Group-based trajectory modeling of fear of disease recurrence among women recently diagnosed with gynecological cancers

Group-based trajectory modeling for fear of cancer recurrence in cancer survivors: a systematic review

PURPOSE

We aimed to systematically review studies that used a group-based trajectory modeling approach to explore the categories of fear of cancer recurrence (FCR) trajectories and their predictors in cancer survivors.

METHODS

MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science were searched. Three authors independently reviewed the literature for predefined eligibility criteria. The Joanna Briggs Institute critical appraisal tools for Cohort Studies and the Guidelines for Reporting on Latent Trajectory Studies were used to assess the quality of included studies. A qualitative synthesis of the included studies was performed.

RESULTS

Ninety-eight studies were retrieved after removing duplicates, and 11 studies met the criteria for inclusion. There are four types of FCR trajectories: stable, decreasing, increasing, and stable-then-decreasing-then-increasing. The following factors were considered significant predictors of FCR trajectory category in at least one of the included studies: age, race, income, education, employment, cancer stage, physical symptoms, depression, anxiety, satisfaction with medical care, and selected cognitive and behavioral factors.

CONCLUSIONS

There was considerable heterogeneity among the studies included in study design and FCR trajectory results. Factors that significantly predicted FCR trajectory categories mostly focused on psychological characteristics. The correlation of sociodemographic and disease-related predictors with FCR trajectory categories was not consistent among the included studies.

IMPLICATIONS FOR CANCER SURVIVORS

We suggest that future scholars should incorporate more psychological factors when identifying cancer survivors who persistently maintain a high level of FCR and developing FCR mitigation measures.

Impact of fear of recurrence in patients with cancer on caregivers' psychological health: A meta-analysis

Objective

This study aims to quantitatively investigate the relationship between fear of cancer recurrence in patients with cancer and their caregivers' psychological health, examining the extent of the impact of this fear on caregivers.

Methods

We conducted a comprehensive search in PubMed, EMBASE, Cochrane Library, Web of Science, CINAHL, and PsycINFO databases from inception until May 2023 for relevant English publications. Pearson correlation coefficients (r) were utilized as effect sizes to assess the overall relationship between fear of recurrence and psychological outcomes among caregivers of patients with cancer.

Results

A total of 19 eligible studies were included in the analysis. The findings revealed a moderate positive correlation between fear of recurrence in patients with cancer and caregivers' fear of recurrence and depression. A relatively weaker correlation was observed between patients' fear of recurrence and caregivers' anxiety. Due to considerable heterogeneity (I2 ​= ​91.99%, Q ​= ​212.23), the primary outcome of fear of recurrence in patients with cancer influencing caregivers' fear of recurrence was examined through subgroup analyses.

Conclusions

Our meta-analysis established a significant positive correlation between fear of recurrence in patients with cancer and negative psychological consequences among caregivers, including recurrence fear, depression, and anxiety. Future research should explore the evolution of adverse psychological outcomes in both patients with cancer and their caregivers over time and delve into the bivariate psychological impact within the patient-caregiver dyads.

Systematic review registration

PROSPERO, CRD42022383866.

A prospective study of psychological distress among patients with advanced cancer and their caregivers

BACKGROUND

Cancer can impact the psychological well-being of both patients and their informal caregivers. We investigated the joint trajectories of psychological distress among Singaporean advanced cancer patients-caregiver dyads. We also examined predictors of trajectory group membership.

METHODS

This study utilised data from 299 patients with advanced solid cancer and their caregivers over 33 months (12 times points). Group-based trajectory modelling was used to examine the joint trajectories of patient anxiety, patient depression, caregiver anxiety and caregiver depression scores using the Hospital Anxiety and Depression Scale.

RESULTS

Four joint trajectory groups were found: (1) Patient-caregiver low distress (27%), (2) patient-caregiver increasing distress (28.5%), (3) patient low- caregiver borderline distress (25%), (4) patient-caregiver high distress (19.5%). Dyads where the patient is below 50 years of age were more likely to be in Group 4. Dyads where caregiver-patient emotional closeness was low were more likely to be in Groups 2 or 4 where dyads reported increasing/high distress. Dyads that reported financial inadequacy were more likely to be in Groups 2, 3 and 4, while dyads with caregivers who were employed were more likely to be in group 3.

