A register-based approach to identifying treatment-resistant depression-Comparison with clinical definitions

Association between inflammatory joint disease and severe or treatment-resistant depression: population-based cohort and case-control studies in Sweden

OBJECTIVE

To investigate whether the association between depression and inflammatory joint disease (IJD; rheumatoid arthritis [RA], psoriatic arthritis [PsA], ankylosing spondylitis/spondyloarthropathies [AS], and juvenile idiopathic arthritis [JIA]) is affected by the severity or treatment-resistance of depression.

METHOD

Parallel cohort studies and case-control studies among 600,404 patients with a depressive episode identified in Swedish nationwide administrative registers. Prospective and retrospective risk for IJD in patients with depression was compared to matched population comparators, and the same associations were investigated in severe or treatment-resistant depression. Analyses were adjusted for comorbidities and sociodemographic covariates.

RESULTS

Patients with depression had an increased risk for later IJD compared to population comparators (adjusted hazard ratio (aHR) for any IJD 1.34 [95% CI 1.30-1.39]; for RA 1.27 [1.15-1.41]; PsA 1.45 [1.29-1.63]; AS 1.32 [1.15-1.52]). In case-control studies, patients with depression more frequently had a history of IJD compared to population controls (adjusted odds ratio (aOR) for any IJD 1.43 [1.37-1.50]; RA 1.39 [1.29-1.49]; PsA 1.59 [1.46-1.73]; AS 1.49 [1.36-1.64]; JIA 1.52 [1.35-1.71]). These associations were not significantly different for severe depression or TRD.

CONCLUSION

IJD and depression are bidirectionally associated, but this association does not seem to be influenced by the severity or treatment resistance of depression.

Prospective study of antidepressant treatment of psychiatric patients with depressive disorders: treatment adequacy and outcomes

BACKGROUND

Despite numerous national depression care guidelines (DCGs), suboptimal antidepressant treatment may occur. We examined DCG concordance and depression treatment outcomes in psychiatric settings.

METHODS

We evaluated treatment received and outcomes of 128 psychiatric out- and inpatients participating in the PEGAD (Pharmacoepidemiology and Pharmacogenetics of Antidepressant Treatment for Depressive Disorders) study at baseline, two weeks, and eight weeks using interviews and questionnaires. Inclusion criteria were ICD-10 diagnosis of a depressive disorder, a Patient Health Questionnaire-9 symptom (PHQ-9) score ≥ 10, and a new antidepressant prescribed. The primary outcome of the study was within-individual change in PHQ-9 scores.

RESULTS

At baseline, patients had predominately recurrent (83%) and in 19% treatment-resistant depression (TRD). The median preceding duration of the current episode was 6.5 months. At eight weeks, 85% of the patients (n = 107) used a DCG-concordant antidepressant dose. However, due to the scarcity of antidepressant combinations and augmentations, fewer TRD than non-TRD patients (25% vs. 84%, p < 0.005) received adequate antidepressant treatment. Additionally, one-third of the patients received inadequate follow-up. Overall, only 53% received treatment compatible with DCG recommendations for adequate pharmacotherapy and follow-up. The mean decline in PHQ-9 scores (-3.8 ± SD 5.7) was significant (p < 0.0005). Nearly 40% of the patients reached a subthreshold level of depression (PHQ-9 < 10), predicted by a lower baseline PHQ-9 score, recurrent depression, and female sex. However, 45% experienced no significant clinical improvement (PHQ-9 score reduction < 20%).

CONCLUSIONS

Our findings suggest that inadequate treatment continues to occur in psychiatric care settings, particularly for TRD patients.

Exome-wide association study of treatment-resistant depression suggests novel treatment targets

Treatment-resistant depression (TRD) is a severe form of major depressive disorder (MDD) with substantial public health impact and poor treatment outcome. Treatment outcome in MDD is significantly heritable, but genome-wide association studies have failed to identify replicable common marker alleles, suggesting a potential role for uncommon variants. Here we investigated the hypothesis that uncommon, putatively functional genetic variants are associated with TRD. Whole-exome sequencing data was obtained from 182 TRD cases and 2021 psychiatrically healthy controls. After quality control, the remaining 149 TRD cases and 1976 controls were analyzed with tests designed to detect excess burdens of uncommon variants. At the gene level, 5 genes, ZNF248, PRKRA, PYHIN1, SLC7A8, and STK19 each carried exome-wide significant excess burdens of variants in TRD cases (q < 0.05). Analysis of 41 pre-selected gene sets suggested an excess of uncommon, functional variants among genes involved in lithium response. Among the genes identified in previous TRD studies, ZDHHC3 was also significant in this sample after multiple test correction. ZNF248 and STK19 are involved in transcriptional regulation, PHYIN1 and PRKRA are involved in immune response, SLC7A8 is associated with thyroid hormone transporter activity, and ZDHHC3 regulates synaptic clustering of GABA and glutamate receptors. These results implicate uncommon, functional alleles in TRD and suggest promising novel targets for future research.

