(RxWiki News) Many people worry about having high blood pressure, especially if high blood pressure runs in the family. But low blood pressure may also be unsafe.
Having treated blood pressure that was too low was just as dangerous as having high blood pressure, the researchers found.
"Learn safe, healthy ways to regulate your blood pressure."
The research was conducted by John J. Sim, MD, of the Kaiser Permanente Los Angeles Medical Center, and colleagues.
The researchers enrolled 398,419 patients in their study in 2006 and 2007. All participants were 18 or older with high blood pressure and on blood pressure-lowering medication. The researchers followed them until the end of 2010.
The average patient was 64 years old at the start of the study. Most were on diuretics (water pills), although several were on more than one type of blood pressure medication.
The researchers followed the patients to see how many developed end-stage renal failure (ESRD) or died. The researchers defined ESRD as being on dialysis (treatment that purifies the blood like healthy kidneys do) or having a kidney transplant.
During the study period, 25,182 patients (6.3 percent) died, and 4,957 (1.2 percent) were diagnosed with ESRD.
The researchers found that people whose systolic (top number) blood pressure was 130 to 139 and diastolic (bottom number) blood pressure was 60 to 79 were least likely to develop ESRD or die.
Those with the lowest systolic blood pressure (systolic blood pressure less than or equal to 110 ) or highest (systolic blood pressure greater than or equal to 170) were more likely to die. Only those with the highest systolic blood pressure were more likely to have ESRD (6.9 percent) than people with ideal blood pressure.
The rates changed according to how high or low a person's blood pressure was. For example, a person with a systolic blood pressure of 120 to 129 was 10 percent more likely to die or have kidney failure than a person with a systolic blood pressure of 130 to 139. Those whose systolic blood pressures were in the 140 to 149 range were 40 percent more likely to die or have kidney failure than those whose systolic blood pressure was 130 to 139.
Although lower blood pressure is often considered better, too low is not good, either, the researchers noted. They suggested that some people are too aggressively treated for their blood pressure, and the medication may cause their blood pressure to be unhealthily low.
"Physicians have often emphasized the need to bring a patient's blood pressure down as low as possible for the best outcomes," Dr. Sim said in a press release. "However, the findings of our study suggest that treating patients with high blood pressure too aggressively may potentially lead to poor health outcomes."
This study appeared Aug. 4 in the Journal of the American College of Cardiology.
Dr. Sim disclosed receiving research grants from Questcor Pharmaceuticals, Sanofi-Aventis and Keryx Biopharmaceuticals.