July 15, 2020
Go Masks Go! Hard not to be proud of all the contagion-respecting mask wearing we are seeing in Seattle! Plenty of observations within the scientific community continue to indicate the benefits, health and economic, of indoor and crowded-outdoor mask wearing. Many of us feel that mask wearing is less stifling than prolonged shelter-in-place and getting tangled up in our own hair. Speaking of that, Morbidity and Mortality Weekly just published their contact tracing of two symptomatic hair stylists with confirmed COVID-19 (https://tinyurl.com/y7r4lom7). Of 139 exposed clients and their secondary contacts, by 2 weeks after exposure, no COVID-19 symptoms were identified and of the 67 clients who had been tested there were zero positive tests. By contrast, of the 4 household contacts of one of the stylists tested positive. Masks work.
The pressure to lower blood pressure:
Last week we discussed the association of chronic hypertension with increased risk of adverse outcomes in patients with COVID-19, the standard categorizations of chronically elevated blood pressure, and the strong epidemiological link between chronic hypertension and death from heart disease or strokes, pandemic or not.
With all that in mind, what is known about the benefits of using lifestyle or medication to lower your blood pressure?
It is exceptionally hard to randomize people to one lifestyle modification v. the absence of it and track hard outcomes like heart attacks, strokes, and deaths. Still, there is some evidence that lifestyle choices can lower blood pressure:
- Weight loss. In overweight or obese individuals, weight loss can lead to a significant fall in blood pressure independent of exercise and sodium restriction. The weight loss-induced decline in blood pressure generally is about 1 mmHg for every 1 pound lost up to about 10 pounds lost (https://tinyurl.com/yayjbmd4).
- Sodium reduction. In well-controlled randomized trials, the overall impact of moderate sodium reduction is a fall in average blood pressure in hypertensive people of about 5 mmHg (https://tinyurl.com/y79helnl).
- Exercise. Aerobic exercise, and possibly resistance training, can decrease systolic and diastolic pressure by, on average, 4 to 6 mmHg and 3 mmHg, respectively, independent of weight loss. Most studies demonstrating a reduction in blood pressure have employed three to four sessions per week of moderate-intensity aerobic exercise lasting approximately 40 minutes for a period of 12 weeks (https://tinyurl.com/y8vae34a).
There remain gaps in knowledge but a variety of randomized trials have attempted to address the benefit of lowering blood pressure using medications, especially within people of higher risk for cardiovascular disease.
The most cited study is the SPRINT trial, performed in the U.S. on 9361 people age 50+ living with chronic hypertension and one or more of a long list of additional risk factors for cardiovascular disease (https://www.nejm.org/doi/full/10.1056/nejmoa1511939). These people were randomized to standard treatment targeting systolic blood pressure (SBP) <140 mmHg versus intensive treatment targeting SBP <120 mmHg (with up to multiple medications deployed to do so). The trial was halted early, after 3.26 years, by the independent safety monitoring board (only group with such early access to the result data) because the people getting intensive treatment targeting SBP <120 mmHg had 25% fewer adverse cardiovascular events (a composite of heart attacks, strokes, and heart failure) and 27% lower risk of death. Those are big numbers. Importantly, there was no difference between the treatment groups in quality of life or patient satisfaction measures. These strong results surprised many medical scientists and the roar of discussion around the SPRINT trial continues to fill pages of the medical literature.
What about using medications to lower blood pressure in people with chronic hypertension but who are of lower risk for heart attacks and strokes than the people enrolled into the SPRINT trial? It is harder to study those people for sure, since the researchers need to wait longer for results (i.e. healthier people have longer to wait for a heart attack or stroke). Furthermore, there have been no goal blood pressure trials (like SPRINT where people are randomized to one blood pressure goal vs. another) in lower-risk people. However, there are three large trials of lower-risk patients that compared antihypertensive therapy with placebo:
- HOPE-3 trial (N Engl J Med. 2016;374(21):2009). 12,705 patients at moderate risk for cardiovascular disease (none had preexisting cardiovascular disease, and only 38 percent were hypertensive at baseline) were randomly assigned to receive a fixed-dose combination of candesartan plus hydrochlorothiazide or placebo. Active treatment lowered blood pressure by 6/3 mmHg over the course of the trial. At 5.6 years, fewer cardiovascular events occurred among those treated with the fixed-dose combination, although this was not statistically significant.
- MRC trial (Br Med J (Clin Res Ed). 1985;291(6488):97).17,354 patients with a baseline diastolic pressure 90 to 109 mmHg were randomly assigned to bendrofluazide, propranolol, or placebo for up to five years.The mean baseline blood pressure was approximately 161/98 mmHg; the mean attained blood pressure was approximately 137/86 mmHg in the two treated groups and 150/92 mmHg in the placebo group. The treated groups had significantly lower rates of all cardiovascular events (6.7 versus 8.2 per 1000 patient-years) and of stroke but not of coronary events or mortality.
- HDFP trial (JAMA. 1979;242(23):2562).7825 patients with mild hypertension (diastolic pressure of 90 to 104 mmHg) were randomly assigned to intensive therapy in special clinics (stepped care) or to usual source-of-care therapy in the community. The main endpoint was total mortality at five years, which was significantly lower with stepped care (5.9 versus 7.4 percent, absolute benefit 1.5 percent, 95% CI 0.4-2.6 percent).
If your eyes are glazed over now, which assumes you have actually reached this point in the newsletter, and you still aren’t sure how favorable your blood pressure is, take a few weeks to track your blood pressure at home as was described in last week’s newsletter, and send your averages to us for feedback.
Inside dining still risky, socially distanced outdoor small gatherings lower risk.
The data piquing our interest this week doesn’t come from a COVID research study, but rather from JPMorgan-Chase, the financial giant. They released data at the end of June indicating that higher in-person credit card activity at restaurants in an area (as opposed to online orders) tracked well with a time-lagged increase in COVID cases in the same area. Conversely, protests associated with police brutality and racial justice did not result in a rise in COVID cases.
It is likely due to a couple of important factors which relate to how COVID spreads. Protesters were largely masked; they were outside, where air currents disperse viral particles and reduce spread; and they were typically not having prolonged interactions face to face with each other. In contrast, in restaurants, even if tables are 6 ft apart, the people seated at a table are facing each other, unmasked and talking while eating, for more than 15 minutes (which appears to be the threshold above which transmission is much more likely). Sitting at a table outside improves this risk, but does not eliminate it.
Our takeaway: continue to support your local restaurants through purchasing gift cards for later use, and ordering online for pickup, but if you want to share a meal with 5 or fewer friends, do it in your backyard or a park, where you can be 6 ft away from each other when your masks are down.
CALLING ALL READERS
It’s been almost a month since we’ve asked you what books you’re reading. Let us know what you’ve been digging your nose into these days so we can share it with other Wise Patients!
A Doggy Dip
Audrey is taking a dip in water to cool off. What are you doing to beat the heat?