The Individual and Societal Burden of Treatment-Resistant Depression: An Overview

Major depressive disorder is characterized by depressed mood and/or anhedonia with neurovegetative symptoms and neurocognitive changes affecting an individual's functioning in multiple aspects of life. Treatment outcomes with commonly used antidepressants remain suboptimal. Treatment-resistant depression (TRD) should be considered after inadequate improvement with two or more antidepressant treatments of adequate dose and duration. TRD has been associated with increased disease burden including higher associated costs (both socially and financially) affecting both the individual and society. Additional research is needed to better understand the long-term burden of TRD to both the individual and society.

Overview of treatment-resistant depression

Patients with major depressive disorder (MDD) often exhibit an inadequate treatment response or failure to achieve remission following treatment with antidepressant drugs. Treatment-resistant depression (TRD) is proposed to identify this clinical scenario. Compared to those without TRD, patients with TRD have significantly lower health-related quality of life in mental and physical dimensions, more functional impairment and productivity loss, and higher healthcare costs. TRD imposes a massive burden on the individual, family, and society. However, a lack of consensus on the TRD definition limits the comparison and interpretation of TRD treatment efficacy across trials. Furthermore, because of the various TRD definitions, there is scarce treatment guideline specifically for TRD, in contrast to the rich treatment guidelines for MDD. In this chapter, common issues related to TRD, such as proper definitions of an adequate antidepressant trial and TRD, were carefully reviewed. Prevalence of and clinical outcomes related to TRD were summarized. We also summarized the staging models ever proposed for the diagnosis of TRD. Furthermore, we highlighted variations in the definition regarding the lack of or an inadequate response in treatment guidelines for depression. Up-to-date treatment options for TRD, including pharmacological strategies, psychotherapeutic interventions, neurostimulation techniques, glutamatergic compounds, and even experimental agents were reviewed.

Response to electroconvulsive therapy in treatment-resistant depression: nationwide observational follow-up study

BACKGROUND

Previous studies have not investigated response rates after electroconvulsive therapy (ECT) in patients with non-psychotic treatment-resistant depression (TRD).

AIMS

To assess and compare the response rate of ECT for patients with TRD and non-TRD, in a large and clinically representative patient sample.

METHOD

Patients aged ≥18 years, who were treated for a unipolar, non-psychotic depressive episode with at least one ECT session as part of a first-time, index ECT series between 1 January 2011 and 31 December 2017 were included from the Swedish National Quality Register for ECT. Patients who had initiated a third consecutive trial of antidepressants or add-on medications before start of ECT were classified as having TRD. Patients not meeting criteria for TRD were classified as non-TRD. The main outcome was response to ECT according to the Clinical Global Impressions - Improvement Scale (CGI-I), scored as 1 or 2 ('very much' or 'much improved' after ECT, respectively). Logistic regression was used to compare outcome measures between TRD and non-TRD, adjusting for potential confounders.

RESULTS

A total of 4244 patients were included. Of these, 1121 patients had TRD and 3123 patients had non-TRD. The CGI-I response rate was 65.9% in the TRD group compared with 75.9% in the non-TRD group (adjusted odds ratio 0.64, 95% CI 0.54-0.75). Older age and more severe depression were predictors of response in patients with TRD.

CONCLUSIONS

A clear majority of patients with TRD, as well as patients with non-TRD, responded to ECT, although the response rate was somewhat lower for TRD.

Factors associated with antidepressant responses to repetitive transcranial magnetic stimulation in antidepressant-resistant depression

Background

A significant proportion of patients with major depressive disorder (MDD) failed to respond to antidepressant medications. Repetitive transcranial magnetic stimulation (rTMS) is an effective option for treating such treatment-resistant patients with MDD (TRD). Reliable clinical predictors for antidepressant responses to rTMS remain elusive.

