Obstructive sleep apnea and temporal changes in cardiac repolarization in patients undergoing coronary artery bypass grafting

STUDY OBJECTIVES

In coronary artery bypass grafting (CABG), abnormal cardiac repolarization is associated with adverse cardiovascular events that can be measured via the QTc interval. We investigated the impact of obstructive sleep apnea on the change in repolarization after CABG and the association of change in repolarization with the occurrence of major adverse cardiac and cerebrovascular events.

METHODS

A total of 1,007 patients from 4 hospitals underwent an overnight sleep study prior to a nonemergent CABG. Electrocardiograms of 954 patients (median age: 62 years; male: 86%; mean follow-up: 2.1 years) were acquired prospectively within 48 hours before CABG (T1) and within 24 hours after CABG (T2). QTc intervals were measured using the BRAVO algorithm by Analyzing Medical Parameters for Solutions LLC. The change in T2 from T1 for QTc (ΔQTc) was derived, and Cox regression was performed.

RESULTS

Compared with those without, patients who developed major adverse cardiac and cerebrovascular events (n = 115) were older and had (1) a higher prevalence of smoking, hypertension, diabetes mellitus, and chronic kidney disease; (2) a higher apnea-hypopnea index and oxygen desaturation index; and (3) a smaller ΔQTc. Cox regression analysis demonstrated a smaller ΔQTc to be an independent risk factor for major adverse cardiac and cerebrovascular events (hazard ratio: 0.997; P = .032). In the multivariable regression model, a higher oxygen desaturation index was independently associated with a smaller ΔQTc (correlation coefficient: -0.58; P < .001).

CONCLUSIONS

A higher preoperative oxygen desaturation index was an independent predictor of a smaller ΔQTc. ΔQTc within 24 hours after CABG could be a novel predictor of occurrence of major adverse cardiac and cerebrovascular events at medium-term follow-up.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Undiagnosed Sleep Apnea and Bypass OperaTion (SABOT); URL: https://classic.clinicaltrials.gov/ct2/show/NCT02701504; Identifier: NCT02701504.

CITATION

Teo YH, Yong CL, Ou YH, et al. Obstructive sleep apnea and temporal changes in cardiac repolarization in patients undergoing coronary artery bypass grafting. J Clin Sleep Med. 2024;20(1):49-55.

Sleep apnea and temporal changes in cardiac repolarization in patients undergoing coronary artery bypass grafting

Background

In coronary artery bypass grafting (CABG), despite re-establishing coronary reperfusion, myocardial recovery and restoration of contractility often occur later, and the risk of adverse cardiovascular events persists during the post-CABG period. The occurrence of adverse cardiovascular events is linked to abnorm-al cardiac repolarisation that can be measured by surface electrocardiograms (ECGs). Sleep apnoea is an emerging cardiovascular risk factor. The relationship between sleep apnoea, abnorm-al cardiac repolarisation, and the occurrence of adverse cardiovascular events is not well studied.

Purpose

We investigated the impact of sleep apnoea on the change in repolarisation after CABG, and if the change in repolarisation is associated with the occurrence of major adverse cardiac and cerebrovascular events (MACCE).

Methods

Between November 2013 and December 2018, 1007 patients from 4 hospitals underwent an overnight sleep study prior to a non-emergent CABG. ECGs were acquired prospectively within 48h before the CABG (T1), and within 24h after the CABG (T2). QTc intervals were measured in three consecutive heart beats in one lead - the preferential lead measurements were lead II, followed by lead V5. QTc intervals were measured using the BRAVO algorithm by Analysing Medical Parameters for Solutions (AMPS) LLC. The change of T2 from T1 for QTc (ΔQTc) was derived. The mean follow-up duration was 2.1 years. MACCE was a composite of cardiovascular death, myocardial infarction, stroke, and unplanned revascularisation.

Results

A total of 954 patients (median age: 62 years; male: 86%) survived the initial 24 hours and had quality ECGs for analysis. Lead II and V5 were measured in 72% and 25% of the cohort, respectively. A total of 115 patients developed MACCE (MACCE group). Compared with the non-MACCE group, the MACCE group was older, had (a) a higher prevalence of smoking, hypertension, diabetes mellitus, and chronic kidney disease, (b) higher apnoea-hypopnoea index (AHI) and oxygen desaturation index (ODI), and (c) a smaller ΔQTc (Table). In Cox regression analysis, a smaller ΔQTc was independently associated with occurrence of MACCE (HR: 1.003; 95% CI: 1.000–1.006; p=0.032).

Older age, history of previous stroke, chronic kidney disease, more severe sleep apnoea (higher AHI, ODI, and severe oxygen desaturation) were associated with smaller ΔQTc. After adjusting for the effects of confounding variables, a higher ODI was independently associated with a smaller ΔQTc (correlation coefficient: −0.58; p&lt;0.001).

Conclusions

In patients undergoing a non-emergent CABG, a smaller ΔQTc during the first 24 hours after the CABG is associated with a higher incidence of MACCE. A higher pre-operative ODI based on a sleep study is an independent predictor of a smaller ΔQTc. This suggests that change in QTc within 24 hours after CABG could be due to sleep apnoea, and it is a novel predictor of occurrence of MACCE at medium term follow-up.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Transition Award and Clinician Scientist Award from the National Medical Research Council of Singapore (award numbers: NMRC/TA/012/2012; NMRC/CSA-INV/002/2015)

Sleep apnea and recurrent heart failure hospitalizations after coronary artery bypass grafting

STUDY OBJECTIVES

Sleep apnea is prevalent in patients undergoing coronary artery bypass grafting (CABG). We investigated the relationship between sleep apnea and recurrent heart failure hospitalizations in patient undergoing non-urgent CABG.

