To assess the potential prevalence of Posterior Reversible Encephalopathy syndrome (PRES) and its association with cerebral infarction (CI)  in a nationwide database. We also investigated the outcome of CI in association to PRES in terms of inpatient mortality rate and length of stay in the hospital. 

PRES is a very rare syndrome, and its impact on stroke is not well understood. It can be irreversible and life threatening when it is presented with stroke. In this regard, more research studies are needed to improve the outcomes.  

In a total of 21  million patients, the frequency of PRES was 0.03% for all patients compared to 2.2% (OR 4.6, CI 4.23-5.01 p<0.001) in cerebral infarct patients. The prevalence of PRES was significantly higher in  females (female, 63.5% vs male, 36.5%, p< 0.001) and Caucasians (Caucasians 63%, vs others, 37%  p<0.001).  In patients with CI in association to PRES, the outcome was worse in terms of mortality  (11% vs 6%, p<0.001) as well as  LOS (12 vs 6  days, p=0.001). In  addition, we have observed that HTN, pre-eclampsia, polyarteritis nodosa, cryoglobulinemia, porphyria  were associated with PRES ( p<0.001) in this data base. 

 PRES was observed to be associated with enhanced risk of CI. This association was associated with worse outcome. Measures designed to prevent the development of  PRES, or to limit its severity, are warranted.