Seasonal Changes Can Trigger Hospitalization With Sickle Cell

Peak with colder weather for sickle cell anemia patients noted in Brazil study

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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People with sickle cell anemia (SCA) — the most common and the most severe form of sickle cell disease (SCD) — are more commonly hospitalized in the cooler winter and spring seasons than in the hotter summer or fall, according to a study conducted in Brazil.

Better understanding of how sickle cell symptoms tend to fluctuate with changing weather could help patients better manage the condition, its researchers noted.

The study, “Meteorological parameters and hospitalizations of patients with sickle cell anemia: a 20-year retrospective study in Campinas, São Paulo, Brazil,” was published in the International Journal of Environmental Health Research.

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Cold temperature is known to act as a trigger for vaso-occlusive crisis (VOC), a painful acute complication of sickle cell. However, the broader impact of weather on disease severity and healthcare utilization is not fully understood.

“Extremes of temperatures are known to precipitate acute complications with many SCD patients experiencing acute pain following exposure to cold,” the researchers wrote. “Although this association appears real for the patients, surprisingly there is little evidence to support this claim.”

Colder weather’s link to VOCs and flu season may drive hospitalizations

Using hospitalization and meteorological data collected from 1999 to 2018, a team of scientists conducted an analysis looking for associations between a number of weather-related factors and trends in hospitalizations for sickle cell anemia patients hospitalized in Campinas, a city in southeastern Brazil with more than 1 million people.

“To our knowledge, no studies have evaluated the influence of climate on hospitalizations of children and adults with SCA in the southern hemisphere,” the team wrote, adding that “this is the first study of its kind in the subtropics and South America.”

The analysis included 1,462 hospitalizations due to VOC, as well as 1,354 hospitalizations for disease-related reasons other than VOC, covering 1,255 children and 1,561 adults with the SCA. Researchers noted that patients hospitalized due to VOC were generally older and were more commonly adults.

Among the children, the average number of hospitalizations was higher in winter (5.7) and spring (6) than in autumn (4.2) and summer (4.7). The same trend was seen in adults, with more hospitalizations taking place in winter (7.1) and spring (8) than in autumn (4.9) and summer (5.2).

Durations of a hospital stay followed the same seasonal trends in both children and adults.

“The number of hospitalizations was higher in the winter (July–September) and spring (October–December) months than in the summer (January–March) and autumn (April–June) months for all patients, and each group of patients (children and adults),” the researchers wrote.

The increase in hospitalizations during the cooler winter and spring is likely explained, at least partly, by the connection between cold and VOCs, the researchers noted. They wider spread of flu and other diseases during these months, they added, may play a role, which “buttresses the need for prevention via vigorous vaccination against flu and other diseases.”

Analyses of individual weather-related phenomena, like temperature and humidity, showed no significant contemporaneous associations — that is, weather at the time of hospitalization showed no association with hospitalization risk.

However, several numerically small but statistically significant “lag” associations were noted. For example, higher average and maximum atmospheric pressure values were significantly associated with more hospitalizations two months later, and a higher maximum temperature was associated with fewer hospitalizations three months afterwards.

“Although this study showed that there is no immediate effect, lagged associations were observed between some meteorological parameters and the hospitalizations of SCA patients,” the researchers wrote, adding that this finding “buttresses previous studies that showed that meteorological parameters may not influence the number and duration of hospitalizations of SCA patients at the time of hospitalization.”

Associations between meteorological measures and hospitalization patterns with SCA “are important and complex as they might differ with geographical locations, especially across the equator,” the team wrote. “Therefore, understanding the associations between meteorological parameters and patterns of hospitalizations in adults and children with SCA can help physicians appropriately advise SCA patients and their caregivers.”