Hepatitis B virus infection among inpatients of a psychiatric hospital of Mexico

Hepatitis B virus (HBV) infections are an important cause of morbidity and mortality worldwide. More than 400,000,000 persons are chronically infected by HBV [1, 2]. Moreover, the virus is responsible for more than 300,000 cases of liver cancer every year and for similar numbers of gastrointestinal haemorrhage and ascites [2]. In the United States, chronic HBV infection is responsible for about 5,000 annual deaths from cirrhosis and hepatocellular carcinoma [1]. In Latin America, statistical estimates of HBV-related morbidity showed that greater than 150,000 acute HBV cases occur per year [3].

Reports indicate that patients with mental illnesses have a high prevalence of HBV infection [4–7], and the prevalence of this infection in psychiatric patients varies substantially in different countries. For instance, in a Brazilian study, 22.4% of the psychiatric patients studied were positive for HBV infection [8]. In European countries, a study carried out in Spain showed that HBV seropositivity in mentally handicapped adults was 81.3% [9]. In contrast, in Northern Ireland, only 4.5% of the residents of an institution for the mentally handicapped carried any HBV marker [10]. In the U.S.A., a study performed on people with severe mental illness showed a 23.4% prevalence rate of HBV infection [11]. In Asian countries, a Taiwanese study reported that 18.1% of institutionalized psychiatric patients were positive for HBV surface antigen (HBsAg) [12]. Furthermore, a study performed on psychiatric inpatients in Singapore showed that 12.7% were positive for HBsAg, 63.4% were positive for HBV surface antibody (HBsAb), and 69% were positive for HBV core antibody [13].

There is a lack of information concerning the epidemiology of HBV infection in psychiatric patients in Mexico. Therefore, we conducted a cross-sectional, prospective, descriptive survey in order to determine the frequency of HBsAg and HBsAb in a population of inpatients of a psychiatric hospital of Durango, a northern Mexican city. In addition, we sought to determine whether any epidemiological data of the patients correlated with HBV infection.

In this study, 12.1% of the psychiatric inpatients showed seropositivity to either HBsAg or HBsAb. In addition, we found a remarkable and significantly higher HBsAg seropositivity in patients than in blood donors. The frequency of HBsAg seropositivity found in our psychiatric population was also much higher than those reported in Mexican blood donors [15–17]. When comparing our results with those reported in similar psychiatric populations of other countries, our frequencies were only comparable with that found in northern Ireland [10]. However, our figure was much lower than those reported in Brazil [8], the U.S.A. [11], Spain [9], Singapore [13], and Taiwan [12]. A likely explanation for this finding could be differences in the characteristics of the patients studied. For instance, intravenous drug use, an important risk factor, which was not present in our patients studied. Similarly, other risk factors such as blood transfusion and sexual promiscuity were only present in three and one of our patients, respectively. When the characteristics of our patients were analyzed for any association with HBV infection, we observed that an age forty-five years and older were associated with HBV infection (OR = 4.27; 95% CI = 1.02–18.78). A possible explanation of this finding is that the longer the life of a subject, the higher the possibility to contract the virus. Age of psychiatric patients has been correlated with HBV infection [6], but our result conflicts with the lower HBsAg carrier rate in the aged found by Chang et al [12]. Other characteristics of the patients such as gender, clinical diagnosis, number of hospitalizations, duration of last hospitalization, history of drug use, blood transfusion, sexual promiscuity, and surgery were not associated with HBV infection. HBV infection was slightly lower in females than males in our study, and this result agrees with that reported by Chang et al [12]. With respect to clinical diagnosis, risk groups for HBV infection include chronic schizophrenia patients [18], and institutionalized psychotic patients [19]. Nevertheless, frequencies of schizophrenia patients and psychotic patients were not statistically different in HBV positive and HBV negative patients of our study. Likewise, although a long duration of hospitalization has been correlated with HBV infection [9], our HBV positive patients had a slightly longer but not statistically significant mean duration of hospitalization than the HBV negative patients (9.7 years vs. 7.2 years). This result agrees with that reported by Gmelin et al [12].

A high prevalence of HBV infection does not only occur in patients but also in personnel of psychiatric hospitals [20–22]. Therefore, our results highlight the need to take action to prevent and control HBV infection in psychiatric hospitals in Mexico. Immunization is by far the single most effective prevention measure for HBV infection [23]. Hepatitis B vaccine led to a decline in the incidence of hepatitis D virus [24], and reduces incidence of liver cancer [2]. Our results may be used as a guide when the hepatitis B vaccination is being considered for use in a psychiatric hospital. Besides vaccination programs, further recommendations include health education, HBV serologic screening of patients and personnel, and the elimination of overcrowding in psychiatric hospitals.

HBV is an important infectious agent in psychiatric inpatients in Durango, Mexico. Nevertheless, the incidence of HBV infection found is lower than the majority of those reported in other countries. HBV infection was associated with an age of forty-five years and older.