Background: the prevalence of obesity is reaching a pandemic status. The SCALE trials showed that liraglutide 3 mg among people with obesity (PwO) was effective to reduce bodyweight and related complications. The fact that almost two-thirds of patients did not achieve the desired weight loss with the maximum dose of liraglutide made almost mandatory the development of other pharmacological options. The STEP 1-5 trials showed the effectiveness of semaglutide in reducing bodyweight in a dose-dependent manner. Moreover, the STEP 8 trial proved the superiority of semaglutide 2,4 mg/week versus liraglutide 3 mg/daily. We aimed to assess the effects of subcutaneous (s.c.) semaglutide 0.5 mg/weekly compared with s.c. liraglutide 3 mg/daily in PwO on anthropometric parameters in a real world-scenario for 3 months. Methods: we retrospectively evaluated 179 PwO (91.9 % ♀, 45.7 ± 10 years, and 33.3 ± 7 kg/m2) who received treatment with aGLP-1 as add-on therapy to lifestyle interventions. Patients were evaluated at baseline and after 3 months. Ninety-nine patients were prescribed s.c. semaglutide 0.5 mg/weekly with an off-label indication for weight reduction. These patients were compared with 80 patients treated with s.c. liraglutide 3 mg/daily. The main reason for prescribing of s.c. semaglutide was economic. Body composition was evaluated using a bioimpedance device (Tanita MC 580M®). Results: baseline weight was significantly greater with semaglutide compared to liraglutide (97.19 ± 21.09 vs. 90.73 ± 21.88 kg; p < 0.01) as was fat mass (42.43 ± 15.04 vs. 34.84 ± 16.07 kg; p < 0.01), whereas baseline lean mass was lesser among subjects treated with semaglutide (31.62 ± 7.56 vs 45.69 ± 15.51 kg; p < 0.01). PwO experienced a significant reduction in weight using s.c. semaglutide 0.5 mg/weekly (96.67 ± 20.83 vs. 91.44 ± 19.6 kg; p < 0.01) or s.c. liraglutide 3 mg/daily (90.73 ± 21.88 vs. 80.13 ± 18.38 kg; p < 0.01) No significant differences were seen between the amount of weight lost (5.28 ± 4.22 vs 5.72 ± 1.62 kg; p = 0.5) in the two groups. Furthermore, both groups were comparable in fat mass (2.69 ± 5.34 vs 0.96 ± 4.22 kg; p = 0.3) and fat-free mass (0.86 ± 1.63 vs 1.03 ± 0.94 kg; p = 0.07) after 3 months of treatment with both aGLP1. Side effects were gastrointestinal and transient/comparable between groups Conclusions: subcutaneous semaglutide 0.5 mg and subcutaneous liraglutide 3 mg are effective treatments for reducing weight safely among PwO in a real-world scenario at short term and without a negative impact on fat-free mass. Moreover, low doses of semaglutide were similar to liraglutide 3 mg in reducing bodyweight at short term.
