Cardiovascular risk after hospitalisation for unexplained syncope and orthostatic hypotension

Abstract

ObjectiveTo investigate the relationship of hospital admissions due to unexplained syncope and orthostatic hypotension (OH) with subsequent cardiovascular events and mortality.MethodsWe analysed a population-based prospective cohort of 30 528 middle-aged individuals (age 58±8 years; males, 40%). Adjusted Cox regression models were applied to assess the impact of unexplained syncope/OH hospitalisations on cardiovascular events and mortality, excluding subjects with prevalent cardiovascular disease.ResultsAfter a median follow-up of 15±4 years, 524 (1.7%) and 504 (1.7%) participants were hospitalised for syncope or OH, respectively, yielding 1.2 hospital admissions per 1000 person-years for each diagnosis. Syncope hospitalisations increased with age (HR, per 1 year: 1.07, 95% CI 1.05 to 1.09), higher systolic blood pressure (HR, per 10 mm Hg: 1.06, 95% CI 1.01 to 1.12), antihypertensive treatment (HR: 1.26, 95% CI 1.00 to 1.59), use of diuretics (HR: 1.77, 95% CI 1.31 to 2.38) and prevalent cardiovascular disease (HR: 1.59, 95% CI 1.14 to 2.23), whereas OH hospitalisations increased with age (HR: 1.11, 95% CI 1.08 to 1.12) and prevalent diabetes (HR: 1.82, 95% CI 1.23 to 2.70). After exclusion of 1399 patients with prevalent cardiovascular disease, a total of 473/464 patients were hospitalised for unexplained syncope/OH before any cardiovascular event. Hospitalisation for unexplained syncope predicted coronary events (HR: 1.85, 95% CI 1.49 to 2.30), heart failure (HR: 2.24, 95% CI 1.65 to 3.04), atrial fibrillation (HR: 1.84, 95% CI 1.50 to 2.26), aortic valve stenosis (HR: 2.06, 95% CI 1.28 to 3.32), all-cause mortality (HR: 1.22, 95% CI 1.09 to 1.37) and cardiovascular death (HR: 1.72, 95% CI 1.23 to 2.42). OH-hospitalisation predicted stroke (HR: 1.66, 95% CI 1.24 to 2.23), heart failure (HR: 1.78, 95% CI 1.21 to 2.62), atrial fibrillation (HR: 1.89, 95% CI 1.48 to 2.41) and all-cause mortality (HR: 1.14, 95% CI 1.01 to 1.30).ConclusionsPatients discharged with the diagnosis of unexplained syncope or OH show higher incidence of cardiovascular disease and mortality with only partial overlap between these two conditions.

Prognostic significance of noncardiac syncope in the general population: A systematic review and meta‐analysis

“…Of 6590 citations identified and 96 potentially relevant articles retrieved, we included four studies based on four unique cohorts from three different countries (one from the United States, one from Denmark, and two from Sweden), for an overall population of 287 296 individuals (51.6% men; age, 64.5 ± 12.4 years), including 38 757 subjects with a history of noncardiac/unexplained syncope and 248 539 nonrandomized controls (Figure ). The average follow‐up after the first‐syncopal event was 4.4 years.…”

“…Traditionally, patients diagnosed with noncardiac syncope have been seen as a group with benign prognosis, especially at younger age, although, notably, unexplained syncope heralded moderately increased risk of premature death compared with syncope‐free individuals in the general population . Later reports have questioned this view, as hospital discharge with a diagnosis of nonspecific syncope (R55.9) in the absence of obvious CVD indicated a higher mortality and a higher risk of incident CVD in independent populations . When searching for previous studies with a first diagnosis of noncardiac syncope as a discriminating factor, it appeared that surprisingly little has been written on this topic.…”

Syncope and orthostatic hypotension: early markers of cardiac disease in the general population

“…The  Heart publication by Yasa et al 7 from Sweden makes a significant contribution here. The Swedish healthcare system has comprehensive nationwide databases of high quality.…”

“…The Swedish healthcare system has comprehensive nationwide databases of high quality. This allowed Yasa et al 7 to link data from a detailed population-based cohort of 30 528 individuals from the Malmö Diet and Cancer Study (recruited from 1991 to 1996) with the Swedish National Hospital Discharge Register and the Swedish National Cause of Death. They then identified all individuals who were hospitalised for syncope (1.7%) or OH (1.7%) from baseline through follow-up and then compared these subjects to the rest of the cohort.…”

“…The scope of the paper is, however, much broader and epidemiologically applicable. The study by Yasa et al 7 adds an important input that will set the framework for more studies on how to target and evaluate this group of patients from the background population who seem at low risk but who are at higher risk of developing significant cardiovascular morbidity and increased mortality? It also underlines and is in agreement with recent reports from other countries stating this fact.…”