Ambulatory blood pressure variability in young adults with Long-Covid syndrome 2022 Ternushchak et al

[Andy]

Abstract

Objective: The aim: To perform an overall assessment of BP and BP variability using ambulatory measurements in young adults with long COVID syndrome.

Patients and methods: Materials and methods: We enrolled young patients with diagnosed long-COVID syndrome (n = 58, mean age 23.07 ± 1.54 years), compared with an age-matched healthy subjects who had not suffered from COVID-19 (n = 57, mean age 22.9 ± 1.83 years). Patients with long-COVID syndrome had recovered from mild/moderate illness and none had required hospitalization. Ambulatory 24 hours blood pressure (AMBP) parameters (mean BP, daytime BP, nighttime BP, pulse pressure, nocturnal systolic BP dipping, dipper status) were measured in all participants. The variability of systolic BP (SBP) and diastolic BP (DBP) values was assessed by the following common metrics, including the average real variability (ARV), the coefficient of variation (CV), the standard deviation (SD), and the weighed SD of SBP and DBP.

Results: Results: The average values of 24-hour ambulatory blood pressure, mean BP, daytime and nighttime systolic BP, diastolic BP and pulse pressure were found to be significantly different among patients with long COVID syndrome and control group. Group analyses showed that this difference was in SBP mean values (127.1 ± 6.65 mmHg and 115.93 ± 6.24 mmHg respectively) and DBP mean values (73.31 ± 5.30 mmHg and 68.79 ± 5.5 mmHg respectively) mainly at night. PP values at daytime were almost similar among groups, but PP values at nighttime were higher in patients with long-COVID syndrome (53.8 (52.44- 55.14) mmHg and 47.14 (46.45 - 47.88) mmHg respectively). Nocturnal SBP dipping was better in control group than in patients with long-COVID syndrome ( 5.3 ± 5.68 and 3.1 ± 3.79 mmHg respectively). Only 13 (22.4%) patients with long-COVID syndrome had normal dip-per status while more than half - 38 (66.7%) in healthy subjects. The values of ARV of SBP and DBP over 24-hour, awake, and asleep time frames were found to be greater in patients with long COVID syndrome than healthy controls (p < 0.05).

Conclusion: Conclusions: Patients with long- COVID syndrome have higher BP mean values of 24-hour ABPM particularly at nightime, significant blood pressure BP variability, which increases the risk of cardiovascular events in future. Nevertheless, the further prospective investigations is warranted to investigate the potential mechanisms and causality associations.

Only PubMed abstract available at time of posting, https://pubmed.ncbi.nlm.nih.gov/36472284/

 

[Hutan]

This looks interesting. I look forward to reading the full paper.

Nocturnal SBP dipping

that's a lowering of the systolic blood pressure at night time.

dipper status

from another paper: normal variation in blood pressure (BP) is characterized by a 10% to 20% reduction in BP from day to night [1]. Individuals with this decline in nocturnal BP are known as “dippers”, and those who experience a blunted decline in nocturnal BP are known as “non-dippers” [2].



This is useful background from another paper:

"Nighttime blood pressure (BP) is a stronger predictor of cardiovascular risk than clinic or daytime ambulatory BP.1 Blunted nighttime BP “dipping,” the magnitude of fall in BP from day to night, is a strong prognostic indicator of cardiovascular morbidity and mortality for both hypertensive and nonhypertensive individuals.1–3 Clinical characteristics associated with blunted nighttime BP dipping include advancing age, increasing body mass index (BMI), diabetes, renal and cardiovascular disease, smoking and administration of a greater number of antihypertensive medications.4 Female sex also has been identified as an independent predictor of blunted nighttime BP dipping.4 In addition, greater target organ damage has been observed among women who experience an attenuated BP dip at night,5,6 and the association between nighttime BP and cardiovascular outcome has been recently reported to be stronger in women compared with men.7

...
Our analyses also sought to determine whether daytime physical activity and nighttime sleep quality might account for some of the variation in BP dipping associated with CAD and advancing age. Multivariable regression models showed that both of these behavioral characteristics were associated with BP dipping and were independently associated with SBP dipping; however, they did not account for the relationships with CAD or age, which also remained independently related to SBP dipping when all of these factors were included in multivariable regression models.

Our findings provide further evidence for the role of physical activity in cardiovascular health, and support previous reports that increased levels of physical activity may benefit BP dipping.22–24 Evidence regarding the role of physical activity and BP dipping, however, has been inconsistent, and may be related to study sample characteristics."

So, I think we would want to see if the Long Covid participants had gender-matched controls with similar BMIs, given that there may be sex differences and BMI differences in nocturnal BP dipping.

There are at least two other sources of confounding:
1. Different levels of physical activity seem to affect nocturnal BP. The Long Covid participants will probably being doing less physical activity, and so the finding of fewer LC participants having normal dipper status might just be a product of that.

2. Sleep efficiency affects nocturnal BP. I think that's mostly because if you are awake during the night, your BP is likely to look like a day time BP. So, if your sleep schedule is skewed, or you wake frequently, then your nocturnal BP will be higher than that of someone not experiencing those issues. So the finding of higher BP might just be a product of disturbed or reduced night-time sleep.

Therefore, it's hard to know how important the finding is. Could differences in nocturnal blood pressure account for (some) LC/ME/CFS symptoms? I'm inclined to think not, because of what looks to be an overlap in results here. For example, 88% of LC patients didn't have a "normal" dipper status, but 33% of the healthy controls didn't either.

Still, it's a good thing to be looking at, and it seems that more investigation (e.g. over longer periods) is warranted. I just hope that the researchers don't suggest increased physical activity and sleep hygiene are the solutions to LC.