Primary Care Corner with Geoffrey Modest MD: BP Self-Monitoring/Self-Titrating Decreases BP

By Dr. Geoffrey Modest

Article in JAMA on benefit of patients’ blood pressure monitoring and self-management (see doi:10.1001/jama.2014.10057). In this UK study 552 high-risk patients (at least 35 yo with history of stroke or TIA; coronary artery disease with either CABG, MI or poorly controlled angina; diabetes; or chronic kidney disease stage 3 with GFR 30-59, and a baseline BP>130/80), were randomized (unblinded) to the intervention (blood pressure self-monitoring with individualized self-titration algorithm) vs control (usual care), with target BP of 125/75). Patients were excluded if BP>180/100, or on more than 3 BP meds. Main outcome was difference in systolic blood pressure after 12 months. Results:

• Mean baseline BP was 143/80. mean age 70, 60% men, 97% white, BMI 31, 79% professional or skilled workers
• After 12 months: the intervention group achieved BP 128/74, control group 139/77, with a significant difference from the baselines of each group of 9.2/3.4. Data at 6 months was 6.1/3.0 difference. More meds in intervention group (mean daily dose, per WHO criteria, 3.34 vs 2.61). Subgroup analysis: no diff by underlying disease, gender, age
• No diff in adverse events

For perspective, a few points:

1. Hypertension is leading risk  factor for disease burden/cause of premature mortality globally; and in the US, only about 1/2 meet the guideline-suggested goal (which, is better with JNC-8 criteria, but still in the 50% range)
2. There are evident issues with this study methodology: those in the intervention group had more personal training and contact with health professionals; this was a pretty particular group with very particular inclusions and exclusions; the group was a pretty educated white middle-class group so ?? generalizability
3. Blood pressure goals have changed since this study started (are higher), so is this useful?

BUT…

1. There probably is a real utility in empowering patients in terms of their health (i.e., converting the traditional doctor-patient relationship from one of the patient passively accepting the wisdom and instruction of the clinician to one where the patient is actively involved in monitoring and fixing the problem). And there are some old medication adherence studies from the 1970s which found that in the group of patients who were not taking hypertension meds regularly, giving them blood pressure cuffs and training led to much higher levels of medication taking (my recollection: in 2 studies, one in a workplace and one in a shopping mall, they found patients who were not taking their meds and acknowledged it, were given BP cuffs and instructions, and on follow-up about 30% of them had achieved improved medication-taking and blood pressure control).
2. In my own practice over the years (in a predominantly poor, non-English speaking community), home blood pressure monitoring has improved blood pressure control (I always ask the patient to bring in their cuff to make sure it is accurate), and a few patients with more erratic blood pressure have done exceedingly well self-titrating their medications depending on the blood pressure readings (with my giving them clear instructions about how to do so). My guess is that part of the benefit of this self-titration approach is that blood pressure does vary significantly from day-to-day (related to food intake, variability of smoking/alcohol, weather – e.g. esp. my older patients have lower blood pressure on hot days when they sweat a lot, exercise, etc.), and that self-titration allows better day-to-day control (sort of similar to diabetics who can check their blood sugar after a meal to see which foods are good or bad for them, as well as adjust their rapid insulin based on the result)
3. There are relatively impressive data suggesting that home blood pressure evaluation is more predictive of clinical events than office-based blood pressure readings, adding another aspect validating this home-based approach. E.g., see meta-analysis (htn ambulat bp monitor metanal bmj 2011 in dropbox, or doi: 10.1136/bmj.d3621) or the really extensive (and really good, from my perspective) NICE recommendations (see https://www.nice.org.uk/guidance/qs28/resources/guidance-quality-standard-for-hypertension-pdf for a summary of recommendations, or http://www.ncbi.nlm.nih.gov/pubmed/22855971 for full recommendations)
4. It seems reasonable to assume that the above technique would apply equally well to the higher BP goals we currently accept.