Article Text
Abstract
Objective To investigate the relationship of hospital admissions due to unexplained syncope and orthostatic hypotension (OH) with subsequent cardiovascular events and mortality.
Methods We 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.
Results After 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).
Conclusions Patients 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.
- orthostatic hypotension
- unexplained syncope
- hospital admission
- cardiovascular disease
- mortality
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Footnotes
Contributors EY: conception and study design, interpretation of data, manuscript drafting and approval of the version of the manuscript to be published. FR: statistical analysis and interpretation of data, manuscript drafting, critical revision of the article and approval of the version of the manuscript to be published. MM: conception and study design, manuscript drafting, critical revision of the article and approval of the version of the manuscript to be published. RS: conception and study design, manuscript drafting, critical revision of the article and approval of the version of the manuscript to be published. SG: interpretation of data, critical revision of the article and approval of the version of the manuscript to be published. RDC: interpretation of data, critical revision of the article and approval of the version of the manuscript to be published. OM: data collection, critical revision of the article and approval of the version of the manuscript to be published. AF: conception and study design, data collection, statistical analysis and interpretation of data, critical revision of the article and approval of the version of the manuscript to be published.
Funding This work was supported by grants from the Swedish Medical Research Council, the Swedish Heart and Lung Foundation, the Medical Faculty of Lund University, Malmö University Hospital, the Albert Påhlsson Research Foundation, the Crafoord Foundation, the Ernhold Lundströms Research Foundation, the Region Skane, the Hulda and Conrad Mossfelt Foundation, the King Gustaf V and Queen Victoria Foundation, The Wallenberg Foundation and the Lennart Hanssons Memorial Fund.
Competing interests All authors have completed the ICMJE uniform disclosure at www.icmje.org/coi_disclosure.pdf and declare: AF reports personal fees from Cardiome Corp. and a patent Thermo Fisher pending outside the submitted work; RDC reports grants from Boehringer-Ingelheim, Bayer and BMS/Pfizer, personal fees from Boehringer-Ingelheim, Bayer, BMS/Pfizer, Daiichi-Sankyo and Lilly outside the submitted work; RS reports personal fees and other from Medtronic Inc., St. Jude Medical Inc. outside the submitted work; RS performs consultancy for Medtronic Inc.; RS is a member of the speaker’s Bureau St. Jude Medical/Abbott Inc.; RS is shareholder in Boston Scientific Inc., Edwards Lifesciences Inc., Shire PLC, Roche SA and Astrazeneca PLC; no other relationships or activities that could appear to have influenced the submitted work.
Ethics approval Regional Ethical Review Board in Lund, Sweden.
Provenance and peer review Not commissioned; externally peer reviewed.