Background and Objectives: Although reversible cerebral vasoconstriction syndrome (RCVS) is a rare disease, the condition may occur with COVID-19 infection. We aimed to investigate the clinical characteristics of RCVS through a systematic review of case reports and case series that reported on COVID-19-related RCVS. Methods: A literature search was performed in PubMed (MEDLINE), SCOPUS, and Web of Science. The search was confined to articles published between 17 November 2019 and 14 August 2024. The search terms were (“COVID-19” OR “SARS CoV-2”) AND (“RCVS” OR “Reversible cerebral vasoconstriction syndrome”). The search protocol was registered in PROSPERO (CRD42024491818). A total of twenty-four cases were included, nine case series consisting of nineteen cases and five cases from our hospital. Clinical characteristics were investigated, including risk factors, symptoms, brain and angiographic findings, treatment options, and prognoses. Results: The average age was 37.1 years, and females comprised 70.8% of the cohort. COVID-19 vaccination was administered in five cases. Vasoconstriction was most frequently noted in middle cerebral arteries (90.9%). Among the included patients, 12 (50.0%) experienced strokes as a complication of RCVS, and the mortality rate was 9.1%. Follow-up imaging findings were available for 14 of the 24 cases (58.3%). Among these, vasoconstriction was fully improved in 64.3%, partially improved in 28.6%, and aggravated in 7.1%. Conclusions: While the recovery rate of vasoconstriction on brain angiographic findings was not uncommon, our systematic review indicates a potential for a relatively poor neurological prognosis in COVID-19-related RCVS.

Low back pain (LBP) is a major global health concern and remains a leading contributor to healthcare expenditure in the United States (US). Few recent studies have systematically analyzed the temporal, geographic, and demographic patterns of LBP burden and its associated risk factors in the US. This study aimed to examine the burden of LBP and its risk factors in the US from 1990 to 2021. We conducted a systematic analysis of LBP in the US from 1990 to 2021 using the Global Burden of Disease 2021 dataset. Estimates of LBP burden, including prevalence, incidence, and years lived with disability (YLDs), were analyzed along with attributable risk factors. Disease burden estimates were generated using DisMod-MR 2.1, a Bayesian meta-regression tool. Age-standardized rates were stratified by age group, sex, region, and sociodemographic index. Age–period–cohort effect analysis was used to examine the temporal dynamics. In 2021, the age-standardized LBP prevalence and YLD rates in the US were 10,670 and 1179 per 100,000, respectively, representing decreases of 7% and 8% compared with 1990. Geographic disparities were evident, with the East South Central exhibiting the highest prevalence and YLD rates, whereas New England demonstrated the lowest. At the regional level, the Midwest exhibited the highest burden, while the Northeast had the lowest. LBP prevalence was consistently higher in females than in males, across all age groups. Additionally, YLD rates were inversely correlated with sociodemographic index both nationally and across the 9 Census divisions (ρ = −0.583, P < 0.001). Age–period–cohort analysis showed that LBP burden increased with advancing age and in more recent periods. Among modifiable risk factors, high body mass index, smoking, and occupational ergonomic factors collectively accounted for 43% of LBP-related YLDs. LBP has remained a leading cause of disability in the US for over 3 decades, disproportionately affecting women and older adults and showing pronounced regional and demographic disparities. Strengthening subnational surveillance is essential to facilitate integrated, evidence-based LBP prevention and multidisciplinary management, particularly for high-burden populations and regions. Future research should evaluate scalable interventions targeting modifiable risk factors (e.g., obesity and smoking) to reduce inequities.