Association and impact of hypertension defined using the 2017 AHA/ACC guidelines on the risk of atrial fibrillation in the ARIC cohort Open Access

Rattani, Anas (Spring 2018)

Permanent URL: https://etd.library.emory.edu/concern/etds/8c97kq448?locale=en%255D
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Abstract

Background

            Atrial Fibrillation (AF) is a common chronic arrhythmia, occurring in 2.3 million adults in the United States (4). Amongst the risk factors for AF, hypertension has the largest population attributable fraction for AF incidence and plays a major role in the management and prognosis of AF (1, 2, 10). The most recent hypertension guideline, released in the Fall of 2017 by the American College of Cardiology/American Heart Association refined the guidelines released by JNC7 and JNC8 by lowering the threshold to define hypertension (5, 6, 18, 39). The goal of this study was to understand the association between hypertension and risk of AF using the diagnostic categories in the new guidelines, and evaluate the population attributable fraction of hypertension with the new definitions.

Methods

            We conducted a prospective analysis of the Atherosclerosis Risk in Communities Study (ARIC) cohort data from 1987 to 2016. Cox proportional models were used to estimate hazard ratios of AF among individuals with hypertension based on the JNC7 and 2017 ACC/AHA guidelines. We performed stratified analyses by sex and race to explore effect modification. We also calculated population-attributable fractions (PAFs) to determine the possible impact of preventing hypertension on AF occurrence. Poisson models were used to obtain the risk ratios.

Results

We identified 1573 cases of incident AF during the study period. The prevalence of hypertension was 28.5% and 42.9% using the JNC7 and 2017 ACC/AHA definitions, respectively. In terms of the JNC7 guidelines, the hazard ratio was 1.6, 95% CI [1.49, 1.83] after adjusting for age, sex and race. The AF incidence rate per 1000 person-years was 6.6 and 10.8 for no hypertension and hypertension respectively. In terms of the 2017 AHA/ACC guidelines, the hazard ratio was 1.5, 95% CI [1.37, 1.68] after adjusting for age, sex and race. The AF incidence rate per 1000 person-years was 6.4 and 9.6 for no hypertension and hypertension respectively (Table 5). The PAF was 12% (95% CI [0.09, 0.14]) and 14% (95% CI [0.10, 0.18]) under the old and new guidelines, respectively.

Conclusions

In conclusion, our study showed a slight increase in PAF values. However, there was no difference in the risk of AF by hypertension status between the JNC7 and 2017 AHA/ACC guidelines. These results indicate that changes in the blood pressure cutoff to define hypertension will only have a limited impact regarding the incidence of AF. Additional studies are needed to confirm this finding. Moreover, further studies should incorporate other variables we had not considered such as: aspirin and statin medications, ECG p wave terminal force 1 in V1, HF history, MI history, and diabetes history that may influence the risk of AF.  

Table of Contents

Table of Contents

Chapter 1: Literature Review and Background           1

Atrial Fibrillation         1

Burden of Atrial Fibrillation    3

Hypertension and Atrial Fibrillation   4

JNC7 and JNC8 Guidelines      6

The 2017 ACC/AHA Guideline 8

Chapter 2: Thesis Manuscript 11

Introduction    11

Methods          13

Results 17

Figures and Tables      20

Chapter 3: Discussion/Conclusions    29

Chapter 4: Implications and Recommendations        34

References:     35

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