Cause-specific life years lost in individuals with treatment-resistant depression: A Danish nationwide register-based cohort study

Cause-specific mortality in treatment-resistant major depression: Population-based cohort study

BACKGROUND

Limited evidence-base on long-term prognosis of treatment-resistant major depression (TRD) is a barrier to clinical decision-making. Therefore, the purpose of this study was to establish cause-specific mortality in TRD compared to non-TRD major depression.

METHOD

We identified all individuals with a diagnosis of major depression (MDD) who were treated with an antidepressant aged 15 to 65 years during 2004-2016 in Finland. Persons with over two treatment trials were defined to have TRD. Data were analysed with Cox proportional hazard models.

RESULTS

176,942 individuals with MDD (63 % women, median age at index diagnosis 40 years), of whom 11 % (n = 19,305) fulfilled the TRD criteria, were followed-up for 1,525,646 person-years (median 8.9 years). There were 959 deaths (6.1 deaths/1000 person-years) in TRD and 7662 deaths (5.6/1000 person-years) in non-TRD. All-cause mortality was 17 % higher (adjusted hazard ratio (aHR), 1.17; 95 % confidence interval (CI), 1.09-1.25) in TRD compared to non-TRD, when sex and age at index antidepressant prescription were controlled for. In TRD, increased mortality was observed for suicides (aHR, 1.90; 95%CI, 1.64-2.20) and for accidental poisonings (aHR, 1.81; 95%CI, 1.48-2.22), but not for natural causes (aHR, 0.98; 95%CI, 0.90-1.07). A higher proportion of accidental drug overdoses was observed in TRD than in non-TRD (62 % vs 42 %, respectively).

LIMITATIONS

Definition of TRD lacks consensus. We used routine data to define TRD.

CONCLUSIONS

The markedly increased mortality due to suicides and accidental overdoses suggests that persons with TRD may experience higher intensity symptoms and more severe suicidal ideation than persons with non-TRD major depression.

Excess mortality and life-years lost in people diagnosed with depression: A 20-year population-based cohort study of 126,573 depressed individuals followed for 1,139,073 persons-years

Depression is associated with premature mortality, but evidence is mainly derived from Western countries. Very limited research has evaluated shortened lifespan in depression using life-years-lost (LYLs), a recently developed mortality metric taking into account the illness onset for life expectancy estimation. Temporal trends of differential mortality gap are understudied. This population-based cohort study, which utilized a territory-wide medical-record database of public inpatient and outpatient healthcare services in Hong Kong, evaluated the extent of premature mortality in 126,573 individuals with depression (persons-years=1,139,073) between January 2002 and December 2021 regarding the standardized mortality ratio (SMR) and excess LYLs. Trends in annual SMRs over 20 years were assessed by joinpoint analyses. The results showed that individuals with depression exhibited significantly higher all-cause (SMR=1.84 [95% CI=1.82-1.88]), natural-cause (1.69 [1.66-1.72]), and unnatural-cause (5.24 [4.97-5.51]) mortality rates than the general population. Suicide-specific SMR was markedly elevated (7.92 [7.47-8.38]), particularly in the 15-34 year-olds (12.75 [10.87-14.79]). Respiratory diseases, cardiovascular diseases and cancers accounted for the majority of deaths. Excess LYLs extended to men (5.67 years, 95% CI = 5.45-5.90) and women (4.06 years, 95% CI = 3.89-4.23). Overall and natural-cause mortality rates improved over time, but unnatural-cause and suicide-related mortality gaps persisted. Taken together, this study indicates that depression is associated with increased premature mortality and reduced lifespan in a predominantly Chinese population, mainly attributed to natural causes. Relative suicide-specific mortality is substantially elevated, especially among young people. The pronounced mortality gap underscores an urgent need for effective interventions targeting improved physical health and suicide risk reduction in individuals with depression.

Efficacy of Deep Brain Stimulation for Treatment-Resistant Depression: Systematic Review and Meta-Analysis

BACKGROUND

Treatment-resistant depression affects about 30% of individuals with major depressive disorder. Deep brain stimulation is an investigational intervention for treatment-resistant depression with varied results. We undertook this meta-analysis to synthesize outcome data across trial designs, anatomical targets, and institutions to better establish efficacy and side-effect profiles.

