Does a medical history of hypertension influence disclosing genetic testing results of the risk for salt-sensitive hypertension, in primary care?

Abstract

Objective

Disclosing genetic testing results may contribute to the prevention and management of many common diseases. However, whether the presence of a disease influences these effects is unclear. This study aimed to clarify the difference in the effects of disclosing genetic testing results of the risk for developing salt-sensitive hypertension on the behavioral modifications with respect to salt intake in hypertensive and nonhypertensive patients.

Methods

A cross-sectional study using a self-administered questionnaire was conducted for outpatients aged >20 years (N=2,237) at six primary care clinics and hospitals in Japan. The main factors assessed were medical histories of hypertension, salt preferences, reduced salt intakes, and behavior modifications for reducing salt intake. Behavioral modifications of participants were assessed using their behavior stages before and after disclosure of the hypothetical genetic testing results.

Results

Of the 2,237 participants, 1,644 (73.5%) responded to the survey. Of these respondents, 558 (33.9%) patients were hypertensive and 1,086 (66.1%) were nonhypertensive. After being notified of the result “If with genetic risk”, the nonhypertensive participants were more likely to make positive behavioral modifications compared to the hypertensive patients among all participants and in those aged <65 years (adjusted relative ratio [ad-RR], 1.76; 95% confidence interval, 1.12−2.76 and ad-RR, 1.99; 1.11−3.57, respectively). In contrast, no difference in negative behavioral modifications between hypertensive and nonhypertensive patients was detected after being notified of the result “If without genetic risk” (ad-RR, 1.05; 95% confidence interval, 0.70−1.57).

Conclusion

The behavior of modifying salt intake after disclosure of the genetic testing results differed between hypertensive and nonhypertensive patients. Disclosing a genetic risk for salt-sensitive hypertension was likely to cause nonhypertensive patients, especially those aged <65 years, to improve their behavior regarding salt intake. We conclude that disclosing genetic testing results could help prevent hypertension, and that the doctor should communicate the genetic testing results to those patients with a medical history of hypertension, or those who are at risk of developing hypertension.

Keywords:

• attitude to health
• genetic testing
• hypertension
• outpatient
• sodium-restricted

Acknowledgments

The authors thank S Fujiwara, MD, PhD, D Matsuhima, MD, PhD, K Nakayasu, MD, C Ishida, MD, Y Ishibashi, MD, S Ohguri, R Kobayashi, and K Kawabata for their assistance with data collection. This study was supported by a Grant-in-Aid for Scientific Research (B) (21390168) from the Japan Society for the Promotion of Science.

This paper was presented at the WONCA Asia Pacific Regional Conference 2014 as a poster presentation with interim findings. The poster’s abstract was published in “Poster Abstracts” in Malaysian Family Physician, Official Journal of the Academy of Family Physicians of Malaysia, and Family Medicine Specialists Association, WONCA Asia Pacific Regional Conference 2014.

Author contributions

MO and TT contributed to the conception, design, and acquisition of data; the analysis and interpretation of data; and the writing and revision of the manuscript. MH and RA contributed to the design and acquisition of data, the analysis and interpretation of data, and the writing and revision of the manuscript. EK contributed to the conception and design and the writing and revision of the manuscript.

Disclosure

The authors report no conflicts of interest in this work.