Introduction

Tuberculosis (TB), often caused by Mycobacterium tuberculosis (MTB) in humans, is a widespread global health issue with a high risk of mortality.[1,2] Specifically preferring to localize in macrophages, MTB is an acid-fast facultative intracellular rod-shaped obligate aerobe.[3] People with the illness cough, sneeze, or spit, which causes the aerosol to be released into the air.[4] Because MTB is an aerobic intracellular binding bacteria and favors tissues that are constantly in touch with high oxygen levels, such as the lung, TB is a very frequent chronic infection condition.[5] Depending on the immunological condition, the person may acquire the disease after breathing the bacillus, which spreads by minute droplets of saliva. MTB may spread to any area of the body after it has settled in the lungs.[5,6] One-third of the 33.2 million people living with HIV are thought to simultaneously have MTB.[7,8]

TB and HIV share an immune-compromising impact mechanism that increases mortality in HIV-infected individuals, so TB control continues to be a worldwide concern.[9,10] Almost one in ten people diagnosed with TB also have HIV. Similarly, nearly one-third of HIV-positive patients also have TB infections. Majority of them belong to developing countries with low socioeconomic features. HIV causes active TB to develop by encouraging the progression of MBT infections from latent as well as newly acquired TB infections to active TB.[11] TB has been identified as a leading cause of mortality among people with HIV, and literature also reports that HIV infection is a significant predictor of TB infection and illness.[12] Considering the fact that active TB itself is assumed an HIV-defining disease and a clinical criteria to start ART therapy, the simultaneous diagnosis of both conditions is highly recommended to identify patients with co-infection.[13]

Data on prevalence and risk factors of co-infection of the human immunodeficiency virus (HIV) in TB cases are not widely available. The prevalence of HIV in TB cases ranges from 0.34%[14] to 32.8%.[15] Alarmingly, the incidence of TB is rising in many countries making it the largest infectious cause of mortality globally. The prevalence of MTB is increasing with time and HIV is considered one of its primary determinants. The co-infection of HIV and TB has more serious and life-threatening outcomes compared to the presence of any of these diseases alone.[16]

A number of studies have been conducted on the prevalence of TB and HIV separately, but a limited amount of data is available on HIV and TB co-infection and contains some disparities in reported results. Hence, this meta-analysis aims to review the available literature on HIV-TB co-infection and comprehensively presents pooled results about its prevalence.

Methods

Flow chart of studies

We followed the PRISMA flow chart. The details are given in Figure 1.

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Figure 1

PRISMA criteria for literature search and studies selection for meta-analysis

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Results

A total of 18 studies were included with a total sample size of 44943. The minimum sample size was 192[20] and the maximum sample size was taken as 18461.[14]

Prevalence of HIV in diagnosed TB patients

The minimum prevalence of HIV-TB was reported in a study from Pakistan as 0.29%[14] (95% CI = 0.22–0.38) and the maximum prevalence of HIV-TB was found in Nigeria, that is, 44.20%[21] (95% CI = 38.19–50.66) Table 1. The details for the prevalence of HIV-TB co-infection are given in Forest plot [Figure 2] and the details of consideration of publication bias are given in Figure 3.

Table 1 Prevalence of HIV-TB co-infection

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Figure 2

Forest plot for the prevalence of HIV-TB co-infection

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Figure 3

Publication bias using Funnel plot

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According to Egger’s test, there was publication bias in these studies while Begg’s test suggests that there was no publication bias. As Begg’s test is preferred over Egger’s test, hence we will consider that in these studies there was no publication bias. There is high heterogeneity among the studies, (Q-test = 6462.6642, P < 0.0001 and I2 = 99.74%, 95% CI for I2 99.71–99.76). Due to high heterogeneity among studies, random affect methods were used for pooled prevalence. Hence, the pooled prevalence of HIV/TB was 16.291% (95%; 9.57–24.38) using the random effect method Table 2.

