A recent study published in the American Journal of Ophthalmology compared five risk factors in patients following a retinal vein occlusion (RVO) diagnosis.
Give me some background.
While previous research has evaluated the rate of RVO against the risk for potential cerebrovascular disease (CVD) and other conditions—such as myocardial infarction (MI)—the results have been largely inconsistent.
According to the study authors, some studies have reported no increased rates of stroke, MI, or death in RVO patients. Others have cited increased risk for death or subsequent cardiovascular events.
Thus, a more accurate finding was needed.
So what was the goal?
Investigators aimed to examine five key risk factors associated with RVO patients, including the rates of:
- Deep vein thrombosis (DVT)
- Pulmonary embolism (PE)
Now talk about the study.
In this retrospective cohort study, researchers used an electronic health records (EHR) research network (the TriNetX network, comprised of multiple large health organizations in the U.S./world) that could aggregate the health record data of over 119 million patients.
The search identified 45,303 patients (average age of 68.1 ± 14.3 years) in each of two cohorts:
- Cohort 1: Diagnosed with RVO
- Cohort 2: Diagnosed with age-related cataracts (control)
Of note, patients who had experienced any of the targeted five risk factors within 2 years of diagnosis for RVO or cataract were excluded.
Additionally, the control cohort was closely matched for age, gender, ethnicity, race, and systemic morbidities of diabetes, hypertension, and hyperlipidemia.
What was measured?
Both cohorts were assessed at Year 1, 5, and 10 for rate of stroke, MI, death, DVT, or PE.
Further, a secondary analysis at the same time points was performed on cohort 1 (RVO) to examine the percentage rate of systemic vascular events in patients with central retinal vein (CRVO; 47%) vs branch retinal vein occlusion (BRVO; 54%).
Each cohort had the following number of patients (based on year of follow-up):
- 1 year → 45,303 patients
- 5 years → 25,024 patients
- 10 years → 13,048 patients
The following data on each risk factor rates was noted:
- Death: Significantly higher after RVO diagnosis
- 1 year, 5 years, 10 years
- Stroke: Significantly higher after RVO diagnosis
- 2 weeks, 5 years, 10 years
- MI: Significantly higher after RVO diagnosis
- 1 year, 5 years
- DVT: Significantly higher after RVO diagnosis
- 1 year
The rate of DVT after RVO diagnosis at 5 years and 10 years was about the same compared to the control group of patients with cataract, while the rate of PE was similar at all three time points between each cohort.
What about that secondary analysis?
Investigators noted an increased risk of death in the CRVO cohort compared to BRVO at all the time points; however, no significant increases were noted for the remaining four risk factors.
Such factors that come with the analysis of examining large sets of de-identified aggregated medical health records data were noted, including (but not limited to):
- Reliance on accurate ICD-10 diagnosis and coding
- No isolation of patients with hemi-retinal vein occlusion (HRVO) from the BRVO and CRVO cohorts
- No control for all possible risk factors between both cohorts (RVO vs cataract)
The authors concluded that, on the whole, the data indicates an increase risk of subsequent vascular events—death, stroke, MI—for the RVO cohort compared to a control population for follow-up at years 1, 5, and 10, as well as a minimal risk of subsequent DVT or PE in RVO patients.
However, they noted that, “this trend was not seen at 5 or 10 years of follow up.”
Additionally, they recommended that further research is needed to explore the potential reason for the elevated risk of death in CRVO patients compared to BRVO patients.
In light of these findings, the authors advised ophthalmologists to be aware of an elevated risk of death and vascular events in RVO patients; long-term systemic evaluation for cardiovascular risk factors (with primary care providers) should also be considered for BRVO/CRVO patients.