METHODS

Between November 2013 and December 2018, 1007 patients completed a sleep study prior to CABG and were followed up until April 2020. Recurrent heart failure hospitalizations were analyzed by Poisson, negative binomial, Andersen-Gill, and joint frailty models, with partial and full adjustment for covariates.

RESULTS

At an average follow-up of 3.3 years, the number of patients with 0, 1, or ≥2 heart failure hospitalizations were 908 (90.2%), 62 (6.2%), and 37 (3.7%), respectively. The total number of heart failure hospitalizations was 179, comprising 62 (35%) first and 117 (65%) repeat events. The numbers of heart failure hospitalizations for the sleep apnea (n = 513, 50.9%) and non-sleep apnea groups were 127 and 52, respectively. Negative binomial regression demonstrated that sleep apnea was associated with recurrent heart failure hospitalizations (fully adjusted rate ratio, 1.71; 95% confidence interval [CI], 1.12-2.62; p = 0.013). Similar results were found in Poisson (1.63; 95%CI, 1.15-2.31; p = 0.006), Andersen-Gill (1.66; 95% CI, 1.01-2.75; p = 0.047), and joint frailty models (1.72; 95% CI, 1.00-3.01; p = 0.056).

CONCLUSIONS

In patients after CABG, repeat events accounted for two-thirds of heart failure hospitalizations. Sleep apnea was independently associated with recurrent heart failure hospitalizations.

Cortical haemodynamic response during the verbal fluency task in patients with bipolar disorder and borderline personality disorder: a preliminary functional near-infrared spectroscopy study

BACKGROUND

Functional near-infrared spectroscopy (fNIRS) is an emerging neuroimaging modality that provides a direct and quantitative assessment of cortical haemodynamic response during a cognitive task. It may be used to identify neurophysiological differences between psychiatric disorders with overlapping symptoms, such as bipolar disorder (BD) and borderline personality disorder (BPD). Hence, this preliminary study aimed to compare the cerebral haemodynamic function of healthy controls (HC), patients with BD and patients with BPD.

METHODS

Twenty-seven participants (9 HCs, 9 patients with BD and 9 patients with BPD) matched for age, gender, ethnicity and education were recruited. Relative oxy-haemoglobin and deoxy-haemoglobin changes in the frontotemporal cortex was monitored with a 52-channel fNIRS system during a verbal fluency task (VFT). VFT performance, clinical history and symptom severity were also noted.

RESULTS

Compared to HCs, both patient groups had lower mean oxy-haemoglobin in the frontotemporal cortex during the VFT. Moreover, mean oxy-haemoglobin in the left inferior frontal region is markedly lower in patients with BPD compared to patients with BD. Task performance, clinical history and symptom severity were not associated with mean oxy-haemoglobin levels.

CONCLUSIONS

Prefrontal cortex activity is disrupted in patients with BD and BPD, but it is more extensive in BPD. These results provide further neurophysiological evidence for the separation of BPD from the bipolar spectrum. fNIRS could be a potential tool for assessing the frontal lobe function of patients who present with symptoms that are common to BD and BPD.

Efficacy of digital cognitive behavioural therapy for insomnia: a meta-analysis of randomised controlled trials

OBJECTIVES

Although cognitive behavioural therapy for insomnia (CBT-I) has been recommended the initial therapy for insomnia, its clinical usage remains limited due to the lack of therapists. Digital CBT-I (dCBT-I) can potentially circumvent this problem. This meta-analysis aims to evaluate the short-term and long-term efficacy of dCBT-I for adults with insomnia.

METHODS

Systematic search of PubMed, EMBASE, PsycINFO, and CENTRAL from inception till 5 March 2020 was conducted. Randomised controlled trials (RCTs) comparing dCBT-I with controls (wait-list/treatment-as-usual/online education) in adults with insomnia were eligible. The primary outcome was insomnia severity index (ISI) at post-intervention, short-term follow-up (ranging 4 weeks to 6 months) and 1-year follow-up. Mean differences were pooled using the random-effects model.

RESULTS

94 articles were assessed full-text independently by two team members and 33 studies were included in this meta-analysis. 4719 and 4645 participants were randomised to dCBT-I and control respectively. dCBT-I significantly reduces ISI at post-intervention with mean difference -5.00 (95% CI -5.68 to -4.33, p < 0.0001) (I² = 79%) compared to control. The improvements were sustained at short-term follow-up, -3.99 (95% CI -4.82 to -3.16, p < 0.0001) and 1-year follow-up, -3.48 (95% CI -4.21 to -2.76, p < 0.0001). Compared to dCBT-I, face-to-face CBT-I produced greater improvement in ISI, 3.07 (95% CI 1.18 to 4.95, p = 0.001). However, this was within the non-inferiority interval of 4 points on ISI.