CONCLUSIONS

A substantial proportion of patients and caregivers reported anxiety and/or depression that lasted or increased throughout the study duration. We found significant heterogeneity in how dyads experienced psychological distress, suggesting that efforts should consider dyadic differences when providing psychological support. Particular focus should be placed on identifying dyads that are at risk and who require additional support.

Predictors and trajectories of fear of cancer recurrence in Chinese breast cancer patients

OBJECTIVE

Fear of cancer recurrence (FCR) is one of the most common and aversive psychological phenomena among cancer patients. This study explored the trajectories of FCR over the 18 months following discharge, and evaluated the associations between baseline demographic and clinical variables and FCR trajectories among Chinese women treated for breast cancer.

METHODS

This is a longitudinal prospective study. All participants were asked to completed a battery of questionnaires (FCR-7, PHQ-9, GAD-7 and MPQ-VAS) at baseline, 6, 12, and 18 months after discharge. Generalized linear mixed model and group-based trajectory analyses were conducted.

RESULTS

Three hundred women with breast cancer were recruited. Latent class growth modeling analysis showed that three-group trajectory solution was the best fitting (i.e., 'intermediate level-stable group' (63.3%), 'low level-increasing group' (18.3%), and 'high level-decreasing group' (18.3%). Patients reported significant higher FCR at baseline assessment compared to other time points. Significant positive associations were found between anxiety, depression and FCR. Patients who had no baseline depression (estimate = -2.14, 95% CI: -2.78-(-1.51), P < 0.001) or anxiety (estimate = -2.77, 95% CI: -3.44-(-2.10), P < 0.001) tended to report significant lower FCRs over time. Women with none/mild life stress exhibited significant lower FCRs than those with moderate/high life stress, and participants with a family history of cancer or pessimism reported higher FCRs.

CONCLUSION

>60% of the breast cancer women showed intermediate level-stable FCRs over the 18 months after discharge. Baseline anxiety, depression, life stress, family cancer history and pessimism predicts higher FCR levels. Clinical teams responsible for continuing patient care following treatment should develop clearer strategies for management of FCR.

Trajectories of distress in women with gynaecological cancer treated with curative-intent radiotherapy

OBJECTIVE

The aims of this study were to investigate trajectories of anxiety and depression symptoms among gynaecological cancer (GC) patients having curative-intent radiotherapy (RT) treatment and identify which patient characteristics predict anxiety and depression trajectories.

METHODS AND MEASURES

Latent profile analysis (LPA) was used to identify unique trajectories of anxiety and depression symptoms, spanning prior to the start of RT until 12-month post-RT, among 151 GC patients in the PeNTAGOn randomized control trial. Demographic and clinical characteristics were assessed at baseline, and anxiety and depression symptoms were assessed five times over 12 months. A bias-adjusted 3-step maximum likelihood approach was used to identify demographic and clinical predictors of trajectory profiles.

RESULTS

Four latent profiles each were identified for anxiety and depression trajectories. Most patients had minimal to mild levels of anxiety or depression that remained steady or declined over 12 months following treatment. A minority of patients were in profiles that exhibited clinically significant distress; either 'High fluctuating' anxiety or 'Mild-moderate fluctuating' depression. Anxiety and depression profiles were predicted by clinical and demographic factors, such as age, living arrangements, RT type, cancer stage, physical symptom distress and use of support services.

CONCLUSIONS

Psychological care of patients in the higher distress trajectories is paramount and, importantly, they could be identified prior to treatment based on the factors identified. Review for at least a month post-RT is warranted.

Introducing FCR 6 – Brain: Measuring Fear of Cancer Recurrence in Brain Tumor Patients and Their Caregivers

Background

Fear of cancer recurrence (FCR) is a psychological consequence of cancer diagnosis that impacts quality of life in neuro-oncology. However, the instruments used to assess FCR have not been tested for validity in patients with brain tumors. The present study explored the psychometric properties of a brief FCR scale in patients with primary brain tumor (PBT) and their caregivers.

Methods

Adult patients with PBT (n = 165) and their caregivers (n = 117) completed the FCR–7-item scale (FCR7) and measures of psychological functioning. Exploratory factor analyses (EFA) were conducted for both patient and caregiver FCR7. Convergent validity, prevalence, the difference between FCR in patients and caregivers, and relationships with relevant medical and demographic variables were explored.

