LAUSR

OBJECTIVE To estimate the incidence of hospitalization for reversible cerebral vasoconstriction syndrome (RCVS), we identified RCVS-related hospital admissions across 11 U.S. states in 2016. METHODS We tested the validity of ICD-10 code I67.841 in 79 patients with hospital admissions for RCVS or other cerebrovascular diseases at one academic and one community hospital. After determining that this code had a sensitivity of 100% (95% CI, 82-100%) and a specificity of 90% (95% CI, 79-96%), we applied it to administrative data from the Healthcare Cost and Utilization Project on all ED visits and hospital admissions. Age- and sex-standardized RCVS incidence was calculated using census data. Descriptive statistics were used to analyze associated diagnoses. RESULTS Across 5,067,250 hospital admissions in our administrative data, we identified 222 patients with a discharge diagnosis of RCVS in 2016. The estimated annual age- and sex-standardized incidence of RCVS hospitalization was 2.7 (95% CI, 2.4-3.1) cases per million adults. Many patients had concomitant neurologic diagnoses, including subarachnoid hemorrhage (37%), ischemic stroke (16%), and intracerebral hemorrhage (10%). In the 90 days before the index admission, 97 patients had an ED visit and 34 patients a hospital admission, most commonly for neurologic, psychiatric, and pregnancy-related diagnoses. Following discharge from the RCVS hospital admission, 58 patients had an ED visit and 31 had a hospital admission, most commonly for neurologic diagnoses. CONCLUSIONS Using population-wide data, we estimated the age- and sex-standardized incidence of hospitalization for RCVS in U.S. adults as approximately 3 per million per year.