THE SEVERITY of Raynaud’s disease, a common early manifestation of systemic sclerosis, is not only linked to very low temperatures, but also hot environments that reach 35°C and above, according to recent research.
Whilst it is well known that cold temperatures can trigger Raynaud’s episodes, researchers aimed to examine the impact of a broad temperature spectrum on Raynaud’s disease in patients with systemic sclerosis. The researchers analysed data from the Scleroderma Patient-centered Intervention Network Cohort, in which participants with Raynaud’s phenomenon secondary to systemic sclerosis completed severity assessments on a 0-10 numerical scale at enrolment and every three months. Temperature data, including daily mean and “feels like” temperature (adjusted for wind chill and humidity), was collected from weather stations near each participant’s location.
Using linear mixed models with basis splines, the team assessed non-linear changes in Raynaud’s severity as temperature varied. Between April 2014 and August 2023, 2,243 participants contributed 20,233 Raynaud’s severity assessments. The cohort was predominantly female (88%) and White (82%), with an average age of 54.8 years. The highest predicted severity score was 6.8 points, occurring at –25°C (95% CI: 5.6–8.1). Severity remained relatively unchanged between –15°C and 5°C but declined more notably between 5°C and 25°C. The lowest severity was observed at 25°C (2.6 points; 95% CI: 2.5–2.7), followed by a gradual increase at higher temperatures, reaching 5.6 points at 40°C.
The results demonstrate that Raynaud’s phenomenon is most severe in extreme cold, but also worsens in hot environments, potentially due to the impact of people moving between hot outdoor temperatures and very cold temperatures in air-conditioned buildings. For clinical practice, this suggests that management plans should account for environmental conditions, particularly temperature. Additionally, clinical trials for Raynaud’s treatments should be designed with consideration for temperature variability to better reflect real-world patient experiences.
Reference
Virgili-Gervais G et al. The association of outdoor temperature and self-reported Raynaud’s phenomenon severity among people with systemic sclerosis: a Scleroderma Patient-centered Intervention Network Cohort study. Lancet Rheumatol. 2024;6(10):e684-e692.
