Viral Load Suppression Among Adults with HIV on Antiretroviral Therapy: Outcomes from a Lusaka District Hospital, Zambia

Background of the Study

The Human Immunodeficiency Virus (HIV) attacks the human immune system, causing an infection that leads to the deterioration of the body system. The virus can cause a condition known as Acquired Immune Deficiency Syndrome (AIDS).^[1] HIV/AIDS remains a significant global public health issue^[2] and ranks among the top 10 causes of death, especially in low-income countries.^[3] It was estimated that by the end of 2021, there were about 38.4 million People Living with HIV (PLWHIV), with around 26 million in the African region, which has the highest HIV/AIDS prevalence in the world.^[4] The Joint United Nations Programme on HIV/AIDS (UNAIDS) set 2025 goals to reduce HIV-related morbidity and mortality, with an ultimate aim to eliminate HIV/AIDS by 2030. These goals include targets related to HIV services.^[5] The UNAIDS has set the “95-95-95” targets for 2025, aiming for 95% awareness of HIV status, 95% of those aware of receiving antiretroviral therapy (ART), and 95% of those on ART achieving viral suppression (viral load less than 1000 copies/mL) among HIV-positive individuals.^[6]

Zambia, a low-middle-income country in sub-Saharan Africa, faces a significant HIV/AIDS burden with an estimated 10.8% adult prevalence, 1.3 million individuals living with HIV, 38,000 new infections, and 19,000 AIDS-related deaths in 2021.^[7] According to the 2021 Zambia population-based HIV impact assessment (ZAMPHIA) report, 86% of HIV-positive adults in Zambia achieved viral suppression, slightly below the UNAIDS goal of 95%. This statistic supports the “Undetectable = Untransmissible” (U = U) strategy, which aims to reduce virus transmission.^[8] In Zambia, multiple strategies and interventions are being implemented to achieve undetectable viral loads in PLWHIV. This not only improves their health but also lowers HIV transmission rates.^[9] Furthermore, Zambia provides free and comprehensive HIV treatment.^[10]

Objective of the Study

The objective of this study was to determine factors associated with achieving viral suppression in adults aged 15 years and older receiving HIV treatment at Chawama First-Level Hospital in Lusaka, Zambia. Furthermore, the study sought to investigate and identify the factors and effects associated with VLS among adults accessing ART.

Study Variables

This study primarily focused on viral load status, categorized as either unsuppressed or suppressed. Several independent variables were considered, including sex, age category (less than 25 years to 50 years and above), ART regimen, [Tenofovir, Lamivudine, and Dolutegravir (TLD); Tenofovir, Alafenamide, Emtricitabine, and Dolutegravir (TAFED)], and other regimens, treatment duration, grouped by years, from less than 1 year to 5 years and above, and multi-month dispensation (MMD) categorized as not MMD, 3 MMD, and 6 MMD.

Statistical Analysis

The Pearson Chi-square test was used to determine whether or not there was an association between the categorical independent variables and the categorical outcome variable. Furthermore, logistic regression was used to explain the relationship between the independent variables and the binary outcome variable. All analyses were done using STATA version 14.2 from Stata Corp LP, College Station, TX.

Socio-demographic Characteristics

The socio-demographic characteristics of 10,758 study participants are shown in Table 1. A majority of the participants were female (66.19%), and the age distribution revealed that most were aged 50 and above, with a minority under 25 (6.64%). The predominant ART regimen was TLD (84.35%), followed by TAFED (14.61%), with a small fraction of other regimens (1.04%). Concerning treatment duration, the majority had been on treatment for 5 years or more (54.97%), while 11.51% were on treatment for less than a year, 9.09% for 4 years, 8.09% for 1 year, and 6.99% for 2 years. Dispensation intervals were mostly 3 to 5 months (68.38%), with 27.88% on 6 months or more, and a minority not on MMD (3.75%). Almost all participants were virally suppressed (96.64%).

Dependent or Outcome Variable Results

The frequency distribution of the socio-demographic and clinical characteristics of the participants by viral load status and the Chi-square test results are shown in Table 2.

Factors Associated with Viral Suppression Among Adults

The socio-demographic factors associated with viral suppression are shown in Table 2. Age group (p < 0.001), ART regimens (p < 0.001), treatment duration (p < 0.001), and MMD (p < 0.001) were associated with viral suppression.

