Clinical Edge Journal Scan

Commentary: Are "significant" results necessarily clinically meaningful? October 2023

Dr. Feldman scans the journals, so you don’t have to!

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Steven R. Feldman, MD, PhD

In the study by Merola and colleagues, dupilumab significantly improved sleep in adults with atopic dermatitis (AD). The results from the 12-week, placebo-controlled period of the 24-week phase 4 randomized, double-blinded, placebo-controlled DUPISTAD study are fascinating on many levels. The bottom line is not surprising: Dupilumab treatment reduced itch and improved self-reported sleep quality in patients with moderate to severe AD. The placebo group improved considerably, too, though not as much as did the dupilumab group. The use of moisturizers in the study (or some other topical treatments that patients were using at home) may have contributed to the placebo group improvement.

I was excited to see that the study included the use of objective electronic monitoring of sleep quality. This was done using wrist actigraphy, devices on the wrist that measure acceleration movements. What a great tool this could be for measuring how much scratching our patients are doing! With devices like these measuring movements objectively, we wouldn't have to rely on patients' self-report of itch or sleep quality. Sadly, these monitors did not show any meaningful differences between the dupilumab and placebo groups. This technology holds great promise but it isn't yet ready for prime-time assessment of scratching or sleep.

The title of Chiesa Fuxench and colleagues' article, "Risk of Inflammatory Bowel Disease in Patients With Atopic Dermatitis," might be scary to our patients. The authors reported that "children and adults with AD had an increased risk of IBD [inflammatory bowel disease]." The authors concluded, "Clinicians should be aware of these risks, particularly when selecting systemic treatments for AD in patients who may have coincident gastrointestinal symptoms." Bah, humbug, I say!

Be careful when someone tells you there is increased risk. This study was done exceptionally well by an exceptionally good research team. They were working with a huge database and included many controls to ensure that their findings weren't due to chance. And while they did find an "increased risk," they proved — rather conclusively, I believe — that the increased risk is tiny and not something we need to worry about.

The results of this study suggest that there is a scientific link between AD and IBD, probably some genetic inflammatory signaling contributing to both conditions. But even in the highest-risk group, it would take seeing well over 1000 patients for a year to see one more case of IBD due to AD. This article is a good foundation for researchers who want to explore the underlying connection between AD and IBD. The study is an even better foundation for physicians who want to reassure patients that there is little to no meaningful increased risk for IBD in patients with AD.

Am I allowed to just say "Ditto!"? Wan and colleagues' article "Incidence of Cardiovascular Disease and Venous Thromboembolism in Patients with Atopic Dermatitis" does show a statistically significant increased risk for cardiovascular (CV) disease in patients with AD. Is that increase clinically significant? This study was also exceptionally well done by an exceptionally good research team. They concluded, "Atopic dermatitis, particularly when severe, is associated with increased risks of venous thromboembolism and CV disease, which may influence the monitoring of patients and selection of treatments for AD." I look at their findings and conclude that AD, even when severe, is associated with little if any clinically meaningful increased risks for venous thromboembolism or CV disease, and we don't need to add any special CV monitoring of AD patients.

The key data are presented in Table 2 of their manuscript. In children, the risk for deep vein thrombosis (DVT) in those with severe AD was about 3 times (0.16) that of those with no AD (0.05). But those numbers are per 1000 patient-years. Therefore, the increased risk is 0.16 - 0.05 = 0.11/1000 patient-years. Thus, you'd expect to see one more case of DVT per year in every 9000 children with severe AD. Does that mean we need to monitor all 9000 for DVT? Would that be cost-effective? Might the monitoring cause more problems than it would solve?

CV disease is much more common in adults than in children, but still, with a difference in risk of about 0.5-1 per 1000 patient-years, you'd only expect one more event due to AD in every 1000-2000 patients, and even that is assuming that the entire risk difference was due to AD and not to some other variable that wasn't measured.

With so much drug development for AD, I think we are going to be inundated with companies wanting us to hear their message over and over again. One way to do that is to mine clinical trial data for more papers. In Merola and colleagues' article "Safety and Efficacy of Tralokinumab in Older Adults With Moderate-to-Severe Atopic Dermatitis" we see just that. We already know that tralokinumab is effective for moderate to severe AD from past publications of clinical trial data. Here, the investigators report on a subset of the clinical trial data — the data on older adults — and, not surprisingly, the drug worked. The efficacy rate, 17% getting clear or almost clear, doesn't sound particularly exciting compared with the higher rates we've seen for other products, but perhaps that lower rate is due in part to differences in studies. Instead of more cuts of data from the same trials, it would be nice to see how tralokinumab compares with other AD treatments on a head-to-head basis.

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