Equipercentile linking of the Sheehan Disability Scale and the World Health Organization Assessment Schedule 2.0 scales in people with mental disorders.

BACKGROUND: The Sheehan Disability Scale (SDS) and the World Health Organization Disability Assessment Scale (WHODAS 2.0) have been widely used to measure functional impairment and disability. To ensure that the scores from these two scales are practically exchangeable across diseases, therapies, and care programmes, the current study aimed to examine the linkage of the WHODAS 2.0 with the SDS and develop a simple and reliable conversion table for the two scales in people with mental disorders. METHODS: A total of 798 patients (mean age = 36.1, SD = 12.7) were recruited from outpatient clinics of the Institute of Mental Health, and the Community Wellness Clinic in Singapore. Using a single-group design, an equipercentile equating method with log-linear smoothing was used to establish a conversion table from the SDS to the WHODAS 2.0 and vice versa. RESULTS: The conversion table showed that the scores were consistent for the entire range of scores when the scores were converted either from the SDS to the WHODAS 2.0 or from the WHODAS 2.0 to the SDS. The agreement between the WHODAS 2.0's raw and converted scores and SDS's raw and converted scores were interpreted as good with intraclass correlation coefficient of 0.711 and 0.725, respectively. CONCLUSION: This study presents a simple and reliable method for converting the SDS scores to the WHODAS 2.0 scores and vice versa, enabling interchangeable use of data across these two disability measures.

Validation of the 12-item World Health Organization Disability Assessment Schedule 2.0 in individuals with schizophrenia, depression, anxiety, and diabetes in Singapore.

BACKGROUND: There is limited evidence on the reliability and validity of the 12-item World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) in an Asian patient population with mental and physical disorders. The current study aimed to examine the psychometric properties of the WHODAS 2.0 among patients with schizophrenia, depression, anxiety, and diabetes. METHODS: A total of 1076 patients (M = 40.9 years, SD = 14.7) were recruited from the outpatient clinics of a tertiary psychiatric hospital and a primary care clinic. Internal consistency and test-retest reliability, structural validity, convergent validity, agreement, and floor and ceiling effects were examined. RESULTS: Our confirmatory factor analysis (CFA) showed that the 1-factor model fits our data. Multigroup CFA demonstrated metric and scalar invariance, indicating the scores can be compared across the four conditions. The WHODAS 2.0 scale had excellent reliability in the overall sample and good to excellent reliability across conditions. The test-retest reliability and agreement between self-administered and interviewer-administered modes were good. The WHODAS 2.0 scores had moderate to strong correlations with the Social and Occupational Functioning Scale and the Sheehan Disability Scale scores in the overall sample and across four conditions. CONCLUSION: Findings suggest that the WHODAS 2.0 is a valid tool to measure functioning and disability in those with schizophrenia, anxiety, depression, and diabetes in an Asian patient population.

Neurostimulation therapies in major depressive disorder: A decision-analytic model.

AIM: Neurostimulation techniques are effective treatments for major depressive disorders (MDD). However, the optimal sequence of electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) as part of antidepressant treatment algorithm is unclear. We examined the cost-effectiveness of ECT and TMS in MDD. METHODS: A decision-analytic model was developed to determine total costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) for 10 strategies. Each strategy comprised four treatment lines with ECT and TMS incorporated as second, third, or fourth line. A scenario analysis that explored the cost-effectiveness of maintenance approach by continuing ECT and TMS after acute treatment was performed. RESULTS: In the base case, fourth-line TMS after three preceding trials of antidepressants was least costly at US$ 5523 yielding 1.424 QALYs. Compared with this strategy, fourth-line ECT and third-line TMS followed by ECT were cost-effective with ICERs of US$ 7601 per QALY gained and US$ 11 388 per QALY gained, respectively. In the scenario analysis where continuation treatments of ECT and TMS were provided, third-line TMS followed by ECT was cost-effective, with an ICER of US$ 17 198 per QALY gained. Effectiveness of ECT and cost of managing severe depression were influential parameters affecting the cost-effectiveness results. CONCLUSIONS: In acute treatment of MDD, fourth-line ECT was the most cost-effective strategy. In maintenance treatment, the strategy that incorporated third-line TMS and fourth-line ECT was cost-effective. The overall findings confirmed the value of neurostimulation therapies which should be offered early in the process of managing depression.

