Understanding exacerbations in patients with GPP documented in US electronic health records

Aaron S. Farberg, MD: We are always excited when we get approval for different drugs for these diseases because it means that we are conducting research to study the pathophysiology and most importantly, we are developing treatments for these diseases for patients that we see and want to treat and make better.

Let’s give some background information about generalized pustular psoriasis [GPP]. We know it’s rare. It is a lifelong skin disease. As we heard from Dr. Crowley, there is an acute phase and then there is a chronic phase. Every patient is worried and concerned that it might happen again. As you can see, it has to do with these periodic eruptions. You never know when they will strike.

Patients with GPP have been noted to have significant health care utilization. They experience different costs and many comorbidities compared to patients with plaque psoriasis or the general population. Limited information is known about the distribution of GPP or GPP flares. Most data come from single-center or even case-based studies examining small samples of hospitalized patients. This is a rare disease. Until recently, there were no approved treatments, so we are just beginning to gather all the data needed to understand this disease and its pathophysiology.

What was the purpose of this research? They wanted to characterize GPP outbreaks and their treatment and describe differences between patients with and without documented GPP outbreaks using our EHR in the United States [electronic health record] systems that clinicians know and love. We love EHRs.

What were the methods? This was a retrospective observational cohort study using Optum, de-identified EHR, commercial, Medicare, and Medicaid payers, and self-pay data in adults 18 years of age or older who had a GPP. The search was conducted through December 31, 2019. This was a database search from 2016 to 2019, identifying over 48.6 million patients with available EHR notes. Of these, 1,535 received a GPP diagnosis. Can you imagine being the dermatologist who had to go through 48 million patient charts? Thank God we have computers. The index GPP diagnosis was the first occurrence of GPP from 2016 to 2019, with no other GPP diagnosis in the previous 6 months. That’s how you know it’s the start of the index case. GPP patient records with 12 months of health activity or notes were included, so we have real follow-up. These are not just one-off cases.

Seizure episodes were defined as consecutive days with EHR-documented seizures. This was documented in the health record. They were characterized by the frequency of patient occurrence, the medical facility where the outbreak was identified, the specialist who identified it, and the type of treatment.

The methodology for searching the database for keywords was natural language processing, selected through literature review and input from clinical experts, possibly people like Dr. Crowley. Some of the key terms that were searched were rash or erythema, pustule or lesion, GPP symptoms, attacks and clinically relevant synonyms of all these above terms. You have to look for everything. Associated visits were defined by clinician type or primary reason for visit for each skin-related diagnosis that was ICD-10 [International Classification of Diseases, 10th revision] code L40.1. Each flare, pustule, or lesion term was categorized, and each term in the pustular lesion category plus each flare was assigned to it. Dermatology-related visits were defined by clinician type and primary reason for the visit, for each skin-related diagnosis. This includes a flare, pustule or lesion as a category, or any pustular lesion category, plus any flare attributed to it.

Transcript edited for clarity

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