CONCLUSION

This meta-analysis provides strong support for the effectiveness of dCBT-I in treating insomnia. dCBT-I has potential to revolutionise the delivery of CBT-I, improving the accessibility and availability of CBT-I content for insomnia patients worldwide.

Sleep apnoea and cardiovascular outcomes after coronary artery bypass grafting

OBJECTIVE

Patients with advanced coronary artery disease are referred for coronary artery bypass grafting (CABG) and it remains unknown if sleep apnoea is a risk marker. We evaluated the association between sleep apnoea and major adverse cardiac and cerebrovascular events (MACCE) in patients undergoing non-emergent CABG.

METHODS

This was a prospective cohort study conducted between November 2013 and December 2018. Patients from four public hospitals referred to a tertiary cardiac centre for non-emergent CABG were recruited for an overnight sleep study using a wrist-worn Watch-PAT 200 device prior to CABG.

RESULTS

Among the 1007 patients who completed the study, sleep apnoea (defined as apnoea-hypopnoea index ≥15 events per hour) was diagnosed in 513 patients (50.9%). Over a mean follow-up period of 2.1 years, 124 patients experienced the four-component MACCE (2-year cumulative incidence estimate, 11.3%). There was a total of 33 cardiac deaths (2.5%), 42 non-fatal myocardial infarctions (3.7%), 50 non-fatal strokes (4.9%) and 36 unplanned revascularisations (3.2%). The crude incidence of MACCE was higher in the sleep apnoea group than the non-sleep apnoea group (2-year estimate, 14.7% vs 7.8%; p=0.002). Sleep apnoea predicted the incidence of MACCE in unadjusted Cox regression analysis (HR 1.69; 95% CI 1.18 to 2.43), and remained statistically significant (adjusted HR 1.57; 95% CI 1.09 to 2.25), after adjustment for age, sex, body mass index, left ventricular ejection fraction, diabetes mellitus, hypertension, chronic kidney disease and excessive daytime sleepiness.

CONCLUSION

Sleep apnoea is independently associated with increased MACCE in patients undergoing CABG.

TRIAL REGISTRATION NUMBER

NCT02701504.

Cortical haemodynamic response measured by functional near infrared spectroscopy during a verbal fluency task in patients with major depression and borderline personality disorder

Background

Functional near infrared spectroscopy (fNIRS) provides a direct and quantitative assessment of cortical haemodynamic function during a cognitive task. This functional neuroimaging modality may be used to elucidate the pathophysiology of psychiatric disorders, and identify neurophysiological differences between co-occurring psychiatric disorders. However, fNIRS research on borderline personality disorder (BPD) has been limited. Hence, this study aimed to compare cerebral haemodynamic function in healthy controls (HC), patients with major depressive disorder (MDD) and patients with BPD.

Methods

fNIRS signals during a verbal fluency task designed for clinical assessment was recorded for all participants. Demographics, clinical history and symptom severity were also noted.

Findings

Compared to HCs (n = 31), both patient groups (MDD, n = 31; BPD, n = 31) displayed diminished haemodynamic response in the frontal, temporal and parietal cortices. Moreover, haemodynamic response in the right frontal cortex is markedly lower in patients with MDD compared to patients with BPD.

Interpretation

Normal cortical function in patients with BPD is disrupted, but not as extensively as in patients with MDD. These results provide further neurophysiological evidence for the distinction of patients with MDD from patients with BPD.

A systematic review and meta-analysis of randomized controlled trials of cognitive behavioral therapy for hemodialysis patients with depression

OBJECTIVE

The aim of this meta-analysis was to examine the efficacy of cognitive behavioral therapy (CBT) for hemodialysis patients with comorbid depression and to identify which other aspects, including anxiety and quality of life, can be improved through intervention.

METHODS

A systematic literature review was performed using multiple databases (PubMed, EMBase, PsycINFO, CENTRAL). The inclusion criteria included randomized controlled trials (RCTs) of CBT conducted in hemodialysis patients with depression. Study reporting quality was assessed with the Cochrane tool and Review Manager version 5.3 was used to obtain pooled results.

RESULTS

Eight RCTs, with a total sample size of 540 participants, met the inclusion criteria. Compared with control groups, the CBT groups had statistically significant improvements in depression (standardized mean differences [SMD] = -0.68, 95% confidence interval [CI] (-0.94 to -0.42), P < .001), anxiety (SMD = -0.99, 95%CI (-1.99 to 0.00), P = .05) and quality of life (SMD = 0.34, 95%CI (0.13 to 0.54), P < .001).

CONCLUSIONS

The results of this meta-analysis showed that CBT could have an effective role in reducing symptoms of depression and anxiety as well as improving quality of life in hemodialysis patients with comorbid depression.

