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Diagnosis and control of hypertension in the elderly populations of Japan and the United States

antihypertensives. The improvement of blood pressure control in the U.S. in recent years
(Crimmins, Garcia, and Kim, 2010; Cutler, Sorlie, Wolz et al., 2008; Hajjar and Kotchen,

2003) is generally credited to the increasing use of polytherapy (concomitant prescription
of multiple classes of antihypertensive medications). In 2004, approximately 60% of anti-
hypertension drug treatment regimens involved multiple drugs (Ma, Lee, and Stafford,
2006) . In 2002 a large study of Japanese treatment of hypertensives found that combina-
tion therapy occurred in only 35.3% of patients (Mori, Ukai, Yamamoto et al., 2006).
Another possible explanation for the observed differences could be goal-oriented man-
agement of hypertension which is more common in the U.S. while a fixed drug treatment
algorithm is more common in Japan (Cushman and Basile, 2006) .
All of these factors point to interventions in clinical practice to reach optimal blood
pressure control. Regular monitoring, providing diagnoses, prescribing medications so that
they can be easily obtained, and titration of drug regimens are all crucial to control of
hypertension. However, underlying differences in the level of blood pressure between so-
cieties may still have an effect on outcomes.
The results of our study reveal the complexities of looking at international differences
in health. Given their increased life expectancy and universal health care access, one
would have expected the Japanese diagnosis and control of hypertension to be superior to
that in the U.S. We find that the U.S. is relatively effective in diagnosing and treating
hypertension. However, hypertensive treatment may not reflect other medical treatments.
Lastly, hypertensive related mortality is primarily linked to stroke, which is not the leading
or even second leading cause of death in both countries and may therefore not contribute
as much as cancer or cardiovascular mortality to overall life expectancy (Glei, Mesle, and
Vallin, 2010). Mortality from stroke has dropped markedly in Japan in recent years; al-
though it remains somewhat higher in Japanese men and women than in Americans.
We should note some limitations of our study. We were only able to compare national
samples for 2006 and hypertensive state and the use of medications are changing rapidly in
both countries so that future research should examine changes after 2006. In addition we
do not consider all the determinants of hypertensive state in this analysis. For instance,
there are life style factors that may be related to hypertension such as obesity and smoking
(Davarian, Crimmins, Takahashi et al., 2013). Further investigation of these in compara-
tive analyses may provide greater insights into the root of these differences.

Conflict of Interest and Funding

There are no potential conflicts of interest. The data collection in Japan was partially sup-
ported by the Academic Frontier Project for Private Universities: matching fund subsidy
from MEXT (Ministry of Education, Culture, Sports, Science and Technology), 2006–2010.
Acknowledgements and Author Contributions

Support for the HRS data collection was primarily provided by the National Institute on
Aging (U01 AG009740). Analysis was supported by the National Institute on Aging of the
United States (P30AG017265). Authors are responsible for the content of the article.
The author contributions are as follows:
• Yasuhiko Saito: Collected data, performed data analysis, drafted and revised article
• Shieva Davarian: Performed initial data analysis and contributed to drafting and re-
vising
• Atsuhiko Takahashi: Collected data, contributed to revising article
• Edward Schneider: Drafted and revised article
• Eileen M. Crimmins: Conceptualized article, performed analysis, drafted and re-
vised article

International Journal of Population Studies | 2015, Volume 1, Issue 1 26