The results showed that most poisonings occurred in spring. This was contrary to the findings of Jalali (2012) study in which most poisonings were in autumn [16]. The reason for this discrepancy might be due to the geographical diversity and incidence of envenomation. Seasonal distribution of poisoning varies among different studies, and the incidence may occur at any time of the year. Most cases of poisoning in Mehrpour (2015) and Shokrzadeh (2018) study were in summer [17, 18]. The results of present study also showed that the rate of poisoning in patients between 15 and 25 years was higher than the other age groups. For this age group, psychological factors are considered as the determinative indicator [19, 20]. Inability to develop coping skills seems to be probable in young adults [21]. This was consistent with the findings of some other studies [22–24]. Based on related studies, findings generally indicate that the highest rate of intoxication occurs in adolescents, tragically happens among the active workforce. Intentional poisonings were the most common cause of intoxication in the current study. We found that deliberate self-poisoning was accounted for half of the patients. A total of 7 patients were criminal cases, of which 5 cases were female, thereby the rate of criminal poisoning was 0.8%. In all of them, the route of exposure was oral. Criminal poisoning was more common in spring, similar to the seasonal distribution for all other patients.
Significant gender differences were not observed in the number of referred poisoning cases to the hospital. A slight female predominance in poisoning cases, similar to our findings, was reported by Lam et al., (2010) [25]. Moreover, the incidence of poisoning cases in married couples was higher than the single population, and this may be contrary to expectations. However, the geographic region seems to be associated with marital status and as a result, there were more married cases of acute poisonings than single ones. Furthermore, intimate partner violence, sexual coercion and age disparity might be the underlying causes of such differences. Findings of studies of Shokrzadeh (2018) [18], Nair and Revi (2015) [26] and Guntheti (2011) [27] confirm the present study in this regard.
Education is deterrent to the incidence of poisoning or suicide. The incidence of poisoning is higher among patients without a college degree than those possessing university education levels. Most patients referred to the hospital in a short time after the incident. Early referral to the hospital revealed its impact as full recovery for 66.0% of the population. In Jalali et al., (2012) study, 65.4% of poisoned patients referred to a hospital less than 3 hours of incidence [16]. During the studied period, 74.6% of patients lived in urban areas and the rest (25.4%) were in rural settings. This can be contributed to urbanization and the point that poisoned residents in the cities are quickly or more frequently referred to a hospital. De Silva and Ratnayake (2008) also showed that drug poisonings were higher in urban areas [28]. Employment rates among poisoned patients found to be 55.0% in our study. Noticeably, poisonings rate was high in students (25.3%). The impact of romance issues, weak social connections and inability to use coping skills are probably the causes of intoxication in students who lie in adolescents and youth age range. Another study showed that students tend to attempt self-poisoning with pharmaceutical agents. In this study, the most common reason for the suicide attempt was family conflict followed by romantic issues, and the most common psychiatric disorders among students who attempt suicide were adjustment disorder and major depression [29]. The matter of intoxication in students should be seriously taken into consideration.
Toxicity among most cases in our study was related to pharmaceutical products (45.8%) which were administered orally (90.7%) at home (72.8%). More medication supervision should be performed to prevent easy access to drugs and decrease poisoning and overdose. The matter becomes more important when it is understood that home and pharmacy access were more common among the patients. Another study evaluated epidemiology and agents of poisoning in poisoned patients admitted to the referral intensive care unit in Birjand and found that pharmaceutical medication, opioids, and pesticides were the most common exposures [30]. Shokrzadeh et al., (2018) [18], also showed that poisoning cases were due to drug overdose. In Shokrzadeh et al., (2018) study, 227 out of 800 cases of hospitalized poisonings were related to non-pharmaceutical products [18]. Based on our findings, half of the patients had no previous history of diseases. Among patients with a previous medical history, addiction was the most common. Although opioid poisoning accounts for only 9.4% of all cases, the number of poisoned patients with a history of drug abuse is not small. Several studies in different regions of Iran showed that the most common type of toxicants were due to narcotics. For instance, Farzaneh et al., (2016) in Ardabil (northwest of Iran) [31], Afzali et al., (2008) in Hamedan (western of Iran) [6] and Ayatollahi et al., (2011) in Yazd (central of Iran) [32] showed drug abuse as the most common cause of acute intoxication. Iran is heavily involved in opioids abuse as either medication or non-medication. This mainly is due to shared border with Afghanistan [33]. Hassanian-Moghaddam et al., (2014) found that opium and methadone were the most common drugs of abuse in acute adults’ poisonings in Tehran. Narcotics toxicity contributed to 24.7% of deaths [34]. Apart from narcotics, some studies reported benzodiazepines, tricyclic antidepressants [30], psychoactive drugs [35], antiepileptics and sedative-hypnotics [34] as the leading agent of poisonings. Vallersnes et al., (2015) reported that benzodiazepines and paracetamol were the leading cause of toxicity among poisoned patients [36]. Following addiction, psychiatric disorders were common in our findings. Dragisic et al., (2015), found that psychiatric history and addiction were the most common amongst patients committed suicide [37]. Senanayake and Karalliedde (1988) showed that intentional poisonings in cases between 11–30 years old in Serilanka happened in people with a history of psychiatric disorder [38].
The majority of patients required less than four days of treatment. The duration of hospitalization varied in different studies. Sing and Aacharya (2007) reported that hospital stay was 1–16 days [22]. Nair and Revi (2015) reported that mean of hospitalization period was 5.5 days [26]. Abubakar et al, (2014) showed that the duration of hospitalization for poisoning cases ranged from 1–41 days [39]. While mortality rate in our study was 0.8%, death rate in some other studies were 0.3% [16], 1.3% [24], 7.8% [38], 4.2 [26], and 16% [37].