Acute care visits increase with ‘anomalously warm weather’ among patients with MS

Inpatient and ED visits increased among patients with MS in relation to warm weather anomalies, according to the results of a retrospective cohort study scheduled for presentation at the American Academy of Neurology Annual Meeting.

“Heat sensitivity is a recognized clinical feature of MS, a chronic demyelinating disorder of the central nervous system,” the researchers wrote. “Periods of anomalously warm weather are expected to become more frequent under climate change, yet few studies have specifically examined the health services implications of weather anomalies for individuals living with MS.”

Holly Elser, a medical student at Stanford University School of Medicine, and colleagues aimed to determine the relationship between “anomalously warm weather” and the risk for MS-related outpatient, inpatient and ED visits. The retrospective cohort study included individuals with MS aged 18 to 64 years in a nationwide, patient-level commercial and Medicare Advantage claims database.

The researchers used previously validated algorithms to identify individuals with MS as those with at least three MS-related claims for inpatient, outpatient or disease-modifying therapy within a 365-day period. They defined anomalously warm weather as any month in which local average temperatures surpassed the long-term average temperature for the month by at least 1.5 degrees Celsius.

Elser and colleagues identified 106,225 patients with MS from a pool of 75,395,334 individuals (0.14%). Most of these patients were women (76.6%) and were aged from 36 to 55 years at baseline (59%).

Adjusted generalized log-linear models demonstrated that warm weather anomalies correlated primarily with acute care visits, according to the study results. The researchers observed increased risks for ED visits (RR = 1.04; 95% CI, 1.03-1.06) and inpatient visits (RR = 1.03; 95% CI, 1.01-1.055) related to MS. They reported effect estimates that were similar for men and women, were strongest among older individuals and displayed “substantial” regional and seasonal variation.

“As global temperatures rise, individuals with MS may represent a subpopulation uniquely susceptible to associated periods of anomalously warm weather, with implications for both health care providers and systems,” the researchers wrote.

Reference:

American Academy of Neurology. Could rising temperatures send more people with MS to the hospital? Available at: https://www.aan.com/PressRoom/Home/PressRelease/4866. Accessed March 3, 2021.