Androgen deprivation therapy and depression in men with prostate cancer treated with definitive radiation therapy

The mechanism of cancer-depression comorbidity

Cancer and depression are closely interrelated, particularly in patients with advanced cancer, who often present with comorbid anxiety and depression for various reasons. Recently, there has been a growing interest in the study of depression in cancer patients, with the aim of assessing the possible triggers, predictors, adverse events, and possible treatment options for depression in several common cancers. The objective of this narrative review is to synthesize the extant literature on the relationship between the occurrence and progression of depression in several common patient categories. The authors conducted a comprehensive review of 75 articles published in PubMed over the past five years. This review was further evaluated in the present paper. Ultimately, it was determined that depression is a prevalent and detrimental phenomenon among cancer patients, particularly those with advanced disease. Consequently, there is a pressing need to prioritize research and interventions aimed at improving the quality of life and psychosocial well-being of cancer patients, including those with advanced disease. The relationship between cancer and depression has been evolving dynamically in recent times. The current research findings indicate a strong association between cancer and depression. However, the direction of causality remains unclear. Focusing on depression in cancer patients may, therefore, be beneficial for these patients.

Androgen deprivation therapy for prostate cancer and neurocognitive disorders: a systematic review and meta-analysis

BACKGROUND

Prostate cancer is a prevalent disease that urgently needs to address its treatment-related complications. By examining existing evidence on the association between Androgen Deprivation Therapy (ADT) and dementia, this study contributes to the understanding of potential risks. We sought to analyze the currently available evidence regarding the risk of dementia, Alzheimer's disease (AD), vascular dementia, and Parkinson's disease (PD) in patients undergoing ADT.

METHODS

A systematic search of PubMed, EMBASE, Scopus, and Google Scholar was performed to identify studies published from the databases' inception to April 2023. Studies were identified through systematic review to facilitate comparisons between studies with and without some degree of controls for biases affecting distinctions between ADT receivers and non-ADT receivers. This review identified 305 studies, with 28 meeting the inclusion criteria. Heterogeneity was assessed using Higgins I2%. Variables with an I2 over 50% were considered heterogeneous and analyzed using a Random-Effects model. Otherwise, a Fixed-Effects model was employed.

RESULTS

A total of 28 studies were included for analysis. Out of these, only 1 study did not report the number of patients. From the remaining 27 studies, there were a total of 2,543,483 patients, including 900,994 with prostate cancer who received ADT, 1,262,905 with prostate cancer who did not receive ADT, and 334,682 patients without prostate cancer who did not receive ADT. This analysis revealed significantly increased Hazard Ratios (HR) of 1.20 [1.11, 1.29], p < 0.00001 for dementia, HR 1.26 [1.10, 1.43], p = 0.0007 for Alzheimer's Disease, HR 1.66 [1.40, 1.97], p < 0.00001 for depression, and HR 1.57 [1.31, 1.88], p < 0.00001 for Parkinson's Disease. The risk of vascular dementia was HR 1.30 [0.97, 1.73], p < 0.00001.

CONCLUSION

Based on the analysis of the currently available evidence, it suggests that ADT significantly increases the risk of dementia, AD, PD, and depression.

Development of depression in patients using androgen deprivation therapy: A systemic review and meta-analysis

BACKGROUND

Androgen deprivation therapy (ADT) is an effective treatment for advanced prostate cancer (PCa). Multiple studies have highlighted serious consequences this therapy poses to mental health, particularly depression. We aimed to review the incidence and association between ADT in men with PCa and the risk of depression.

METHODS

We systematically searched multiple databases, including MEDLINE, Scopus till August 2023 for studies that compared ADT versus control for treating PCa reporting depression as outcome. Meta-analysis was performed using random-effects models and results presented as odds ratios (ORs) with 95% confidence interval (CI). Quality assessment of the included studies was conducted using Joanna Briggs Institute critical appraisal checklists.

RESULTS

A total of 38 studies (17 retrospective studies, 16 prospective studies, two cross-sectional studies and two randomized trials) with 360,650 subjects met the inclusion criteria and were included in this meta-analysis. The estimated pooled incidence of depression among ADT patients is 209.5 (95% CI = 122.3; 312.2) per 1000 patients. There is statistically significant relationship between ADT treatment and depression (OR = 1.46, 95% CI = 1.28, 1.67; p = 0, I2 = 86.4%). The results remained consistent across various subgroups. No risk of publication bias was detected by funnel plot and Eggers's test (p > 0.05).

