Influence of pre-hypertension on all-cause and cardiovascular mortality: the Singapore Cardiovascular Cohort Study.
BACKGROUND
The effect of "pre-hypertension" (pre-HTN) itself, and in combination with other cardiovascular disease (CVD) risk factors in relation to mortality has not been assessed in Asian populations.


METHODS
From three cross-sectional studies conducted in Singapore (baseline 1982-1995), 5830 persons were grouped into normotensive (NT), pre-HTN or hypertensive (HTN). Follow-up (median 12.0 yrs, IQR 12-19 yrs) was done by linkage to the National Death Register. Outcomes included all-cause and CVD (ischaemic heart disease (ICD-9 410-414) and cerebrovascular accidents (ICD-9 430-438)). Cox's proportional hazards model was used to obtain adjusted hazard ratios (HRs) for risk of mortality.


RESULTS
After adjustment, pre-HTN was not associated with a statistically significant increased risk of all-cause or CVD mortality. However, an increased risk for all-cause and CVD mortality, in the presence of diabetes (adjusted HR 1.8; 95%CI 1.0-2.9 and 4.4; 95%CI 1.9-10.4), smoking (adjusted HR 2.2; 95%CI 1.3-3.5 and 4.9; 95%CI 1.8-13.3), and especially, pre-existing CVD (adjusted HR 3.1; 95%CI 1.5-6.4 and 9.3; 95%CI 3.3-25.9) was found.


CONCLUSIONS
Pre-HTN was not an independent risk factor for mortality. However an increased risk of mortality for pre-HTN in the presence of other CVD risk factors was observed. This finding supports current recommendations to screen for these risk factors in the pre-HTN Asian population.
Lee
Jeannette
J
Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. cofleejm@nus.edu.sg
Heng
Derrick
D
Ma
Stefan
S
Chew
Suok-Kai
SK
Hughes
Kenneth
K
Tai
E-Shyong
ES
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology* / Q000401:mortality*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D055815:Young Adult