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Emergency Department Visits for Heat Stroke in the United States, 2009 and 2010

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Background The effect of extreme heat on health has become a growing public health concern due to climate change. We aimed to examine the epidemiological patterns of hospital-based emergency department (ED) visits for heat stroke in the United States. Findings We analyzed data from the 2009 and 2010 Nationwide Emergency Department Sample, the largest ED data system sponsored by the Agency for Healthcare Research and Quality. ED visits for heat stroke were identified by screening the recorded diagnoses using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 992.0. Annual incidence rates of ED visits for heat stroke were computed according to demographic characteristics and geographic regions. In 2009 and 2010, there were an estimated 8,251 ED visits for heat stroke in the United States, yielding an annual incidence rate of 1.34 visits per 100,000 population (95% Confidence Interval [CI] = 1.23-1.45). Significantly higher incidence rates were found in males (1.99 per 100,000; 95% CI = 1.82-2.16), adults aged ≥ 80 years (4.45 per 100,000; 95% CI = 3.73-5.18), and residents living in the southern region (1.61 per 100,000; 95% CI = 1.43-1.79). The majority (63.1%) of ED visits for heat stroke occurred during the summer months of June, July and August. Over one-half (54.6%) of the ED visits for heat stroke required hospitalization and 3.5% of the patients died in the ED or hospital. Conclusions Heat stroke results in approximately 4,100 ED visits each year in the United States, with the majority occurring in the summer months and requiring admission to the hospital. Men, the elderly, and people living in the south region are at heightened risk. Electronic supplementary material The online version of this article (doi:10.1186/2197-1714-1-8) contains supplementary material, which is available to authorized users.
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... It is estimated that, annually, 1300 people die every year in the U.S. from extreme heat 3 . In 2009 and 2010 alone, over 8250 emergency room visits in the US were caused by heat stroke 4 , with lowincome, minority, and elderly populations being disproportionally affected 3 . A large portion of these deaths may have been prevented if people could cool their homes properly. ...
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Income-based energy poverty metrics ignore people’s behavior patterns, particularly reducing energy consumption to limit financial stress. We investigate energy-limiting behavior in low-income households using a residential electricity consumption dataset. We first determine the outdoor temperature at which households start using cooling systems, the inflection temperature. Our relative energy poverty metric, the energy equity gap, is defined as the difference in the inflection temperatures between low and high-income groups. In our study region, we estimate the energy equity gap to be between 4.7–7.5 °F (2.6–4.2 °C). Within a sample of 4577 households, we found 86 energy-poor and 214 energy-insecure households. In contrast, the income-based energy poverty metric, energy burden (10% threshold), identified 141 households as energy-insecure. Only three households overlap between our energy equity gap and the income-based measure. Thus, the energy equity gap reveals a hidden but complementary aspect of energy poverty and insecurity. In the summer, low-income households in the Arizona, US wait 4 - 7 °F (2.6–4.2 °C) longer than high-income households to turn on their AC units to save money on energy bills. This energy limiting behavior indicates a hidden form of energy poverty.
... It is estimated that, annually, 1,300 people die every year in the U.S. from extreme heat 3 . In 2009 and 2010 alone, over 8,250 emergency room visits in the US were caused by heat stroke 4 , with low-income, minority, and elderly populations being disproportionally affected 3 . A large portion of these deaths could have been prevented if people could cool their homes properly 5,6 . ...
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Income-based energy poverty metrics miss people's behavior (i.e., reducing energy consumption to limit financial stress). We introduce a novel method for calculating energy-limiting behavior in low-income households using a residential electricity consumption dataset. We first determine the outdoor temperature at which households start using cooling systems, the inflection temperature. Our energy poverty metric, the energy equity gap , is defined as the difference in the inflection temperatures between low and high-income groups. In our study region, we estimate the energy equity gap to be between 4.7°F and 7.5°F. In 2015–2016, within our sample of 4,577 households, we found 86 energy-poor and 214 energy-insecure households. In contrast, the income-based energy burden metric identified 141 households as energy insecure when the threshold was set to 10%. Only three households overlapped between the energy equity gap and energy burden measures. Thus, the energy equity gap reveals a hidden but complementary aspect of energy poverty.
... Our study reported an in-hospital mortality rate of 5%, which has been previously reported ranging from 3% to 7%. 16,20,21,30,33 When considering mortality as a result of heatstroke, environmental heatwaves are an important external factor to consider. Previous data showed a concerning rise in deaths during heat wave in Europe in August 2003 and Chicago in the summer of 1995. ...