Methods

In total, 212 patients with MDD who failed to respond to at least one adequate antidepressant trial and had a detailed evaluation before rTMS were recruited for chart review. Demographic data, clinical characteristics, psychiatric comorbidities, symptom ratings [e.g., objective and subjective depression, life stress, depression refractoriness by Maudsley Staging Method (MSM)], and antidepressant treatment responses were analyzed.

Results

MSM-subitem1 (duration of current depressive episode; Beta = 0.209, p = 0.004), MSM-subitem5 (a history of ECT treatment; Beta = –0.210, p = 0.004), and psychiatric admissions (Beta = 0.241, p = 0.001) predicted antidepressant response of rTMS treatment. ECT was underutilized (only 3.3%). Psychiatric admissions [Exp(B) = 1.382, p = 0.021], a comorbidity of OCD [0.047, 0.005], and life stress level [0.984, 0.029] predicted the history of ECT treatment.

Conclusion

Several clinical variables (e.g., number of psychiatric admissions, OCD as a comorbidity, and life stress level) were reliable clinical factors associated with antidepressant responses of rTMS treatment and may be utilized in combination with MSM subitems to evaluate levels of TRD.

Health care utilisation in treatment-resistant depression: a Swedish population-based cohort study

OBJECTIVE

To investigate the health care utilisation (HCU) among patients with treatment-resistant depression (TRD) compared to patients with depression not meeting TRD criteria.

METHODS

Nationwide Swedish registers were used to identify patients 18-69 years old with incident depression and antidepressant treatment. Patients were followed prospectively and defined as having TRD at start of the third distinct consecutive treatment episode. Each of the 16,329 identified TRD patients were matched with five comparators with depression not meeting criteria for TRD. Main outcome measure was total number of inpatient days and outpatient visits, and secondary outcome was HCU in connection with a main diagnosis of depression or suicide attempt.

RESULTS

TRD patients had a significantly higher risk of all-cause inpatient care than comparators (first year adjusted risk ratio [aRR] 3.03 [95%CI 3.01-3.05], years 1-3 aRR 2.15 [2.13-2.16]). This was more pronounced when the main diagnosis was depression (first year aRR 4.41 [4.36-4.45]), and after suicide attempt (first year aRR 4.43 [4.26-4.60]). Outpatient visits were also markedly more frequent for patients with TRD (first year aRR 2.05 [2.03-2.07]). Higher HCU among TRD patients persisted throughout follow-up.

CONCLUSIONS

Patients with TRD may have a twofold to fourfold higher HCU than other patients with depression.KEYPOINTSThis register-based prospective study investigated health care utilisation (HCU) among patients with treatment-resistant depression (TRD) compared to other patients with depression.Patients with TRD had a two to fourfold higher HCU regarding all measured outcomes, including inpatient hospital days and outpatient visits.The elevated HCU persisted for more than three years, although decreasing gradually. This should correspond to increased costs and individual burden for patients with TRD.

Healthcare utilization, costs, and productivity losses in treatment-resistant depression in Finland - a matched cohort study

BACKGROUND

Due to its relatively high prevalence and recurrent nature, depression causes a major burden on healthcare systems, societies and individuals. Our objective was to investigate healthcare resource utilization and costs associated with treatment-resistant depression (TRD) compared with non-treatment-resistant depression in Finland.

METHODS

Of all patients aged 16-65 years and diagnosed with depression in Finland during 2004-2016, persons with TRD (N = 15,405) were identified from nationwide registers and matched 1:1 with comparison persons with depression who initiated antidepressant use but did not have TRD at the time of matching. TRD was defined as initiation of a third treatment trial after having failed two pharmacological treatment trials. Follow-up period covered 5 years after TRD or corresponding matching date (until end of 2018). Health care resource utilization was studied with negative binomial regression and costs of TRD (per patient per year) with generalized estimating equations, by adjusting for baseline costs, comorbidity and baseline severity of depression.