CONCLUSION

There is a higher risk of depression for men receiving ADT. Further studies evaluating optimal treatments for depression in men on ADT are warranted.

Racial Disparities in Diagnosis and Treatment of Depression Associated with Androgen Deprivation Therapy for Prostate Cancer

OBJECTIVE

To analyze potential racial disparities in the diagnosis and management of depression associated with androgen deprivation therapy.

METHODS

TriNetX health record network was queried for prostate cancer patients treated with androgen deprivation therapy from 2003-2023. Differences in rates of depression diagnosis and treatment were compared between White and Black patients. Means, odds ratios, and t tests were calculated in univariate analysis with 95% confidence intervals (CI).

RESULTS

Data were queried from 93 health care organizations to yield 78,313 prostate cancer patients treated with androgen deprivation therapy. Patients on androgen deprivation therapy had 60% greater odds of developing depression vs other patients [9% vs 6%; odds ratio (OR) 1.6; 95% CI (1.5-1.7); P <.0001]. Of those with depression secondary to androgen deprivation therapy, only 35% were treated with antidepressants. After starting androgen deprivation therapy, White patients had 30% greater odds of being diagnosed with depression, compared to Black patients [10% vs 8%; OR 1.3; 95% CI (1.2-1.4); P <.001]. White patients also had higher odds of being treated with a first line antidepressant than Black patients [56% vs 48%; OR 1.4, 95% CI (1.2-1.6), P <.001].

CONCLUSION

This analysis confirms a significant association between androgen deprivation therapy and the development of clinical depression, and highlights its medical undertreatment. Importantly, our findings also indicate significant racial disparities in the identification and treatment of depression. Routine screening initiatives that account for social determinants of health may alleviate this disparity. Limitations of this study include retrospective design and lack of data describing severity of depression, which might correlate with need for medication.

Mental health care utilization among men with castration-resistant prostate cancer receiving abiraterone or enzalutamide

BACKGROUND

Abiraterone and enzalutamide are castration-resistant prostate cancer (CRPC) therapies with potentially distinct associations with mental health symptoms given their differing antiandrogen targets.

METHODS

We used national Veterans Health Administration data to identify patients with CRPC who received first-line abiraterone or enzalutamide from 2010 to 2017. Using Poisson regression, we compared outpatient mental health encounters per 100 patient-months on drug between the abiraterone and enzalutamide cohorts adjusting for patient factors (e.g., age). We compared mental health encounters in the year before versus after starting therapy using the McNemar test.

RESULTS

We identified 2902 CRPC patients who received abiraterone (n = 1992) or enzalutamide (n = 910). We found no difference in outpatient mental health encounters between the two groups (adjusted incident rate ratio [aIRR] 1.04, 95% confidence interval [CI] 0.95-1.15). However, men with preexisting mental health diagnoses received 81.3% of the outpatient mental health encounters and had higher rates of these encounters with enzalutamide (aIRR 1.21, 95% CI 1.09-1.34). Among patients with ≥1 year of enrollment before and after starting abiraterone (n = 1139) or enzalutamide (n = 446), there was no difference in mental health care utilization before versus after starting treatment (17.0% of patients vs. 17.6%, p = 0.60, abiraterone; 16.4% vs. 18.4%, p = 0.26, enzalutamide).

CONCLUSION

We found no overall differences in mental health care utilization between CRPC patients who received first-line abiraterone versus enzalutamide. However, men with preexisting mental health diagnoses received the majority of mental health care and had more mental health visits with enzalutamide.

Monoamine oxidase A (MAOA): A promising target for prostate cancer therapy

Monoamine oxidase A (MAOA) is a mitochondrial enzyme that catalyzes the oxidative deamination of monoamine neurotransmitters and dietary amines. Previous studies have shown that MAOA is clinically associated with prostate cancer (PCa) progression and plays a key role in almost each stage of PCa, including castrate-resistant prostate cancer, neuroendocrine prostate cancer, metastasis, drug resistance, stemness, and perineural invasion. Moreover, MAOA expression is upregulated not only in cancer cells but also in stromal cells, intratumoral T cells, and tumor-associated macrophages; thus, targeting MAOA can be a multi-pronged approach to disrupt tumor promoting interactions between PCa cells and tumor microenvironment. Furthermore, targeting MAOA can disrupt the crosstalk between MAOA and the androgen receptor (AR) to restore enzalutamide sensitivity, blocks glucocorticoid receptor (GR)- and AR-dependent PCa cell growth, and is a potential strategy for immune checkpoint inhibition, thereby alleviating immune suppression and enhancing T cell immunity-based cancer immunotherapy. MAOA is a promising target for PCa therapy, which deserves further exploration in preclinical and clinical settings.

