334. Weight Change Associated with Antiretroviral Therapy Switch to Integrase Strand Transfer Inhibitor-Based Regimens

BACKGROUND: An association between switching antiretroviral therapy (ART) to integrase strand transfer inhibitor (INSTI)-based ART and weight gain has been previously reported. However, insufficient data exists on risk factors associated with such weight gain. METHODS: We reviewed charts of 119 virally-suppressed HIV-positive patients switched from nonnucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (PI)-based ART to INSTI-based ART and compared their weight change over 17 months to 56 virally-suppressed patients who were maintained on NNRTI-based regimens over the same period.We looked at variables associated with weight gain including age, weight, body mass index (BMI), gender, CD4 count, starting ART, and final INSTI-based ART. RESULTS: The 119 patients switched to INSTI-based ART gained an average of 6.9 lbs compared with an average 1 lbs weight gain in the 56 patients who were maintained on NNRTI-based ART (P = 0.002). There was also a statistically significant difference in the percentage % weight change between the two groups (4.2% vs. 0.7%, P < 0.001).There was an average 1.2 lbs weight loss in 92 of the 119 patients with weights recorded 17 months before switching ART, compared with an average 6.7 lbs weight gain after the switch (P < 0.001).There was no association between gender, CD4 count at the time of switch, starting ART, or final INSTI-based ART with weight gain. However, patients weighing < 150 lbs at the time of switch had a greater % weight gain than patients weighing >200 lbs (6.9% vs. 2.7%, P = 0.02) and a trend to greater % weight gain than those weighing ≥150 to ≤ 200 lbs (6.9% vs. 3.8%, P = 0.06). There was marginal statistical significance when comparing those with BMIs < 25 to those with BMIs ≥25 to ≤ 30 (8.2 vs. 6.5 lbs, P = 0.069) and those with BMIs >30 (8.2 vs. 5.0 lbs, P = 0.057). There was an inverse correlation between age and weight gain, indicating that less weight was gained when switching to INSTI-based ART as the age of the patient increased (ρ = -0.211, P = 0.021). CONCLUSION: Our study showed a statistically significant weight gain in patients switched from NNRTI- or PI- to INSTI-based ART compared with patients maintained on NNRTI-based ART.Baseline variables associated with greater weight gain included weight <150 lbs, BMI <25 and younger age. DISCLOSURES: All authors: No reported disclosures.