The drug advertisement suggests that BoXeva should be added to metformin for the treatment of patients with type 2 diabetes mellitus. A 56-year-old woman comes to the office for follow-up. She has a history of type 2 diabetes mellitus and hypertension. The patient has been on metformin therapy for the past 6 months. Despite adhering to a diabetic diet and increasing her level of physical activity, she has been unable to lose weight. At the current visit, her blood pressure is 145/90 mm Hg, and heart rate is 72/min. Her weight is 82 kg (180 lb) . HbA_1c is 7.6%, and serum creatinine is 0.9 mg/dL.
Compared to adding BoXeva, adding glimepiride to this patient's current regimen will most likely lead to which of the following at 52 weeks of treatment?

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Explanation: The drug advertisement compares the effect of adding either BoXeva or glimepiride to metformin on 3 outcomes. Adding BoXeva was associated with statistically significant weight loss (-3.6% versus +2.1% starting from similar baseline weight, p <0.01), and a statistically significant decrease in blood pressure (-2.7 mm Hg versus +1.6 mm Hg, p <0.01, baseline blood pressure not given for each group). These were both secondary endpoints. The graph on the right shows that the addition of BoXeva (blue line) was associated with a lower A_1c at 52 weeks than the addition of glimepiride (dotted red line). However, the standard error of measurement (SEM) error bars of the 2 curves (shown to the right of the graph as blue and red vertical bars) overlap. This means that the change in A_1c was not statistically significant, reflecting a similar effect on glycemic control (Choice A). As a rule of thumb, for similarly sized samples, overlapping SEM error bars suggest a non-statistically significant difference (not always true with other error bar types). _1c (Choices B and C) Although glimepiride was associated with increased weight, there is no information provided regarding stroke risk or insulin resistance, making it difficult to draw conclusions. (Choice D) No specific data is presented regarding compliance, although the graph references intention-to-treat (ITT) analysis, in which patients are analyzed based on their initial group assignment (eg, BoXeva versus glimepiride) regardless of adherence. ITT can help preserve the effects of randomization and reduce bias (eg, due to crossover). Educational objective: Overlapping standard error of measurement error bars suggest a non-statistically significant difference. References: Understanding statistical significance. (http://www.ncbi.nlm.nih.gov/pubmed/20445438) Clinical versus statistical significance: interpreting P values and confidence intervals related to measures of association to guide decision making. (http://www.ncbi.nlm.nih.gov/pubmed/21507834)

The Drug Advertisement Suggests That BoXeva Should Be Added to Metformin