WHO recommends a DTG-based regimen as the preferred first- or second-line regimen for ART. DTG-based regimens are highly effective. In this retrospective cohort study, we showed that excessive BMI increase was observed in 25% of participants 24 months after treatment initiation. Patients on the DTG-based regimen had a significantly higher BMI increase than those on the EFV-based regimen. Our findings are coherent with previous research, showing significant weight gain when ART-naïve patients began DTG-based therapy in the United States [8, 9]. It has also been observed in patients who switched from a non-INSTI-based to an INSTI-based regimen in some LMICs and upper-middle-income countries such as Thailand [10, 11].

While in many previous studies weight gain was quantified as kilograms gained over time [9, 12], Calza et al. and Esber et al. investigated weight gain as a number of BMI units over time. Calza et al. showed a mean increase in BMI of 0.84 kg/m2, observed in DTG-based treated patients at month 12 post ART initiation (p value > 0.05) [13]. Differences between his findings and ours may be explained by differences in the study population characteristics and the length of the follow-up period. Indeed, Calza et al. investigated weight gain using a holistic approach, including BMI, after 12 months of treatment in ART-naïve HIV patients starting an INSTI-based or darunavir/ritonavir-based regimen, among whom the vast majority were Caucasian, while black race had been identified as one of the risk factors for weight gain in many other studies [8, 10]. However, our results, showing a higher increase at 24 months for DTG-based than for EFV-based regimens, complements those of Esber et al.who showed an annual mean change in BMI at one year of 1.25 kg/m2 [6].

In Eswatini at present, more than 80% of PLHIV on ART receive DTG-based therapy. Considering that 25% of patients in our study had an excessive BMI increase, and the dual burden of HIV and overnutrition in Eswatini, our findings underscore the importance of educating patients about the risk of overweight/obesity and nonpharmacological interventions such as diets and physical exercise when initiating DTG-based therapy. When deciding which ART regimen is most appropriate for a patient, clinicians should know that ART regimens can have an effect beyond mere viral load suppression and may result, or not, in body weight maintenance [10]; they should therefore consider the patient’s baseline BMI and have a clinical and laboratory monitoring plan in place to prevent obesity and its cardiometabolic complications.

Our study was the first of its kind at MHC. It was carried out using routinely collected data, and reflects the completeness and accuracy with which the ART clinic from MHC has collected data. Therefore, it encourages other healthcare organisations to own and generate quality data for clinical decision-making.

Our study had some limitations. This is a retrospective observational study of routinely collected data. Given this design, we could only show an assocation but not assess a possible causal relationship between the use of DTG versus EFV and excessive weight gain. We collected the main variables of interest (height, weight, and BMI) for this study from patients records. However, data was lacking for some relevant factors, such as history of hypertension, lifestyle, waist circumference, lipid profile, and blood glucose. Most patients had a low socio-economic status and educational level. This is because all the participants came from MHC, a health centre in a remote area where most people are known to be poor and illiterate. Therefore, our results may not be generalizable to PLHIV from other settings.However, the findings are coherent with those from other studies conducted in black populations [8, 10].

In conclusion, in our cohort, 24 months after starting therapy, excessive BMI increase was significantly higher among patients on a DTG-based compared with an EFV-based regimen. DTG-based therapy will remain the preferred ART regimen in Eswatini, due to its effectiveness and circulating resistance to NNRTIs. However, DTG-based ART should be considered as a risk factor for overweight/obesity in PLHIV. To prevent obesity-associated NCDs, using an upstream approach, clinicians should consider the patient’s baseline BMI and have a clinical and laboratory monitoring plan in place. Moreover, the Eswatini national AIDS program should develop guidelines for clinical and laboratory monitoring of weight and management of obesity, including rules for ART switching, to reduce the risk of cardiometabolic complications associated with obesity.