Results

EFAs revealed a single factor with one item demonstrating poor loading for both patients and caregivers. Removal of the item measuring hypervigilance symptoms (checking for physical signs of tumor) greatly improved the single factor metrics. The amended scale (FCR6-Brain) demonstrated good convergent validity. Caregiver FCR was significantly higher than patient. Clinical guidance to identify clinically significant FCR was introduced. Age, gender, and time since diagnosis were related to FCR, with higher FCR in younger women more recently diagnosed.

Conclusions

The FCR6-Brain is the first validated instrument to assess FCR in this population and should be used to identify individuals at risk for FCR and guide development of future psychotherapeutic interventions. This study highlights the distinct characteristics of FCR in neuro-oncology. Symptoms of hypervigilance in PBT patients need further investigation.

Change in worry over time among Hispanic women with thyroid cancer

PURPOSE

The purpose of this study is to assess change in worry over time in Hispanic women with thyroid cancer.

METHODS

Worry about recurrence, quality of life, family at risk, death, and harm from treatments was assessed in 273 Hispanic women with thyroid cancer diagnosed in 2014-2015. Subjects were recruited from Surveillance, Epidemiology, and End Results (SEER) Los Angeles. Participants were surveyed at two points in time (time 1: 2017-2018 and time 2: 2019). Multivariable logistic regression was used to determine correlates with high worry (somewhat, quite a bit, very much) versus low worry (not at all, a little) at time 2.

RESULTS

For the five worry items, 20.1-39.6% had high worry at both time 1 and time 2. An additional 7.6-13.4% had low worry at time 1 that became high worry at time 2. In multivariable logistic regression controlling for age, recurrence status, education level, and number of complications or side effects symptoms, younger age (20-39) as compared to older (40-79) was associated with high worry about thyroid cancer recurrence (OR 2.16, 95% CI 1.12-4.17). History of recurrent or persistent disease was associated with high worry about harms from treatment (OR 2.94, 95% CI 1.29-6.67). Greater number of complications or side effects of symptoms was associated with more worry across all five items.

CONCLUSIONS

Some Hispanic women with thyroid cancer have persistently high worry, with young adult Hispanic women vulnerable to worry about recurrence.

IMPLICATIONS FOR CANCER SURVIVORS

Hispanic women with thyroid cancer may benefit from targeted psychosocial support during survivorship, with interventions informed by patient and cancer characteristics.

Longitudinal patterns in fear of cancer progression in patients with rare, advanced cancers undergoing comprehensive tumour genomic profiling

INTRODUCTION

Fear of cancer progression (FCP) impacts quality of life and is a prevalent unmet need in patients diagnosed with advanced cancer, particularly as treatment options are reduced. We aimed to identify longitudinal patterns in FCP over 6 months in patients with advanced cancer receiving comprehensive tumour genomic profiling (CTGP) results, and their correlates.

METHODS

Patients with pathologically confirmed metastatic disease (∼70% rare cancers) receiving or post their last line of standard therapy completed questionnaires at T0 (prior to CTGP), T1 (immediately post CTGP results) and T2 (2 months later).

RESULTS

High stable (N = 52; 7.3%) and low/moderate stable (N = 56; 7.8%) FCP patterns over time typified the largest participant groups (N = 721). Those with an immediately actionable variant versus a non-actionable variant (p = 0.045), with higher FCP (p < 0.001), and lower Functional Assessment of Chronic Illness Therapy-Spiritual Well-being (FACIT-Sp) scores (p = 0.006) at T0, had higher FCP at T1. Those with higher FCP at T0 (p < 0.001) and at T1 (p < 0.001), lower FACIT-Sp scores at T1 (p = 0.001), lower education (p = 0.031) and female gender (p = 0.027) had higher FCP at T2.

DISCUSSION

Routine screening for psychological/spiritual characteristics in those about to undergo CTGP may help to identify patients who may benefit from closer monitoring and provision of psychosocial support. Future studies should explore interventions to best address FCP in this vulnerable group, as interventions assessed to date have almost all addressed patients with curative cancers or newly diagnosed advanced disease.

