Impact of blood pressure control on the risk of stroke and mortality in patients with atrial fibrillation across different ages: a nationwide population-based study

Abstract Background High blood pressure in patients with atrial fibrillation (AF) is strongly associated with adverse outcomes, including stroke and death. The impact of blood pressure (BP) control on stroke and mortality rates among different age groups in patients with AF has not been extensively studied. Purpose To examine the impact of blood pressure on stroke and death in AF patients by age group. Methods Based on data from the Korean National Health Insurance Service database, we enrolled 194,302 patients newly diagnosed with AF between January 2009 and December 2016, who underwent health check-ups within two years. We divided patients into four groups based on age: 40-49 years, 50-59 years, 60-69 years, and 70 years and above, to analyze the primary outcome based on the level of BP control within each group. BP control was categorized into five levels. Patients with systolic BP (SBP)<120 mmHg and diastolic BP (DBP)<80 mmHg (Level 1), 120≤SBP<130 mmHg and DBP<80 mmHg (level 2), 130≤SBP<140 mmHg and 80≤DBP<90 mmHg (Level 3), 140≤SBP<160 mmHg and 90≤DBP<100 mmHg (Level 4), and patients with SBP≥160 mmHg and DBP ≥100 mmHg (Level 5). We also divided patients into five groups based according to their SBP levels. We analyzed the occurrence of stroke and death based on the level of BP control within each age group. Results Among a total of 194,302 patients, 55,142 (28%) were included in Level 1, 24,925 (13 %) in Level 2, 88,020 (46%) in Level 3, 23,179 (12%) in Level 4, and 3,036 (1%) in Level 5, categorized by blood pressure. During a median follow-up of 5.2±2.4 years, 14,409 patients had an incident stroke (incidence rate, 14.2 per 1000 person-years), and 27,230 patients died (incidence rate, 25.8 per 1000 person-years). The lowest incidence of stroke was in the group with 120≤SBP<130 mmHg and DBP<80 mmHg (Level 2) across most age groups (Figure). Stroke risk significantly increased with BP levels above 160/100 mmHg, and BP≥140/90 mmHg was associated with stroke occurrence from the age of 50 onwards. Higher SBP (160 mmHg) was consistently associated with a higher incidence of stroke across all ages (HR 1.32, 95% confidence interval (CI) 1.22-1.43 compared to SBP<100 mmHg). Mortality incidence was also lowest in Level 2, and a trend of gradually increasing mortality was observed as BP levels rise above this level. (Figure). Especially when SBP exceeded 160 mmHg, the probability of death also significantly increased across all age groups below 70 years old. Conclusion Uncontrolled hypertension (especially SBP>160 mmHg) was associated with higher risks of stroke and mortality in patients with AF. This association is notably more significant in the middle-aged group, specifically those between 40 and 59 years old, compared to older age groups. Therefore, particularly in middle-aged groups, it is crucial to emphasize adequate blood pressure control in patients with AF.Figure_DeathFigure_Stroke