METHODS

We conducted a systematic PubMed review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seven randomized controlled trials (n = 198) and 8 open-label trials (n = 77) were included spanning 2009 to 2020. Outcome measures included Hamilton Depression Rating Scale or Montgomery-Åsberg Depression Rating Scale scores, as well as response and remission rates over time. Outcomes were tracked at the last follow-up and quantified as a time course using model-based network meta-analysis. Linear mixed models were fit to individual patient data to identify covariates.

RESULTS

Deep brain stimulation achieved 47% improvement in long-term depression scale scores, with an estimated time to reach 50% improvement of around 23 months. There were no significant subgroup effects of stimulation target, time of last follow-up, sex, age of disease onset, or duration of disease, but open-label trials showed significantly greater treatment effects than randomized controlled trials. Long-term (12-60 month) response and remission rates were 48% and 35%, respectively. The time course of improvement with active stimulation could not be adequately distinguished from that with sham stimulation, when available.

CONCLUSIONS

Deep brain stimulation produces significant chronic improvement in symptoms of treatment-resistant depression. However, the limited sham-controlled data do not demonstrate significant improvement over placebo. Future advancements in stimulation optimization and careful blinding and placebo schemes are important next steps for this therapy.

Risk of suicidal behavior in patients with major depression and bipolar disorder - A systematic review and meta-analysis of registry-based studies

Suicide is a health priority and one of the most common causes of death in mood disorders. One of the limitations of this type of research is that studies often establish rates of suicide behaviors in mood disorders by using diverse comparison groups or simply monitoring cohort of patients over a time period. In this registry-based systematic review, national registers were identified through searches in six academic databases, and information about the occurrence of suicide behaviors in mood disorders was systematically extracted. Odds ratios were subsequently calculated comparing rates of death by suicide in mood disorders in comparison with age and period matched rates of death by suicide in the general population obtained from country-wide national registers. The aim was to provide the most recent summary of epidemiological and clinical factors associated to suicide in mood disorders whilst calculating the likelihood of death by suicide in mood disorders in comparison with non-affected individuals according to national databases. The study follows the Preferred Reporting Guidelines for Systematic Reviews and Meta-analyses and was prespecify registered on Prospero (CRD42020186857). Results suggest that patients with mood disorders are at substantially increased risk of attempting and dying by suicide. Several epidemiological, clinical and social factors are reported to be associated with clinical populations at risk of suicide. Meta-analyses of completed deaths by suicide suggest that the likelihood for dying by suicide in mood disorders is 8.62 times higher in major depression and 8.66 times higher in bipolar disorder with higher number of untoward events in women compared to men in both conditions. The likelihood of dying by suicide in major depressive disorders is higher in the first year following discharge. Clinical guidelines might consider longer periods of monitoring following discharge from hospital. Overall, due to the higher risk of suicide in mood disorders, efforts should be made to increase detection and prevention whilst focusing on reducing risk in the most severe forms of illness with appropriate treatment to promote response and remission at the earliest convenience.

Life expectancy and years of potential life lost in people with mental disorders: a systematic review and meta-analysis

Background

Mental disorders are associated with premature mortality. There is increasing research examining life expectancy and years-of-potential-life-lost (YPLL) to quantify the disease impact on survival in people with mental disorders. We aimed to systematically synthesize studies to estimate life expectancy and YPLL in people with any and specific mental disorders across a broad spectrum of diagnoses.

Methods

In this systematic review and meta-analysis, we searched Embase, MEDLINE, PsychINFO, WOS from inception to July 31, 2023, for published studies reporting life expectancy and/or YPLL for mental disorders. Criteria for study inclusion were: patients of all ages with any mental disorders; reported data on life expectancy and/or YPLL of a mental-disorder cohort relative to the general population or a comparison group without mental disorders; and cohort studies. We excluded non-cohort studies, publications containing non-peer-reviewed data or those restricted to population subgroups. Survival estimates, i.e., life expectancy and YPLL, were pooled (based on summary data extracted from the included studies) using random-effects models. Subgroup analyses and random-effects meta-regression analyses were performed to explore sources of heterogeneity. Risk-of-bias assessment was evaluated using the Newcastle-Ottawa Scale. This study is registered with PROSPERO (CRD42022321190).

