# Precipitation, EMS use, and time to presentation of Acute Ischemic stroke in the get with the guidelines-stroke registry

## TL;DR

This study found that rain delays hospital arrival for stroke patients, suggesting the need for better emergency systems during bad weather.

## Contribution

This is the first study to examine the impact of precipitation on stroke presentation delays and its interaction with EMS use.

## Key findings

- Mild precipitation delays hospital arrival by ~4.6 minutes, and major precipitation by ~7.7 minutes.
- EMS use reduces delays, especially during mild precipitation, but not during major precipitation.
- Extreme weather is increasing, so stroke care systems should adapt to support timely treatment.

## Abstract

Delayed presentation to the hospital is a barrier for delivering acute stroke treatments. The effects of weather on delay are unstudied. We examined the relationship between precipitation and time to arrival nationwide.

We studied patients with acute ischemic stroke who presented at a Get With the Guidelines®-Stroke hospital from 2010–2019. The exposure variable was total daily precipitation on the day of presentation, obtained from the National Oceanic and Atmospheric Administration, and categorized as none (0 inches/day), mild (>0–1 inch/day), and major (>1 inch/day). The primary outcome was time to hospital arrival after stroke (in minutes). We conducted multivariate regression analysis, including analysis of interaction between precipitation level and EMS usage.

In ~2.7 million patients, 50.7% were female and 38.6% were ≥75 years old. Median time to hospital arrival was 212 minutes in no precipitation, 219 minutes in mild precipitation, and 223 minutes in major precipitation. In adjusted analyses, compared to no precipitation, mild precipitation was associated with 4.63 minutes of delay [95% CI: (2.77, 6.49)]. Major precipitation was associated with 7.69 minutes of delay [95% CI: (2.86, 12.52)]. EMS usage improved arrival time overall, and there was an interaction with mild precipitation (−6.09 minutes [95% CI: (−9.79 to −2.39)]). However, there was no interaction with major precipitation (−2.72 minutes [95% CI: (−12.38 to 6.93)]).

Precipitation was associated with delayed presentation to the hospital in acute stroke. Increased frequency of extreme weather calls for developing EMS strategies and infrastructure to support climate-ready stroke systems of care.