Indices of Change, Expectations, and Popularity of Biological Treatments for Major Depressive Disorder between 1988 and 2017: A Scientometric Analysis

Background. Major Depressive Disorder (MDD) is the most common psychiatric disorder with high prevalence and disease burden. Biological treatments of MDD over the last several decades include a wide range of antidepressants and neurostimulation therapies. While recent meta-analyses have explored the efficacy and tolerability of antidepressants, the changing trends of biological treatments have not been evaluated. Our study measured the indices of change, expectations, and popularity of biological treatments of MDD between 1988 and 2017. Methods. We performed a scientometric analysis to identify all relevant publications related to biological treatments of MDD from 1988 to 2017. We searched the Web of Science websites for publications from 1 January 1988 to 31 December 2017. We included publications of fluoxetine, paroxetine, citalopram, sertraline, amitriptyline, fluvoxamine, escitalopram, venlafaxine, duloxetine, milnacipran, desvenlafaxine, levomilnacipran, clomipramine, nortriptyline, bupropion, trazodone, nefazodone, mirtazapine, agomelatine, vortioxetine, vilazodone, electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation (rTMS), vagus nerve stimulation (VNS), deep brain stimulation (DBS), and transcranial direct current stimulation (tDCS). We excluded grey literature, conference proceedings, books/book chapters, and publications with low quality as well as publications not related to medicine or human health. The primary outcomes assessed were indices of change, expectations, and popularity. Results. Of 489,496 publications identified, we included 355,116 publications in this scientometric analysis. For the index of change, fluoxetine, sertraline and ECT demonstrated a positive index of change in 6 consecutive periods. Other neurostimulation therapies including rTMS, VNS, DBS and tDCS had shown a positive index of change since 1998. We calculated the index of change of popularity index (PI), which indicates that from 2013 to 2017, the number of publications on tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) were reduced by 85.0% and 81.3% respectively, as compared with the period 2008–2012. For the index of expectation, fluoxetine and ECT showed the highest index of expectations in six consecutive periods and remained the highest in 2013–2017. For popularity, the three antidepressants with highest PI were fluoxetine (4.01), paroxetine (2.09), and sertraline (1.66); the three antidepressants with lowest PI were desvenlafaxine (0.08), vilazodone (0.04) and levomilnacipran (0.03). Among neurostimulation therapies, ECT has the highest PI (2.55), and tDCS the lowest PI (0.14). The PI of SSRI remained the highest among all biological treatments of MDD in 2013–2017. In contrast, the PI of ECT was reduced by approximately 50% during the period 2008 to2012 than that in the period 2013 to 2017. Conclusions. This scientometric analysis represents comprehensive evidence on the popularity and change in prospects of biological treatments for MDD from 1988 to 2017. The popularity of SSRI peaked between 1998 and 2002, when their efficacy, tolerability and safety profile allowed them to replace the TCAs and MAOIs. While the newer neurostimulation therapies are gaining momentum, the popularity of ECT has sustained.

Prevalence of Burnout in Medical and Surgical Residents: A Meta-Analysis

The burnout syndrome is characterized by emotional exhaustion, depersonalization, and reduced personal achievement. Uncertainty exists about the prevalence of burnout among medical and surgical residents. Associations between burnout and gender, age, specialty, and geographical location of training are unclear. In this meta-analysis, we aimed to quantitatively summarize the global prevalence rates of burnout among residents, by specialty and its contributing factors. We searched PubMed, PsycINFO, Embase, and Web of Science to identify studies that examined the prevalence of burnout among residents from various specialties and countries. The primary outcome assessed was the aggregate prevalence of burnout among all residents. The random effects model was used to calculate the aggregate prevalence, and heterogeneity was assessed by I² statistic and Cochran's Q statistic. We also performed meta-regression and subgroup analysis. The aggregate prevalence of burnout was 51.0% (95% CI: 45.0-57.0%, I² = 97%) in 22,778 residents. Meta-regression found that the mean age (β = 0.34, 95% CI: 0.28-0.40, p < 0.001) and the proportion of males (β = 0.4, 95% CI = 0.10-0.69, p = 0.009) were significant moderators. Subgroup analysis by specialty showed that radiology (77.16%, 95% CI: 5.99-99.45), neurology (71.93%, 95% CI: 65.78-77.39), and general surgery (58.39%, 95% CI: 45.72-70.04) were the top three specialties with the highest prevalence of burnout. In contrast, psychiatry (42.05%, 95% CI: 33.09-51.58), oncology (38.36%, 95% CI: 32.69-44.37), and family medicine (35.97%, 95% CI: 13.89-66.18) had the lowest prevalence of burnout. Subgroup analysis also found that the prevalence of burnout in several Asian countries was 57.18% (95% CI: 45.8-67.85); in several European countries it was 27.72% (95% CI: 17.4-41.11) and in North America it was 51.64% (46.96-56.28). Our findings suggest a high prevalence of burnout among medical and surgical residents. Older and male residents suffered more than their respective counterparts.

Prevalence of Depression among Migrants: A Systematic Review and Meta-Analysis

As the number of migrants worldwide increases, it is worthwhile to examine the extent to which depression has affected this group of often vulnerable individuals. The purpose of this systematic review and meta-analysis is to examine the aggregate prevalence of depression among international migrants and to explore the variations in prevalence with demographic and educational factors. A search was conducted on the online databases PubMed and ScienceDirect whole using the terms "depression", "depressive disorder", "immigration", "immigrant", "migration", and "migrant". A total of 25 studies met our inclusion criteria. A random-effects model meta-analysis calculated an aggregate prevalence of 15.6% among migrants. Heterogeneity was identified by meta-regression and subgroup analyses, and the level of educational attainment, employment status, and length of residency spent in country of migration were found to be significant moderators contributing to depression prevalence. In conclusion, newly arrived migrants appear to be susceptible to developing depression and it is imperative that more in the form of preventive strategies and increased assistance be incorporated to ensure their psychological wellbeing and improve their mental health outcomes. Further research should be conducted to better understand the risk of psychiatric disorders among members of this subpopulation.