Findings

Of 35,865 studies identified in our research, 109 studies from 24 countries or regions including 12,171,909 patients with mental disorders were eligible for analysis (54 for life expectancy and 109 for YPLL). Pooled life expectancy for mental disorders was 63.85 years (95% CI 62.63-65.06; I2 = 100.0%), and pooled YPLL was 14.66 years (95% CI 13.88-15.98; I2 = 100.0%). Disorder-stratified analyses revealed that substance-use disorders had the shortest life expectancy (57.07 years [95% CI 54.47-59.67]), while neurotic disorders had the longest lifespan (69.51 years [95% CI 67.26-71.76]). Substance-use disorders exhibited the greatest YPLL (20.38 years [95% CI 18.65-22.11]), followed by eating disorders (16.64 years [95% CI 7.45-25.82]), schizophrenia-spectrum disorders (15.37 years [95% CI 14.18-16.55]), and personality disorders (15.35 years [95% CI 12.80-17.89]). YPLLs attributable to natural and unnatural deaths in mental disorders were 4.38 years (95% CI 3.15-5.61) and 8.11 years (95% CI 6.10-10.13; suicide: 8.31 years [95% CI 6.43-10.19]), respectively. Stratified analyses by study period suggested that the longevity gap persisted over time. Significant cross-study heterogeneity was observed.

Interpretation

Mental disorders are associated with substantially reduced life expectancy, which is transdiagnostic in nature, encompassing a wide range of diagnoses. Implementation of comprehensive and multilevel intervention approaches is urgently needed to rectify lifespan inequalities for people with mental disorders.

Funding

None.

Suicide-specific mortality among patients with treatment-resistant major depressive disorder, major depressive disorder with prior suicidal ideation or suicide attempts, or major depressive disorder alone

BACKGROUND

The impact of treatment-resistant depression (TRD) or prior suicidal ideation/suicide attempt (SI/SA) on mortality by suicide among patients with major depressive disorder (MDD) is not well known. This retrospective, observational, descriptive cohort study characterized real-world rates of suicide-specific mortality among patients with MDD with or without TRD or SI/SA.

METHODS

Adult patients with MDD among commercially insured and Medicare enrollees in Optum Research Database were included and assigned to three cohorts: those with treatment-resistant MDD (TRD), those with MDD and SI/SA (MDD+SI/SA), and those with MDD without TRD or SI/SA (MDD alone). Suicide-specific mortality was obtained from the National Death Index. The effects of demographic characteristics and SI/SA in the year prior to the end of observation on suicide-specific mortality were assessed.

RESULTS

For the 139,753 TRD, 85,602 MDD+SI/SA, and 572,098 MDD alone cohort patients, mean age ranged from 55 to 59 years and the majority were female. At baseline, anxiety disorders were present in 53.92%, 44.11%, and 21.72% of patients with TRD, MDD+SI/SA, and MDD alone, respectively. Suicide-mortality rates in the three cohorts were 0.14/100 person-years for TRD, 0.27/100 person-years for MDD+SI/SA, and 0.04/100 person-years for MDD alone. SI/SA during the year prior to the end of observation, younger age, and male sex were associated with increased suicide risk.

CONCLUSIONS

Patients with TRD and MDD+SI/SA have a heightened risk of mortality by suicide compared with patients with MDD alone. Suicide rates were higher in patients with recent history versus older or no history of SI/SA, men versus women, and those of young age versus older age.

Rates and associations of relapse over 5 years of 2649 people with bipolar disorder: a retrospective UK cohort study

BACKGROUND

Evidence regarding the rate of relapse in people with bipolar disorder (BD), particularly from the UK, is lacking. This study aimed to evaluate the rate and associations of clinician-defined relapse over 5 years in a large sample of BD patients receiving routine care from a UK mental health service.