The role of testosterone, the androgen receptor, and hypothalamic-pituitary-gonadal axis in depression in ageing Men

Considerable research has shown that testosterone regulates many physiological systems, modulates clinical disorders, and contributes to health outcome. However, studies on the interaction of testosterone levels with depression and the antidepressant effect of testosterone replacement therapy in hypogonadal men with depression have been inconclusive. Current findings indicate that low circulating levels of total testosterone meeting stringent clinical criteria for hypogonadism and testosterone deficiency induced by androgen deprivation therapy are associated with increased risk for depression and current depressive symptoms. The benefits of testosterone replacement therapy in men with major depressive disorder and low testosterone levels in the clinically defined hypogonadal range remain uncertain and require further investigation. Important considerations going forward are that major depressive disorder is a heterogeneous phenotype with depressed individuals differing in inherited polygenic determinants, onset and clinical course, symptom complexes, and comorbidities that contribute to potential multifactorial differences in pathophysiology. Furthermore, polygenic mechanisms are likely to be critical to the biological heterogeneity that influences testosterone-depression interactions. A genetically informed precision medicine approach using genes regulating testosterone levels and androgen receptor sensitivity will likely be essential in gaining critical insight into the role of testosterone in depression.

Androgen deprivation therapy and depression in the prostate cancer patients: review of risk and pharmacological management

Purpose: Despite the effectiveness of androgen deprivation therapy in advanced prostate cancer, serious neuropsychiatric consequences in androgen deprivation therapy (ADT)-treated patients, mainly depression, have been concerning and gained more attention recently. This narrative review aims to shed light on the risk and pharmacological management of ADT-induced depression in PCa patients.Methods: We searched PubMed, Scopus and Google Scholar databases using MESH keywords "Prostate cancer OR prostate neoplasm" AND "Depression" AND "Androgen Deprivation Therapy" AND "antidepressants". Search was limited to English and studies conducted on humans. Studies' titles and abstracts were screened, and further information were obtained from the text, if necessary, to decide whether studies are to be included in this review.Results: Our review revealed 23 studies confirming the occurrence and worsening of depressive symptoms in ADT-treated patients, which frequently require pharmacological interventions; whereas 10 studies indicated otherwise. All studies were prospective, retrospective, cross-sectional or case reports. Based on the incidence of depression provided by the observational studies, the average among ADT-treated patients was 18.23% (range: 2.1-46.9%), while it was 8.42% (range: 1.4-23.3%) in the non-ADT patients. Although several treatments have been used for depression in cancer patients, current knowledge lacks observational and controlled studies as well as clinical guidelines that demonstrate efficacy and safety of antidepressants and guide clinicians to the appropriate treatment in these patients, respectively. On the other side, a few clinical studies have been published regarding the efficacy of selective serotonin reuptake inhibitors, selective serotonin and norepinephrine reuptake inhibitors and/or saftey on other ADT associated adverse effects.Conclusions: Our work supports the recent attention towards mood issues as an adverse effect of ADT, and that greater awareness of this is warranted among clinicians. Clinical studies published regarding the use of antidepressants for other ADT associated adverse effects established the foundation that can be adopted to examine these therapies on ADT-induced depression.

Mental Health in Urologic Oncology

This article is a systematic review of mental health in urologic oncology patients with prostate cancer (PCa), bladder cancer (BC), renal cell carcinoma (RCC), testicular cancer (TC), or penile cancer (PeCa). For all pathologies, a focus on increasing quality of life post-treatment demonstrated a positive impact in reducing Mental Health Illness (MHI) prevalence. Cancer specific mental health care may be given to patients to reduce suicide risk in BC patients and sexual identify and masculinity counseling may improve mental health for TC or PeCa patients. In order to better accommodate patient’s mental health needs when undergoing GU cancer treatment, we recommend incorporation of mental health metrics such as questionnaires to assess early treatment of MHI, a greater emphasis on psychosocial support with the patient’s loved ones, peers, and healthcare team, alongside advising healthy habits such as exercise which has been shown to drastically reduce MHI incidence across all pathologies. We hope that these measures conducted by urologists and oncologists, alongside possible coordination with psychiatrists and psychologists for psychotherapy, psychopharmacology, and neuro-stimulation treatment modems may be helpful in the long term to reduce MHI incidence in urology oncology patients. Given the higher incidence of MHI in oncology patients and in the patient population after the Covid-19 pandemic, MHI awareness in the sphere of urologic oncologic treatment continues to be crucial when creating a collaborative treatment platform for patients.

