Sleep Health | Sleep Review
Adults with type 1 or type 2 diabetes, whose blood pressure rose at night, had more than twice the risk of death compared to their own, according to a 21-year-old study presented at the American Heart Association’s Hypertension Scientific Sessions whose blood pressure had “plummeted” while sleeping in 2021. The meeting took place virtually from September 27-29, 2021.
Blood pressure usually goes down or down during sleep. If the blood pressure does not drop sufficiently during the night, one speaks of “not immersion”. If the blood pressure rises at night compared to the daytime level, the phenomenon is called “reverse dipping”. These abnormal blood pressure patterns are linked to an increased risk of cardiovascular complications and death in adults with type 1 or type 2 diabetes.
“Previous studies have shown that non-immersion is associated with kidney and cardiovascular disease in healthy individuals and in people with high blood pressure or type 1 or type 2 diabetes,” says study author Martina Chiriacò, MD, Examiner in the Department of Clinical and Experimental Medicine at the University of Pisa in Pisa, Italy, in a communication. “However, the long-term effects of non-immersion on death in people with diabetes remain unclear and there is very little information about reverse dippers. We wanted to examine these two aspects to show whether altered blood pressure patterns could predict the risk of death in people with type 1 or type 2 diabetes. “
The researchers also looked at the role of heart rate variability in their study group. Heart rate variability is a measure of the variation in times between each heartbeat.
“Low heart rate variability is associated with poorer health in people with heart failure and increases the risk of coronary artery disease in the general population. However, there is still a lack of long-term information on the link between decreased heart rate variability and mortality in people with type 1 or type 2 diabetes, ”says Chiriacò
Researchers studied 349 adults with diabetes in Pisa, Italy, as of 1999. Half of the participants were women, 284 had type 2 diabetes and 65 had type 1 diabetes. Chiriacò reports that 82% of patients had high blood pressure and 73% of the general population had uncontrolled hypertension despite taking antihypertensive drugs. There were 136 deaths during the 21-year follow-up – through 2020. All had 24-hour ambulatory blood pressure monitoring.
Participants were categorized as dippers if their blood pressure dropped 10% or more at night compared to the hours of the day. Non-dippers were those whose nightly blood pressure decreased by less than 10% compared to the daytime, and reverse dippers had a nighttime blood pressure increase of 0.1% or more compared to the daily values.
The researchers found that more than half of the participants had no drop in blood pressure during the night, and 20% were reverse dippers. They also found:
- Almost a third of reverse dippers had cardiac autonomic neuropathy versus 11% of those who did not have dips. Cardiac autonomic neuropathy is a serious complication of diabetes in which the nerves that control the heart and blood vessels are damaged. This nerve damage affects the regulation of blood pressure and heart rate and increases the risk of death and cardiovascular events.
- Compared to dippers, inverted dippers had an average of 2.5 years reduced survival and non-dippers had an average of 1.1 years reduced survival.
- Reverse dippers showed more than a two-fold increase in the risk of death from all causes compared to those who had dippers and a 1.9-fold increase in risk compared to non-dippers. There was no significant difference in mortality risk between dippers and non-dippers.
- Reverse dippers were more likely to be older and need treatment for high blood pressure and showed signs of heart damage related to high blood pressure.
- Participants with hypertension only during the night showed a similar shortening in survival as those who had long-term high blood pressure for 24 hours, with an average shortening of survival of 1.2 years.
- Individuals with low heart rate variability over 24 hours had an average survival reduction of 1.8 years.
“Our study shows that 1 in 10 people with type 1 or type 2 diabetes could be a reverse dipper and that this condition likely more than doubled the risk of dying regardless of blood pressure control over a period of 21 years . “Chiriac says. “It is important that healthcare professionals look for abnormal patterns of blood pressure drop in people with type 1 or type 2 diabetes. There are strategies for lowering blood pressure during the night. “
It notes that ambulatory blood pressure monitoring is an inexpensive, widely used screening and monitoring tool for diagnosing abnormal circadian fluctuations in blood pressure and heart rate. Chiriacò says: “We support the use of this screening to optimize the treatment of people with diabetes.”
One limitation of the study is that the researchers did not define the prevalence of cardiovascular disease in participants with diabetes at the start of the study, which could help determine whether there are differences in mortality risk between those with pre-existing cardiovascular disease. Disease and those who did so did not give. In addition, the study participants were predominantly white adults, so the results should be validated in populations with more racial and ethnic diversity. “This is especially important as it has been reported that non-immersion is more common among people with African or Hispanic ancestry,” says Chiriacò.
Co-authors are Luca Sacchetta, MD; Giovanna Forotti, MD, PhD; Simone Leonetti; Lorenzo Nesti, MD; Stefano Taddei, MD; Andrea Natali, MD; Anna Solini, MD, PhD; and Domenico Tricò, MD, PhD.
The study was funded by the University of Pisa.