Using the recently updated American College of Cardiology/American Heart Association (ACC/AHA) definitions for hypertension, this large-scale Korean study investigated the impact of hypertension stage on the risk for retinal vascular occlusion. Under these new definitions, worse hypertension showed strong correlations with increased risk of retinal vein occlusion (RVO), though retinal artery occlusion risk was not significantly impacted.
Study design
This Korean population-based, retrospective, cohort study used data from the National Health Insurance Service–Health Screening Cohort database from 2002 to 2015 to examine the correlation between stage of hypertension and the risk of retinal vascular occlusion. Patients younger than 40 years of age and those with previous history of retinal vascular occlusion were excluded. The study used the new ACC/AHA blood pressure definitions, updated in 2017, to define 4 groups: normal blood pressure (systolic <120 mm Hg and diastolic <80 mm Hg), elevated blood pressure (systolic 120–129 mm Hg and diastolic <80 mm Hg), stage 1 hypertension (systolic 130–139 or diastolic 80–89), and stage 2 hypertension (systolic ≥140 systolic or diastolic ≥90). Additional patient details such as smoking and alcohol use, income, residence, body mass index, and comorbidities were also collected.
Outcomes
Of the 379,008 patients in the study, 9.2% had elevated blood pressure, 34% had stage 1 hypertension, and 27.9% had stage 2 hypertension. Compared to the normal blood pressure group, higher hazard ratios were noted in both the stage 1 and the stage 2 hypertension groups. There was a statistically significant increase in RVO risk with increasing blood pressure, with stage 2 hypertension associated with the greatest risk of RVO, but no significant correlations were noted between blood pressure stage and retinal artery occlusion. Overall, there was a higher incidence rate of RVO with any diagnosed hypertension in comparison to normal blood pressure. Treatment of hypertension reduced the risk of recurrence of subsequent retinal vascular occlusion.
Limitations
Some limitations include those related to using International Classification of Disease coding nomenclature, which may differ from other classification systems. With limited medical record information included in the database, and data that was accessed cross-sectionally, changes in blood pressure over time were not taken into account. The population was also biased toward males, who made up 57% of the study population; this may have been due to the database sampling method. In addition, the database reflects a Korean population, which may yield different results than other populations.
Clinical significance
It is important to understand the new ACC/AHA guidelines for defining hypertension and that this updated information can change our risk stratification strategy for RVO. Aggressive treatment for high blood pressure in all stages of hypertension appears to be beneficial in decreasing the risk of subsequent RVO. Also of note in this study: while increased risk of RVO was related to hypertension, retinal artery occlusion was not.
Financial Disclosures: Dr. Jessica Randolph discloses financial relationships with Astellas and Genentech (Consultant/Advisor).