PS-C08-7: TIME IN THERAPEUTIC RANGE IS NOT A RISK FACTOR FOR CARDIOVASCULAR DISEASE WHEN ADJUSTED FOR MEAN SYSTOLIC BLOOD PRESSURE

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Background: Time in therapeutic range (TTR) has been suggested as a novel metric to assess blood pressure (BP) control, the quality of antihypertensive therapy, and the risk of cardiovascular events in people with hypertension. Methods: We used a validated electronic health record dataset, including all BP recordings in primary care in two Swedish counties from 1993 to 2011. People were eligible if they were 18 years or older, had a diagnosis of hypertension, no previous cardiovascular events, and at least five BP recordings during the first five years from the date of hypertension diagnosis. TTR was defined as the percentage of BP readings with a systolic value less than 140 mmHg. Participants were followed until death, migration or the 31st of December 2019. The risk of myocardial infarction and stroke was assessed using Cox proportional hazards model with TTR as independent variable, with and without mean systolic BP as a covariate. All analyses were adjusted for age, sex, diabetes, county, income and educational level. Results: 72 724 participants (56% female, mean age 62 years) were included in the analyses. The mean BP level during the first five years after diagnosis was 151/85 mmHg, with a median TTR of 17.7% (interquartile range 0–40%). During an average 7.7 years of follow-up, 6551 participants experienced a first-ever stroke and 5513 a first-ever myocardial infarction. In the unadjusted analyses, the risk of stroke decreased by 7% (HR 0.93, 95%CI 0.92–0.94) and the risk of myocardial infarction decreased by 6% (0.94, 0.93–0.95) for each 10 percentage points increase in TTR. When including mean systolic BP as a covariate, however, TTR was not associated with either stroke (0.99, 0.97–1.01) or myocardial infarction (1.00, 0.99–1.02). Conclusion: TTR for systolic BP is not an independent risk factor for stroke and myocardial infarction in clinical practice and does not add importantly to mean systolic BP as a measure of BP control.