Prostate Cancer and Sleep Disorders: A Systematic Review

Simple Summary

Longer survival times for prostate cancer patients due to efficient treatments consisting of local radiotherapy, prostatectomy and androgen-deprivation therapy, as well as androgen-receptor-targeted agents, increases the importance of side effect management. Sleep disturbances are higher in this group than the general population and no clear mechanism(s) explains this. This systematic review finds a reported effect in 14 of 16 included studies on sleep quality changes for these patients. All reported treatments showed some kind of negative effect on sleep quality, including ADT. Limitations are discussed and recommendations made for progressing the understanding and then for mitigation strategies of these side effects.

Abstract

Prostate cancer (PCa) treatment involves multiple strategies depending on the disease’s stage. Androgen deprivation therapy (ADT) remains the gold standard for advanced and metastatic stages. Sleep quality has been suggested as being additionally influenced also by local radiotherapy, prostatectomy and androgen-receptor (AR)-targeted agents. We performed a systematic review exploring the landscape of studies published between 1 January 1990 and 31 July 2021, investigating sleep disturbances in PCa patients receiving active treatments, including the influence of hormonal therapy on sleep quality as a factor affecting their quality of life. Out of 45 articles identified, 16 studies were selected, which recruited patients with PCa, undergoing active treatment in either a prospective longitudinal or cross-sectional study. Development of sleep disorders or changes in sleep quality were reported in 14 out of 16 trials included. Only five trials included objective measurements such as actigraphy, mostly at one time point and without a baseline assessment. Limitations to be addressed are the small number of existing trials, lack of randomized trials and heterogeneity of methodologies used. This systematic review outlines the lack of prospective trials investigating sleep disorders, with a rigorous methodology, in homogeneous cohorts of PCa patients. Future trials are needed to clarify the prevalence and impact of this side effect of PCa treatments.

Depression, Anxiety, and Patterns of Mental Health Care Among Men With Prostate Cancer Receiving Androgen Deprivation Therapy

BACKGROUND

Androgen deprivation therapy (ADT) use is associated with an increased risk of developing depression and anxiety. Little is known about how the mental health of these men is treated.

MATERIALS AND METHODS

We identified men with prostate cancer who received ADT between 2001 and 2015 using Optum's de-identified Clinformatics Data Mart Database. We determined the incidence of depression or anxiety diagnoses, mental health treatments, and the specialty of providers initiating psychotropic medications, after the start of ADT. Outcomes were compared with those of men with prostate cancer not receiving ADT and men without prostate cancer.

RESULTS

Of 37 388 men with prostate cancer treated with ADT, 3964 (10.6%) received a new diagnosis of depression or anxiety. Of those 3964 men, 1892 (47.7%) did not receive a documented treatment, 10 (0.3%) received psychotherapy, 1321 (33.3%) a selective serotonin reuptake inhibitor, and 744 (18.8%) a benzodiazepine. The median time from initiation of ADT to a depression or anxiety diagnosis was 9.3 months. Primary care physicians were the most common prescribers of psychotropic medications (72.2%). The proportion of men not receiving mental health treatments of interest (47.7%) was similar compared to men without prostate cancer (49.1%), but statistically significantly lower compared to men with prostate cancer not receiving ADT (52.7%).

CONCLUSIONS

In men with prostate cancer receiving ADT with a new diagnosis of depression or anxiety, nearly half are not receiving mental health care while one in five is introduced to a benzodiazepine. Further investigation toward improving the mental health care for men on ADT is needed.

Androgen deprivation therapy and acute kidney injury in patients with prostate cancer undergoing definitive radiotherapy

BACKGROUND

Androgen deprivation therapy (ADT) is frequently utilized in conjunction with radiotherapy (RT) in the definitive management of prostate cancer. Prior studies have suggested an association between ADT use and acute kidney injury (AKI), however, these included heterogeneous populations undergoing a variety of treatments and relied on billing codes to ascertain the incidence of AKI.

METHODS

We analyzed a cohort of 27,868 veterans undergoing definitive RT + /- ADT for prostate cancer between 2001 and 2015 using the Veterans Affairs Informatics and Computing Infrastructure (VINCI). Exposure was defined as use of ADT within one year of diagnosis. The primary outcome was AKI, defined by an increase in serum creatinine to at least 1.5 times the baseline value. AKIs were classified as mild, moderate, or severe in accordance with international guidelines. A multivariate competing risks model was used to account for demographic and oncologic factors as well as medications and procedures known to influence the risk of AKI.