The Effect of Methylphenidate and Atomoxetine on Heart Rate and Systolic Blood Pressure in Young People and Adults with Attention-Deficit Hyperactivity Disorder (ADHD): Systematic Review, Meta-Analysis, and Meta-Regression

Objectives: This meta-analysis aims to study the effects of atomoxetine and methylphenidate on heart rate (HR), systolic blood pressure (SBP), and a number of adverse cardiac events on patients receiving treatment for attention-deficit hyperactive disorder (ADHD) in comparison to placebo and between atomoxetine and methylphenidate. Methods: We searched the following databases: PubMed, EMBASE, and ScienceDirect. Meta-analysis was performed on studies that examined the relationships between methylphenidate or atomoxetine and HR, SBP, as well as a number of adverse cardiac events. These studies were either placebo-controlled or comparison studies between methylphenidate and atomoxetine. Meta-regression identified patient- and treatment-related factors that may contribute to heterogeneity. Results: Twenty-two studies were included and the total number of participants was 46,107. Children/adolescents and adults treated with methylphenidate had more significant increases in post- vs. pre-treatment HR (p < 0.001) and SBP (p < 0.001) than those treated by placebo. Children and adolescents treated with atomoxetine had more significant increases post- vs. pre-treatment HR (p = 0.025) and SBP (p < 0.001) than those treated with methylphenidate. Meta-regression revealed mean age of participants, mean dose, and duration of atomoxetine and methylphenidate as significant moderators that explained heterogeneity. There were no differences in the number of adverse cardiac events between participants with methylphenidate treatment and placebo or atomoxetine. Conclusions: Children/adolescents and adults treated with methylphenidate resulted in significant increases in post- vs. pre-treatment HR and SBP as compared to placebo. Similarly, children and adolescents treated with atomoxetine had significant increases in post- vs. pre-treatment HR and SBP than those treated with methylphenidate. These findings have potential implications for continuous monitoring of HR and SBP throughout the course of treatment although the risk for adverse cardiac events were insignificant.

IL-1β, IL-6, TNF- α and CRP in Elderly Patients with Depression or Alzheimer's disease: Systematic Review and Meta-Analysis

We carried out systematic review and meta-analysis to evaluate whether peripheral levels of pro-inflammatory markers including Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Tumor Necrosis Factor-α (TNF- α) and C-Reactive Protein (CRP) are significantly higher in elderly with depression and Alzheimer's disease. We searched Pubmed, PsycINFO and Embase, and thirty-four relevant studies (2609 with Depression, 1645 with Alzheimer's disease and 14363 Controls) were included. Compared with controls, IL-1β (pooled standardized mean difference [SMD]: 0.642; 95% confidence interval [CI]: 0.078-1.206; significant heterogeneity: I2 = 86.28%) and IL-6 (pooled SMD: 0.377; 95% CI: 0.156-0.598; significant heterogeneity: I2 = 88.75%) were significantly elevated in depression. There was no difference in TNF-α (p = 0.351) and CRP (p = 0.05) between those with depression and controls. Compared with controls, IL-1β (pooled SMD: 1.37, 95% CI: 0.06-2.68, significant heterogeneity: I2 = 96.01%) was significantly elevated in Alzheimer's disease. There were no differences in IL-6 (p = 0.138), TNF-α (p = 0.451) and CRP (p = 0.07) between elderly with Alzheimer's disease and controls. After Bonferroni adjustment, only IL-6 remained significantly higher in depression. Elderly with depression have higher IL-6 than controls, while those with Alzheimer's disease did not have higher peripheral inflammatory markers.

Prevalence of Depression in the Community from 30 Countries between 1994 and 2014

The prevalence of depression may be affected by changes in psychiatric practices and the availability of online mental health information in the past two decades. This study aimed to evaluate the aggregate prevalence of depression in communities from different countries between 1994 and 2014 and to explore the variations in prevalence stratified by geographical, methodological and socio-economic factors. A total of 90 studies were identified and met the inclusion criteria (n = 1,112,573 adults) with 68 studies on single point prevalence, 9 studies on one-year prevalence, and 13 studies on lifetime prevalence of depression. A random-effects model meta-analysis that was performed to calculate the aggregate point, one-year and lifetime prevalence of depression calculated prevalences of 12.9%, 7.2% and 10.8% respectively. Point prevalence of depression was significantly higher in women (14.4%), countries with a medium human development index (HDI) (29.2%), studies published from 2004 to 2014 (15.4%) and when using self-reporting instruments (17.3%) to assess depression. Heterogeneity was identified by meta-regression and subgroup analysis, and response rate, percentage of women and year of publication, respectively, were determined contribute to depression prevalence. This meta-analysis allows benchmarking of the prevalence of depression during the era when online health information emerged, facilitating future comparisons.

Mental health problems among medical students in Brazil: a systematic review and meta-analysis

Objective:

To provide a comprehensive picture of mental health problems (MHPs) in Brazilian medical students by documenting their prevalence and association with co-factors.

Methods:

We systematically searched the MEDLINE/PubMed, SciELO, LILACS, and PsycINFO databases for cross-sectional studies on the prevalence of MHPs among medical students in Brazil published before September 29, 2016. We pooled prevalences using a random-effects meta-analysis, and summarized factors associated with MHP.