Examining fear of cancer recurrence in primary brain tumor patients and their caregivers using the Actor-Partner Interdependence Model

OBJECTIVE

Fear of cancer recurrence (FCR) is related to psychological distress and poor quality of life in cancer patients and their caregivers. However, no studies have investigated FCR in neuro-oncology. Given the varied prognosis, treatment, and disease trajectory of brain cancer, FCR may affect patients and their caregivers differently.

METHODS

Eighty adult primary brain tumor (PBT) patients and 52 caregivers completed questionnaires assessing FCR and psychological distress (depressive symptoms, generalized anxiety, and death anxiety). Differences in patient and caregiver FCR by demographic and medical characteristics were examined. Using multilevel modeling, the Actor-Partner Interdependence Model (APIM) was used to investigate the interrelationship between patient and caregiver FCR with demographics and psychological distress measures.

RESULTS

Caregivers reported significantly higher FCR than patients. There were no effects of demographic or medical characteristics on patient FCR. Time since diagnosis was negatively related to caregiver FCR. All measures of psychological distress exerted a significant actor effect on FCR among both patients and caregivers. Two partner effects were found: caregiver depressive symptoms and death anxiety negatively predicted patients' FCR.

CONCLUSIONS

This is the first investigation of FCR in PBT patients and their caregivers. Most demographic and medical characteristics were not related to patient or caregiver FCR. Caregiver FCR may be higher at the time of diagnosis and decrease over time. APIMs revealed actor effects on patient and caregiver FCR for all measures of psychological distress. Results demonstrated the dyadic effects of a brain tumor diagnosis, emphasizing the need to include caregivers in psychotherapy for neuro-oncology patients.

Individual courses and determinants of fear of cancer recurrence in long-term breast cancer survivors with and without recurrence

Objective

This study investigated the prevalence, individual courses, and determinants of fear of cancer recurrence (FoR) in long-term breast cancer survivors (BCSs) with and without recurrence.

Methods

A total of 184 breast cancer survivors were surveyed at four measurement time points: during hospitalization (T1), 10 weeks (T2), 40 weeks (T3), and 5–6 years (T4) after hospital discharge. Descriptive statistics, chi-square tests, and logistic regression were performed.

Results

Respondents were females and 57 years old, on average. At T1, T3, and T4, 54.8%, 31.6%, and 29.7% of BCSs, respectively, were classified as having dysfunctional levels of FoR. Dysfunctional FoR decreased from T1 to T3 (χ²(1) = 17.11, p = 0.000; N = 163) and remained stable afterwards. Eight subgroups of individual courses of FoR over time could be described: (1) constant functional FoR; (2) constant dysfunctional FoR; (3) improving from dysfunctional to functional FoR from T1 to T3; (4) improving from dysfunctional to functional FoR from T3 to T4; (5) worsening from functional to dysfunctional FoR from T1 to T3; (6) worsening from functional to dysfunctional FoR from T3 to T4; (7) dysfunctional FoR at T1 and T4, and functional FoR in between; and (8) functional FoR at T1 and T4, and dysfunctional FoR in between. Logistic regression analysis revealed that being divorced/widowed, showing high levels of fatigue, being treated by chemotherapy, and having low confidence in treatment were associated with dysfunctional FoR 5 to 6 years after diagnosis (Nagelkerkes’ Pseudo-R2 = 0.648).

Conclusions

The findings reveal that FoR is a significant issue in long-term BCSs and has the potential to become a persistent psychological strain. We emphasize the need for increased awareness of FoR among BCSs and the need for support programs.

Health anxiety and illness-related fears across diverse chronic illnesses: A systematic review on conceptualization, measurement, prevalence, course, and correlates

BACKGROUND

Patients with chronic diseases commonly report fears of illness or symptoms recurring or worsening. These fears have been addressed from an illness-specific perspective (e.g., fear of cancer recurrence), a generic illness perspective (e.g., fear of progression), and a psychiatric perspective (DSM-5 illness anxiety disorder and somatic symptom disorder). The broader concept of health anxiety (HA) can also be applied to patients with a chronic disease. This review was conducted to investigate the conceptual, theoretical, measurement-overlap, and differences between these distinct perspectives. We also aimed to summarize prevalence, course, and correlates of these fears in different chronic illnesses.

METHODS

We used PsycINFO, PubMED, CINAHL, Web of Science, SCOPUS, and PSYNDEX to conduct a systematic review of studies pertaining to these fears in chronic illness published from January 1996 to October 2017. A total of 401 articles were retained.

