Global warming could increase emergency room visits and hospitalizations

According to a new study published in the journal Science Advances, global warming may lead to an increase in medical visits and hospitalizations, despite the expected decrease in mortality due to the reduction in the number of cold days. Scientists from the University of California carefully analyzed the health data of more than 12 million Californians from 2006 to 2017 and concluded that climate warming brings with it both positive and negative consequences, and the latter often remain hidden in traditional approaches to assessing the damage from climate change.

Research in detail

The researchers compared medical data on emergency room visits, hospitalizations, and deaths with daily temperature readings. They analyzed different age groups and reasons for visits, which allowed them to identify subtle differences in how the population reacts to extreme temperatures.

• In total, the following were analyzed:
  • 123 million emergency department visits.
  • 45 million hospitalizations.
  • 2.9 million deaths.

The data were carefully correlated with temperature conditions, categorized from extremely cold to extremely hot days.

Key findings of the study:

1. The impact of heat on health

• On hot days (above 30°C), a significant increase in emergency room visits has been recorded, especially among children under 5 years of age, who react to the heat with a sharp deterioration in their health.
• Hospitalizations also increase during hot periods, but the most vulnerable to extreme heat are older people over 65, who are most likely to suffer from cardiovascular and respiratory complications.
• An increase in mortality during heat waves is also observed, but it is less pronounced compared to the increase in the number of requests for medical care.

2. The effect of cold on health

• On cold days (below 6°C), on the contrary, mortality increases significantly, especially among the elderly, mainly due to cardiovascular complications.
• At the same time, the number of visits to emergency departments on cold days, on the contrary, decreases. Scientists believe that this may be due to the fact that people leave their homes less often and suffer fewer injuries, but seriously ill people are more often immediately hospitalized, bypassing emergency departments.

Why do mortality and morbidity respond differently?

The researchers found that the response of morbidity and mortality to temperature extremes differed for several reasons:

• Age of patients:

  • Mortality is concentrated among older people, in whom cold is more likely to trigger severe cardiovascular and respiratory events.

  • Young people and children are more likely to visit emergency departments on hot days, mainly due to dehydration, heat stroke, and general symptoms such as headache and weakness.

• Reasons for requests:

  • The causes of death differ from the reasons for seeking medical care. Deaths are mainly caused by chronic diseases (cardiovascular, respiratory diseases), while emergency department visits cover a wider range of causes: injuries, general symptoms, infections, mental disorders, etc.

• Population behavior:

  • On cold days, people become less active, the number of accidents decreases, and, accordingly, fewer people go to emergency rooms.

Forecast for the future

Using climate models and data on population change, scientists calculated the likely impacts of climate change in California by 2050 and 2100:

• By 2050:

  • An estimated 1.5 million additional emergency department visits are expected due to the increase in hot days.

  • However, mortality could fall by about 53,500 cases, mainly due to a reduction in the number of cold days, which are especially dangerous for the elderly.

• By the end of the 21st century:

  • The number of emergency room visits may increase even more, but the decline in mortality will also remain.

At the same time, the researchers note that the economic damage from increased morbidity (treatment costs, loss of ability to work, and decreased quality of life) may be comparable to or even exceed the benefits from reduced mortality.

Conclusions and recommendations of the study authors

The study's authors emphasize the need to take into account not only changes in mortality, but also carefully analyze changes in morbidity, since they form a significant part of the social and economic burden.

These results suggest that local authorities and health systems need to prepare in advance for increased pressure on emergency services and hospitals due to the expected increase in extreme heat days.

In addition, the study confirms the importance of developing and implementing adaptation strategies for different population groups, taking into account their age and vulnerability to temperature anomalies. Prevention programs and health protection measures during hot periods (e.g., expanding air conditioning in public places, public information, preventive measures for children and the elderly) can become key tools for mitigating the effects of climate change in the future.