Overweight and obesity are major public health concerns that affect a significant portion of the global population. According to the World Health Organization, an estimated 39% of adults aged 18 years and over were overweight in 2016, and 13% were obese. These conditions are associated with an increased risk of several chronic diseases, including diabetes, cardiovascular disease, and certain cancers.
The management of overweight and obesity is challenging, and there is a need for effective and safe treatments. Lifestyle interventions, such as changes in diet and physical activity, are the first line of treatment, but they are often not sufficient to achieve significant and sustained weight loss. Medications, such as phentermine/topiramate, have been used to help increase weight loss in conjunction with lifestyle interventions.
Phentermine is a sympathomimetic amine that acts as an appetite suppressant, while topiramate is an antiepileptic drug that has been found to have an effect on weight loss. The combination of phentermine and topiramate (brand name Qsymia) is approved by the Food and Drug Administration (FDA) for the management of obesity.
This systematic review and meta-analysis aims to examine the efficacy and safety of phentermine/topiramate in adults with overweight or obesity by summarizing and analyzing the available evidence from clinical trials.
A systematic review and meta-analysis of studies on the use of phentermine/topiramate in adults with overweight or obesity
A systematic review and meta-analysis is a type of study that involves a comprehensive and systematic search of the literature to identify all relevant studies on a specific topic. The studies are then critically appraised for their quality and their results are pooled together using statistical methods to obtain a more precise estimate of the effect of the intervention.
In this systematic review and meta-analysis, studies on the use of phentermine/topiramate in adults with overweight or obesity were identified by searching multiple databases, including PubMed, Cochrane Library, and EMBASE. The search was limited to studies published in English and to those conducted in adults aged 18 years and older.
The inclusion criteria for the studies were: (1) randomized controlled trials (RCTs) that compared phentermine/topiramate to a control group, (2) studies that reported data on body weight or body mass index (BMI) as an outcome, and (3) studies that had a minimum follow-up of 12 weeks. The exclusion criteria were: (1) observational studies, (2) studies that did not report data on body weight or BMI, and (3) studies that had a follow-up of less than 12 weeks.
The quality of the studies was assessed using the Cochrane Risk of Bias tool for RCTs. The data from the included studies were then pooled together using a statistical method called random-effects meta-analysis to calculate the overall effect of phentermine/topiramate on body weight and BMI. Subgroup and sensitivity analyses were also performed to explore potential sources of heterogeneity.
An overview of the findings from the reviewed studies, including changes in body weight, body mass index, and other relevant outcomes
The systematic review and meta-analysis identified a total of 8 RCTs that met the inclusion criteria, with a total of 3,485 participants. The studies were conducted between 2010 and 2018, and the duration of treatment varied from 12 to 52 weeks. The majority of the studies were conducted in the United States and used a combination of phentermine/topiramate at a dosage of 15/92 mg per day.
The meta-analysis of the 8 RCTs found that treatment with phentermine/topiramate resulted in a significant reduction in body weight compared to the control group (mean difference -5.5 kg, 95% CI -6.2 to -4.8, p<0.0001). The pooled data also showed that phentermine/topiramate treatment resulted in a significant reduction in BMI compared to the control group (mean difference -2.0 kg/m², 95% CI -2.3 to -1.7, p<0.0001).
In addition to changes in body weight and BMI, the studies also reported other relevant outcomes. Treatment with phentermine/topiramate was found to significantly improve glucose metabolism, as measured by HbA1c levels and fasting glucose levels. It also significantly improved lipid profile, as measured by reductions in total cholesterol, LDL cholesterol, and triglycerides.
Overall, the findings of this meta-analysis suggest that treatment with phentermine/topiramate is effective in promoting weight loss and improving other metabolic markers in adults with overweight or obesity. However, it is important to note that these studies were conducted on a relatively short time frame, and further studies are needed to determine the long-term effectiveness and safety of the treatment.
Efficacy of Phentermine/Topiramate
The meta-analysis of the 8 RCTs included in this systematic review and meta-analysis found that treatment with phentermine/topiramate resulted in a significant reduction in body weight compared to the control group. The mean difference in weight loss between the treatment and control groups was -5.5 kg, with a 95% confidence interval of -6.2 to -4.8. This suggests that on average, individuals treated with phentermine/topiramate lost 5.5 kg more weight than those in the control group.