RESULTS

There were commonalities across different conceptualizations and diseases: a high prevalence of clinical levels of fears (>20%), a stable course over time, and a deleterious impact on quality of life. Reviewed studies used definitions, models, and measures that were illness-specific, with only a minority employing a psychiatric perspective, limiting cross-disease generalizability. There appears to be some applicability of DSM-5 disorders to the experience of fear of illness/symptoms in patients with a chronic illness. While conceptualizing HA on a continuum ranging from mild and transient to severe may be appropriate, there is a lack of agreement about when the level of fear becomes 'excessive.' The definitions, models, and measures of HA across chronic illnesses involve affective, cognitive, behavioral, and perceptual features.

CONCLUSIONS

The concept of HA may offer a unifying conceptual perspective on the fears of illness/symptoms worsening or returning commonly experienced by those with chronic disease.

The role of metacognition and its indirect effect through cognitive attentional syndrome on fear of cancer recurrence trajectories: A longitudinal study

OBJECTIVE

This longitudinal study mapped distinct trajectories of fear of cancer recurrence (FCR) over 12 months among patients with breast (BC) or colorectal (CRC) cancer, and examined if metacognition, indirectly via attentional bias, intrusive thoughts and avoidance (hallmarks of cognitive attentional syndrome; CAS) predicted FCR trajectory membership.

METHODS

Two hundred and seventy BC (n = 163) or CRC (n = 107) patients were assessed at 8-weeks, 3-, 6-, and 12-months postsurgery on a measure of FCR (FCRI-SF). Metacognition (MCQ-30), Intrusive and Avoidant Thoughts (CIES-R) and attentional bias (dot-probe tasks) were assessed at baseline. Latent growth mixture modeling identified FCR trajectories. Fully-adjusted Multinomial Logistic Regression identified whether direct and indirect effects of metacognition through CAS determined FCR trajectory membership.

RESULTS

Three distinct FCR trajectories were identified, namely, low-stable (62.4%), high-stable (29.2%), and recovery (8.3%). Negative beliefs about worry, cognitive confidence, and age predicted FCR trajectories (χ² (6) = 38.31, P<.001). Compared with Low-stable group, Recovery FCR patients held greater Negative beliefs about worry (OR = 1.13, P = .035) and High-stable FCR patients reported poorer Cognitive confidence (OR = 1.12, P = .004). The effect of Negative beliefs about worry was partially mediated by avoidance (β = .06, 95% CIs 0.03-0.12) and fully mediated by intrusive thoughts (β = .14, 95% CIs 0.08-0.20). Attentional bias did not predict FCR trajectories.

CONCLUSIONS

While most patients experienced low level of FCR, 3 in 10 persistently worried about cancer returning over the first 12-months postsurgery. Modifying metacognitive knowledge to interrupt maladaptive cognitive processing including intrusion and avoidance may be an effective therapeutic intervention for patients at risk of persistent FCR.

Longitudinal course and predictors of communication and affect management self-efficacy among women newly diagnosed with gynecological cancers

OBJECTIVE

Self-efficacy is an important psychological resource to assist people in managing chronic illness and has been associated with psychological outcomes among patients coping with cancer. Little is known about the course of self-efficacy among gynecological cancer patients coping with cancer and the sociodemographic, medical, and psychological factors that are associated with the course of self-efficacy among these patients.

METHODS

One hundred twenty-five women recently diagnosed with gynecological cancer completed a measure of communication and affective management self-efficacy at baseline, 5 weeks, 9 weeks, 6 months, 1 year, and 18 months post-baseline. Participants also completed measures of functional impairment, holding back, perceived unsupportive behaviors of family and friends, emotional expressivity, cancer concerns, depressive symptoms, cancer-specific intrusions and avoidance, problem-solving, and positive reappraisal coping.

RESULTS

Growth curve modeling suggested that women varied considerably in their average reports of self-efficacy and varied with regard to their linear trajectories of self-efficacy over time. Average affect management self-efficacy increased significantly over time. Greater functional impairment, more holding back, more unsupportive responses from friends and family, less emotional expressivity, more cancer concerns, depression, intrusions, or avoidance predicted lower average self-efficacy over time. Women who were less emotionally expressive or held back sharing concerns less reported lower self-efficacy which increased over time.

