AHA 2017: More Time at Target Blood Pressure Is Associated With Lower Risk of Incident Cardiovascular Diseases in Patients With Hypertension
November 15, 2017—Anaheim, California—More time at target blood pressure is associated with lower risk of incident cardiovascular diseases in patients with hypertension, independent of widely used indicators of blood pressure “control.”
This outcome of a study of linked electronic health records over a 13-year period was reported at the American Heart Association’s Scientific Sessions 2017, from November 11 - 15.
Mar Pujades-Rodriguez, MD, PhD, of the Farr Institute, University College London, and the School of Medicine, University of Leeds, UK, explained that time at blood pressure target might be an important measure of hypertension treatment effectiveness but one which has yet to be evaluated in the general population.
Dr. Pujades-Rodriguez and colleagues set out to answer the three research questions:
- What is the average time in a year that blood pressure remains at treatment target in hypertensive patients?
- How do patient characteristics and use of blood pressure-lowering medications influence the time at blood pressure target?
- To what extent is time at blood pressure target, independent of other indicators of blood pressure control, such as a single measure of “control” or variability in blood pressure from visit to visit, associated with clinical outcomes?
“We undertook this study,” Dr. Pujades-Rodriguez told Elsevier’s PracticeUpdate, “because we were interested in evaluating the importance of achieving and sustaining long-term blood pressure control in a real-world population of patients with hypertension to improve patient outcomes.”
She continued, “The current clinical convention is to assess blood pressure 'control' at a one-off time point. Guidelines do not recommend a frequency of blood pressure monitoring, nor how repeat measures might be used.”
“Furthermore,” she said, “recent clinical trials evaluate the efficacy of decreasing target blood pressure levels. Previous studies, however, have shown that suboptimal blood pressure control to current management targets, measured at a one-off time point, is common.”
“We wanted to evaluate time spent at target by patients newly identified with high blood pressure and its use as an indicator of the effectiveness of hypertension management in the general population.”
The investigators assessed the average time per year spent at blood pressure treatment target (TIme at TaRgEt [TITRE]) in newly identified hypertensive patients, and tested the hypothesis that this time period would provide important information on cardiovascular outcomes, in addition to other blood pressure control measures.
The investigators identified a population-based cohort of 169,082 individuals with newly identified high blood pressure and free of cardiovascular disease from 1997 to 2010.
The researchers used linked electronic health records from primary and hospital care [Clinical research using LInked Bespoke studies and Electronic health Records (CALIBER)].
CALIBER links patient records from four different data sources: primary care (Clinical Practice Research Datalink, disease registry (Myocardial Ischaemia National Audit Project registry), hospital care (Hospital Episodes Statistics), and death registry (Office of National Statistics).
For each individual, the TITRE was calculated based on the most recent clinical guidelines. The three primary endpoints were:
- A composite of incident cardiovascular death, myocardial infarction, and stroke
- Incident heart failure
- A composite of any cardiovascular disease or death
A total of 1.64 million clinical blood pressure readings were used (median 7, interquartile range 3, 16) measures per patient) were used during a median of 4.9 years of follow-up.
Median TITRE among all patients was 2.8 (interquartile range 0.3, 5.6) months per year. Only 0.6% (n=977) of patients had a TITRE ≥11 months.
Compared with patients with a TITRE of 3 - 5.9 months, patients with a TITRE of 6 - 8.9 and 9 - 11.9 months were at 27% and 30% lower odds of the composite of cardiovascular death, myocardial infarction, and stroke [adjusted odds ratios 0.73 (95% confidence interval 0.60, 0.89) and 0.70 (95% confidence interval 0.50, 0.98), respectively].
A lower TITRE value, of 0 and <3 months, increased the odds of disease by 4.5 (95% confidence interval 3.7, 5.5) and 1.8 (95% confidence interval 1.2, 2.7).
These graded, stepwise associations between higher TITRE and lower risk of outcomes were consistent for incident heart failure and the composite of any cardiovascular disease and death, and for all secondary endpoints.
A reduced risk of the endpoints was also observed among patients whose blood pressure was not “controlled” on a single occasion during the first year of follow-up.
Dr. Pujades-Rodriguez concluded that few newly diagnosed hypertensive patients sustained complete, year-round on-target blood pressure over time. More time at target blood pressure was associated with a lower risk of incident cardiovascular diseases, independent of widely used blood pressure “control” indicators.
It was estimated that over 1823 cases of cardiovascular disease and death might be prevented or deferred per 100,000 newly diagnosed hypertensive patients over 5 years by increasing patients’ times spent at blood pressure target by 3 months.
Interventions to raise time spent at blood pressure target need to be evaluated and compared to those aiming to achieve a lower blood pressure target.
Dr. Pujades-Rodriguez concluded that few newly diagnosed hypertensive patients sustained complete, year-round on-target blood pressure over time. More time at target blood pressure was associated with a lower risk of incident cardiovascular diseases, independent of widely used blood pressure “control” indicators.
It was estimated that over 1823 cases of cardiovascular disease and death might be prevented or deferred per 100,000 newly diagnosed hypertensive patients over 5 years by increasing patients’ times spent at blood pressure target by 3 months.
Interventions to raise time spent at blood pressure target need to be evaluated and compared to those aiming to achieve a lower blood pressure target.
“We found,” Dr. Pujades-Rodriguez remarked, “that almost all patients newly identified with high blood pressure failed to achieve and sustain consistent blood pressure control. More time at target was associated with lower risk of incident cardiovascular diseases. The TITRE was a stronger predictor of clinical outcomes than other measures of blood pressure management used.”
“The implications are that efforts to lower cardiovascular risk among hypertensive patients should fully utilize multiple measurements of blood pressure in usual care or via self-monitoring.”
“Clinical guidelines could consider recommending time at target as a measure of the quality of care provided to patients with hypertension, complementing the current snapshot definition of control.”
“This recommendation,” she said, “could be implemented in clinical care through electronic health record systems and by patients using home blood pressure monitoring and apps and can be evaluated in future studies.”
“Our results also support more frequent blood pressure monitoring, for example, every 3 months, given the evidence of graded, stepwise lower cardiovascular risk with every 3 months of increase in TITRE.”
“Our findings also suggest,” she added, “that before considering more aggressive treatment and lower blood pressure targets, it might be more effective to focus on developing and implementing interventions to achieve and maintain blood pressure control using existing blood pressure targets, such as initiating antihypertensive treatment earlier and improving treatment adherence to increase the time spent at target.”
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