Factors Associated with Viral Suppression

The logistic regression results of the factors associated with viral suppression are shown in Table 3. Participants aged 30–34 years were 75.9% more likely to be virally suppressed than those under 25 years old (OR: 1.75, 95% CI: 1.22, 2.53). Participants aged 35–39 years were 2.72 times more likely to be virally suppressed than those under 25 years old (OR: 2.72, 95% CI: 1.85, 4.00). Participants aged 40–44 years were 2.64 times more likely to be virally suppressed than those under 25 years old (OR: 2.64, 95% CI: 1.81, 3.84). Participants aged 45–49 years were 3.41 times more likely to be virally suppressed than those under 25 years old (OR: 3.41, 95% CI: 2.24, 5.19). Participants aged 50 years and above were 6.66 times more likely to be virally suppressed than those under 25 years old (OR: 6.66, 95% CI: 4.12, 10.77). Participants on the TAFED regimen were four times more likely to be virally suppressed than those on the TLD regimen (OR: 3.93, 95% CI: 2.34, 6.61). Participants on other regimens were 77.3% less likely to be virally suppressed than those on TLD (OR: 0.23, 95% CI: 0.13, 0.39). Participants on treatment for one year were three times more likely to achieve viral suppression compared to those on treatment for less than one year (OR: 3.34, 95% CI: 2.32, 4.82). Adjusting for other variables increased this likelihood to five times (AOR: 5.39, 95% CI: 3.54, 8.19). Participants on treatment for two years were five times more likely to achieve viral suppression compared to those on treatment for less than one year (OR: 4.57, 95% CI: 2.92, 7.15). Adjusting for other variables, this likelihood increased to eight times (AOR: 8.18, 95% CI: 4.92, 13.61). Participants on treatment for three years were six times more likely to achieve viral suppression compared to those on treatment for less than one year (OR: 5.56, 95% CI: 3.53, 8.76). Adjusting for other variables also resulted in an eight times higher likelihood (AOR: 8.48, 95% CI: 5.09, 14.12). Participants on treatment for four years were five times more likely to achieve viral suppression compared to those on treatment for less than one year (OR: 5.34, 95% CI: 3.54, 8.06). Adjusted odds also showed an eight-fold higher likelihood (AOR: 8.37, 95% CI: 5.243, 13.36). Participants on treatment for five years or more were nine times more likely to achieve viral suppression compared to those on treatment for less than one year (OR: 8.83, 95% CI: 6.79, 11.49). After adjusting for other variables, this likelihood increased to 12 times (AOR: 12.13, 95% CI: 8.63, 17.06). Participants on three to five months of dispensation were 19 times more likely to achieve viral suppression compared to those not on MMD (OR: 19.48, 95% CI: 14.73, 25.76). After adjusting for other variables, this likelihood remained high at 18 times (AOR: 18.26, 95% CI: 13.47, 24.74). Participants on six months or more dispensation were nine times more likely to achieve viral suppression compared to those not on MMD (OR: 8.60, 95% CI: 6.46, 11.448). After adjusting for other variables, this likelihood increased to 22 times (AOR: 22.14, 95% CI: 15.45, 31.72).

Effect of Sex and Age on Viral Suppression

The study revealed that there was no significant difference in viral suppression rates between males (96.2%) and females (96.64%). These findings align with the summary sheet, which also showed a relatively small difference in VLS between males and females (85.5% vs. 86.6%).^[11] The findings align with other studies.^[12,^13] Age was a significant predictor of viral suppression. Participants under 25 years had similar odds of viral suppression as those aged 25–29 years. However, those aged 30–34 years had a 75.9% higher likelihood of suppression, decreasing to 55.5% after adjustments. For those aged 35–39 years, the likelihood was 2.72 times higher, while those aged 40–44 and 45–49 years were three times more likely to be suppressed. Participants aged 50 years and above had a seven times higher likelihood, decreasing to two times after adjustments. Viral suppression odds increased with age. This finding is in line with the findings from Jiamsakul et al.^[14]

Effect of ART Regimen, Treatment Duration, and MMD on Viral Suppression

In this study, participants on the TAFED anti-retroviral regimen had a four-fold higher likelihood of achieving viral suppression compared to those on the TLD regimen. To this effect, various studies have indicated that, despite being used for many years in the treatment of HIV, TDF is associated with long-term side effects such as bone and kidney issues.^[15] On the other hand, tenofovir alafenamide (TAF), which is a newer formation of tenofovir allows for lower doses and has lower effects on the kidneys and bones.^[16] This may suggest higher adherence among those on TAFED combination compared to those on TDF-based combinations.^[17,^18] In contrast, our findings contradict the NADIA study which was done in Zambia, where the first group showed lower viral suppression with TAFED (86% vs. 88%), but the second group indicated higher viral suppression with TAFED (95% vs. 93%). Overall, the study concluded that TAFED was not inferior to TLD in assessing viral suppression.^[19] This was also supported by the VISEND study.^[20] The choice of TAFED or TLD regimens is mainly based on the patient’s clinical profile^[21] whereas those on regimens other than TLD were 77.3% less likely to be virally suppressed. This finding is in line with findings from a multinational African cohort study.^[22] Additionally, second-line antiretrovirals (ARVs), administered on an individualized basis, address unique circumstances.^[23] However, these regimens may carry a pill burden,^[17] and determining the optimal combination for specific individual circumstances can be complex and speculative.^[24] The outcome has the potential to impact the likelihood of achieving viral suppression, either enhancing or diminishing the chances.^[25]

The study revealed a strong association between longer treatment durations and higher odds of achieving viral suppression. Participants on treatment for one year had three times higher odds, and those on treatment for two years were five times more likely to achieve viral suppression. These findings align with a study done in the USA^[26] and Kenya^[27] but contrary to a study in Ethiopia.^[28]

Participants receiving three to five months of medication were initially 19 times more likely to achieve viral suppression compared to those not on MMD. After adjustments, this likelihood decreased slightly, with participants on three to five months of dispensation being 18 times more likely to achieve viral suppression. Similarly, those on six months or more dispensation were initially nine times more likely to be virally suppressed, which increased to 22 times more likely after adjusting for other factors. Various studies were consistent with our findings, that MMD improved VLS among adolescents living with HIV, and PLWHIV during the pandemic, and participants accessing community-based ART, respectively.^[29,^30]

Strengths and Limitations of the Study

Strength: This study shed light on important aspects of viral load suppression (VLS).

Limitation: Absence of control over external factors like socio-economic status, education, mental health and co-morbidities, which are known to impact VLS.

Key Messages

1. Nearly all participants achieved viral suppression, surpassing the targets set by the joint United Nations Programme on HIV/AIDS. 2. The study examined the influence of sex on viral suppression and found no significant difference between males and females. 3. The duration of treatment was strongly associated with viral suppression, as longer treatment periods corresponded to higher odds of achieving viral suppression. 4. Individuals on regimens other than tenofovir disoproxil fumarate and tenofovir alafenamide were found to be less likely to attain viral suppression, a noteworthy observation for further investigation.