RESULTS

Persons with TRD (mean age 38.7, SD 13.1, 60.0% women) had more health care utilization and work disability (sick leaves and disability pensions), adjusted incidence rate ratio for work disability days was 1.72 (95% CI 1.64-1.80). This resulted in 1.9-fold higher total costs for persons with TRD (15,907 versus 8335 EUR), adjusted mean difference 7572 (95% CI 7215-7929) EUR per patient per year, higher productivity losses (due to sick leaves and disability pensions, mean difference 5296, 95% CI 5042-5550), and direct healthcare costs (2003, 95% CI 1853-2151) compared with non-TRD patients. Mean difference was the highest during the first year after TRD (total costs difference 11,760, 95% CI 11,314-12,206) and the difference decreased gradually after that.

CONCLUSION

Treatment-resistant depression is associated with about two-fold cost burden compared with non-treatment-resistant depression.

Treatment-resistant depression and labor market affiliation in the Danish welfare society: a register-based study

PURPOSE

We explored if patients with treatment-resistant depression (TRD) go through different states of labor market affiliation during their course of illness before they return to work or obtain early retirement as compared to patients without TRD.

METHODS

All adults between 18 and 58 years with a first-time hospital contact due to depression in Danish patients' registers from 2000 to 2014 were followed in a nationwide labor market database. At time of TRD (index week), TRD patients were matched with patients without TRD in a 1:2 ratio. Sequence analysis and logistic regression were applied to explore the association of TRD and labor market affiliation and measures of transitions between labor market states 52 weeks before and after the index week.

RESULTS

At the index week, 14.1% of patients with TRD were in employment, whereas the proportion was 26.4% among non-TRD patients. Over time, the proportion of patients in employment increased slightly to 25.5% for TRD and 33.7% for non-TRD patients. The proportion of TRD patients with sickness absence at index was 47.0%, while the proportion was 26.2% for non-TRD patients. The adjusted odds of a below mean volatility of labor market transitions, characterized by more episodes in passive social transfer payments and disability pension, were higher among patients with TRD compared with non-TRD patients (OR 1.63, 95% CI [1.56-1.69]). Similarly, the adjusted odds of a below mean integration into employment were 1.63 higher among TRD patients compared with non-TRD patients (95% CI [1.56-1.70]).

CONCLUSION

Patients with TRD have higher levels of sickness absence and lower levels of reintegration into the labor market after meeting the criteria for TRD compared with patients without TRD.

Bidirectional associations between treatment-resistant depression and general medical conditions

Depression is associated with general medical conditions (GMCs), but it is not known if treatment-resistant depression (TRD) affects GMC risk and vice versa. We estimated bidirectional associations between TRD and GMCs (prior and subsequent). All individuals aged 18-69 years, born and living in Denmark, with a first-time prescription for an antidepressant between 2005 and 2012 were identified in the Danish Prescription Registry (N = 154,513). TRD was defined as at least two shifts in treatment regimes. For prior GMCs, we estimated odds ratios (ORs) using conditional logistic regression comparing TRD patients with matched non-TRD controls adjusted for other GMCs and number of other GMCs. For subsequent GMCs, we used Cox regression to calculate hazard ratios (HRs) in TRD vs. non-TRD patients adjusted for age at first prescription, calendar time, other GMCs and number of other GMCs. Patients with TRD had higher prevalence of prior GMCs related to the immune or neurological systems; musculoskeletal disorders (women aOR: 1.35, 95% CI: 1.26-1.46, men aOR: 1.30, 95% CI: 1.19-1.42) and migraine (women aOR: 1.22, 95% CI: 1.09-1.36, men aOR: 1.25, 95% CI: 1.00-1.56). Subsequent GMCs were related to a broader spectrum; cardiovascular (women aHR: 1.43, 95% CI: 1.32-1.54, men aHR: 1.31, 95% CI: 1.19-1.43), endocrine (women aHR: 1.52, 95% CI: 1.37-1.67, men aHR: 1.24, 95% CI: 1.07-1.44), and neurological disorders (women aHR: 1.24, 95% CI: 1.13-1.35, men aHR: 1.19, 95% CI: 1.07-1.34). Our study presents a broad overview of comorbid medical conditions in patients with TRD and further studies are needed to explore the associations in detail.

Treatment patterns in patients with treatment-resistant depression in Danish patients with major depressive disorder

OBJECTIVE

To describe treatment patterns in patients with treatment-resistant depression (TRD) and major depressive disorder (MDD) stratified by depression severity and year of diagnosis. Patterns of treatment were also compared to country-specific guidelines.

