In this large, diverse cohort from Thailand, we found that HIV-infected TB patients frequently reported attitudes consistent with high TB stigma and had important knowledge gaps about TB and HIV.
In our study, high TB stigma was independently associated with patients taking antibiotics before they sought TB treatment and with first seeking care from a private practitioner. After being diagnosed with TB, patients with high TB stigma were also more likely to have been hospitalized for TB, a marker of disease severity. Two of the most important indicators of TB program performance—case finding and treatment success—may, therefore, be adversely impacted by stigma. Self-treatment for TB or receipt of care outside the public TB control system could reduce case finding, since cases from the private sector are often not reported, and severe TB disease could lead to worse TB treatment outcomes.
This problem is beginning to receive more attention. In its Second Global Plan to Stop TB, World Health Organization emphasizes that case finding and treatment outcomes can be improved by community education and outreach to reduce TB-related stigma and discrimination.
Multiple studies from the past 10 years have documented the importance of addressing community perceptions of TB, rather than simply individual patient or family members' attitudes.
At least one study in Nicaragua has shown that TB-related stigma leads patients to conceal their TB diagnosis from others, reducing adherence and treatment completion rates.
Unfortunately, evidence-based strategies for reducing either patient or community-wide stigma are lacking. Self-help, advocacy, and support groups have been recommended, but their impact at a population-level and on TB control has not been firmly established.
We found that disease-specific knowledge may need to be improved among HIV-infected TB patients in Thailand. We would have expected patients' knowledge about TB disease to have been high, because patients were enrolled in this study after being registered for TB treatment and the TB registration process in Thailand involves standardized patient education. We found that low TB knowledge was closely associated with patients who had severe illness, i.e., high TB severity score, hospitalized, treated at the national infectious diseases referral hospital. Possible explanations for this association include that patients received less TB-specific education or retained less information from TB-specific education, because they were so severely ill. It is also possible that patients with less TB knowledge may be less likely to seek care until they are severely ill, although we did not find a relationship between TB diagnostic delay and knowledge to support this hypothesis. We found that HIV-specific knowledge was high, likely due to Thailand's national initiatives to prevent HIV infection.
Nevertheless, a surprisingly large number of patients incorrectly thought that mosquito bites and sharing a meal could transmit HIV and that all HIV patients must look sick. As with TB diagnosis, patients in this study already knew their HIV diagnosis and had received post-test HIV counseling. Our finding of a relationship between low TB knowledge and low HIV knowledge suggests that TB clinic staff should consider expanding the depth and frequency of patient education about both diseases.
Our study is subject to important limitations. First, no gold standards exist for measuring TB stigma, TB knowledge, and HIV knowledge. Because this analysis was embedded within a larger study, we used a standardized approach, involving quantitative analysis of a small number of questions. One recent study in Thailand developed a standardized set of questions and scoring system for quantifying TB and HIV stigma among TB patients.
A more complete assessment of stigma and knowledge in our study population would require use of such standardized, quantitative instruments or of extensive patient interviews and qualitative analysis. Second, we do not have sufficient data to assess the true public health importance of the scores that we created. Although we found statistically significant associations that were epidemiologically plausible, we do not have independent data to validate the public health significance of our stigma and knowledge scores, e.g., do patients with a high stigma score truly have higher levels of stigmatizing beliefs?
In conclusion, we found that stigma and low disease-specific knowledge were common among HIV-infected TB patients and associated with similar factors, such as TB disease severity. Further research is needed to determine whether reducing stigma and increasing TB and HIV knowledge among the general community and patients reduces diagnostic delays and improves patient outcomes.