Gender Differences and Treatment Outcome among Drug Induced Hepatotoxicity Tuberculosis Patients

1. INTRODUCTION

Tuberculosis (TB) is one of the pre-historical diseases known to mankind and still remains the leading single infectious cause of death among adults [1]. It is believed that one in three is either infected with Mycobacterium tuberculosis, or is at risk of developing the disease [2]. The WHO classified Malaysia as an ‘intermediate’ TB burden country in 2004. In the last 20 years, the incidence rate has been stagnating, although there was a slight upward trend between 2004 and 2006, from 60.3 to 62.6 per 100,000 [3].

The global increasing threat of drug resistance and multi-drug resistant TB (MDR-TB) is another important reason for the TB epidemic. In 2008, MDR-TB emerged with an estimated 440,000 cases globally [2]. Almost 50% of MDR-TB cases worldwide are estimated to occur in China and India [2]. The non-standardised and interrupted chemotherapy treatment of TB is the main risk factor for MDR-TB [4].

The experience of the WHO since 1997 in assisting high TB burden countries to set up standardised TB surveillance systems shows that globally, men account for a higher proportion of notified TB cases (63% or 64%) [5]. Data on sex differentials in TB from some Western European countries during the period from 1930 to 1950, when the disease burden there was still high, present a different picture: no significant difference in TB between the sexes in childhood and pre-adolescence, a higher incidence in female than in male adolescents and young adults, and a higher incidence in men than in women over 40 years of age. Studies in various countries have also shown that progression from TB infection to disease is likely to be faster for women compared to men in their reproductive years, and faster for men over 40 years of age [6].

The most frequent adverse effects of anti-tuberculosis treatment are hepatotoxicity, skin reactions, and gastro-intestinal and neurological disorders [7]. Hepatotoxicity is the most serious adverse effect of anti-tuberculosis therapy [8]. Anti-tuberculosis drug-induced hepatotoxicity (ATDH) causes substantial morbidity and mortality and diminishes treatment effectiveness. Asymptomatic transaminase elevations are common during anti-tuberculosis treatment, and hepato-toxicity can be fatal if not recognized early and when therapy is not interrupted in time. Isoniazid, rifampicin and pyrazinamide are potentially hepatotoxic drugs. The incidence of ATDH during standard multidrug TB treatment has been variably reported as between 2% and 28%. This rate depends on the investigators’ definition of hepatotoxicity as well as the population studied [9].

Tuberculosis drugs are commonly safe. However, in certain scenarios, the use of these drugs may cause some problems such as the occurrence of ADRs. The purpose of the current manuscript is to determine the association between gender differences and drug-induced hepatotoxicity in anti-tuberculosis therapy in Bukit Mertajam Hospital and Penang Hospital (PGH), Malaysia.

2. METHODOLOGY

3. RESULTS

Table 1 demonstrates the socio-demographic characteristics of the study subjects at the time of diagnosis. The study subjects were predominant males (n=146, 76.8%), with only 23.2% females (n=44). The mean body weight was 45.83kg. The age of the patients was divided into two groups as shown in Table 1. The majority of patients (n=153, 80.5%) were above 35 years of age, with 37 patients (19.5%) below 35 years of age. The mean age was 46.92 years. There was no significant difference between both groups (p = 0.136).

Malaysia is a multi-ethnic country with three large race groups: Malay, Chinese and Indian. Hence in this study, the race is categorized into four groups: Malay, Chinese, Indian and other. Other races here stand for patients from other countries: Indonesia, Myanmar, Bangladesh and Nepal. The occurrence of DIH with anti-tubercular is as follows: Malay 64 (34%), Chinese 90 (47%), Indian 25 (13%), and others 11 (6%), which shows non-significant differences (p = 0.239).

A significantly higher percentage of these patients was from urban areas (n=151, 79.5%), and particularly unmarried males (n=99, 81.8%). There were no significant differences in the employment status (p=0.448) and education level (p=0.247).

In this study, male patients were found to be more strongly associated with smoking (95.1%) being one of the main risk behaviours (p<0.001). Moreover, non-alcoholic (n=109, 95.6%) and non-IVDU (n=103, 71.0%) male patients showed significant differences (p=0.001) (Table 1).

Majority of the cases were newly registered (n=163, 85.8%); and 27 (14.2%) were relapse cases. Positive for sputum smear for M.tuberculosis showed similar results in this study as illustrated in Table 2. However, patients with non-diabetes mellitus history (n=130, 79.3%) and non- HIV/AIDS history (n=107, 72.8%) had significant differences (p<0.05) as shown in Table 2.

85 (72%) male and 33 (28%) female patients had a successful treatment outcome. Statistically, patients’ gender had a significant association (p=0.044) with treatment outcome. It is also shown that being a female has a statistically significant positive association with successful treatment outcome (OR=1.83, 0.988-3.390 95% CI) (Table 3).