METHOD

We utilised de-identified electronic health records to sample people with BD at baseline. Relapse was defined as either hospitalisation, or a referral to acute mental health crisis services, between June 2014 and June 2019. We calculated the 5-year rate of relapse and examined the sociodemographic and clinical factors that were independently associated with relapse status and the number of relapses, over the 5-year period.

RESULTS

Of 2649 patients diagnosed with BD and receiving care from secondary mental health services, 25.5% (n = 676) experienced at least one relapse over 5 years. Of the 676 people who relapsed, 60.9% experienced one relapse, with the remainder experiencing multiple relapses. 7.2% of the baseline sample had died during the 5-year follow-up. Significant factors associated with experiencing any relapse, after adjustment for relevant covariates, were history of self-harm/suicidality (OR 2.17, CI 1.15-4.10, p = 0.02), comorbidity (OR 2.59, CI 1.35-4.97, p = 0.004) and psychotic symptoms (OR 3.66, CI  1.89-7.08, p < 0.001). Factors associated with the number of relapses over 5 years, after adjustment for covariates, were self-harm/suicidality (β = 0.69, CI 0.21-1.17, p = 0.005), history of trauma (β = 0.51, CI = 0.07-0.95, p = 0.03), psychotic symptoms (β = 1.05, CI 0.55-1.56, p < 0.001), comorbidity (β = 0.52, CI 0.07-1.03, p = 0.047) and ethnicity (β = - 0.44, CI - 0.87 to - 0.003, p = 0.048).

CONCLUSIONS

Around 1 in 4 people with BD in a large sample of people with BD receiving secondary mental health services in the UK relapsed over a 5-year period. Interventions targeting the impacts of trauma, suicidality, presence of psychotic symptoms and comorbidity could help to prevent relapse in people with BD and should be considered in relapse prevention plans.

Reduced numbers of naïve CD4 + T cells and an altered CD4/CD8 balance in depressed common variable immune deficiency (CVID) patients. Is thymosin-α1 a possible treatment?

In the 1990's the macrophage-T-cell-theory of depression was posed stating that low grade inflammation and an abnormal T cell system destabilize the development and function of the emotional brain in such a way, that individuals become ultrasensitive to stress. Recently we gathered evidence that indeed higher frequencies of CD4+ memory T cells, lower frequencies of naive CD4 + T cells, higher frequencies of CD8 + T cells (the latter two in part elicited by Cytomegalovirus, CMV, infection) are a characteristic of Major Depressive Disorder (MDD). In MDD patients with a history of childhood trauma and severe depression monocytes are inflammatory activated. Low grade inflammation and T cell system defects have also been reported in patients with Common Variable Immune Deficiency (CVID) (next to antibody production defects). CVID patients show a higher prevalence of mild depression. The aim of this study was to determine T cell frequencies and monocyte inflammatory activation in CVID patients with and without depression. This study confirms that CVID patients have CMV independent decreases in the frequency of naïve CD4 + T cells and it de novo shows a CMV dependent increase in the expression of inflammatory genes in monocytes. CVID patients with depression are additionally characterized by a CMV independent increase in the frequency of naïve CD8 + T cells, while lacking monocyte inflammatory activation. In conclusion, depressed CVID patients have T cell abnormalities comparable to that of patients with regular MDD. These abnormalities are presently targeted by thymosin α1 in an open-label proof of concept trial.

Treatment resistant depression in elderly

Treatment refractory depression (TRD) in the elderly is a common psychiatric disorder with high comorbidity and mortality. Older adults with TRD often have complicated comorbidities and several predisposing risk factors, which may lead to neuropsychiatric dysfunction and poor response to treatment. Several hypotheses suggest the underlying mechanisms, including vascular, immunological, senescence, or abnormal protein deposition. Treatment strategies for TRD include optimization of current medication dose, augmentation, switching to an alternative agent or class, and combination of different antidepressant classes, as well as nonpharmacological adjuvant interventions such as biophysical stimulation and psychotherapy. In summary, treatment recommendations for TRD in the elderly favor a multimodal approach, combining pharmacological and nonpharmacological treatments.

