Diet as an intervention
Other research has looked at the strong link between metabolic abnormalities and psoriasis and PsA. Some diets, such as the Mediterranean diet, show promise in improving the metabolic profile of these patients, making it a candidate as a potential intervention to reduce PsA risk. Another strategy would be to focus on limiting calories and promoting weight reduction.
One study in the British Journal of Dermatology looked at the associations between PsA and smoking, alcohol, and body mass index, identifying obesity as an important risk factor. Analyzing more than 90,000 psoriasis cases from the U.K. Clinical Practice Research Datalink between 1998 and 2014, researchers identified 1,409 PsA diagnoses. Among this cohort, researchers found an association between PsA and increased body mass index and moderate drinking. This finding underscores the need to support weight-reduction programs to reduce risk, Dr. Eder and Alexis Ogdie, MD, of the University of Pennsylvania, Philadelphia, wrote in a related editorial.
While observational studies such as this one provide further guidance for interventional trials, confounders can affect results. “Patients who lost weight could have made a positive lifestyle change (e.g., a dietary change) that was associated with the decreased risk for PsA rather than weight loss specifically, or they could have lost weight for unhealthy reasons,” Dr. Eder and Dr. Ogdie explained. Future research could address whether weight loss or other interventional factors may reduce PsA progression.
To make this work, “we would need to select patients that would benefit from diet. Secondly, we’d need to identify what kind of diet would be good for preventing PsA. And we don’t know that yet,” Dr. Eder further elaborated.
As with any prevention trial, the challenge is to follow patients over a long period of time, making sure they comply with the restrictions of the prescribed diet, Dr. Eder noted. “I do think it’s a really exciting type of intervention because it’s something that people are very interested in. There’s little risk of side effects, and it’s not very expensive.”
In other research on weight-loss methods, an observational study from Denmark found that bariatric surgery, especially gastric bypass, reduced the risk of developing PsA. This suggests that weight reduction by itself is important, “although we don’t know that yet,” Dr. Eder said.
A risk model for PsA
Dr. Eder and colleagues have been working on an algorithm that will incorporate clinical information (for example, the presence of nail lesions and the severity of psoriasis) to provide an estimated risk of developing PsA over the next 5 years. Subsequently, this information could be used to identify high-risk psoriasis patients as candidates for a prevention trial.
Other groups are looking at laboratory or imaging biomarkers to help develop PsA prediction models, she said. “Once we have these tools, we can move to next steps of prevention trials. What kinds of interventions should we apply? Are we talking biologic medications or other lifestyle interventions like diet? We are still at the early stages. However, with an improved understanding of the underlying mechanisms and risk factors we are expected to see prevention trials for PsA in the future.”