RESULTS

Most (n = 18,754) men received RT alone; 9,114 men received RT + ADT. The incidence of AKI at two years after diagnosis was 10.5% in the RT + ADT group and 7.9% in the RT group (Gray's test p < 0.01). Multivariate analysis confirmed ADT usage was associated with an increased risk for any AKI (SHR = 1.24, 95% CI = 1.14-1.36, p < 0.01). ADT was also associated with an increased risk of mild AKI (SHR = 1.13, 95% CI = 1.01-1.27, p = 0.04) and moderate AKI (SHR = 1.45, 95% CI = 1.20-1.76, p < 0.01), though not severe AKI (SHR = 1.33, 95% CI = 0.93-1.91, p = 0.11).

CONCLUSIONS

Our findings confirm that use of ADT is associated with an increased risk of AKI in patients undergoing definitive RT for prostate cancer. Clinicians should be alert to the potential for renal dysfunction in this population.

Mindfulness-based interventions for psychological wellbeing and quality of life in men with prostate cancer: A systematic review and meta-analysis

OBJECTIVE

Mindfulness-based interventions (MBIs) are increasingly being encouraged for managing treatment-related symptoms but much less is known about the extent to which mindfulness is effective in relieving the psychosocial distress experienced by men with prostate cancer. A systematic review was conducted to synthesise the literature on MBIs for psychological wellbeing and quality of life improvement in men with prostate cancer.

METHODS

Embase, CINAHL, MEDLINE, PsycINFO, PsycArticles and Web of Science were searched up to 7th November 2020. Included studies were assessed for quality using appropriate appraisal tools. Homogeneous study results were pooled in a meta-analysis while narrative synthesis was used to summarise the findings from heterogeneous results. Effect size was expressed as Cohen's d (95% confidence intervals) and statistical significance (p-value) was set at 0.05.

RESULTS

Four studies comprising three randomised trials and one non-randomised study met the inclusion criteria. MBIs for men with prostate cancer showed small to moderate effect for improving psychological outcomes. The pooled result of quality of life and post-traumatic growth in study participants showed moderate (d = -0.29 [-1.29, 0.71], p = 0.57) and large (d = 0.77 [-0.33,1.88], p = 0.000) effects, respectively.

CONCLUSION

MBI is potentially promising for psychological outcomes, quality of life and post-traumatic growth symptoms improvement in men with prostate cancer but recommendations cannot be made based on current evidence due to limited research and inadequate methodological rigour of published literature. Robust research is needed to draw a reliable conclusion about its sustained effect in men with advanced disease.

Prostate Cancer From a Sex and Gender Perspective: A Review

INTRODUCTION

Factors influencing patient behavior regarding risk of prostate cancer (PCa) and outcomes of PCa treatments are poorly understood. Similarly, how PCa treatments affect patient sexual function and sense of their masculinity has not been fully investigated. A better understanding of the relationship between sex and gender for patients with PCa could significantly improve their care and quality of life.

OBJECTIVES

To review how concerns about sex and gender influence men's attitudes toward PCa screening, diagnosis, and treatment. To explore how PCa influences sexual function and self-perceived masculine identity. To examine contexts for PSA screening for transgender individuals.

METHODS

We reviewed biomedical and sociological literature exploring the impact of PCa on patient sexual function and self-perceived masculinity using OVID, PubMed, and other databases. We similarly reviewed how masculine gender norms influence patient willingness to engage with PCa screening, diagnoses, and treatment.

RESULTS

Gender norms and sexual function concerns influence patient engagement in all aspects of PCa care. This includes PSA screening, digital rectal examinations, active surveillance, and androgen deprivation therapy (ADT) amongst others. ADT is particularly challenging to sexual function, self-esteem, and masculine identity. Our research suggests that sex and gender are not separate concepts, but rather tightly intertwined, particularly when dealing with the realities experienced by patients with PCa.

CONCLUSION

Interventions to help patients deal with the challenges of PCa and its treatment are likely to be most effective if they concurrently address patients' sexual needs and understanding of gender norms. PSA screening should be considered for transgender individuals who are at greater risk of cancer and on long-term hormone therapy. More research is needed on how concerns over sex and gender influence PCa screening, diagnosis, and treatment. There is also a need for long term data on the oncological outcomes of prolonged exposure to hormone therapy for patients who are transgender. Muermann MM, Wassersug RJ. Prostate Cancer From a Sex and Gender Perspective: A Review. Sex Med Rev 2021;XX:XXX-XXX.