Results:

We included 59 studies in the analysis. For meta-analyses, we identified the summary prevalence of different MHPs, including depression (25 studies, prevalence 30.6%), common mental disorders (13 studies, prevalence 31.5%), burnout (three studies, prevalence 13.1%), problematic alcohol use (three studies, prevalence 32.9%), stress (six studies, prevalence 49.9%), low sleep quality (four studies, prevalence 51.5%), excessive daytime sleepiness (four studies, prevalence 46.1%), and anxiety (six studies, prevalence 32.9%). Signs of lack of motivation, emotional support, and academic overload correlated with MHPs.

Conclusion:

Several MHPs are highly prevalent among future physicians in Brazil. Evidence-based interventions and psychosocial support are needed to promote mental health among Brazilian medical students.

Prevalence of depression amongst medical students: a meta-analysis

CONTEXT

Medical schools are known to be stressful environments for students and hence medical students have been believed to experience greater incidences of depression than others. We evaluated the global prevalence of depression amongst medical students, as well as epidemiological, psychological, educational and social factors in order to identify high-risk groups that may require targeted interventions.

METHODS

A systematic search was conducted in online databases for cross-sectional studies examining prevalences of depression among medical students. Studies were included only if they had used standardised and validated questionnaires to evaluate the prevalence of depression in a group of medical students. Random-effects models were used to calculate the aggregate prevalence and pooled odds ratios (ORs). Meta-regression was carried out when heterogeneity was high.

RESULTS

Findings for a total of 62 728 medical students and 1845 non-medical students were pooled across 77 studies and examined. Our analyses demonstrated a global prevalence of depression amongst medical students of 28.0% (95% confidence interval [CI] 24.2-32.1%). Female, Year 1, postgraduate and Middle Eastern medical students were more likely to be depressed, but the differences were not statistically significant. By year of study, Year 1 students had the highest rates of depression at 33.5% (95% CI 25.2-43.1%); rates of depression then gradually decreased to reach 20.5% (95% CI 13.2-30.5%) at Year 5. This trend represented a significant decline (B = - 0.324, p = 0.005). There was no significant difference in prevalences of depression between medical and non-medical students. The overall mean frequency of suicide ideation was 5.8% (95% CI 4.0-8.3%), but the mean proportion of depressed medical students who sought treatment was only 12.9% (95% CI 8.1-19.8%).

CONCLUSIONS

Depression affects almost one-third of medical students globally but treatment rates are relatively low. The current findings suggest that medical schools and health authorities should offer early detection and prevention programmes, and interventions for depression amongst medical students before graduation.

A meta-analysis of serum and cerebrospinal fluid autoantibodies in neuropsychiatric systemic lupus erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) is one of the most devastating presentations of SLE and comprises of psychiatric, central and peripheral neurological signs and symptoms. Previous studies suggest the possible associations between various autoantibodies (Abs) and NPSLE. The magnitudes of such association varied between studies. We performed a meta-analysis to pool data on serum and cerebrospinal fluid (CSF) levels and positivity of Abs in blood and cerebrospinal fluid in patients with NPSLE and SLE. A systematic literature search was conducted to identify studies that fulfilled inclusion criteria. A random-effects model was used to calculate overall combined odd ratio (OR) and mean levels with its corresponding 95% confidence interval to evaluate the relationship between individual Abs and NPSLE patients relative to SLE patients. Forty-one studies met the inclusion criteria and were used in this analysis. There was a significantly greater proportion of NPSLE patients who demonstrated positivity for serum anti-cardiolipin (aCL) Abs (OR=1.63, p=0.016), lupus anticoagulants (LA) Abs (OR=1.91 p=0.01), anti-phospholipid (APL) Abs (OR=2.08, p=0.001), anti-ribosomal P Abs (OR=2.29, p<0.001), anti-neuronal Abs (OR=9.50, p<0.001) as compared to SLE patients. In NPSLE patients, there was a significant increased prevalence of positive titres for CSF anti-neuronal Abs (OR=36.84, p=0.001) as compared to SLE patients. Among the 19 neuropsychiatric syndromes, the positivity of these serum autoantibodies were found specifically significantly associated with the manifestations of mood disorder, psychosis, cerebrovascular disease, seizure disorders, acute confusional state, cognitive dysfunction, headache, movement disorder, demyelinating syndrome and polyneuropathy, with ORs ranging from 1.84 to 4.73. Meta-regression identified proportion of women as significant moderator for the heterogeneity of aCL (p=0.004) and anti-neuronal Abs (p=0.0007); mean age for the heterogeneity of aCL (p=0.042) and LA (p=0.020) Abs, mean duration of illness for the heterogeneity of aCL Abs (p=0.035), and mean SLEDAI scores for the heterogeneity of anti-ribosomal P Abs (p=0.014). NPSLE patients are more likely to have elevated serum levels of aCL, LA, APL, anti-ribosomal P Abs and anti-neuronal Abs compared with SLE patients. Further research is required to evaluate the accuracy of using the above antibodies as an adjunct diagnostic tool in NPSLE.

Abstract 435: The Association Between Initial Antihypertensive Prescription Interval And Medication Adherence: A Cohort Study Among 203,259 Patients

Background: Optimal adherence with antihypertensive medications is crucial to prevent hypertension-related complications. This study evaluated whether the interval of initial antihypertensive prescriptions is associated with better medication adherence among hypertensive patients who received their first-ever antihypertensive agent.