Association of Treatment-Resistant Depression With Patient Outcomes and Health Care Resource Utilization in a Population-Wide Study

Importance

The totality of the societal and individual impact of treatment-resistant depression (TRD) is unknown, as is the potential to prognosticate TRD. The generalizability of many observational studies on TRD is limited.

Objective

To estimate the burden of TRD in a large population-wide cohort in an area with universal health care by including data from both health care types (psychiatric and nonpsychiatric) and, further, to develop a prognostic model for clinical use.

Design, Setting, and Participants

This cohort study, a population-based observational study, assessed data from the Stockholm MDD Cohort for episodes of major depressive disorder (MDD) between 2010 and 2017 that fulfilled predefined criteria for TRD (≥3 consecutive antidepressant treatments). Data analysis was performed from August 2020 to May 2022.

Main Outcomes and Measures

Outcomes were psychiatric and nonpsychiatric comorbid conditions, antidepressant treatments, health care resource utilization, lost workdays, all-cause mortality, and intentional self-harm and, in the prognostic model, TRD.

Results

A total of 158 169 unipolar MDD episodes (in 145 577 patients) were identified between January 1, 2012, and December 31, 2017 (64.7% women; median [IQR] age, 42 years [30-56]). Of these, 12 793 episodes (11%) fulfilled criteria for TRD. The median (IQR) time from the start of MDD episode to TRD was 552 days (294-932). Selective serotonin reuptake inhibitor was the most common class of antidepressant treatment in all treatment steps, and 5907 patients (46.2%) received psychotherapy at some point before initiation of the third pharmacological antidepressant treatment. Compared with matched non-TRD episodes, TRD episodes had more inpatient bed-days (mean, 3.9 days; 95% CI, 3.6-4.1, vs 1.3 days; 95% CI, 1.2-1.4) and more lost workdays (mean, 132.3 days; 95% CI, 129.5-135.1, vs 58.7 days; 95% CI, 56.8-60.6) 12 months after the index date. Anxiety, stress, sleep disorder, and substance use disorder were all more common comorbid conditions in TRD episodes. Intentional self-harm was more than 4 times more common in TRD episodes. The all-cause mortality rate for patients with MDD with TRD episodes was 10.7/1000 person-years at risk, compared with 8.7/1000 person-years at risk for patients with MDD without TRD episodes (hazard ratio, 1.23; 95% CI, 1.07-1.41). Median time from start of the first antidepressant treatment to start of the second, and from start of the second antidepressant treatment to start of the third, was 165 and 197 days, respectively. The severity of MDD, defined using the self-rating Montgomery-Åsberg Depression Rating Scale (MADRS-S) at time of MDD diagnosis, was found to be the most important prognostic factor for TRD (C index = 0.69).

Conclusions and Relevance

In this cohort study, TRD was a common variant of MDD when including patients from both health care types, which is associated with a high disease burden for both patients and society. The median time between initiation of new antidepressant treatments was longer than recommended in current treatment guidelines, suggesting room for more structured and timely depression care.

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.

Courses of treatment and risk factors for treatment-resistant depression in Finnish primary and special healthcare: A nationwide cohort study

OBJECTIVE

Investigate incidence, risk factors and courses of treatment for treatment-resistant depression (TRD) in primary and special healthcare.

METHODS

All patients identified from nationwide registers, aged 16-65 years, diagnosed with depression in Finland during 2004-2016 were included. New antidepressant users were identified with six-month washout period and followed-up for two years to observe for presence of TRD, which was defined as initiation of a third trial after having failed two pharmacological treatment trials with adequate duration.

RESULTS

During follow-up, 177,144 persons had their first registered antidepressant treated depression (mean age: 39.5, 62.5% women). Of them, 10.9% (N = 19,322) met TRD criteria. Among the TRD patients, most common first and second antidepressants trials were: SSRIs (44.6%), mirtazapine (19.0%) and SNRIs (16.5%). As the third treatment line, antidepressant monotherapy (44.2% of TRD patients) was most common, followed by a combination of ≥2 antidepressants (32.1%), antipsychotic or mood stabilizer augmentation and an antidepressant (15.8%), both combination of antidepressants and an augmentation with a mood stabilizer or antipsychotic (4.9%), antipsychotic or mood stabilizer monotherapy (2.7%) and ECT (0.3%). Of TRD patients, 16.5% (N = 3188) progressed to the fifth treatment line, in which the most common treatments were antidepressant monotherapy (33.4%), antidepressant combinations (27.5%) and augmentation (24.2%). Factors associated with higher risk of TRD included male gender, younger age, higher initial disease severity and hospitalization at initial onset of depression.

