Isolated Nocturnal Hypertension: A Looming Problem in China
Isolated Nocturnal Hypertension: A Looming Problem in China
Murray Epstein, MD: We are now in New York at the American Society of Hypertension's annual meeting. We have been fortunate to invite Dr. Wang to join us today to discuss specific aspects of hypertension in China.
Jiguang Wang, MD, PhD: Years ago in 2005 we looked at 24-hour blood pressure monitoring data in population studies. We found that the Chinese population -- and also the Japanese and people living [on the island of] Taiwan -- had a very low nighttime decline in systolic and diastolic blood pressure, meaning higher nighttime blood pressure in this population.
We then looked at these data carefully and we found that some people either did not have any decline in nighttime blood pressure or even had an increase of blood pressure at night, with a defined disease phenomenon, isolated nocturnal hypertension -- which we believe could be a very special clinical entity in this population -- with higher pressure at night, but pretty normal blood pressure in the daytime. They would have never been treated because they always had normal blood pressure in the daytime, [notably] at clinical visit time.
We then looked at the population data on this very special form of hypertension --lower pressure in the daytime, but high pressure at night -- and we see isolated nocturnal hypertension. We looked at the population data prevalence of this problem. We found that the Chinese, Japanese, and South Africans have around 10% prevalence. The Europeans, regardless of whether they live in west or east Europe, have only 6% prevalence, meaning 50% lower than the Chinese, Japanese, or African populations. Probably if we look at the global data and start on the sensitivity probability, the Chinese and East Asians and African people have a higher prevalence of sensitive hypertension.
We also looked at the clinical consequences of isolated nocturnal hypertension. We found that in those people with elevated blood pressure only at night, they already had increased arterial stiffness. They actually had arterial stiffness [that was] quite similar [to that of] patients with sustained day and night hypertension, and they had significantly increased arterial stiffness compared with normotensive subjects. This very special pathophysiology could to some extent explain the high incidence of stroke in Eastern Asians.
If we look at the World Health Organization data incidence of stroke, we can see the Chinese had the highest incidence rate and the Japanese were second. It means the Eastern Asians had a very high incidence of stroke but a relatively lower incidence of coronary artery disease, especially in Japan in past years. They have been very successful in controlling high blood pressure. Their incidence of stroke was lower than in the Chinese but remained higher than people living in other parts of the world. If we look at the longitudinal data in the Chinese population on stroke and coronary artery disease incidence, even for me it is a very difficult phenomenon to explain to anybody, because in China, unlike in other countries, stroke and coronary artery disease increased in the last 15 years about onefold. If we don't work even harder in the next 15 years, we probably will have even more stroke and coronary artery disease in this population, which could be very detrimental to healthcare in China.
Dr. Epstein: In summary, I would like very much to thank Dr. Wang for his excellent presentation. We were delighted that he was able to come from Shanghai to be with us here this morning and to share with us his perception and his views based on his extensive experience in China of what hypertension is like and how it differs. Thank you so much for joining us this morning and for sharing your expertise with the audience.
Dr. Wang: Thank you very much for inviting me here. Thank you.
Murray Epstein, MD: We are now in New York at the American Society of Hypertension's annual meeting. We have been fortunate to invite Dr. Wang to join us today to discuss specific aspects of hypertension in China.
Jiguang Wang, MD, PhD: Years ago in 2005 we looked at 24-hour blood pressure monitoring data in population studies. We found that the Chinese population -- and also the Japanese and people living [on the island of] Taiwan -- had a very low nighttime decline in systolic and diastolic blood pressure, meaning higher nighttime blood pressure in this population.
We then looked at these data carefully and we found that some people either did not have any decline in nighttime blood pressure or even had an increase of blood pressure at night, with a defined disease phenomenon, isolated nocturnal hypertension -- which we believe could be a very special clinical entity in this population -- with higher pressure at night, but pretty normal blood pressure in the daytime. They would have never been treated because they always had normal blood pressure in the daytime, [notably] at clinical visit time.
We then looked at the population data on this very special form of hypertension --lower pressure in the daytime, but high pressure at night -- and we see isolated nocturnal hypertension. We looked at the population data prevalence of this problem. We found that the Chinese, Japanese, and South Africans have around 10% prevalence. The Europeans, regardless of whether they live in west or east Europe, have only 6% prevalence, meaning 50% lower than the Chinese, Japanese, or African populations. Probably if we look at the global data and start on the sensitivity probability, the Chinese and East Asians and African people have a higher prevalence of sensitive hypertension.
We also looked at the clinical consequences of isolated nocturnal hypertension. We found that in those people with elevated blood pressure only at night, they already had increased arterial stiffness. They actually had arterial stiffness [that was] quite similar [to that of] patients with sustained day and night hypertension, and they had significantly increased arterial stiffness compared with normotensive subjects. This very special pathophysiology could to some extent explain the high incidence of stroke in Eastern Asians.
If we look at the World Health Organization data incidence of stroke, we can see the Chinese had the highest incidence rate and the Japanese were second. It means the Eastern Asians had a very high incidence of stroke but a relatively lower incidence of coronary artery disease, especially in Japan in past years. They have been very successful in controlling high blood pressure. Their incidence of stroke was lower than in the Chinese but remained higher than people living in other parts of the world. If we look at the longitudinal data in the Chinese population on stroke and coronary artery disease incidence, even for me it is a very difficult phenomenon to explain to anybody, because in China, unlike in other countries, stroke and coronary artery disease increased in the last 15 years about onefold. If we don't work even harder in the next 15 years, we probably will have even more stroke and coronary artery disease in this population, which could be very detrimental to healthcare in China.
Dr. Epstein: In summary, I would like very much to thank Dr. Wang for his excellent presentation. We were delighted that he was able to come from Shanghai to be with us here this morning and to share with us his perception and his views based on his extensive experience in China of what hypertension is like and how it differs. Thank you so much for joining us this morning and for sharing your expertise with the audience.
Dr. Wang: Thank you very much for inviting me here. Thank you.
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