1. Introduction

Poisoning is a common health problem all around the world. In the United States, more than 5 million people are treated for exposure to biological or chemical agents and hemodialysis is performed for 300,000 patients, annually [1, 2]. In a similar manner, poisoning is very prevalent in Iran. About, 25000 cases are intoxicated by drug and chemicals per year in Tehran out of whom 12000 are admitted in hospital and 1200 cases are transferred to intensive care unit (ICU) and at least 120 cases die [3]. There are several ways for the management of intoxicated patients, including: supportive cares, antidote therapy, gastrointestinal decontamination, and extracorporeal treatment (ECTR) [4]. ECTR include hemodialysis (HD), and peritoneal dialysis (PD), hemoperfusion (HP), Blood exchange, and plasmapheresis. ECTR is required for 0.1% of toxins [5]. Many chemicals and drugs can be removed from the body by extracorporeal method. One of the most common methods of extracorporeal treatments is hemodialysis [4]. Some conditions affect the ability of extracorporeal therapies to eliminate toxins. As a case in point, first, the toxin substances must be very diffusible from the dialysis membrane, and the toxicity must be related to the blood level of the toxin. In addition, the body's detoxification mechanisms must be insufficient (such as acute renal failure, congestive heart failure, and pneumonia) or the toxin causes significant damage to the kidneys [6]. Also, some parameters affect the ability of hemodialysis to eliminate toxins including the small molecule, low volume of distribution, low protein binding, and highly distribution from tissue to plasma [7]. Today, ECTR is used to treat intoxication with methanol, ethylene glycol, lithium, salicylate, and phenobarbital [8-12]. Hemodialysis was first used for the treatment of Aspirin in 1950 [5]. Hemodialysis can be used to correct water and electrolyte disorders as well as the treatment of refractory metabolic acidosis and acute renal failure [4]. Likewise, hemodialysis is used in the treatment of poisoning with two purposes: 1) to remove dialysable toxins, 2) for the treatment of poisoning induced nephrotoxicity [6]. In a study in California in 2013, hemodialysis was the most common extracorporeal procedure used to remove toxins such as salicylate and ethylene glycol poisoning [13]. Since limited studies (if any) have been conducted on the evaluation of hemodialysis in poisoned patients in Taleghani Hospital, Urmia as the poisoning center of West Azerbaijan province, in the present study the researchers decided to evaluate the hemodialysis in poisoned patients from 2016-2020.

2. Materials and Methods

In this cross-sectional study, 200 hospitalized patients, who underwent hemodialysis admitted to the poisoning center at Taleghani Hospital, Urmia, Iran, from 2016-2020 were evaluated. To conduct this study, the researchers included all hospitalized intoxicated patients who underwent hemodialysis at ages of 14 years or older during the study period. The demographic, clinical and some laboratory findings in survivor and non-survivor group were studied and evaluated in relation to outcome of the patients. Also some important data such as type of toxic substance and causes of hemodialysis were evaluated. The hospital’s clinical toxicologists had visited the patients and provided further information to establish the diagnosis on admission to the ED. Patients who had no complete documents and laboratory tests during admission and were discharged with personal consent were excluded from this study. No personal identification data were recorded and all information was kept strictly confidential. Approval for performing this research was issued by the ethics committee of Urmia University of Medical Sciences, Iran. (Code: IR.UMSU.REC.1398.446). The data were analyzed using SPSS version 16 specially descriptive statistics including mean and Standard Deviation (SD). The data consisted of the demographic characteristics and clinical outcomes for each patient. The variables were also grouped into survivors and non-survivors. In this study, the differences in quantitative variables with normal distributions and abnormal distributions were evaluated by the T-test and Mann–Whitney U-test, respectively. The relationships between categorical variables and the outcomes were evaluated using Chi square test where appropriate. Also, p-value <0.05 and confidence interval of 95% found to be statistically significant.

3. Results

In this study, among 13245 hospitalized patients in poisoning ward, 200 (158 males, 42 females) patients underwent hemodialysis on admission time. Male to female ratio was 3.7. The patients’ median age was 32 (min=14, max=80) years old. The mortality rate was 31.5% (79% males, 21% females). Table 1 presents the patients’ demographic characteristics and clinical features. The highest prevalence of hemodialysis (89.9%) was reported in the age group of 14-30 years. About 53 (26.5%) of patients had history of drug and Alcohol abuse. Also, 55 (27.5%) of patients were rural and 145 (72.5%) of them were urban. About 125 (62.5%) of patients were married. Toxic Alcohol (methanol, ethylene glycol) 86 (43%), paraquat 58 (29%), opiate or opium (methadone, tramadol) 24 (12%), multidrug 24 (12%), methamphetamine 3 (1.5%), lithium 2 (1%), organophosphate 2 (1%) and mushroom 1 (0.5%) were the main causes of poisoning among the patients treated with hemodialysis, respectively. Also, loss of consciousness 82 (41%), nausea, vomiting, and epigastric pain 68 (34%) and respiratory failure 31 (15.5%), vertigo 5 (2.5%), weakness 5 (2.5%), chest pain 3 (1.5%), mucosal lesions and inflammation of oral cavity and pharynx 2 (1%) and seizure 2 (1%) were the most signs and symptoms in patients. The results of the blood chemistry analysis range and P value at admission are presented in Table 2. Statistically significant relationships (p value < 0.05) were found between the outcome of the patients and demographic (admission service), clinical features (level of consciousness, hypotension and respiratory failure) laboratory profile (BUN, Creatinine, pH, WBC, Blood glucose, and acute renal failure) and treatment with hemodialysis (causes of hemodialysis). Moreover, statistically significant relationships (p value < 0.05) were found between the acute renal failure and causes of poisoning. On the other hand, there were not statistically significant relationships between the outcome of the patients and demographic (history of drug abuse, duration of hospital stays, amount of ingestion, living area, marital status and history of substance abuse), clinical features (nausea, vomiting and epigastric pain, vertigo, weakness, chest pain, hypertension, seizure, loss of vision, metabolic acidosis sinus bradycardia, and tachycardia) laboratory profile (serum Hco3, Sodium, Potassium, and Platelet) and treatment with hemodialysis (the number of hemodialysis and duration of hemodialysis). Finally, 137 patients (68.5%) were discharged with full recovery and 63 cases (31.5%) passed away.