Differences in the Psychological, Sexual, and Childhood Experiences Among Men with Extreme Interests in Voluntary Castration

Some genetic males seek voluntary castration. We designed a survey to compare the psychological, sexual, and childhood experiences for subgroups of men with extreme interest in castration. The survey was posted on the Eunuch Archive, an online platform for individuals interested in the topic. Data from 822 individuals were included in the analyses. Respondents were divided into four groups: Interested (claiming only an interest in castration topics), Fantasy (fantasize about castration sexually, but not desiring castration), Wannabe (considering being castrated in the future), and Castrated (already castrated). More individuals desiring castration (Wannabe and Castrated groups) claimed equal attraction to both sexes than individuals in the Interested group. The Interested group was more religious than the other groups, and the Fantasy group had lower sexual guilt than those with castration desire. All groups had similar psychological well-being and body image acceptance, despite the Castrated group having lower sexual functioning than the others. Childhood trauma was more common in those with castration desire than those without. The Interested group had a lower desire for castration, lower erotic attraction to castration, and pretended to be castrated at a younger age than the others. Childhood trauma and sexual guilt are common, but not limited, predictors for castration desire and erotic attraction to castration, respectively. In conclusion, childhood experiences, as well as psychological and sexual parameters, may vary in different subgroups of males with interests in castration.

Analysis of Brain Functions in Men with Prostate Cancer under Androgen Deprivation Therapy: A One-Year Longitudinal Study

The relationship between cognitive decline and androgen deprivation therapy (ADT) under luteinizing hormone-releasing hormone (LHRH) analogues is unclear, and there is a scarcity of longitudinal studies considering the interaction between cognition, depressive symptoms and sleep quality in men with prostate cancer (PCa) treated with ADT. This study aimed to determine if there were differences in the scores obtained in cognitive assessment, depressive symptoms, and sleep quality after one year of ADT and determine the interrelations between sleep, mood, and cognitive status. A prospective longitudinal observational study was designed, in which a cohort of men (mean age was 70.8 years) newly treated with androgen-deprivation therapy was assessed in the first six months of treatment and 12 months later. Analysis of cognitive function by the Mini-Mental State Examination (MMSE) scores indicated a significant (p < 0.05) increase after one year of treatment and by the Brief Scale for Cognitive Evaluation (BCog) scores indicated no changes in the scores before and after one year of treatment. Analysis of depressive symptoms with the Geriatric Depression Scale and sleep quality with the Athens Insomnia Scale (AIS) scores showed significant (p < 0.05) changes after one year of treatment with ADT, with men describing more depressive symptoms and more sleep disturbances. No statistically significant differences were found in the cognitive performance between men with impaired sleep or depression results and those without them. Our study showed no clinical evidence of the relationship between ADT under luteinizing hormone-releasing hormone (LHRH) analogues and cognitive deterioration in 1-year follow-up, but there are impairments in the sleep quality in men with PCa undergoing ADT and an increase in depressive symptoms which has important implications for clinicians as they would impair quality of life and adherence to treatment.

A review of the use of time-varying covariates in the Fine-Gray subdistribution hazard competing risk regression model

In survival analysis, time‐varying covariates are covariates whose value can change during follow‐up. Outcomes in medical research are frequently subject to competing risks (events precluding the occurrence of the primary outcome). We review the types of time‐varying covariates and highlight the effect of their inclusion in the subdistribution hazard model. External time‐dependent covariates are external to the subject, can effect the failure process, but are not otherwise involved in the failure mechanism. Internal time‐varying covariates are measured on the subject, can effect the failure process directly, and may also be impacted by the failure mechanism. In the absence of competing risks, a consequence of including internal time‐dependent covariates in the Cox model is that one cannot estimate the survival function or the effect of covariates on the survival function. In the presence of competing risks, the inclusion of internal time‐varying covariates in a subdistribution hazard model results in the loss of the ability to estimate the cumulative incidence function (CIF) or the effect of covariates on the CIF. Furthermore, the definition of the risk set for the subdistribution hazard function can make defining internal time‐varying covariates difficult or impossible. We conducted a review of the use of time‐varying covariates in subdistribution hazard models in articles published in the medical literature in 2015 and in the first 5 months of 2019. Seven percent of articles published included a time‐varying covariate. Several inappropriately described a time‐varying covariate as having an association with the risk of the outcome.