Posterior Reversible Encephalopathy Syndrome: Risks in Women, Black Patients

Incidence of posterior reversible encephalopathy syndrome (PRES) is estimated to occur in 3 per 100,000 cases annually in the United States; however, the condition disproportionately affects women and Black individuals, according to study findings published in Neurology.

PRES is characterized by symptoms of acute headache, confusion, visual disturbance, seizures, and/or focal neurologic impairments associated with radiologically confirmed cerebral edema affecting both parieto-occipital lobes. After identification of PRES in 1996, it has become increasingly recognized using magnetic resonance imaging (MRI) brain scans.

Researchers in the United States conducted a retrospective cohort study, obtaining relevant data from State Inpatient Databases of Florida (2016-2019), Maryland (2016-2019), and New York (2016-2018). They analyzed the incidence of PRES according to age, sex, and race specific demographic factors.

During the study period, 3716 incident hospitalizations due to PRES were documented in these 3 states: Florida (2026), Maryland (539), and New York (1151). The mean age of patients was 56.5 and 70.9% were women. In 30.3% of admissions, PRES was the primary diagnosis and 87.7% of these were present on admission. When PRES was the secondary diagnosis, common primary diagnoses included sepsis, hypertensive emergency, preeclampsia, and seizure disorder.

The researchers calculated the overall incidence of PRES in these selected states to be 2.7 cases/100,000/year (95% CI, 2.5-2.8).

The researchers noted that PRES occurred more frequently in women than men (3.7 vs 1.6 cases/100,000/year; P <.001), although the incidence of PRES increased as age increased in both women and men (P-trend <.001).

Explanations for this sex disparity remain unclear, especially since the etiology underlying PRES itself is unknown. Possible explanations for PRES include disruption of the blood-brain barrier due to impaired cerebral autoregulation and/or endothelial dysfunction. The researchers suggest that the autoimmune inflammatory conditions that preferentially affect women may also play a similar role in PRES; however, comorbid autoimmune conditions occurred with low prevalence in this cohort, so it is unlikely that this is a contributing factor.

The data demonstrated racial disparities as incidence of PRES was significantly higher among Black individuals (4.2/100,000/year) compared to non-Hispanic White individuals (2.7/100,000/year) and Hispanic individuals (1.2/100,000/year; P <.001 for pairwise comparisons).

The researchers discovered that less than 50% of individuals diagnosed with PRES are discharged home without assistance. Many survivors of severe PRES remained functionally impaired 3 months after hospitalization, requiring extensive rehabilitation. This suggests that people with PRES experience some degree of disability upon hospital discharge, despite the reversible nature of the condition and the anticipated favorable outcomes.

The racial disparities in PRES diagnosis identified in the study may be attributed to the diseases that can drive the development of PRES, according to the researchers. For example, compared with the general population, Black individuals are more likely to have severe hypertension, preeclampsia, and renal failure, they acknowledged.

“Our findings indicate that increased PRES risk may be an additional pathway through which structural racism may be contributing to increased morbidity in Black patients compared to other races,” the researchers wrote.

Study limitations included the restriction of patients to just 3 states as opposed to the entire United States, the potential misclassification of PRES due to coding errors, and the difficulty in recognizing PRES, which may lead to a significant number of undetected hospital cases.