In univariate analysis, patients with relapse TB (OR = 0.297, P-value = 0.006), co-morbidities (OR = 0.501, P-value = 0.028) and HIV (OR = 0.346, P-value = 0.004) had statistically significant negative associations with successful treatment outcomes (Table 4).

Upon multivariate analysis, successful treatment outcome was observed in smokers (OR =2.345, P-value = 0.033), whereas Indian ethnicity (OR = 0.173, P-value = 0.024) and patients with relapse TB (OR= 0.332, P-value = 0.032) and HIV (OR= 0.217, P-value = 0.027) were less likely to have successful treatment outcomes (Table 5).

4. DISCUSSION

The use of a multi-drug regimen for the treatment of TB, such as the combination of INH, RIF and PZA, has been associated with an increased incidence of hepatotoxicity when compared with INH monotherapy used for anti-TB prophylaxis [12, 13]. The occurrence of anti-TB hepatotoxicity is variable. In the current study, 6.1% of patients developed anti-TB DIH, an incidence less than those stated in reports available from India (8.0-19.8%) [13] but more than those from the West (4.3%) [14]. In Malaysia, the incidence of anti-TB DIH was reported at 9.7% and 8.7% [15,16]. The variation in the incidence of anti-TB DIH observed in the current study may be due to differences in patients’ characteristics, regimens used, type of monitoring, and the diagnostic criteria defining hepatotoxicity [13].

The current study comparatively assessed the socio-demographic profiles between the genders of these patients. A higher percentage of anti-TB DIH was found in male than female patients. Not surprisingly, we observed that male patients had a higher percentage of concurrent risk factors such as smoking, diabetes mellitus, and alcohol consumption which predispose to the incidence of tuberculosis. The social and cultural values may play an important role in the higher incidence of TB among men. The literature suggests that the higher incidence of TB among males might be due to their large social contacts whereas culturally women tend to stay at home or work in the field in developing countries. However, if countries are developed, such cultural and social differences may not play the same role, as both genders have high social contacts. In such cases, biological mechanisms play an important role in determining gender differences in infection rates. In a 15-year prospective study of 280,000 subjects, it was reported that progression from infection to disease was 8.6% among men and 3.1% among women [17]. This difference may also be due to men's greater exposure to risk factors that include smoking and alcohol.

Gender differences were highly observed in many studies and it has been reported that females are at increased risk of hepatotoxicity compared to males. A study by Batool et al., (2006) [18] reported that out of 60 patients, 38 female patients had anti-TB DIH. Another study showed that 44 (44%) males and 56 (56%) females had anti-TB DIH [19]. A recent study by Alima et al. (2013) reported 17 female patients (51.5%) who had anti-TB drug-induced hepatotoxicity and 53 (53.5%) among the control group [10].

However, several other studies explained hepatotoxicity as a higher risk factor in males than females [20]. A study by Lee et al. showed that 84 (57%) male and 64 (43%) female patients had anti-TB DIH. Another study by Amer et al. (2010) reported males (n=75, 59.5%) were more affected then females (n=51, 40.5%) [16, 21]. Drug-induced hepatotoxicity was more common in males (n=36, 56%) than females (n=29, 44%) [22]. In this study, the incidence of anti-TB DIH is higher in male patients (n=146, 76.8%) than female patients (n=44, 23.2%). The results reflect that the incidence is higher in males which correlates to that reported by Marzuki et al. [20].

Age was divided into a younger age group (≤35 years of age) and older age group (>35 years of age) for the purpose of this analysis, based on previous studies [23, 24]. Although it has been reported that advanced age can be a risk factor for anti-TB DIH [10, 11], in the present study no correlation was found between age groups and the risk of developing anti-TB DIH (p=0.136). Also in other studies, advanced age was not a risk for anti-TB DIH [25, 26]. In this study, 121 (79.1%) male patients and 32 (20.9%) female patients aged 35 and above developed anti-TB DIH compared to 25 (67.6%) male patients and 12 (32.4%) female patients below 35 years of age. The mean age for the males and females were 47.49 ± 14.28 and 45.0 ± 14.96 years, respectively.

CONCLUSION

The incidence of anti-TB DIH observed in the current study is similar to those reported from Western countries and in Malaysia. A number of factors including residence, smoking habit, alcohol consumption and intra venous drug user’s patients were found to be significantly associated with anti-TB DIH. Female TB DIH patients were more likely to have TB treatment success when compared to their counterparts. Likewise, our analysis suggests that Indian ethnicity, patients with relapse tuberculosis (TB) and patients with Human Immune Virus (HIV) were less likely to have successful treatment outcomes. Intensive monitoring of patients on anti-TB drugs with identified risk factors, especially during the first month of treatment, might help to identify potential hepatotoxicity in time and to withdraw drugs at the right time to prevent severe hepatotoxicity which may be fatal.

DECLARATION

The current paper is and will not be submitted elsewhere until a final decision is reached. All authors are made aware that the current manuscript is submitted to Open Medicine Journal. The manuscript has undergone English editing and grammar services by English editing Netherlands (english-editing.nl)

REFERENCES