Syncope recurrence and mortality: a systematic review

Syncope and Its Impact on Occupational Accidents and Employment

Background—

First-time syncopal episodes usually occur in adults of working age, but their impact on occupational safety and employment remains unknown. We examined the associations of syncope with occupational accidents and termination of employment.

Methods and Results—

Through linkage of Danish population-based registers, we included all residents 18 to 64 years from 2008 to 2012. Among 3 410 148 eligible individuals, 21 729 with a first-time diagnosis of syncope were identified, with a median age 48.4 years (first to third quartiles, 33.0–59.5), and 10 757 (49.5%) employed at time of the syncope event. Over a median follow-up of 3.2 years (first to third quartiles, 2.0–4.5), 622 people with syncope had an occupational accident requiring hospitalization (2.1/100 person-years). In multiple Poisson regression analysis, the incidence rate ratio in the employed syncope population was higher than in the employed general population (1.44; 95% confidence interval [CI], 1.33–1.55) and more pronounced in people with recurrences (2.02; 95% CI, 1.47–2.78). The 2-year risk of termination of employment was 31.3% (95% CI, 30.4%–32.3%), which was twice the risk of the reference population (15.2%; 95% CI, 14.7%–15.7%), using the Aalen–Johansen estimator. Factors associated with termination of employment were age <40 years (incidence rate ratio, 1.48; 95% CI, 1.37–1.59), cardiovascular disease (1.20; 95% CI, 1.06–1.36), depression (1.72; 95% CI, 1.55–1.90), and low educational level (2.61; 95% CI, 2.34–2.91).

Conclusions—

In this nationwide cohort, syncope was associated with a 1.4-fold higher risk of occupational accidents and a 2-fold higher risk of termination of employment compared with the employed general population.

Transient loss of consciousness assessment in a University Hospital: From diagnosis to prognosis

Background

Transient loss of consciousness (TLoC) is a symptom that has several differential etiologic diagnosis, causes significant morbidity and mortality with impact on quality of life.

Objective

The purpose of this study was to access the diagnosis and prognosis of these patients admitted in a Portuguese University Hospital.

Methods

The study included 125 patients with TLoC admitted in the emergency room and then admitted to the hospital during the year 2013. Patients were contacted by phone for follow-up evaluations, during the 18 months from the date of admission.

Results

Cardiogenic syncope was the most common etiology of TLoC (39.2%). The 18-month overall mortality was 11.2%, however this was higher in patients with unexplained TLoC, with an 18-month mortality of 27.8% (p = 0.031); It was found that half of patients who died, did so in the first month from admission date; 20% of patients had recurrent episodes of TLoC (mean number of 5.6 episodes), with a higher percentage of recurrence occurring in patients with reflex syncope (35.3%; p = 0.023). 60% of patients with recurrent episodes suffered accidents and/or injuries, and 20% of recurrence patients gave up driving (p = 0.019).

Conclusion

The results obtained highlight the burden of TLoC in terms of morbidity and mortality, similar results to those previously published, except for the prevalence of the etiology, cause of death and recurrence's etiology of TLoC. This study emphasizes the significant implications that TLoC leads on morbidity and mortality being essential its accurate diagnosis.

Implantable loop recorder versus conventional diagnostic workup for unexplained recurrent syncope

BACKGROUND

The most recent syncope guideline recommends that implantable loop recorders (ILRs) are implanted in the early phase of evaluation of people with recurrent syncope of uncertain origin in the absence of high-risk criteria, and in high-risk patients after a negative evaluation. Observational and case-control studies have shown that loop recorders lead to earlier diagnosis and reduce the rate of unexplained syncopes, justifying their use in clinical practice. However, only randomised clinical trials with an emphasis on a primary outcome of specific ILR-guided diagnosis and therapy, rather than simply electrocardiogram (ECG) diagnosis, might change clinical practice.

OBJECTIVES

To assess the incidence of mortality, quality of life, adverse events and costs of ILRs versus conventional diagnostic workup in people with unexplained syncope.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, 2015), MEDLINE, EMBASE, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) Search Portal in April 2015. No language restriction was applied.

SELECTION CRITERIA

We included all randomised controlled trials of adult participants (i.e. ≥ 18 years old) with a diagnosis of unexplained syncope comparing ILR with standard diagnostic workup.

DATA COLLECTION AND ANALYSIS

Two independent review authors screened titles and abstracts of all potential studies we identified as a result of the literature search, extracted study characteristics and outcome data from included studies and assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We contacted authors of trials for missing data. We analysed dichotomous data (all-cause mortality and aetiologic diagnosis) as risk ratios (RR) with 95% confidence intervals (CI). We used the Chi(2) test to assess statistical heterogeneity (with P < 0.1) and the I² statistic to measure heterogeneity among the trials. We created a 'Summary of findings' table using the five GRADE considerations (study limitations, consistency of effect, imprecision, indirectness and publication bias) to assess the quality of a body of evidence as it relates to the studies which contribute data to the meta-analyses for the prespecified outcomes.

MAIN RESULTS

We included four trials involving a total of 579 participants. With the limitation that only two studies reported data on mortality and none of them had considered death as a primary endpoint, the meta-analysis showed no evidence of a difference in the risk of long-term mortality between participants who received ILR and those who were managed conventionally at follow-up (RR 0.97, 95% CI 0.41 to 2.30; participants = 255; studies = 2; very low quality evidence) with no evidence of heterogeneity. No data on short term mortality were available. Two studies reported data on adverse events after ILR implant. Due to the lack of data on adverse events in one of the studies' arms, a formal meta-analysis was not performed for this outcome.Data from two trials seemed to show no difference in quality of life, although this finding was not supported by a formal analysis due to the differences in both the scores used and the way the data were reported. Data from two studies seemed to show a trend towards a reduction in syncope relapses after diagnosis in participants implanted with ILR. Cost analyses from two studies showed higher overall mean costs in the ILR group, if the costs incurred by the ILR implant were counted. The mean cost per diagnosis and the mean cost per arrhythmic diagnosis were lower for participants randomised to ILR implant.Participants who underwent ILR implantation experienced higher rates of diagnosis (RR (in favour of ILR) 0.61, 95% CI 0.54 to 0.68; participants = 579; studies = 4; moderate quality evidence), as compared to participants in the standard assessment group, with no evidence of heterogeneity.

AUTHORS' CONCLUSIONS

Our systematic review shows that there is no evidence that an ILR-based diagnostic strategy reduces long-term mortality as compared to a standard diagnostic assessment (very low quality evidence). No data were available for short-term all-cause mortality. Moderate quality evidence shows that an ILR-based diagnostic strategy increases the rate of aetiologic diagnosis as compared to a standard diagnostic pathway. No conclusive data were available on the other end-points analysed.Further trials evaluating the effect of ILRs in the diagnostic strategy of people with recurrent unexplained syncope are warranted. Future research should focus on the assessment of the ability of ILRs to change clinically relevant outcomes, such as quality of life, syncope relapse and costs.