CONCLUSIONS

It will be important for providers to identify gynecological cancer patients who report low ability to communicate feelings and needs and manage emotional reactions to cancer and offer them interventions which bolster self-efficacy.

The fear of cancer recurrence literature continues to move forward: a review article

PURPOSE OF REVIEW

The volume of literature addressing fear of cancer recurrence (FCR) is rapidly increasing. A summary of key developments in the research and treatment of FCR was published by Sharpe et al. in 2017, and the current review focuses on works published thereafter.

RECENT FINDINGS

A comprehensive literature review was conducted to provide an up-to-date summary of peer-reviewed publications focusing on FCR. The search consisted of the most recent FCR reports published between 2016 and 2017, which can be broadly categorized as: methods of assessment; associations with FCR; FCR and caregivers; and FCR interventions.

SUMMARY

FCR assessments continue to undergo revisions, which may have positive implications for clinicians and researchers seeking shorter measures to assess the FCR of their patients and study participants. However, research is needed to determine if a shorter FCR measure could be created using items that measure the construct alone, yet still retaining optimal sensitivity and specificity, or also with its determinants and consequences. Doing so would result in either unidimensional or multidimensional measure of FCR. Notwithstanding these matters in FCR assessment, the state of the literature continues to advance our understanding about characteristics of survivors with highest FCR, which is useful to identify patients in need of FCR interventions. These empirical results are useful to further investigate the theoretical distinctions of FCR.

Fear of cancer recurrence in adolescent and young adult cancer survivors: A systematic review of the literature

OBJECTIVE

The current systematic review aims to provide an overview of fear of cancer recurrence (FCR) in adolescent and young adult cancer survivors (15-39 years at cancer diagnosis, AYAs).

METHODS

MEDLINE, PubMed, PsycINFO, and Embase databases were independently searched to identify relevant quantitative articles. PRISMA systematic review procedures were followed with quality assessment.

RESULTS

Seventeen studies were included in the current review. All were quantitative studies that utilized a cross-sectional study design. Seven articles reported results of FCR prevalence, six studied determinants related to FCR, and 11 articles provided information about consequences of FCR. Prevalence of FCR ranged from 31% to 85.2% among AYA survivors. Associations between sociodemographic/clinical variables and FCR were inconsistent. Psychological distress and higher treatment intensity were positively associated with higher FCR levels. Lower scores on levels of physical, psychological functioning, and overall health-related quality of life (QoL) were identified as consequences of increased FCR.

CONCLUSION

FCR appears to be a prevalent concern among adolescent and young adult cancer populations. Adequate assessment to determine need for support and intervention is still required. Longitudinal studies in AYAs are warranted to understand the development and potential influence of FCR. Age-appropriate and flexible psychological care would be more successful potentially with this crucial background information.

Fear of cancer recurrence trajectory during radiation treatment and follow-up into survivorship of patients with breast cancer

BACKGROUND

Fear of cancer recurrence (FCR) has been shown to be higher in patients treated with external beam radiotherapy (RT) compared to those untreated. However, little is known about the dynamics of patient's FCR during and after RT. The aim of this study was to examine FCR levels in a longitudinal panel design with breast cancer patients receiving RT.

METHODS

Consecutive newly-diagnosed breast cancer patients (n = 94) attending a single cancer centre were invited to complete a 7-item FCR scale (FCR7) that was collected weekly by paper instrument and at a follow-up phone call 6-8 weeks after completion of RT. Descriptive statistics, and Latent Growth Curve Modelling (LGCM) were utilised to analyse the data.

RESULTS

Women who were younger, single/separated, had chemotherapy, had extra boost radiation treatment, taking Herceptin and treated by 4-field technique reported higher recurrence fear at baseline. There was strong evidence of substantial variation in the trajectory of FCR (z = - 3.54, p < .0001). The average trajectory of FCR over RT was negative (unstandardized estimate = - 0.59) and associated with FCR follow-up level (standardised estimate = 0.36, z = 3.05, p < .002), independent of baseline recurrence fears.

CONCLUSION

Patients vary in their trajectory of recurrence fears over RT which predicts FCR approximately 2 months following treatment. Review appointments by therapy radiographers presents an opportunity to intervene in FCR trajectories.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02599506 . Prospectively registered on 11th March 2015.