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Background This study aimed to assess inpatient prevalence, characteristics, outcomes, and resource utilisation of hospitalisation for heatstroke in the United States. Additionally, this study aimed to explore factors associated with in‐hospital mortalities of heatstroke. Methods The 2003‐2014 National Inpatient Sample database was used to identify hospitalised patients with a principal diagnosis of heatstroke. The inpatient prevalence, clinical characteristics, in‐hospital treatments, outcomes, length of hospital stay, and hospitalisation cost were studied. Multivariable logistic regression was performed to identify independent factors associated with in‐hospital mortality. Results A total of 3372 patients were primarily admitted for heatstroke, accounting for an overall inpatient prevalence of heatstroke amongst hospitalised patients of 36.3 cases per 1 000 000 admissions in the United States with an increasing trend during the study period (P < .001). Age 40‐59 was the most prevalent age group. During the hospital stay, 20% required mechanical ventilation, and 2% received renal replacement therapy. Rhabdomyolysis was the most common complication. Renal failure was the most common end‐organ failure, followed by neurological, respiratory, metabolic, hematologic, circulatory, and liver systems. The in‐hospital mortality rate of heatstroke hospitalisation was 5% with a decreasing trend during the study period (P < .001). The presence of end‐organ failure was associated with increased in‐hospital mortality, whereas more recent years of hospitalisation was associated with decreased in‐hospital mortality. The median length of hospital stay was 2 days. The median hospitalisation cost was $17 372. Conclusion The inpatient prevalence of heatstroke in the United States increased, while the in‐hospital mortality of heatstroke decreased.
... Specifically, EHS is more commonly associated with young adults, whereas nonexertional heat stroke (ie, classical heat stroke) more often affects infants and the elderly. 15,16 Across age ranges, thermoregulatory function in response to exercise heat stress changes. Older adults have been observed to have blunted sudomotor function and skin blood flow, which increased their heat strain compared with younger adults. ...
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Context Sex, age, and wet-bulb globe temperature (WBGT) have been proposed risk factors for exertional heat stroke (EHS) despite conflicting laboratory and epidemiologic evidence. Objective To examine differences in EHS incidence while accounting for sex, age, and environmental conditions. Design Observational study. Main Outcome Measure(s) Using data from the Falmouth Road Race, a warm-weather 7-mi (11.26-km) running road race, we reviewed records from patients treated for EHS at medical tents. The relative risk (RR) of EHS between sexes and across ages was assessed with males as the reference population. Multivariate linear regression analyses were calculated to determine the relative contribution of sex, age, and WBGT to the incidence of EHS. Results Among 343 EHS cases, the female risk of EHS was lower overall (RR = 0.71; 95% confidence interval [CI] = 0.58, 0.89; P = .002) and for age groups 40 to 49 years (RR = 0.43; 95% CI = 0.24, 0.77; P = .005) and 50 to 59 years (RR = 0.31; 95% CI = 0.13, 0.72; P = .005). The incidence of EHS did not differ between sexes in relation to WBGT (P > .05). When sex, age, and WBGT were considered in combination, only age groups <14 years (β = 2.41, P = .008), 15 to 18 years (β = 3.83, P < .001), and 19 to 39 years (β = 2.24, P = .014) significantly accounted for the variance in the incidence of EHS (R2 = .10, P = .006). Conclusions In this unique investigation of EHS incidence in a road race, we found a 29% decreased EHS risk in females compared with males. However, when sex was considered with age and WBGT, only younger age accounted for an increased incidence of EHS. These results suggest that road race medical organizers should consider participant demographics when organizing the personnel and resources needed to treat patients with EHS. Specifically, organizers of events with greater numbers of young runners (aged 19 to 39 years) and males should prioritize ensuring that medical personnel are adequately prepared to handle patients with EHS.
... Approximately, heatstroke in the United States (U.S.) results in 4100 emergency department visits per year, with most occurring during the summer and requiring hospitalization [7]. The mortality rate ranges between 3-7% and is expected to rise in coming years due to climate change [8][9][10]. ...
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Background: This study aimed to assess the risk factors and the association of circulatory failure with treatments, complications, outcomes, and resource utilization in hospitalized patients for heatstroke in the United States. Methods: Hospitalized patients with a principal diagnosis of heatstroke were identified in the National Inpatient Sample dataset from the years 2003 to 2014. Circulatory failure, defined as any type of shock or hypotension, was identified using hospital diagnosis codes. Clinical characteristics, in-hospital treatment, complications, outcomes, and resource utilization between patients with and without circulatory failure were compared. Results: A total of 3372 hospital admissions primarily for heatstroke were included in the study. Of these, circulatory failure occurred in 393 (12%) admissions. Circulatory failure was more commonly found in obese patients, but less common in older patients aged ≥60 years. The need for mechanical ventilation, blood transfusion, and renal replacement therapy were higher in patients with circulatory failure. Hyperkalemia, hypocalcemia, metabolic acidosis, metabolic alkalosis, sepsis, ventricular arrhythmia or cardiac arrest, renal failure, respiratory failure, liver failure, neurological failure, and hematologic failure were associated with circulatory failure. The in-hospital mortality was 7.1-times higher in patients with circulatory failure. The length of hospital stay and hospitalization costs were higher when circulatory failure occurred while in the hospital. Conclusions: Approximately one out of nine heatstroke patients developed circulatory failure during hospitalization. Circulatory failure was associated with various complications, higher mortality, and increased resource utilizations.
... An estimated 8251 emergency department visits for NEHS occurred in the United States between 2009 and 2010, a rate of 1.34 visits per 100,000 population. 13 During a two-week heat wave in 2006 in California there were 655 heat-related deaths, 1620 additional hospitalizations, and more than 16,000 additional emergency department visits, estimated to have cost $5.4 billion. 14 The United States Armed Forces reported 578 incidents of heat stroke in [ 3 8 6 _ T D $ D I F F ] 2018, 0.45 cases per 1000 person-years, with the highest incidence amongst young men, persons of Asian and pacific island ethnicity and trainees. ...
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