Cost-Effectiveness Modeling of Repetitive Transcranial Magnetic Stimulation Compared to Electroconvulsive Therapy for Treatment-Resistant Depression in Singapore.

BACKGROUND: Compared to electroconvulsive therapy (ECT), the cost-effectiveness of repetitive transcranial magnetic stimulation (rTMS) in the management of treatment-resistant depression (TRD) remains unclear. OBJECTIVE/HYPOTHESIS: This study evaluated the cost-effectiveness of rTMS vs. ECT for TRD from Singapore societal perspective. METHODS: We constructed a Markov model to project the cost and benefit of rTMS compared with ECT over one year in patients with TRD. The relative treatment effects between rTMS and ECT were obtained from meta-analyses of published trials. The effectiveness and quality of life data for patients using ECT, resource use for TRD and their associated costs were derived from the national tertiary mental institution in Singapore. RESULTS: At one year, rTMS was cost-effective relative to ECT. The incremental cost-effectiveness ratio (ICER) associated with ECT was Singapore dollars (SGD) 311,024 per quality-adjusted life-year (QALY) gained. This exceeded the willingness-to-pay threshold of SGD 70,000 per QALY gained. A similar trend was observed for ICER per remission achieved (i.e., SGD 143,811 per remission achieved with ECT). In the subgroup analysis, rTMS was found to be less costly and more effective than ECT in nonpsychotic depressive patients. In the scenario analysis, ECT employed as an ambulatory service yielded a much smaller ICER (i.e., SGD 78,819 per QALY gained) compared to the standard inpatient setting. CONCLUSIONS: rTMS was a cost-effective treatment compared to ECT in TRD over one year. The cost-effectiveness of rTMS was attenuated when ECT was used in the outpatient setting.

Network Meta-Analysis and Cost-Effectiveness Analysis of New Generation Antidepressants.

BACKGROUND: Major depressive disorder (MDD) impacts health, quality of life and workplace productivity. Antidepressant treatment is the primary therapeutic intervention. This study assessed the efficacy and tolerability of new generation antidepressants and their cost-effectiveness in the Singapore healthcare system. METHODS: We conducted a systematic search for head-to-head randomised controlled trials on ten antidepressants (agomelatine, duloxetine, escitalopram, fluvoxamine, fluoxetine, mirtazapine, paroxetine, sertraline, trazodone and venlafaxine) employed as monotherapy in acute MDD management. We performed a network meta-analysis to compare their relative efficacy. The outcome measures for efficacy were response and remission rate, and mean change in Hamilton Depression Rating Scale (HDRS) score; and for tolerability, study withdrawal rates due to adverse events. To evaluate their relative cost effectiveness, a decision tree simulating a cohort of MDD patients using antidepressant as monotherapy was constructed from a societal perspective over 6 months. We used effectiveness data from our network meta-analysis and local data on resource use for depression in Singapore. The incremental cost expected for each additional quality-adjusted life-year (QALY) gained was calculated and presented as the incremental cost-effectiveness ratio (ICER). RESULTS: We identified 76 relevant articles for the network meta-analysis. Of the ten agents included in the analysis, mirtazapine and agomelatine were most efficacious in achieving response and remission, respectively. Mirtazapine and duloxetine resulted in the greatest magnitude of change in the HDRS score. Agomelatine, escitalopram and sertraline were the best tolerated of the drugs analysed, while duloxetine was the least well tolerated drug. Using a composite outcome of efficacy (response and remission rates) and tolerability, agomelatine, escitalopram and mirtazapine were the favoured treatments. In the cost-effectiveness analysis, apart from agomelatine, all the treatments were dominated by mirtazapine. Against mirtazapine, agomelatine was not cost effective given that its ICER exceeded the threshold value. CONCLUSION: Agomelatine, escitalopram and mirtazapine had favourable balance between efficacy and tolerability. In addition, mirtazapine was a cost-effective option in the Singapore healthcare system.