Table 2 Heterogeneity and publication bias testing

Discussion

The co-infection of HIV and TB has been labeled as “the cursed duet” due to the high mortality and morbidity associated with these, especially when MTB is involved.[21] HIV and MTB co-infection have been reported as one of the major determinants of global mortality among all infectious causes.[21] The annual mortality rate due to HIV is 1 million and from TB is 1.3 million.[13] HIV almost diminishes the immunity making it easier for TB to spread way faster and cause organ failures or extreme damage, costing lives. Therefore, mortality in TB-diagnosed patients with HIV-positive status has higher mortality rates compared to HIV-negative patients. It is therefore important to diagnose both diseases together to identify cases with co-infection and work rigorously for their treatment.[33] Although several studies have published the prevalence of HIV and TB separately, there is limited data available on HIV-TB co-infection, their risk factors, and potential health outcomes. Therefore, this study aimed to review and conduct a meta-analysis on the prevalence of HIV-TB co-infection.

Various studies are done with different prevalences of HIV-TB confection, as a Pakistani study reported that the prevalence of HIV among pulmonary TB patients was 0.29% and among extrapulmonary TB patients was 0.48% (P = 0.09).[14]

In 2015 a study done in China, by Li et al. reported the prevalence of HIV in TB cases as 128 (4.8%) tested positive.[34] An Indian study reported the prevalence of HIV-TB as 8.9%.[20] Another Indian, study was done to evaluate the prevalence of HIV infection in patients with TB, so they reported out of 75, 9 (12%) patients were found to be HIV positive. The male-female ratio among HIV-positive cases was 2:1.[35] A Malaysian study was designed to describe the clinical manifestation of TB infection cases in Malaysia and to determine the individual risk factors for their occurrence. They reported that the provenance of HIV in TB patients was 12.5%.[36]

In 2015, Belay et al. from Ethiopia found that 105 (32.3%) of the 325 lung TB suspects had positive cultures and 44 (13.5%) had positive smear results. Five of the smear-positive patients had negative cultures, for a total of 110 (33.8%) suspected pulmonary TB patients with bacteriological confirmation. About 82 (28.5%) of 287 pulmonary TB suspects who underwent HIV testing were HIV positive.[37] Another research from Ethiopia looked at 602 instances of TB patients receiving treatment and found that 133 (22.1%) of them also had HIV, whereas 469 (77.9%) had TB as their sole diagnosis. They also came to the conclusion that there was a rising incidence of TB-HIV co-infection from 23.9% to 35% from 2009 to 2011 and a declining rate from 35% to 12% from 2011 to 2013.[28]

Oladeinde et al. from Nigeria found one of the highest prevalences of HIV among TB patients, that is, 32.8%.[15] In China, where the overall prevalence of HIV infection was 0.9% (0.6–1.4%) in 29 studies, it was determined that this group might be a feasible target for HIV screening.[38]

The current study found that the minimum prevalence of HIV-TB was reported in a study from Pakistan as 0.29% and the maximum prevalence of HIV-TB was found in Nigeria, that is, 44.20%. The pooled prevalence of HIV/TB co-infection was 16.291% (95%; 9.57–24.38) using the random effect method. This difference might be because people who live in urban areas differ from those who live in rural ones, and people in urban areas are more susceptible to dual infections. Moreover, high-risk groups may from commercial sex workers, military personnel, long-distance drivers, law enforcement officers, and others.[39] These groups are also unfairly distributed across the nation’s regions due to the inappropriate topography of the nation, which makes it difficult for them to access the few available health services, and they are also poorly monitored and evaluated.[39]

Conclusion

The study concludes that the pooled prevalence of HIV/TB was found to be 16.291% (95%; 9.57–24.38). A higher prevalence of HIV-TB co-infection may increase infectious-related mortality and hence, early screening and integrated health-care interventions should be considered on an urgent basis to cope with this situation.

Recommendations

HIV in diagnosed TB patients is fairly common and increases the risk of mortality among these patients. It is, therefore, imperative to timely rule out the possibility of any co-infection and manage such patients with extra cautiousness to minimize worse health outcomes. Hence, appropriate two-way preventive and control strategies should be developed for various TB patients. For instance, better information should be shared about TB and HIV infection, and blood transfusion monitoring has to be reinforced. Furthermore, to lower the rate of co-infection, individuals should be encouraged to follow safe sexual practices and have a better awareness of HIV prevention.