Methods: From a validated clinical database of all patients in the public healthcare sector in Hong Kong, we included all patients who were newly prescribed an antihypertensive agent from 2001 to 2005. They were followed-up for 12 months, and optimal adherence was defined as having the Proportion of Days Covered (PDCs) ≥ 0.80. A binary logistic regression analysis was conducted to test the association between initial prescription interval and adherence level in the subsequent 12 months.

Results: From 203,259 eligible patients with an average age of 58.7 years (SD 17.3), the overall adherence rate was 32.4% [65,856/203,259]. The proportions of patients whose initial prescriptions lasted for ≤ 6 days; 7-14 days; 15-28 days and ≥ 29 days were 23.7%, 24.3%, 15.1% and 37.0%, respectively. After controlling for patients’ age, sex, socioeconomic status, service type, antihypertensive drug class, and district of residence, those whose initial prescription was 15-28 days (adjusted odds ratio [AOR]: 1.90, 95% C.I. 1.82-1.99, p<0.001) and ≥ 29 days (AOR=4.13, 95% C.I. 3.96-4.31, p<0.001) were significantly more likely to be adherent than those who were prescribed for ≤ 6 days.

Conclusions: These findings showed that short initial prescription interval was associated with poorer medication adherence, and this practice should be cautious.

Abstract 425: The Effectiveness Of Metoprolol Versus Atenolol On Prevention Of All-cause And Cardiovascular Mortality In A Large Chinese Population: A Cohort Study

Background: Existing trials almost exclusively used atenolol to represent the entire beta-blocker class. We compared the incidence of all-cause and cardiovascular (CVS) mortality, blood pressure (BP) control and adherence levels between patients newly prescribed atenolol vs. metoprolol.

Methods: This cohort study included all public, clinical settings in Hong Kong between 2001 and 2005, followed up till 2010. We compared outcomes between 22,479 new atenolol users and 29,972 new metoprolol users. The difference in mortality between drugs was evaluated by Cox proportional hazard regression models. Binary logistic regression analyses were used to compare the BP control rates and adherence levels.

Results: Among atenolol and metoprolol users, 7.0% (1,577 of 22,479) and 13.1% (3,940 of 29,972) died, respectively (p<0.005). The incidence of CVS mortality among atenolol users was lower than metoprolol users (1.4% vs. 3.7%, p<0.001). When compared with atenolol users, metoprolol users were 1.13-fold (95% C.I. 1.06-1.20) and 1.56-fold (95% C.I. 1.27-1.90), respectively, more likely to encounter all-cause and CVS mortality; less likely to be drug adherent (Adjusted Relative Risk [RR]: 0.95, 95% C.I.: 0.90-0.99, p=0.013); and less likely to achieve optimal overall BP control (RR 0.94, 95% C.I. 0.90-0.99, p=0.023) and diastolic BP control (RR 0.86, 95% C.I. 0.77-0.97, p=0.013).

Conclusions: These findings imply an intra-class difference for beta-blockers when used as first-line antihypertensive prescriptions in real-life clinical settings. More outcome studies on the effectiveness of different subtypes within other major antihypertensive drug classes are warranted.

Abstract 434: Exposure To Air Pollutants And Mortality In Hypertensive Patients According To Demography: A 10 Year Case-crossover Study

Background: Relatively few studies have explored the relationship between air pollution and cause-specific mortality among hypertensive patients. This study evaluated whether short term exposures to nitrogen dioxide (NO2), ozone (O3), particulate matter <10 mm in diameter (PM10) were associated with higher risk of mortality among a large hypertensive patients.

Methods: A total of 223,287 hypertensive patients who attended any public health-care services in Hong Kong and prescribed at least 1 antihypertensive agent for the first time between 2001 and 2005 were followed up until 2010. A time-stratified, bi-directional case-crossover design was adopted to study the association between environmental exposures and mortality outcomes.

Results: For all-cause mortality, significant positive associations were observed for NO2 and PM10 at lag 0 to 3 days per 10 MIUg/m3 increase in concentration and the excess risks ranged from 1.187%- 2.501%. Significant positive associations were found for O3 at lag 1 and 2 days and the excess risks were 1.654% (95% C.I. 0.469%, 2.852%) and 1.207% (95% C.I. 0.025%, 2.404%), respectively. We found similarly positive associations between NO2 (excess risks: 1.786%-2.798%), PM10 (1.126%-1.847%), O3 (3.035%-3.355%) and mortality due to respiratory disease. In stratified analysis, these significant results were observed amongst those aged >65 years and in cold seasons only.

Conclusions: Older hypertensive patients are susceptible to all-cause and respiratory disease-specific deaths from these air pollutants in cold weather. This implies urgent need for protective air pollution standards for this susceptible population.