METHODS

All adults registered first time with a hospital contact due to MDD from 1996 through 2015 were identified and followed for all dispensed prescriptions of antidepressants, antipsychotics, lithium, initiation of electroconvulsive therapy (ECT), and psychotherapy in Danish registers 12 months before and after their hospital MDD diagnosis. TRD was characterized by two shifts in treatment.

RESULTS

We identified 197,615 patients of whom 15% developed TRD. In total, 88% of patients started treatment with antidepressants or ECT. Selective serotonin reuptake inhibitors (SSRIs) were the most frequently used treatment during the study period and more than half (50.7%) of patients changed treatment at least once. Among patients with TRD, serotonin and noradrenaline reuptake inhibitors (SNRIs) were the most frequently used treatment (55.9%), and 37.0% initiated a new treatment the following year. SSRIs and SNRIs were part of most combinations of treatment, regardless of depression severity, year of diagnosis, or presence of TRD.

CONCLUSION

15% of patients met the criteria for TRD. Irrespective of patient characteristics and year of diagnosis, SSRIs and SNRIs are the most used treatments for depression, even after patients met the criteria for TRD. We confirm that guidelines for first treatment were followed for most patients diagnosed with MDD in Denmark, but for patients with TRD, choice of treatment was arbitrary.

Treatment-resistant depression and risk of all-cause mortality and suicidality in Danish patients with major depression

OBJECTIVE

Treatment-resistant depression (TRD) has been associated with higher mortality and risk of suicide, but this has mainly been showed in few studies which did not include self-harm. The aim was to investigate the association of TRD with all-cause mortality, suicide and self-harm in a nationwide cohort of patients with major depression and explore any differences in relation to patient characteristics.

METHODS

First-time hospital contacts for major depression between January 1, 1996 and December 31, 2014 were identified in Danish patient registers (ICD-10: F32 and F33). TRD was defined as two shifts in antidepressant treatment, assessed from one year prior depression diagnosis until one year after. Information on mortality, suicide and self-harm was obtained from Danish registers and associations between TRD and the three prognostic outcomes were analyzed using Cox Proportional Hazard Regression.

RESULTS

TRD was not associated with all-cause mortality the first year of follow-up (adjusted HR (aHR) 1.04, 95% confidence interval (CI) [0.98-1.11]), and the HR for mortality was lower the following 1-5 years. However, TRD was associated with higher rates of suicide (0-1 year: aHR 2.20, 95% CI [1.77-2.74]; 1-5 years: aHR 1.70, 95% CI [1.42-2.03]) and self-harming behavior (0-1 year: aHR 1.51, 95% CI [1.36-1.66]; 1-5 years: aHR 1.59, 95% CI [1.48-1.70]). The above risk estimates varied only slightly across sociodemographic and clinical patient characteristics.

CONCLUSIONS

Patients with TRD have higher rates of suicide and self-harm compared with non-TRD patients, whereas there seems to be no increase overall in all-cause mortality - in fact, there was a lower rate at follow-up after 1 year. We found only a few differences in HRs for mortality or suicidality across patient characteristics.

Excess deaths in treatment-resistant depression

BACKGROUND

Patients with treatment-resistant depression (TRD) have an increased mortality risk compared with other patients with depression, but it is not known how this translates into absolute numbers of excess deaths.

METHODS

Swedish national registers were used to identify a cohort of 118,774 antidepressant initiators 18-69 years old with a depression diagnosis. Patients who initiated a third consecutive treatment trial were classified as having TRD. Flexible parametric survival models were used to estimate the mortality risk due to all causes and external causes (suicides and accidents), comparing TRD patients with patients with other depression while adjusting for clinical and sociodemographic covariates and including interactions with TRD, age, and Charlson comorbidity index (CCI) for a number of somatic comorbidities. Standardized survival was estimated, as were numbers of excess deaths among TRD patients within each age and comorbidity category.

RESULTS

Compared with the mortality risk of other depressed patients, patients with TRD experienced excess deaths in most age and comorbidity categories in the range of 7-16 deaths per 1000 patients during 5 years. Highest numbers for all-cause excess deaths were found among patients 18-29 years old with CCI 1, where 16 [95% confidence interval 5-28] of the expected 37 [25-48] deaths per 1000 patients were excess deaths. The majority of the excess deaths were due to external causes.

CONCLUSION

Patients with TRD experience significant numbers of excess deaths compared with other patients with depression.