CONCLUSIONS

Antidepressant monotherapies were still the most common fifth line of depression treatment. Severe depression, hospitalization due to depression, young age and male gender may predispose to TRD.

Mortality-causing mechanisms and healthcare resource utilisation of treatment-resistant depression: A six-year population-based cohort study

Background

Few studies investigated the mechanisms of treatment-resistant depression (TRD) leading to the worsened survival outcome, and economic evidence was mostly restricted to short follow-ups. We aimed to examine the association and potential mediators between TRD and all-cause mortality, and estimate a longer-term associated health resource utilisation pattern.

Methods

This was a population-based cohort study using territory-wide electronic medical records in Hong Kong. Incident depression patients diagnosed in 2014 were followed up from the first diagnosis to death or December 2019 for TRD identification. We matched the TRD cohort 1:4 to the non-TRD cohort on propensity scores estimated by age, sex, history of physical disorders, and history of psychiatric conditions before depression diagnoses.

Findings

18% of incident patients developed TRD within six years of follow-up. Cox model showed that patients with TRD had 1⋅52-fold (95% CI: 1⋅14-2⋅02) greater risk of all-cause mortality, compared with non-TRD patients. Path analysis suggested that post-TRD psychiatric conditions significantly mediated 41⋅6% of mortality in patients with TRD (p=0.003). TRD was associated with 1⋅8-fold (95%CI: 1⋅63-2⋅00) higher healthcare costs compared to non-TRD patients over six years in negative binomial regression, with higher costs for both psychiatric and non-psychiatric services utilisation in all settings.

Interpretation

Identifying patients with TRD and subsequent monitoring for post-TRD psychiatric diagnoses could be a way to reduce premature mortality. Multidisciplinary care involving both psychiatric and general medical professionals is also warranted to relieve the multifaceted impacts on healthcare resources and overall cost.

Funding

Unconditional educational grant from Janssen.

Early labor force exits in patients with treatment-resistant depression: an assessment of work years lost in a Danish nationwide register-based cohort study

BACKGROUND

Depression is one of the leading causes of premature workforce exit in many Western countries, but little is known about the extent to which treatment-resistance reduces number of work-years. We compared the risk of premature workforce exit among patients with treatment-resistant depression (TRD) relative to non-TRD patients and estimated work years lost (WYL) before scheduled retirement age.

METHODS

The study population, identified in the Danish National Prescription Registry, included all individuals born and living in Denmark who redeemed their first antidepressant (AD) prescription for depression at age 18-60 years between 2005 and 2012. TRD was defined as failure to respond to at least two different treatment trials. Premature workforce exit was measured using disability pension records. We used Cox regression to estimate the hazard ratio (HR) for premature workforce exit in TRD relative to non-TRD patients, adjusting for calendar year, psychiatric and somatic comorbidity, and educational level. Differences in WYL in patients with TRD and all depression patients were estimated through a competing risks model.

RESULTS

Out of the total sample of patients with depression (N = 129,945), 7478 (5.75%) were classified as having TRD. During follow up, 17% of patients with TRD and 8% of non-TRD patients received disability pension, resulting in a greater than three-fold larger risk of premature workforce exit [adjusted HR (aHR) 3.23 95% confidence interval (CI) 3.05-3.43]. The TRD group lost on average six work-years (95% CI 5.64-6.47) more than the total sample due to early labor force exit. The association between TRD and age at premature workforce exit was inversely U-shaped; the hazard rate of premature workforce exit for patients with TRD compared with non-TRD patients was highest in the age groups 31-35, 36-40, and 41-45 years.

CONCLUSION

Patients with TRD constitute a small group within depression patients, but contribute disproportionally to societal costs due to premature workforce exit at a young age.