People with psoriasis are at a higher risk to develop type 2 diabetes than those without psoriasis, with risk increasing dramatically based on disease severity according to study results recently published in the Journal of the American Academy of Dermatology. “Typically, when disease affects more than 5% to10% of the BSA, we treat the patient with phototherapy, pills, or biologics, as topical treatments are difficult to use or ineffective in those with more severe extensive disease,” says Dr. Gelfand. “We know psoriasis is linked to higher rates of diabetes, but this is the first study to specifically examine how the severity of the disease affects a patient’s risk,” says Dr. Gelfand. The researchers also found that patients with psoriasis covering more than 10% of their body were 64% more likely to develop diabetes than those without the condition, independent of traditional risk factors like body weight.

“The severity of psoriasis is commonly defined by the amount of the body covered by red scaly patches,” says Joel M. Gelfand, MD, MSCE. “The body surface area (BSA) involved is highly variable. About 70% of patients have mild disease affecting less than 2% to 3% of the BSA (typically just the elbows and knees). About 30% of patients have more extensive involvement.”


A Closer Look at the Study

For this study, Dr. Gelfand and colleagues assessed 8,124 adults with psoriasis and 76,599 adults without psoriasis over 4 years. The study revealed 3.44% incident cases of diabetes in the psoriasis group and 2.44% incident cases of diabetes in those without psoriasis (Table 1). After adjustment for age, sex, and BMI, the hazard ratios for development of incident diabetes were 1.21, 1.01, and 1.64 in the groups with 2% or less of their BSA affected, 3% to 10% of their BSA affected, and 10% or more of their BSA affected, respectively, when compared non- psoriasis participants (Table 2).

On average, 5.97 of every 1,000 people will be diagnosed with diabetes in a given year, explains Dr. Gelfand. In those with psoriasis covering more than 10% of their BSA, this risk escalates to 12.22 per 1,000 people.

“Remarkably, we found that a simple assessment of BSA affected by psoriasis was predictive of future risk of developing diabetes,” says Dr. Gelfand. “The risk of diabetes increased as BSA affected by psoriasis increased, with findings most clinically significant in patients for whom psoriasis covered 10% or more of their BSA. We previously showed that psoriasis covering more than 10% of BSA was also predictive of an increased risk of death during 4 years of observation.”

Dr. Gelfand also points that the more inflammation there is in the skin, the more it relates to diseases impacted by inflammation, such as insulin resistance (diabetes) and atherosclerosis (cardiovascular disease).


Important Implications

Dr. Gelfand says that physicians should routinely evaluate the level of affected BSA in patients with psoriasis. Efforts at prevention for diabetes and other preventable diseases, such as cancer and cardiovascular disease, should be emphasized in patients with psoriasis, especially those with psoriasis covering more than 10% of their BSA. Educating patients about the impact of psoriasis severity on their future health provides an opportunity for them to become more engaged in their healthcare and motivated to make healthier lifestyle choices, according to Dr. Gelfand.


Gelfand, J, Mehta, N, Wan, M, et al. Psoriasis and the risk of diabetes: A prospective population-based cohort study. J Am Acad Dermatol. 2018;78(2):315-322. Available at