The more that psoriasis covers the surface area of a body, the greater the risk of the patient’s death, according to a new analysis.
Researchers in the Perelman School of Medicine at the University of Pennsylvania in Philadelphia conducted the first study to link psoriasis severity to an increased risk of death using an objective measure of disease severity rather than treatment patterns, such as whether a patient was receiving oral, injectable, or phototherapy treatment.
The risk of death is almost double in patients with psoriasis on 10% or more of their body, they found.
Psoriasis affects about 7.5 million Americans, according to American Academy of Dermatology estimates. The condition occurs most frequently on the scalp, knees, elbows, hands, and feet but also may appear on the lower back, face, genitals, and nails.
“It’s well established that psoriasis is associated with an increased risk for other comorbidities like chronic kidney disease, diabetes, and cardiovascular disease, but we don’t yet understand how the severity of psoriasis impacts future risk of major health problems,” said the study’s senior author, Joel M. Gelfand, MD, Professor of Dermatology and Epidemiology at Penn, in a press release.
Dr Gelfand and his team used Body Surface Area (BSA), literally a measurement of the percentage of the body covered by psoriasis, as their metric. They looked at 8760 patients from a UK database who had psoriasis and 87,600 persons who did not and sent surveys to patients’ general practitioners to determine the body surface area affected by psoriasis. They also looked at the number of deaths in each group by person-years, a measure that combines the number of persons with the amount of years of data on them in the database.
In a follow-up time of about 4 years, there was an average of 6.39 deaths per 1000 person-years in patients who had psoriasis on more than 10% of their bodies compared with 3.24 deaths in patients who did not.
Even when the researchers adjusted for other demographic factors, patients who had psoriasis with a BSA greater than 10% were 1.79 times more likely to have died than other persons their age and gender who did not. The risk persisted even when controlling for other risk factors, such as smoking, obesity, and other major medical conditions.
“Other studies that have examined this question, including our own prior research, have looked at patients who were receiving treatment for psoriasis, which is not an objective measurement of severity, making it unclear to whom the prior studies apply,” said the study’s lead author, Megan H. Noe, MD, MPH, a dermatologist and postdoctoral research fellow in Dr Gelfand’s laboratory.
“By using BSA, which we can evaluate in a patient’s clinical visit, we can better understand which patients are at highest risk for future medical problems and need preventative care,” she noted.
More research is needed to better understand the specific causes of death in patients with extensive psoriasis and to see if and how treatment can impact the risk, the investigators suggested.
They published their findings online in the Journal of Investigative Dermatology.
The study was supported by a medical dermatology fellowship from the National Psoriasis Foundation and the National Institutes for Health (T32-GM075766, K24-AR064310-36).
Noe MH, Shin DB, Wan MT, Gelfand JM. “Objective Measures of Psoriasis Severity Predict Mortality: A Prospective Population-Based Cohort Study.” J Invest Dermatol. 2017 Aug 23. pii: S0022-202X(17)32808-7. doi: 10.1016/j.jid.2017.07.841. [Epub ahead of print]