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Thursday, September 6, 2012

Japan Earthquake Linked to Blood Pressure Rise in CKD

By Matthew Coleman


Among patients with chronic kidney disease (CKD) in northeast Japan, those treated with sympatholytics did not experience the sudden rise in blood pressure after the 2011 earthquake that their counterparts did, according to a brief communication published in the American Journal of Hypertension (2012;25:951-954).


The study, which was led by Kenichi Tanaka of the Department of Nephrology and Hypertension at Fukushima Medical University, included 132 hypertensive outpatients with Stage 3-4 CKD who were residents of Fukushima City.


Patients had been treated for at least three months before the earthquake and visited the hospital one to three weeks following the disaster. Clinic blood pressures and heart rates were measured at baseline (previous visit within two months before the earthquake) and twice after the earthquake (at one to three weeks and five to seven weeks).


For the 106 patients not taking sympatholytics, mean baseline systolic and diastolic blood pressures were 135 and 78 mmHg, respectively.


On their first visit after the earthquake, mean systolic blood pressure had shot up to 139 mmHg, and diastolic blood pressure to 81 mmHg. By the second visit, systolic blood pressure had gone down to 135 mmHg, and diastolic blood pressure to 77 mmHg.


Sympatholytics were given to 26 (19.7%) of patients with chronic kidney disease. In this group, baseline mean systolic blood pressure was 133 mmHg, and mean diastolic blood pressure was 71 mmHg.


On their first visit after the earthquake, mean blood pressure remained level at 131 mmHg (systolic) and 71 mmHg (diastolic). The second visit showed no significant change, with systolic blood pressure holding at 134 mmHg and diastolic blood pressure at 72 mmHg.


“The beneficial effect of sympatholytics on blood pressure control after the earthquake might reflect that the increases in blood pressure were caused by activation of the sympathetic nervous system after the earthquake in CKD patients,” Dr. Tanaka and colleagues wrote.


The study is limited by the fact that it was only a retrospective analysis of a small group of hypertensive CKD patients without a control group of non-CKD hypertensive patients.


“[F]urther investigation is needed to clarify the association between earthquake-induced deterioration of blood pressure control and cardiovascular events after earthquakes in CKD patients, and whether sympatholytic medications reduce the incidence of cardiovascular disease or mortality.”