impairment.

CONCLUSION

Because these psychological risk factors-meaningful existence, mastery and person-environment fit-are suitable therapeutic targets, they are well positioned to inform prevention and intervention programs.

FOOTFIT Physical Activity mHealth Intervention for Minimally Ambulatory Individuals With Venous Leg Ulcers: A Randomized Controlled Trial

PURPOSE

The purpose of this study was to investigate the use of an mHealth application (app), self-management physical activity intervention FOOTFIT with an added patient-provider connectivity feature (FOOTFIT+), that was designed to strengthen the lower extremities of minimally ambulatory individuals with venous leg ulcers (VLUs).

DESIGN

Randomized controlled trial.

SUBJECTS AND SETTING

Twenty-four adults 18 years and older with VLUs being treated in 2 wound clinics in the Southeastern United States participated in this study.

METHODS

Preliminary estimates and 95% confidence intervals for the medians of short-term functional impacts on foot function, strength, ankle range of motion, walking capacity, depression, and physical functioning were obtained pre- and postassessment after the 6-week intervention trial.

RESULTS

There were negligible changes in either group for foot function. It is noted that both groups experienced substantial foot and ankle impairment at baseline. The greatest improvement in range of motion was noted in the FOOTFIT group for dorsiflexion of the right ankle (4.6 ± 5.22 lb/in over baseline) whereas strength decreased in both ankles for dorsiflexion and plantar flexion in the FOOTFIT+ group. No improvements were noted in walking distance or physical health for FOOTFIT (slight decrease -2.9 ± 5.6) and FOOTFIT+ (slight increase 3.0 ± 6.6) during the 6-week study period.

CONCLUSIONS

In a minimally ambulatory population with VLUs, our mHealth FOOTFIT intervention composed of progressive exercise "boosts" demonstrated minimal short-term effects. We recommend engagement with the app for a longer period to determine longer-term outcomes of lower extremity function.

New avenue for the geriatric depression scale: Rasch transformation enhances reliability of assessment

BACKGROUND

Depression is a common problem in older adults. The 15-item Geriatric Depression Scale (GDS-15) is a widely used psychometric tool for measuring depression in the elderly, but its psychometric properties have not been yet rigorously investigated. The aim was to evaluate psychometric properties of the GDS-15 and improve precision of the instrument by applying Rasch analysis and deriving conversion tables for transformation of raw scores into interval level data.

METHODS

The data was extracted from the prospective cohort Sydney Memory and Ageing Study of initially not demented individuals aged 70 years and older. The GDS-15 items scores of 212 participants (47.2% males) were analysed using the dichotomous Rasch model.

RESULTS

Initially poor reliability of the GDS-15, Person Separation Index (PSI) = 0.68, was improved by combining locally dependent items into seven super-items. These modifications improved reliability of the GDS-15 (PSI = 0.78) and resulted in the best Rasch model fit (χ²(28)=37.72, p = =0.104), strict unidimensionality and scale invariance across personal factors such as gender, diagnostic and language background.

LIMITATIONS

Presence of participants with cognitive impairment may be a potential limitation.

CONCLUSIONS

Reliability and psychometric characteristics of the GDS-15 were improved by minor modifications and now satisfy expectations of the unidimensional Rasch model. By using Rasch transformation tables published here psychiatrists, psychologists and researchers can transform GDS raw scores into interval-level data, which improves reliability of the GDS-15 without the need to modify its original response format. These findings increase accuracy of clinical psychometric assessments, leading to more precise diagnosis of depression in the elderly.

Orthostatic hypotension in patients with late-life depression: Prevalence and validation of a new screening tool

OBJECTIVES

The objective of this study was to assess the prevalence of orthostatic hypotension (OH) in a sample of late life depression (LLD) patients and to determine the validity of a standardized questionnaire, the Orthostatic Hypotension Questionnaire (OHQ). Secondarily, we wished to assess variables associated with OH.

METHODS

We conducted a cross-sectional study on 82 consecutive geriatric outpatients presenting with LLD. OH was defined as a fall in systolic blood pressure of greater than 20 mm Hg and/or 10 mm Hg on diastolic blood pressure on an orthostatic stress test from sitting to standing. Logistic regressions were used to identify factors associated with OH.

RESULTS

The prevalence of OH as measured on the orthostatic stress test and on the OHQ was 28% and 57%, respectively. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the OHQ were 69.6% (95% CI 47%-87%), 47.5% (95%CI 34%-61%), 0.54 (95% CI: 0.43-0.64), 34% (95%CI 21%-49%), and 80% (95%CI 63%-92%), respectively. Females were more likely to have OH (OR: 3.96, 95%CI 1.06-14.89, P = .041), and those married or in a common-law relationship were less likely to have OH (OR: 0.25, 95% CI 0.08-0.72, P = .011).

CONCLUSIONS

OH is common in patients with LLD conferring them a risk of gait instability and falls. Females had a higher risk of having OH while participants who were married or in a common-law relationship were less likely to have OH. Although the OHQ is a quick to administer paper-based screening test, it did not show adequate diagnostic accuracy in patients with LLD seen in a routine psychiatry clinic.

Is the 15-item Geriatric Depression Scale a Fair Screening Tool? A Differential Item Functioning Analysis Across Gender and Age

The 15-item version of the Geriatric Depression Scale (GDS-15) is widely employed to assess depression in old people, but it is unclear if there are biases in the total score depending on respondents' gender and age. In the current study, we investigated the measurement equivalence of the GDS-15 to provide evidence that the test is a fair screening tool when administered to young-old, old-old, and oldest-old men and women. Item Response Theory-based Differential Item Functioning analyses were applied on a large sample of Italian old people. One item exhibited Differential Item Functioning when comparing men and women, and one item showed Differential Item Functioning across different age-groups. Nonetheless, the magnitude of Differential Item Functioning was small and did not produce any differential test functioning. The gender and age measurement equivalence of the GDS-15 confirms that the test can be used for clinical and research screening purposes.