How will I know if my blood pressure medicine is working?

The 2013 Practice guidelines for the management of arterial hypertension of the European Society of Hypertension (ESH) and the European Society of Cardiology (ESC) stress the importance of attending follow up doctor appointments after beginning therapy.¹ These appointments should take place at 2-week to 4-week intervals, in order to evaluate the effects on blood pressure and to asses possible side effects.¹

In addition to regular follow up visits, patients can monitor their own blood pressure (BP) at home with a home blood pressure machine or have their blood pressure checked at a local pharmacy. The Home Blood Pressure Monitoring study, a randomized, controlled, one year clinical trial, compared hypertension management programs in which one group of patients monitored their BP at home while the other group used usual care (UC) to manage BP. In the home BP group, mean follow-up systolic BP was 4.5 mm Hg lower (95% CI: 1.5 mm Hg, 7.6 mm Hg) and mean follow-up diastolic BP was 1.6 mm Hg lower (95% CI: 0.0 mm Hg, 3.3 mm Hg) than the UC group.² At year one, home group systolic/diastolic BP decreased by 1.4 /0.1 mm Hg while UC group systolic/diastolic BP increased by 1.8/1.7 mm Hg.² A meta-analysis of 18 randomized controlled studies also found home blood pressure monitoring (HBPM) to be effective in lowering blood pressure.³ Participants randomized to home monitoring had a 4.2 mm Hg (95% CI: 1.5 mm Hg, 6.9 mm Hg) lower mean systolic blood pressure, and a 2.4 mm Hg (95% CI: 1.2 mm Hg, 3.5 mm Hg) lower diastolic BP than those who only had their BP measured in the office.³

Home blood pressure monitoring has been shown to be a better predictor of cardiovascular events and mortality then office blood pressure monitoring.^4-6 a joint statement, The American Heart Association, The American Society of Hypertension, and The Preventive Cardiovascular Nurses Association, refer to HBPM as the method of choice for evaluating the effects of antihypertensive treatment.⁷  Home blood pressure monitoring should not replace normal follow-up appointments.⁸

Another useful means for monitoring blood pressure is ambulatory blood pressure (ABP) monitoring. ABP monitoring has been found to be an independent predictor of cardiovascular events among hypertensives.^9-14 Therefore, ABP monitoring may be a valuable tool in measuring the efficacy of antihypertensive treatment. Both the British Hypertension Society and the American Heart Association define normal ambulatory BP measurements as  ≤135/85 mm Hg for daytime readings, ≤120/70 mm Hg for nighttime readings, and ≤130/80 mm Hg for 24-hour readings.¹⁶ The National Institute for Care Excellence recommends a target ABP average of <135/85 mm Hg for those less than 80 years of age, and <145/85 mm Hg for those aged 80 years and over.¹⁷ The European Society of Hypertension/European Society of Cardiology define normal ambulatory BP as an average 24 hour measurement <130/80 mm Hg and average daytime BP as <135/85 mm Hg.¹

References

1. Mancia G, Fagard R, Narkiewicz K, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension: the Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Journal of hypertension. Jul 2013;31(7):1281-1357.
2. Soghikian K, Casper SM, Fireman BH, et al. Home blood pressure monitoring: effect on use of medical services and medical care costs. Medical care. 1992:855-865.
3. Cappuccio FP, Kerry SM, Forbes L, Donald A. Blood pressure control by home monitoring: meta-analysis of randomised trials. Bmj. 2004;329(7458):145.
4. Fagard R, Van Den Broeke C, De Cort P. Prognostic significance of blood pressure measured in the office, at home and during ambulatory monitoring in older patients in general practice. Journal of human hypertension. 2005;19(10):801-807.
5. Mallion J-M, Clerson P, Bobrie G, Genes N, Vaisse B, Chatellier G. Predictive factors for masked hypertension within a population of controlled hypertensives. Journal of hypertension. 2006;24(12):2365-2370.
6. Ohkubo T, Imai Y, Tsuji I, et al. Home blood pressure measurement has a stronger predictive power for mortality than does screening blood pressure measurement: a population‐based observation in Ohasama, Japan. Journal of hypertension. 1998;16(7):971-975.
7. Pickering TG, Miller NH, Ogedegbe G, Krakoff LR, Artinian NT, Goff D. Call to Action on Use and Reimbursement for Home Blood Pressure Monitoring: Executive Summary. A Joint Scientific Statement From the American Heart Association, American Society of Hypertension, and Preventive Cardiovascular Nurses Association. 2008;52(1):1-9.
8. James PA, Oparil S, Carter BL, et al. 2014 evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. Feb 5 2014;311(5):507-520.
9. Verdecchia P, Porcellati C, Schillaci G, et al. Ambulatory blood pressure. An independent predictor of prognosis in essential hypertension. Hypertension. 1994;24(6):793-801.
10. Mancia G, Sega R, Bravi C, et al. Ambulatory blood pressure normality: results from the PAMELA study. Journal of hypertension. 1995;13(12):1377-1390.
11. Perloff D, Sokolow M, Cowan R. The prognostic value of ambulatory blood pressures. JAMA. 1983;249(20):2792-2798.
12. KATAYAMA S, MARUNO Y, ITABASHI A, INABA M, OMOTO A, ISHII J. Clinical significance of ambulatory blood pressure monitoring. Japanese heart journal. 1991;32(1):45-55.
13. Kikuya M, Hansen TW, Thijs L, et al. Diagnostic thresholds for ambulatory blood pressure monitoring based on 10-year cardiovascular risk. Circulation. 2007;115(16):2145-2152.
14. Staessen J, Bieniaszewski L, O'Brien E, Imai Y, Fagard R. An epidemiological approach to ambulatory blood pressure monitoring: the Belgian Population Study. Blood pressure monitoring. 1996;1(1):13-26.
15. O'brien E, Coats A, Owens P, et al. Use and interpretation of ambulatory blood pressure monitoring: recommendations of the British Hypertension Society. BMJ: British Medical Journal. 2000;320(7242):1128.
16. Pickering TG, Hall JE, Appel LJ, et al. Recommendations for blood pressure measurement in humans and experimental animals. Circulation. 2005;111(5):697-716.
17. McCormack T, Krause T, O'Flynn N. Management of hypertension in adults in primary care: NICE guideline. Br J Gen Pract. 2012;62(596):163-164.