ADVANCEMENT OF THE SCIENCE
events in the cold season. We found that <1% of ED visits were water-related during the cold season and no water-related ED vis- its or hospitalizations were identified dur- ing the hot season. Additionally, only 2% of deaths were water-related in the cold season, while 6% of deaths in the hot season were water-related. There were no other clear dis- tinctions between the type of events occur- ring during the hot and cold seasons. For the remaining analysis, we used the case definition implemented by the CDC Envi- ronmental Public Health Tracking Network, which restricts the definition to include only cold-season cases. Hospital Visits During each cold season from 2000 to 2018, there was an average rate of 13.3 cold-related ED visits per 100,000 population ( n = 704) and 2.8 cold-related hospitalizations per 100,000 population ( n = 155). The annual rate of cold-related ED visits and hospital- izations has been trending upward in recent years (Figures 1 and 2). The highest rate of cold-related hospitalizations during this time period occurred in 2018 (Figure 2). Overall, there were more cold-related ED visits than hospitalizations for the years analyzed. Females accounted for approximately 30% of cold-related ED visits and hospitalizations, while males accounted for 70% (Table 2). There was a statistically significant dier- ence between the sex distribution of the rate of cold-related ED visits and hospitalizations. For age distributions by sex, males 15–34 years had the highest rates of cold-related ED visits, while males ≥65 years had the highest rates of cold-related hospitalizations (Table 2). Among females, there was a sta- tistically significant dierence between the rate of cold-related ED visits for the 15–34- year group and all other age groups. Among males, the rate of cold-related ED visits was significantly higher for the 15–34-year group compared with the 0–4, 5–14, and ≥65 age groups. For cold-related hospital- izations, there was a statistically significant dierence between the rates for the ≥65- year group compared with the other age groups for females. For males, the 15–34, 35–64, and ≥65 age groups had significantly higher hospitalization rates compared with the other age groups. There was no statisti- cally significant dierence between the rates
TABLE 1
Number and Proportion of Cold-Related Events by Month in Minnesota
Month
Season
Emergency Department Visits, 2000–2018 # (%)
Hospital Admissions, 2000–2018 # (%)
Deaths, 2002–2019 # (%)
January February
Cold
4,055 (28) 2,809 (19)
844 (26) 651 (20) 354 (11)
160 (26) 93 (15) 91 (15)
March
1,372 (9)
April May June
603 (4) 380 (3) 250 (2) 185 (1) 197 (1) 273 (2) 577 (4)
158 (5)
33 (5) 19 (3)
Hot
99 (3) 60 (2) 43 (1) 49 (1) 60 (2)
6 (1)
July
3 (<1) 3 (<1)
August
September
5 (1)
October
Cold
132 (4) 253 (8) 546 (17)
38 (6)
November December
1,043 (7)
65 (10)
2,917 (20)
108 (17)
Total
14,661 (100)
3,249 (100)
624 (100)
of cold-related hospitalizations or ED visits in the age groups of 0–4 or 5–14 years for males or females. Almost one half of the cold-related ED visits (45%) included diagnosis codes for substance use (Table 3). Other diagnosis codes co-occur- ring with cold-related ED visits included men- tal illness (11%), respiratory disease (8%), car- diovascular disease (7%), and diabetes (7%). Almost all the cold-related hospitalizations had at least one co-occurring diagnosis code (89%), including substance use (66%), men- tal illness (33%), respiratory disease (22%), or cardiovascular disease (20%; Table 3). Deaths We identified an average annual rate of 0.6 cold-related deaths per 100,000 population ( n = 33) over each cold season from 2002 to 2019. Similar to the hospital discharge data, there was a statistically significant dif- ference between the sex distribution of cold- related deaths, with females accounting for approximately 30% of cold-related deaths, while males accounted for 70% (Table 2). For both males and females, there was a statisti- cally significant dierence between the rate of cold-related deaths for the ≥65 age group compared with all other age groups.
More than one half of all cold-related deaths (57%) had co-occurring diagnosis codes (Table 3). Almost one half of all cold- related deaths (44%) included a diagnosis code for substance use. Other co-occurring diagnosis codes included cardiovascular dis- ease (19%), respiratory disease (8%), mental illness (2%), and diabetes (1%). Discussion Our study used hospital discharge data and vital statistics data to explore the case defi- nition and assess the burden of cold-related illness and death in Minnesota. Overall, <10% of cold-related ED visits, hospitaliza- tions, and deaths in Minnesota occurred during the hot season. We were unable to identify any distinct dierence between the type of events occurring in the dierent seasons. We assessed the burden of cold- related illness and death in Minnesota using the case definition developed and adopted by the Cold-Related Illness Content Work Group, which includes cases only in the cold season. Using this case definition, we found that rates of illness and death in Min- nesota were highest among older adults and males, which is consistent with previ- ous studies (Gronlund et al., 2018; Lane
10
Volume 86 • Number 4
Powered by FlippingBook