TB-HIV: Better late than never

Shobha Shukla, Citizen News Service - CNS
Photo credit:
CNS: citizen-news.org
There were interesting presentations at the TB-HIV late-breaker session at the 45th Union World Conference on Lung Health held in Barcelona. They ranged from whole genome sequencing, to impact of GeneXpert MTB/Rif, to developing new biomarkers, to private public partnerships - all with the purpose of finding better solutions for care of people dealing with TB and HIV. A study was done in a large population based cohort in Karonga district of Malawi with high HIV prevalence (60%of all TB patients are HIV positive) on whole genome sequencing (WGS) approach and active follow up for recurrence of TB due to relapse or reinfection.

Risk factors for relapse of TB could be isoniazid resistance; Mycobacterium tuberculosis lineage; treatment date (higher if treated before Rifampicin introduction in 2007); and duration of follow up. Risk factors for reinfection with TB could be due to HIV (lower in recent years), and duration of follow up (lower in first year).

Results of the study showed that:
(i) WGS is a good discrimination of relapse and reinfection;
(ii) HIV greatly increases rate of reinfection but not relapse of TB disease -- relapse is rare after the second year; and
(iii) Lineage may play a role in both relapse and reinfection of the disease.
Photo credit:
CNS: citizen-news.org

Mathematical models of GeneXpert implementation in South Africa predict an annual increase of 30%-37% in number of TB cases diagnosed and improved TB treatment outcomes by 20%-35% due to earlier initiation of treatment. A study done in a well staffed and trained integrated TB-HIV clinic in Kampala, Uganda, investigated the impact of routine GeneXpert on the diagnosis of smear negative TB in HIV infected persons as compared to clinical diagnosis and treatment.
Results showed that although baseline characteristics did not differ, GeneXpert lead to a 7% increase in TB diagnosis-- from 17% to 24%--mostly in patients without a clinical diagnosis of TB. Also experienced clinicians used the GeneXpert as a ‘rule in’ test and only partly as a ‘rule out’ test.

Results of the study
Among those clinically diagnosed, 43% got treatment versus 20% in the non clinically diagnosed arm. Treatment decisions changed mainly among those thought to have TB clinically. There were high rates of empirical treatment as more than 50% of the treated TB patients were GeneXpert negative.
Compared to GeneXpert positives, GeneXpert negatives were more likely to die within the first year after being evaluated for TB. This higher mortality among GeneXpert negatives suggests that these patients might have had more advanced disease or a different disease altogether.

Diagnosing TB among people living with HIV
With 2.33 billion people globally having latent TB infection and 9 million people per year being infected with active TB disease, Dr Hanif Esmail of the  University of Capetown argued for the need to develop diagnostic tests that are more predictive of active TB, especially in the context of HIV. Reliable identification of people early in subclinical phase of active TB may form the basis for more predictive tests. A cost effective point of care test could have a big impact on TB control.

Esmail shared the results of an interesting study done in Khayelitsha on the ‘Use of serum biomarkers for early detection of TB in asymptomatic HIV infected adults’. The study aimed to use FDG-PET/CT (fluoro-deoxyglucose positron emission tomography/computed tomography) to identify pathology consistent with subclinical TB in asymptomatic HIV infected persons who had CD4 greater than 350 and were ART naïve and derive transcriptional signature and serum biomarkers for subclinical TB.

Results of the study
The study identified 6 serum analytes (and 82 transcripts) that could be used to distinguish active and subclinical TB from latent TB. Although further validation is required, but results demonstrate potential to develop a biomarker of subclinical TB. The study also concluded that FDG-PET/CT can be used as a research tool to define pathology consistent with subclinical TB.

Whatever out of the box solutions we develop for TB-HIV care, control and treatment, their full potential can be realized only through judicious private public partnerships, especially in resource limited settings. One such example is The Medical City (TMC) hospital in Philippines. Regina Berba from the I-REACT Clinic of this private hospital spoke about the need for such successful partnerships in countries like Philippines, which has a concentrated HIV epidemic that is rapidly evolving from low and slow to fast and furious, and where every 1.5 hours a Filipino becomes infected with HIV. Philippines is one of the 9 countries where number of people infected with HIV was at least 25% higher in 2011 than in 2001. Berba informed that the HIV Hub at TMC is called I-REACT (I am responsible through early assessment, consultation and treatment). It has been successfully supporting an HIV programme, including those co-infected with TB.

Strategic partnerships between governments, NGOs and private stakeholders can go a long way in delivering quality health services in TB-HIV care, by aligning the interests of the service providers and receivers, keeping the patients always centre-stage.

Shobha Shukla, Citizen News Service (CNS) 
6 November 2014
(The author is the Managing Editor of Citizen News Service - CNS. She is supported by the World Health Organization (WHO)'s Global Tuberculosis Programme to report from the 45th Union World Conference on Lung Health in Spain. She is a J2J Fellow of National Press Foundation (NPF) USA and received her editing training in Singapore. She has earlier worked with State Planning Institute, UP and taught physics at India's prestigious Loreto Convent. She also co-authored and edited publications on gender justice, childhood TB, childhood pneumonia, Hepatitis C Virus and HIV, and MDR-TB. Email: shobha@citizen-news.org, website: www.citizen-news.org)