Home BP monitoring

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From: Geoff A. Modest, M.D.
Sent: Monday, March 12, 2018 7:14 AM
To: Geoff A. Modest, M.D.
Subject: Home BP monitoring

​the TASMINH4 study found that blood pressure self-monitoring led to improved blood pressure control (see bp home monitoring lancet2018 in dropbox, or doi.org/10.1016/ S0140-6736(18)30309-X).

Details:
--1182 hypertensive patients from 138 general practices in the UK were randomized to one of 3 wings:
    --usual care (n=394)
    --home-based blood pressure self-monitoring (n=395), to monitor blood pressure twice each morning and evening for the first week of each month; their primary care clinicians were asked to titrate meds based on these measurements
    --self-monitoring plus telemonitoring (n=393), as above for self-monitoring, plus sending SMS texts of results to a center and alerting their primary care clinician if very high or low recordings, texting reminders if the patient did not check their BP enough, asking them to contact primary care if BP above goal, and sending to primary care an easy-to-read display of their BPs
--inclusion criteria: >35yo, clinic BP >140/90, no more than 3 BP meds; exclusion if not on stable meds for 4 weeks, orthostatic hypotension, atrial fib, dementia, CKD >grade 3 or CKD with proteinuria
--mean age 67, 47% female, 97% white, 78% married, 30% working, 10.2 years of htn, 7% CKD/2% MI/4% CABG or stent/2% stroke/9% DM, BMI 30, baseline 0.8 BP meds/5% current smokers [did not quantify alcohol]
--mean baseline BP=153.1/85.5 mmHg
--goal BP: for clinic 140/90, for home-based 135/85 if <80yo; clinic 150/90, home-based 145/85 if >80yo (these are the acceptable standard goals)
--primary outcome: clinic-based systolic BP after 12 months

Results:
--SBP after 12 months:
    --usual care: 140.4 mmHg
    --self-monitoring: 137.0 mmHg
    --self-monitoring plus telemonitoring: 136.0 mmHg
--statistically significant differences in systolic and diastolic BP at both 6 months and 12 months, comparing either of the self-monitoring groups vs usual care; no difference between self-monitoring without or with telemonitoring
--number of BP meds: 1.55 usual care, 1.63 self-monitoring, 1.70 with telemonitoring
    --med increases predominantly in ACE-I/ARB and calcium channel blocker use
--no difference in self-reported med adherence
--no evidence of a non-pharmacologic effect (eg change in diet, exercise, smoking, alcohol, weight)
--effect was similar for all subgroups (age, sex, BP target, socio-economic status, history of cardiovasc disease)
--no difference in number of clinic visits. and, no effect on the workload of the primary care clinicians (!!!!).
--after 6 months, SBP was minimally but significantly better by adding telemonitoring to self-monitoring
--adverse events similar between groups

Commentary:
--hypertension is the greatest risk factor for cardiovascular morbidity and mortality internationally, per a 1990-2010 assessment of 67 risk factors in the Global Burden of Disease Study
--even the small changes found above would project to a 20% reduction in stroke risk and 10% in coronary heart disease risk by using self-monitoring
--the only measured benefit of telemonitoring was more rapidly reaching blood pressure goal (within 6 months). the investigators intend to do a subsequent economic analysis to see if telemonitoring was worth it.
--A few general comments on blood pressure control
    --50% of those initially screened as being "eligible" were excluded in the above study, 90% because their blood pressure was actually at target. this probably in large part reflects that the prior office-based blood pressures were not checked optimally in the office (see blog: http://gmodestmedblogs.blogspot.com/2017/09/the-most-important-hypertension-blog.html ).
    --and, as perhaps the most important point, office-based blood pressure measurements do not translate to clinical outcomes well, much less accurately than either ambulatory blood pressure monitoring (best studied) and home-based blood pressure (less rigorously studied).  part of the issue is white-coat hypertension, but it seems that in a few studies masked hypertension (BP lower in the clinic than outside) is more common than white-coat (eg see http://gmodestmedblogs.blogspot.com/2018/02/ambulatory-blood-pressure-monitoring.html​ ), and would not have been picked up in the above study since inclusion was based on the office-based BP. the graph below shows that clinical cardiovascular events were independent of the office based SBP, but was only dependent on the ambulatory blood pressure monitoring ABPM -- whether that was masked hypertension, or white-coat htn)
--there have been a slew of prior blogs on ambulatory or home-based blood pressure monitoring. some referenced in the recent blog  http://gmodestmedblogs.blogspot.com/2018/02/ambulatory-blood-pressure-monitoring.html  , including an evaluation of the new AHA guidelines, which promoted out-of-the-office blood pressure determinations. also see http://gmodestmedblogs.blogspot.com/search/label/ABPM ​ for many prior blogs on ABPM and home-based monitoring, including the USPSTF recommendations.
  
so, 
even though they based their outcome on clinic-based blood pressure (which is not as good a predictor of clinical events than either ambulatory or home-based measurement), they did find that patients' home-based measurements improved BP control. other studies have suggested that empowering patients/giving them more involvement and control in their care can lead to higher rates of medication taking (though not so in the above study: perhaps related to its design, the actual group of patients involved, etc). would be great if insurance would cover home blood pressure cuffs (and in fact would be even better to have a national health care system which covered all people and looked ahead at long-term outcomes as a key driver of policy/coverage....)

based on prior studies, for the past several years i have been encouraging patients to get home BP cuffs and routinely using home-based blood pressure measurements as my target, even if the office-based ones are much higher. but first i ask the patient to bring in their blood pressure cuff, and i measure the blood pressure simultaneously on one arm as they do the other, and then vice versa. and, if their cuff is okay, i ask them to check their blood pressure at home when sitting down quietly for 5 minutes, discard the first reading, then write down their second reading a few minutes later. if they have no home BP cuff, i ask them to go to a pharmacy to check the blood pressure, again sitting down relaxed for a few minutes before (though i suspect they are often less relaxed in this often busy setting)
  

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Clement DL. New Engl J Med 2003; 348:2407: shows that the only determinant of clinical cardiovascular outcomes was the 24-hr ambulatory systolic level (though diastolics also paralleled this). those with office systolic <140 and high ABPM are considered to have masked htn; those with office systolic >140 but normal ABPM white-coat htn)