Extreme ambient temperature and emergency healthcare service utilization due to substance use disorders: a systematic review and meta-analysis.

To synthesize the association between extreme ambient temperatures and the utilization of emergency healthcare services for substance use disorder (SUD). We performed a systematic literature review of original research published between 2000 and 2023 using five databases (PubMed, Embase, CINAHL, WoS, and Scopus) for literature search, and assessed study quality and risk of bias. A random-effects meta-analysis was conducted to calculate the odds ratios (OR) for SUD-related emergency healthcare service utilization during periods of extremely high or low ambient temperatures. Of 709 articles screened, eight studies met the eligibility criteria. Six studies focused on emergency department (ED) visits, while two examined on-site emergency care utilization. The risk of SUD-related ED visits was significantly higher when the mean ambient temperature was in the top 5% of the temperature distribution range (pooled OR = 1.11, 95% confidence interval [CI]: 1.07, 1.15). Conversely, the risk of SUD-related ED visits was lower when the mean temperature was in the bottom 5% of the distribution (pooled OR = 0.94, 95% CI: 0.89, 0.99). Our review showed the extremely high ambient temperature is associated with higher risk of SUD-related emergency healthcare service utilization. However, given the high heterogeneity observed across studies, these results should be interpreted with caution. Differences in study design, population characteristics, geographic region, and substance type may have contributed to this heterogeneity. Despite these differences, this finding highlights the importance of considering environmental factors in the management and prevention of SUD-related health issues.