Although the majority of burn injuries are caused by thermal burns, special-cause burn injuries are usually more severe and difficult to manage and often contribute to higher mortality [5, 18]. This population-based analysis characterizes the burden of major burn injury in a major regional burn center in central China, providing critical epidemiologic data for future resource planning and injury prevention efforts. We characterized the epidemiological characteristics of special-cause burn, and determined the risk factors associated with the mortality of burn patients. Overall, older age, male, unmarried, winter, III-IV degree of burn, ≥ 3 burn sites, and larger TBSA were significantly associated with higher burn mortality, and special cause-burn patients suffer more severe injuries, resulting in longer hospital stays and higher health care expenditures.

Special-cause burns often occur in specific environments such as industrial production, disasters and accidents, wars, and terrorist attacks. Moreover, they are often mass injuries and attract high social attention. There were several groups of burn victims of industrial production or traffic accidents in this study, for instance, one such incident was caused by the explosion and combustion of yellow phosphorus during transportation, causing chemical burns to more than 80 onlookers, fire officers, and soldiers [4]. Notably, as a result of the COVID-19 pandemic and China government-imposed lockdown measures from 23/3/2020, which advised people to stay at home [19], reductions in outdoor activities and lifestyle changes contributed to a decrease in the incidence of burns. Our data confirm that the total number of patient visits for burns decreased in 2020 and 2021, and the number of visits for thermal burn patients decreased by nearly 50%, consistent with a prior study [19].

Our study shows that the burn patients were predominantly male, with burns occurring primarily in the upper limbs. Additionally, patients in the age groups 20–30, 30–40, and 40–50 years old are more afflicted than those of other age groups. The above characteristics reveal that special-cause burns are closely associated with occupation-upper limbs are more likely to be injured during work, men are more likely to engage in dangerous work than women, and people of working age have more chances of injury. Since there is an increased incidence of construction and agricultural workload in Wuhan during summer and autumn, and the working hours are long and the work intensity is high during these seasons, most burns incidents analyzed in our study occurred during summer and autumn. However, the timing of burn injuries varies with season or month in different studies, which may be associated with the working environment and industries in those regions [20,21,22,23]. Mirmohammadi et al. investigated the epidemiology of work-related burns and found that 17.1% of people have occupational burns [21], consistent with our study in Wuhan and other studies conducted in other places [24,25,26,27].

Most burn patients had small burn surface areas, but special-cause burn patients had more severe burn degrees, which are difficult to treat. Most special-cause burn patients had ≤ 10% burn surface areas, and the proportion of patients with burn degrees was significantly higher in the special-cause burns cohort than in the thermal burn cohort, during the same period. This could be, in the special-cause burns cohort, the electrical burn was the most common cause (accounting for 63.93% of all special-cause burn patients), followed by chemical burns, thermal crush injuries, fireworks and firecrackers, and radiation burns. As industrialization progressed, the incidence of electrical burns increased substantially [28]. Electrical burns and hot crush injuries often cause destructive deep burns involving tendons, nerves, bones, and other important structures, with a high rate of amputation and disability [29,30,31,32]. Whereas, chemical burns not only cause large local damage, but are also often combined with poisoning, and sometimes even small chemical burns can be fatal [33, 34]. Furthermore, injuries from fireworks and firecrackers can occur not only in the production process but also during transportation and use, often causing extensive burns. Further, the setting off of fireworks and firecrackers often causes burns in important body parts, such as hands and eyes [35]. Radiation burns are more common after tumor radiation therapy, and the wounds caused by radiation are often difficult to heal, requiring prolonged treatment and hospitalisation [36, 37], which is consistent with our study results that special cause-burn patients suffer more severe injuries, resulting in longer hospital stays. Collectively, the common characteristics of these special-cause burns are relatively deep wound that are difficult to heal, the injuries that may require surgery, high amputation rate (specially fingers and toes), long duration of treatment, and the overall high treatment costs.

Special-cause burns accounted for 13.2% of all hospitalized burn patients from January 1, 2004, to December 31, 2021. The electrical burn was determined to be the primary cause of burns among these patients, accounting for 60.9% of all special-cause burns. This may be associated with the socio-economic development of one region [38, 39]. Socioeconomic risk factors are generally highly correlated and can therefore not be individual causal components [40]. With the economic development and increasing application of electrical and chemical products in production and everyday life, the incidence of special-cause burns has also increased. Although increasing attention has been paid to safety production and labor protection, the incidence of special-cause burns has not decreased significantly, and the harm and impact of special-cause burns related to industrial production, transportation, and disasters and accidents are still prevalent; indicating that more work is required for the prevention of special-cause burns. This issue also urgently requires the joint attention of the medical institutions, government, management, and society.

The limitation of this study is that the source of data is only the epidemiological investigation of inpatients in a single burn center. Nevertheless, since the relatively sample sizes in most single-center epidemiological studies on burns and the constraint on data consistency in multicenter research, many results in the previous reports were discrepant and the risk factors of burn injury were still not clear or specific [41]. As the only burn center in Wuhan populated over 11 million and the capital of Hubei province, our center receives patients from a vast surrounding region in central China and this extensive dataset spanning 18 years could provide a potentially accurate reflection of the special-cause burn situation. If a multicenter large-scale survey including outpatients could be conducted in conjunction with other units for future research, it would provide a relatively better and more comprehensive reference for the prevention and treatment of special-cause burns.