Unexplained syncope, OH hospitalizations signal future cardiovascular events
Patients admitted for unexplained syncope or orthostatic hypotension (OH) may be at increased risk of developing cardiovascular disease and mortality, with only partial overlap between the two conditions, according to a study.
Researchers examined a population-based prospective cohort of 30,528 middle-aged individuals (average age 58 years; 40 percent male). Adjusted Cox regression models were used to evaluate the impact of unexplained syncope/OH hospitalizations on cardiovascular events and mortality.
A total of 524 and 504 participants were hospitalized for syncope or OH, respectively, after a median follow-up of 15 years, resulting in 1.2 hospital admissions per 1,000 person-years for each diagnosis.
Syncope hospitalizations particularly increased with age (hazard ratio [HR] per 1 year, 1.07; 95 percent CI, 1.05 to 1.09), higher systolic blood pressure (HR per 10 mm Hg, 1.06; 1.01 to 1.12), antihypertensive treatment (HR, 1.26; 1.00 to 1.59), use of diuretics (HR, 1.77; 1.31 to 2.38) and prevalent cardiovascular disease (HR, 1.59; 1.14 to 2.23). OH hospitalizations, on the other hand, increased with age (HR, 1.11; 1.08 to 1.12) and prevalent diabetes (HR, 1.82; 1.23 to 2.70).
In an analysis excluding 1,399 patients with prevalent cardiovascular disease, a total of 473 and 464 patients were hospitalized for unexplained syncope or OH, respectively, prior to any cardiovascular event.
Hospitalization for unexplained syncope emerged as a predictor of coronary events (HR, 1.85; 1.49 to 2.30), heart failure (HR, 2.24; 1.65 to 3.04), atrial fibrillation (HR, 1.84; 1.50 to 2.26), aortic valve stenosis (HR, 2.06; 1.28 to 3.32), all-cause mortality (HR, 1.22; 1.09 to 1.37) and cardiovascular death (HR, 1.72; 1.23 to 2.42). OH hospitalization predicted stroke (HR, 1.66; 1.24 to 2.23), heart failure (HR, 1.78; 1.21 to 2.62), atrial fibrillation (HR, 1.89; 1.48 to 2.41) and all-cause mortality (HR, 1.14; 1.01 to 1.30).
In light of the data presented, hospital admissions for unexplained syncope and OH should be regarded as a warning sign of future cardiovascular events, researchers said.