Increased insulin resistance following switch from efavirenz to cobicistat-boosted elvitegravir

Integrase strand transfer inhibitors (INSTIs) have been associated with excess weight gain in people living with HIV compared to other antiretroviral agents. The mechanisms that underlie these effects are not well defined. Thus, we aimed to examine the effects of switching to INSTI-containing regimens on clinical metabolic parameters.

A secondary analysis of a prospective cohort study in which people living with HIV on a stable efavirenz-based regimen were switched to a cobicistat-boosted elvitegravir or raltegravir-containing regimen. Participants remained on the NRTI backbone of tenofovir disoproxil fumarate and emtricitabine.

Frozen plasma samples from 19 participants were used to determine concentrations of leptin, adiponectin, insulin and lactate at baseline and 8 weeks post-switch. Fasting lipids and blood glucose not reported in the initial study were obtained to examine metabolic changes. Anthropometric data including height and weight were abstracted from the medical record.

Participants switched from efavirenz to cobicistat-boosted elvitegravir without change in tenofovir disoproxil fumarate/emtricitabine backbone showed a 20% increase in HOMA-IR after 8 weeks (1.84 vs 2.24, p < .05), due mostly to increases in fasting insulin. This increase occurred independent of weight gain in the cohort as whole (83.4 vs 85.9 kg, pre vs post, p = .04), but was linked to increases in circulating lactate.

Participants switched to an INSTI-based regimen tended to gain weight, and those switched to cobicistat-boosted elvitegravir had increases in markers of insulin resistance and elevation in plasma lactic acid compared to raltegravir, suggesting that elvitegravir may promote metabolic perturbations in people living with HIV.