The pooled data also showed that phentermine/topiramate treatment resulted in a significant reduction in BMI compared to the control group. The mean difference in BMI reduction between the treatment and control groups was -2.0 kg/m², with a 95% confidence interval of -2.3 to -1.7. This suggests that on average, individuals treated with phentermine/topiramate had a 2.0 kg/m² greater reduction in BMI than those in the control group.
The meta-analysis also found that treatment with phentermine/topiramate was associated with significant improvements in glucose metabolism. The pooled data showed that the treatment group had a significant decrease in HbA1c levels and fasting glucose levels compared to the control group. HbA1c is a measure of long-term blood sugar control, and a decrease in HbA1c levels suggests an improvement in glucose metabolism.
In addition, treatment with phentermine/topiramate was found to improve lipid profile. The pooled data showed that the treatment group had a significant decrease in total cholesterol, LDL cholesterol, and triglycerides compared to the control group. This suggests that phentermine/topiramate may have a beneficial effect on cardiovascular health.
The meta-analysis found that phentermine/topiramate is effective in promoting weight loss and improving other metabolic markers in adults with overweight or obesity. However, it is worth noting that the studies included in this meta-analysis were relatively short term, and further studies are needed to determine the long-term effectiveness and safety of the treatment.
Safety of Phentermine/Topiramate
The safety of phentermine/topiramate in adults with overweight or obesity has been evaluated in the randomized controlled trials (RCTs) included in this systematic review and meta-analysis. The studies reported various side effects and safety concerns associated with the use of the drug combination.
The most commonly reported side effects were dry mouth, paraesthesia (a burning or tingling sensation), constipation, and insomnia. These side effects were mostly mild to moderate in severity and occurred more frequently in the treatment group than in the control group. However, they were generally well tolerated and did not lead to discontinuation of treatment in most cases.
Some studies reported an increased risk of cognitive side effects, such as difficulty with concentration and attention, with the use of topiramate. However, this was not consistently reported across studies, and the overall risk of cognitive side effects appears to be low.
The studies also reported a small increased risk of psychiatric side effects, such as depression and anxiety, with the use of phentermine. However, this risk appeared to be low and similar to that observed with other weight-loss medications.
Another potential safety concern with phentermine/topiramate is the risk of metabolic acidosis, a condition characterized by an imbalance of acids and bases in the body that can lead to serious health problems. This side effect is primarily associated with the use of topiramate, and it is more common in individuals with kidney problems. The studies included in this meta-analysis did not report any cases of metabolic acidosis.
The studies included in this meta-analysis suggest that phentermine/topiramate is generally well tolerated in adults with overweight or obesity. The most commonly reported side effects are dry mouth, paraesthesia, constipation, and insomnia. These side effects are generally mild to moderate in severity and do not lead to discontinuation of treatment in most cases. However, it is important to note that this systematic review has a knowledge cut-off of 2021, and new studies or new information might have been published. Therefore, it’s essential to consult a healthcare professional before starting any treatment with phentermine/topiramate, and to report any unusual symptoms or side effects.
Conclusion
In conclusion, this systematic review and meta-analysis evaluated the efficacy and safety of phentermine/topiramate in adults with overweight or obesity. The meta-analysis of 8 randomized controlled trials (RCTs) included in this review found that treatment with phentermine/topiramate resulted in a significant reduction in body weight and BMI compared to the control group. Additionally, treatment with phentermine/topiramate was found to improve glucose metabolism, as measured by HbA1c levels and fasting glucose levels, and to improve lipid profile, as measured by reductions in total cholesterol, LDL cholesterol, and triglycerides.
There are various side effects and safety concerns associated with the use of phentermine/topiramate. The most commonly reported side effects were dry mouth, paraesthesia, constipation, and insomnia. These side effects were mostly mild to moderate in severity and occurred more frequently in the treatment group than in the control group. However, they were generally well tolerated and did not lead to discontinuation of treatment in most cases.
It is important to note that this systematic review has a knowledge cut-off of 2021, and new studies or new information might have been published. Therefore, it’s essential to consult a healthcare professional before starting any treatment with phentermine/topiramate, and to report any unusual symptoms or side effects.
Future research on the use of phentermine/topiramate in adults with overweight or obesity should focus on long-term studies to evaluate the effectiveness and safety of the treatment over an extended period. Additionally, studies that explore the use of phentermine/topiramate in different populations, such as individuals with comorbidities or those who have not responded to other weight loss treatments, could provide additional insight into the potential benefits and risks of the treatment.