Retrospective Evaluation of Sibutramine-Topiramate Therapy for Obesity in Real-World Outpatient Practice

This retrospective real-world cohort study aims to evaluate the effectiveness, safety, and tolerability of the combination of sibutramine and topiramate in the treatment of obesity and overweight associated with metabolic comorbidities in adult patients treated in an outpatient clinical setting. Obesity is a chronic, multifactorial, and progressive disease associated with substantial metabolic, cardiovascular, and psychosocial burden. Although newer anti-obesity therapies such as GLP-1 receptor agonists and dual agonists have demonstrated high efficacy, their elevated cost significantly limits accessibility in low- and middle-income populations and restricts widespread implementation in routine clinical practice. Consequently, there is an increasing need for affordable, accessible, and clinically effective pharmacological strategies for obesity management.

Sibutramine is a serotonin and norepinephrine reuptake inhibitor that promotes appetite suppression and increased satiety, while topiramate is a neuromodulatory agent with anorexigenic effects mediated through GABAergic and glutamatergic pathways. The pharmacological combination of these agents has been increasingly used in clinical practice because of their complementary mechanisms of action and relatively low cost. Previous studies and observational data have suggested meaningful weight reduction and acceptable tolerability with this combination under appropriate medical supervision.

The present study is designed as a retrospective observational cohort based on the review of medical records from adult patients treated between January 2023 and December 2025 at a private outpatient clinic in Brazil. Eligible participants include adults aged 18 years or older with obesity (body mass index [BMI] ≥30 kg/m²) or overweight (BMI ≥27 kg/m²) associated with at least one metabolic comorbidity, including type 2 diabetes mellitus, prediabetes, dyslipidemia, or hypertension. Patients must have received concomitant treatment with sibutramine and topiramate for a minimum period of three months and have documented clinical follow-up with at least two consultations containing anthropometric and clinical information.

Patients with pregnancy, breastfeeding, uncontrolled hypertension, significant cardiovascular disease, severe psychiatric disorders, epilepsy, nephrolithiasis, glaucoma, severe renal or hepatic disease, or concomitant use of medications known to significantly interfere with body weight will be excluded. Records lacking sufficient anthropometric or clinical follow-up information will also be excluded from analysis.

Data extracted from medical records will include demographic variables, baseline body weight, BMI, treatment duration, medication doses, percentage weight change over time, adherence to follow-up, eating behavior control, and adverse events reported during treatment. All information will be anonymized before analysis. No identifiable personal information, including names, telephone numbers, addresses, or identification numbers, will be collected. Data will be stored in password-protected electronic databases accessible only to the principal investigator.

The primary outcome is the percentage change in body weight and BMI during treatment with the sibutramine-topiramate combination. Secondary outcomes include the proportion of patients achieving clinically significant weight loss thresholds (≥5%, ≥10%, and ≥15%), early treatment response defined as ≥3% body weight reduction within the first month, treatment adherence, tolerability profile, frequency of adverse events, and subgroup analyses according to age, sex, baseline BMI, and medication dose.

Statistical analyses will include descriptive statistics, paired parametric or nonparametric comparisons, and exploratory regression analyses to identify predictors of therapeutic response. Statistical significance will be established at p<0.05.

Because this is a retrospective observational study using exclusively secondary data from medical records, the protocol is classified as minimal risk. There will be no direct patient contact, no intervention, and no modification of standard medical care. The study was approved by the Research Ethics Committee of the Hospital Universitário Cassiano Antônio de Moraes / Federal University of Espírito Santo (HUCAM/UFES), Brazil, under approval number 8.403.776 and CAAE 94334125.7.0000.5071.