Isolated Systolic Hypertension Declines in Prevalence Interview with:
Xuefeng (Chris) Liu, PhD
Associate Professor, School of Nursing
Ann Arbor, MI 48109

MedicalResearch: What is the background for this study? What are the main findings?

Dr. Liu: Isolated systolic hypertension (ISH), defined as a systolic blood pressure (SBP) of ≥ 140 mm Hg and a diastolic blood pressure (DBP) of < 90 mm Hg, is an important hypertension subtype. Isolated systolic hypertension is often characterized as a phenomenon of aging and becomes the major form of hypertension for people aged 50 or more. Elevated SBP has been thought to be more important than elevated DBP as a risk factor for adverse cardiovascular and renal outcomes. When combined with other risk factors such as poor diet and lack of exercise, untreated Isolated systolic hypertension can lead to serious health problems (e.g. stroke, heart disease, and chronic kidney disease). The existing studies of pattern changes in rates of Isolated systolic hypertension in the US adult population focus on uncontrolled hypertension subtypes among individuals with uncontrolled blood pressure, and the prevalence and changes of untreated ISH in the general population was not the main focus. In addition, the studies were based on the data collected two decades ago. More recent prevalence estimates and long-term changes of ISH among US untreated adults are needed to fill the gap in the hypertension literature.

In our study, we used data from the National Health and Nutrition Examination Survey 1999-2010, conducted by CDC National Center for Health Statistics. We found that the prevalence of untreated ISH significantly decreased from 1999-2004 to 2005-2010. Old persons, females, and non-Hispanic blacks had higher prevalence of untreated Isolated systolic hypertension. Compared with 1999-2004, the prevalence of untreated Isolated systolic hypertension in 2005-2010 declined among older and female individuals. Further stratification analyses showed that treated ISH improved over time for older non-Hispanic whites and blacks, non-Hispanic white females, older individuals with a college education or above and females with a high school education or below.

MedicalResearch: What should clinicians and patients take away from your report?

Dr. Liu: Isolated systolic hypertension was more prevalent in old people and females, and there were significant improvements over time among these groups. The most likely reason for the decline in Isolated systolic hypertension is that more patients with ISH have been treated over time. These findings suggest that public health measures or changes administered by clinicians in clinical practice are trending in the right direction. The prevalence of untreated ISH was relatively high and did not decline over time among old males, old Hispanics and old persons with a high school education or below. To meet Healthy People 2020, clinicians must pay greater attention to these groups in the future.

Our findings have provided individuals with a good sign of decline in Isolated systolic hypertension. However, it is important to note that great concerns in health status and improved lifestyles are still needed to prevent Isolated systolic hypertension to achieve the goal of prevalent hypertension among US adults, particularly in old adults.

MedicalResearch: Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Liu: We hope that our findings will motivate investigators to explore the pathways to explain the decline in the prevalence of Isolated systolic hypertension. One likely reason for the decline in untreated Isolated systolic hypertension is that the percentage of treated hypertensive patients (including all hypertension subtypes) increased over time. This potential explanation is also supported by the finding from another study recently published in Circulation. For future research, it would be interesting to identify other possible reasons for this decline that may include greater awareness of hypertension and the lack of increase in BMI. If the reasons other than treatment play an important role in the prevalence of ISH, the decreased prevalence of Isolated systolic hypertension is a good sign that makes the Healthy People 2020 target goal of prevalent hypertension promising with concerted efforts from health professionals and government agencies.


Prevalence and Trends of Isolated Systolic Hypertension among Untreated Adults in the United States.

Journal of the American Society of Hypertension

Available online 13 January 2015