A new study in the American College of Clinical Pharmacology found that patients on a low-salt diet (LSD) and one of three antihypertensive drug regimens saw a greater reduction in blood pressure (BP) compared to those on a non-low-salt diet (NLSD) and antihypertensive medications, although all groups saw significant reduction in BP.
This prospective, randomized, open-label, parallel-group controlled study randomly assigned 175 patients with mild-to-moderate hypertension aged 18–79 to a LSD or NLSD and one of the three antihypertensive drugs: losartan 100mg, losartan 50mg/hydrochlorothiazide 12.5mg, or irbesartan 150mg/ hydrochlorothiazide 12.5mg. The LSD adhered to the 2010 Chinese Guidelines for the Management of Hypertension that recommended ≤2,300mg sodium per day. Office BP, 24-hour mean BP, and morning BP for both SBP and DBP were monitored before and after two months of treatment.
Office BP, 24-hour mean BP, and morning BP did not differ significantly between the groups prior to treatment. BP significantly decreased with all three regimens of antihypertensive drugs over the two-month period, but a greater BP reduction was seen in those on the LSD vs. the NLSD. Within the LSD group, the degree of BP reduction did not differ significantly among the three antihypertensive drug treatment categories. For the NLSD group, there was no significant difference between losartan/hydrochlorothiazide and irbesartan/hydrochlorothiazide, but both were more effective than losartan alone. The authors pose that diuretics may enhance the antihypertensive effects of angiotensin II receptor blockers (ARBs) when salt intake is relatively high.
The Dietary Guidelines for Americans, 2010 recommend that Americans aged ≥2 consume <2,300mg per day and that those aged ≥51, are African-American, or have high blood pressure, diabetes, or chronic kidney diseases should further reduce sodium intake to 1,500mg per day. Clinicians should discuss the importance of a low-salt diet with their patients taking antihypertensive drugs and consider an ARB/diuretic for those who have difficulties in controlling their salt intake.
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