Effect of HMG-CoA reductase inhibitors on blood pressure in hypertensive patients treated with blood pressure-lowering agents: retrospective study using an anti-hypertensive drug database.

BACKGROUND AND OBJECTIVES We used a Japanese antihypertensive drug database to investigate the blood pressure-lowering effect of statins in hypertensive patients receiving antihypertensive medication. We also examined the class effect of antihypertensive drugs on blood pressure lowering by statins. MATERIAL AND METHODS The Risk/Benefit Assessment of Drugs-Analysis and Response (RAD-AR) Council has developed an antihypertensive drug database which contains the results of post-marketing surveillance for various antihypertensive agents from 143,509 antihypertensive users in clinical settings. Antihypertensive patients in the database with concurrent hyperlipidemia were grouped into statin users and non-users, and changes in systolic and diastolic blood pressure over a three-month period were compared. Further, the class effects of antihypertensive drugs on the lipid lowering effects of statins were also investigated. RESULTS A total of 1070 statin users and 1974 non-users were analyzed. Changes in systolic blood pressure were significantly greater in the statin user than in the non-user group (mean difference: 1.63 mmHg, p = 0.03). In contrast, no significant effect of statin use was observed on the change in diastolic blood pressure (DBP) (0.87 mmHg, p = 0.08). When stratified by antihypertensive class, reductions in blood pressure were greater in statin user groups for all antihypertensive classes without statistical significance, except for a significant change in DBP in those receiving beta-blockers (mean difference: 2.98 mmHg, p = 0.03). DISCUSSION The present study documented that statin's effect on blood pressure in hypertensive patients with hyperlipidemia in clinical setting is statistically significant but has a minimal significance. With regard to class differences among antihypertensive agents, the decrease was greatest in the DBP of patients treated with beta-blockers. In contrast, no significant changes were seen in the ACE inhibitor or Ca antagonist subgroups. One possible explanation for the differential effects of antihypertensive class in our study might be the lack of a vasodilatation effect.