The amino-terminal sequence of pro-opiomelanocortin directs intracellular targeting to the regulated secretory pathway

The molecular signal which targets the pro-opiomelanocortin (POMC) prohormone into the regulated secretory pathway was investigated. DNA sequences encoding the first 10, 26, 50, and 101 N-terminal amino acids of mouse POMC were fused in frame to the chloramphenicol acetyltransferase (CAT) gene and expressed in AtT-20 cells. Immunofluorescence microscopy using antibody directed against CAT indicated that fusion proteins carrying 26, 50 and 101 amino acids of N-POMC were directed to secretory granules. This finding was confirmed by secretion studies in which 1 microM forskolin stimulated the release of fusion proteins carrying 26 and 101 amino acids of N-POMC, whereas no regulated secretion was observed with the shortest fusion protein. Subcellular fractionation studies also indicated the presence of the fusion proteins with 26 and 101 amino acids of N-POMC in secretory granules. These results provide evidence that the signal directing POMC to secretory granules is contained within the N-terminus of the prohormone, with the first 26 amino acids being sufficient for targeting. Binding studies showed that N-POMC1-76 bound to secretory granule membranes specifically on the luminal side and in a pH-sensitive manner. Only N-POMC1-76 bound optimally to secretory granule membranes at pH 5 to 6.5, but not the ACTH1-39 (mid), corticotropin-like intermediate lobe peptide (CLIP) and beta-lipotropin (C-terminal) domains of POMC. Such binding may be involved in the mechanism of sorting POMC to the regulated secretory pathway.

Factors that determine medical student interest in psychiatry

Our study of pre-medical and medical students attending the Universities of British Columbia, Hong Kong and Otago, together with house surgeons, general practitioners, surgeons and psychiatrists in New Zealand, demonstrated many agreements regarding both positive and negative factors affecting their interest in psychiatry. Positive factors included: interest in human behaviour, personal aptitude, and quality of patient care. Negative factors included: the stress of practising psychiatry, faculty attitude and the quality of the science. Differences were determined by age of the students and cultural and personal experiences. We concluded that if more students are to be interested in psychiatry then psychiatrists will need to show that they enjoy their work and give effective treatment.

Production of pro-opiomelanocortin (POMC) by a vaccinia virus transient expression system and in vitro processing of the expressed prohormone by POMC-converting enzyme

Pro-opiomelanocortin (POMC) was expressed in CV-1 (green monkey kidney) cells using a vaccinia virus transient expression system [(1986) Proc. Natl. Acad. Sci. USA 83, 8122]. The system involved infection of cells with a recombinant vaccinia virus carrying the T7 RNA polymerase gene and transfection with a plasmid containing the mouse POMC sequence flanked by the T7 RNA polymerase promoter at its 5'-end and the T7 RNA polymerase terminator at its 3'-end. Assay of the medium from transfected cells showed that 1-2 micrograms of immunoreactive ACTH was produced/10(6) cells. Analysis of the same medium by SDS-PAGE/Western blots revealed a band of 30-36 kDa, which was immunostained with both ACTH and beta-endorphin antisera. Labeling the transfected cells with [3H]Arg, followed by immunoprecipitation and SDS-PAGE showed the synthesis of a major peak of POMC, 33 kDa. Purified [3H]POMC expressed by CV-1 cells was cleaved in vitro by bovine intermediate lobe secretory vesicle pro-opiomelanocortin-converting enzyme to ACTH intermediates (19-25 kDa), beta-lipotropin and beta-endorphin. Thus, this work has demonstrated a technique for expressing microgram quantities of prohormones in mammalian cells, suitable for use as substrates for prohormone-converting enzymes in vitro.

Association of newly synthesized pro-opiomelanocortin with secretory granule membranes in pituitary pars intermedia cells

The prohormone, pro-opiomelanocortin (POMC) is synthesized on ribosomes, subsequently routed to the Golgi apparatus and finally packaged into secretory granules where it is processed to various biologically active hormones (alpha-melanotropin, adrenocorticotropin, beta-endorphin and beta-lipotropin). We report here that in frog and mouse pars intermedia cells, newly synthesized [3H]Arg-labeled POMC is associated with the secretory granule membrane prior to processing. This association with the secretory granule membrane may be related to the intracellular transport and packaging of POMC and/or the facilitation of processing of the prohormone within the organelle.

Measurement of delta pH and membrane potential in secretory vesicles isolated from bovine pituitary intermediate lobe

Pro-opiomelanocortin (ACTH/endorphin prohormone) is processed within the secretory vesicles of pituitary intermediate lobe cells to alpha-melanotropin and beta-endorphin. In order to learn more about the microenvironment in which processing occurs, a method was developed to purify large quantities of bovine intermediate lobe secretory vesicles (ILSV) using isoosmolar metrizamide-sucrose gradients. Analysis of alpha-melanotropin and marker enzymes revealed that the gradients provided a 94-fold purification of secretory vesicles with respect to lysosomes and a 15-fold purification with respect to mitochondria. Pro-opiomelanocortin-converting enzyme activity in the ILSVs was assayed and found to be maximally active around pH 5. From measuring the delta pH across the intact ILSV membrane using 9-aminoacridine fluorescence quenching, the internal pH of ILSVs was determined to be less than 5.6, consistent with the operating pH range of the converting enzyme activity. The pH gradient of the ILSVs collapsed in the presence of ammonium sulfate or by using a combination of nigericin and K+, when the external medium pH was 7. Using the voltage-sensitive dye, oxanol VI, Mg2+ ATP was shown to cause a marked change in the ILSV membrane potential with the inside being positive which was reversed by the proton ionophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone. Thus, the ILSVs appear to have a Mg2+ ATP-dependent electrogenic proton-translocating system.