High BP predicts long-term CV mortality in Japanese

By Piriya Mahendra, medwireNews Reporter

A study in a Japanese population has shown that an above-normal blood pressure (BP) could increase long-term risk for cardiovascular (CV) mortality.

The analysis included 8592 Japanese individuals with a mean age of 49.4 years. At baseline, 18.9% had normal BP (<120/80 mmHg), 41.2% had prehypertension (120-139/80-89 mmHg), 26.0% had stage 1 hypertension (140-159/90-99 mmHg), and 13.9% had stage 2 hypertension (≥160/100 mmHg).

Over a 24-year follow-up period, 689 participants died from CV disease. Compared with individuals with a normal BP, the hazard ratios for CV death were 1.93 for those with prehypertension, 2.74 for those with stage 1 hypertension, and 5.25 for those with stage 2 hypertension.

The researchers found that although the hazard ratios and population-attributable fractions for total CV deaths increased with increasing BP in individuals aged 30-59 years as well as those aged over 60 years, the association between CV mortality and BP was significantly more pronounced in the younger age group.

Naoyuki Takashima (Shiga University, Otsu, Japan) and colleagues say that although it is now widely accepted that BP predicts long-term CV mortality risk in Western populations, corresponding evidence is scarce in Asia, where stroke is common.

Further analysis revealed that 745 participants on antihypertensive medication at baseline had an even higher risk for CV death than non-medicated stage 2 hypertension individuals, at hazard ratios of 2.96 versus 2.48, relative to those with normal BP at baseline.

Further analysis of CVD mortality stratified by gender revealed that adjusted hazard ratios progressively increased for both genders across increasing age and BP categories. The population-attributable fraction for CV deaths associated with a BP above normal was highest in younger men, however: 81% of CV deaths that occurred over the follow-up period in men aged 30-59 were attributed to a BP above normal at baseline.

"Our results demonstrated that higher BP levels at baseline were a long-lasting clinical and public health problem," they write in the Journal of Hypertension. "These results indicate the importance of population-wide primary prevention through lifestyle modification such as salt reduction as well as the necessity for early detection of high BP in young men both in Western and non-Western populations."

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