4. Discussion

Hemodialysis was the most common extracorporeal procedure used to remove toxins such as toxic alcohols and salicylate [13]. The most important causes of hemodialysis in this area were poisoning with toxic alcohols (toxic alcohol poisoning such as methanol and ethylene glycol (43%)) and herbicides such as paraquat (29%), which were shown in Table 2. Table 3 indicated a significant increase in hospitalized patients, who underwent hemodialysis in 2020 compared to previous years due to an epidemic of toxic alcohol poisoning in the first quarter of 2020 in this region. In 2016, more than 2 million cases of poisoning were reported by the US Centers for Disease Control. However, most of these cases were treated at home and did not require hospitalization. The most common poisoning in adult and children were analgesics (11.2%) and cosmetics (13.3%), respectively and about 25% of the patients were hospitalized. Of these, 2825 patients required hemodialysis and 36 patients required hemoperfusion, and finally 1977 patients died [12]. In 2019, Hassanian-Moghaddam et al collected data across the world with modified Delphi process and evaluated outbreak in patients with methanol poisoning. Based on the results of this study, it was shown that extracorporeal treatment (i.e., hemodialysis) and antidotes may be efficient and safe processes in the treatment of intoxicated patients [15]. In this study, among 13245 hospitalized patients in poisoning ward, 200 (1.5%) patients those who underwent hemodialysis on admission time. The mortality rate was 31.5% (79% male, 21% female). The mean age of patients was 32 years (range: 14 - 80). In a previous study, about 6,000 acute intoxicated patients were hospitalized over a 7-year period, and about 40 (0.6%) of them underwent hemodialysis or hemoperfusion. The low ratio of hemodialysis to the number of hospitalized patients in this article compared to our study may be related to different clinical settings, patient characteristics, type and severity of poisoning, and management modalities [16]. In a study conducted by Güngörer et al, in Turkey from 2006 to 2013, from 998 poisoned patients, 40 were treated with extracorporeal methods, of which 27 patients (75.0%) received hemodialysis and 9 patients (25.0%) underwent hemoperfusion charcoal. Among the patients undergoing hemodialysis, the mean age of patients was 40.1 ± 17.9 (range: 18-80) years and 20 patients (55.6%) were male. The lower mean age and the higher percentage of males and the lower percentage of females in this study in comparison to other studies may be associated to the differences between the two communities. In previous study, from 27 hospitalized intoxicated patients, methanol poisoning, valproic acid, fungi, lithium, ethanol, amlodipine, organic phosphorus, paracetamol were 10 (37%), 5(18.5%), 4(14.8%), 3(11.2) %, 2(7.4%), 1(3.7%), 1(3.7%) and 1(3.7%), respectively. Similar to our study, in these studies, toxic alcohol (methanol) poisoning was the most common cause of hemodialysis. Eleven patients died and 25 patients were discharged with full recovery and the death / total patient ratio was approximately 1 to 3 [17]. In a similar study conducted in 2013 in California, USA, hemodialysis was the most common extracorporeal method used to remove toxins. Similar to the present study, the most common causes of hemodialysis were salicylate and ethylene glycol poisoning [10]. Park et al, examined the effect of hemoperfusion and hemodialysis on patients with acute herbicide poisoning and identified that, age (p = 0.013), swallowed volume (p <0.001) and hemodialysis after hemoperfusion (P = 0.014) were significant risk factors for mortality in patients with paraquat poisoning. According to the findings of this study, hemoperfusion and hemodialysis are effective and safe treatments in patients with acute herbicide poisoning. In line with the study of Park et al, in the current study, 29% of patients who underwent hemodialysis had herbicide (paraquat) poisoning [13]. Also, similar to this study, acute renal failure due to organophosphate poisoning was observed in 1% of patients [18].

Study Limitations:

The main limitation of this study was incomplete recording of some laboratory data.

5. Conclusion

Hemodialysis or other extracorporeal therapies are an essential part of the treatment of poisoning. Although a limited number of intoxicated patients require hemodialysis, these treatments are very effective. Our study in this region showed that toxic alcohols, herbicides, and drug poisoning are the most common causes of hemodialysis. Since there are limited studies on the prevalence of hemodialysis in poisoned patients and hemodialysis and other extracorporeal procedures are invasive and costly methods in the treatment of poisoning, further studies are recommended in the future to evaluate the frequency and the risk - benefits of hemodialysis in toxic patients.

Acknowledgements

The authors would like to thank the management and staff of Taleghani Hospitals, Urmia, Iran, for approving its protocol prior to implementation and supporting this study.

Compliance with Ethical Guidelines

The Ethics Committee of Urmia University of Medical Sciences approved this study (Code: IR.UMSU.REC.1398.446).

Funding

This article was supported by Urmia University of Medical Science.

Author's Contributions

Conceptualization [Mohammad Majidi]; Methodology [Mohammad Majidi]; Investigation [Arsalan Yousefpour, Mojhdeh Mehrno]; Writing – original draft [Mohammad Delirrad]; Writing – review & editing [all authors]; Funding acquisition [all authors]; Resources [all authors]; Supervision [Mohammad Majidi].

Conflict of interest

None to be declared.