The relationship between blood pressure and pain sensitivity

1. The relationship between blood pressure and pain sensitivity NogaLutzky Cohen, BA, Robert Nolan,C.Psych, PhD& Joel Katz, C.Psych, PhD Introduction Methods Results Conclusion • There is a strong relationship between having higher blood pressure (hypertension) and lower pain sensitivity (hypoalgesia). Specifically, individuals with higher blood pressure (BP) tend to report less pain and tolerate pain for a longer time.1 • This relationship was also found in individuals who are at risk for developing hypertension.1 • The cause of the relationship is still unknown.2 • This relationship has not been tested in clinical samples with established cardiovascular risk factors, nor has the effect of anti-hypertensive medications on the relationship been determined. 3,4 • Participants • N= 303 • 100% Hypertensive, in both stage I and stage II. • At baseline; SBP: M= 139 SD=0.98 • DBP: M=79 SD=0.6 • 58% females, 42% males. • 72% used anti-hypertensive medications, 28% did not use medications. • Recruited through the I-START trial (Internet-based Strategic Transdisciplinary Approach to Risk Reduction and Treatment).5 • Procedures & Measures • 1. Blood pressure was measured at rest in a laboratory setting. • 2. Participants underwent a venipuncture for a blood sample. • 3. Pain in response to the venipuncture was measured using the McGill Pain Questionnaire (MPQ)- Short Form. • Support for the relationship between hypertension and hypoalgesia was found in our sample, but only with one pain measure. • It is possible that the effect of the medications on blood pressure moderated the relationship. However, when examining only the group that did not take medications, the relationship still was not detected. • Another possible reason is that the pain stimulus used (venipuncture) is not very painful. Thus, the range of pain ratings was very small, with most participants rating it as not painful at all, which may have influenced the ability to find significant differences. • The differences in the medication groups were found in the sensory pain rating, which provides information about the quality of the pain. • The findings support the theory that the cause of the relationship could be a third variable that influences both blood pressure and pain sensitivity in an unknown way.2 • Further research is needed to establish this relationship in populations that are prone to hypertension and cardiovascular disease. In addition, more research is needed to establish how anti-hypertensive medications influence pain ratings. • A Pearson correlation coefficient was computed to assess the relationship between systolic blood pressure (SBP) and pain ratings. Results indicate a significant negative correlation between SBP and pain ratings on the Visual Analogue Scale (VAS) of the MPQ,r=-0.17, p=0.03. • Other pain ratings failed to show significant correlation with SBP. • 2. An independent t-test was used to compare pain ratings in participants who took anti-hypertensive medications and those who did not. Participants who took medications (M=0.31, SD=0.33) reported more pain on the MPQ-sensory subscale than those who did not take medications (M=0.21, SD=0.23), t(133.13) = -2.25, p = 0.03. Objectives • To examine the relationship between hypertension and hypoalgesia in a clinical sample of hypertensive patients at risk for cardiovascular disease. • To examine the effect of anti-hypertensive medications on pain ratings. References 1. France, C. R., Ditto, B., & Adler, P. (1991). Pain perception in offspring of hypertensive at rest and during baroreflex stimulation. Journal of Behavioral Medicine, 14(5), 513-525. 2. France, C. R. (1999). Decreased pain perception and risk for hypertension: Considering a common physiological mechanism. Psychophysiology, 36, 683-692. 3. Sitsen, J. M., & de Jong, W. (1984). Observations on pain perception and hypertension in spontaneously hypertensive rats. Clinical and experimental hypertension, 6(7), 1345 -1356. 4. Wendel, O. T., & Bennett, B. (1981). The occurrence of analgesia in an animal model of hypertension. Life Science, 29, 515-521. 5. Nolan, R. P., Liu, S., Shoemaker, J. K., Hachinski, V., Lynn, H., Mikulis, D. J., Wennberg, R. A., Moy Lum-Kwong, M., & Zbib, A. (2012). Therapeutic benefit of internet-based lifestyle counseling for hypertension. Canadian Journal of Cardiology. 28(3), 390-396. .