PRP Global Cohort Q&A


What is the objective of the PRP Global Cohort?

To establish a 600-member PRP Global Cohort for the purpose of researching the impact of pityriasis rubra pilaris on PRP patients and their caregivers.


Who will be invited to participate as a member of the cohort?

The entire PRP Global Community will be invited to participate to include members of the PRP Facebook Support Group (1,899), members of the PRP Community on RareConnect with are not PRP Facebookers (unknown at this time), and non-aligned PRP patients with valid email addresses (381).


Why is the target size of the PRP Global Cohort 600?

In late 2018, the PRP global community assembled the largest cohort of PRP patients since 1828 when James Shooter walked into St. Batholomew’s Hospital in London, England was a cohort of one. A total of 574 PRP patients participated in a comprehensive survey developed by UCLA David Geffen School of Medicine, USC Keck Medical School, and Kaiser Permanente. A PRP Global Cohort of 600 means we can say…“the largest cohort of PRP patients ever assembled.”


How will we ensure that the PRP Global Cohort is a legitimate PRP research tool?

An effort is already underway to establish a PRP Global Cohort Advisor Group of dermatologists representing Thomas Jefferson University, Oregon Health and Science University, UCLA, USC, Yale, Mayo Clinic and others.

We will confirm and reconfirm what will constitute a legitimate, bona fide dermatology research cohort and then build the PRP Global Cohort accordingly.

Once a PRP Global Cohort of 600 PRP patients is assembled, then what?

Start researching using the tools we already know.

❏   Dermatology Life Quality Index Scoring (DLQI) ❏   Psoriasis Area and Severity Index Scoring (PASI) ❏   Itch Scoring (12-item scale and the 5-D scale) ❏   Pain Scoring

And also issues of importance to patients

❏   Diagnosing PRP ❏   Efficacy of retinoids ❏   Efficacy of immunosuppresants ❏   Efficacy of biiologicals ❏   Efficacy of topicals (prescription vs. over-the-counter) ❏   PRP impact on feet and  impaired mobility ❏   PRP impact on hands and impaired dexterity ❏   PRP impact on eyes and impaired vision

How will each research project be managed?

It is our hope that each SEPARATE research project will be “monitored” by one or more dermatologists who will be authorized to publish the findings individually or collectively.

What are the requirements to participate?

Until we confirm EVERYTHING with a yet-to-be formed PRP Global Cohort Advisor Group of dermatologists, the following are some of the most obvious requirements:

❏   Name ❏   Location: city, state/province/country) ❏   Email address (see privacy/confidentiality statement) ❏   Onset: onset date, onset age ❏   Diagnostic history, e.g. misdiagnosis, elapsed time from onset to Dx ❏   Basic medication overview: What worked. What didn’t  work. ❏   Describe current status: ❏   Current or last dermatologist

Why is an email address required?

When 574 PRP patients participated in the UCLA PRP Survey, NO email address was shared with their researchers. Similarly, UCLA would not even confirm to the PRP Alliance the names of those who participated. Confidentiality and trust is the currency of research.

Simply stated: Your email address will not be shared with anyone.

The PRP Alliance contracts with Constant Contact to send emails and conduct surveys, With their technology I will be able to send 600 emails and know important information:

❏   Who opened the email ❏   Who clicked the link to the survey ❏   Who unsubscribed ❏   Who has a problem with their “in box”

If you have any concerns about the confidentiality of you email address, please  make those concerns known. For some the email address requirement may be a deal breaker, but in eight years even Tierney Ratti did not have access to email addresses in the PRP Global Database.

For the record, as of November 22, 2020, there are 631 members of the PRP Facebook Support Group who have shared their email, addresses.

Will the PRP Global Cohort be Closed (Fixed) or Open?

A closed cohort is one with fixed membership. Once the cohort is defined by enrolling subjects and follow up begins, no one can be added. The number of subjects may decline because of death or loss to follow up, but no additional subjects are added. As a result, closed cohorts always get smaller over time. In contrast, an open cohort is dynamic, meaning that members can leave or be added over time. The PRP Global Cohort will be an Open Cohort. Source Link

What is a cohort — another definition?

Cohort studies are important in research design. The term “cohort” is derived from the Latin word “Cohors” – “a group of soldiers.” It is a type of nonexperimental or observational study design. The term “cohort” refers to a group of people who have been included in a study by an event that is based on the definition decided by the researcher. For example, a cohort of people born in Mumbai in the year 1980. This will be called a “birth cohort.” Another example of the cohort will be people who smoke. Some other terms which may be used for these studies are “prospective studies” or “longitudinal studies.” Source Link

Types of Cohort Studies

Prospective cohort study In this type of cohort study, all the data are collected prospectively. The investigator defines the population that will be included in the cohort. The investigator then follows these participants.

Retrospective cohort study In this type of cohort study, the data are collected from records. Thus, the outcomes have occurred in the past. Even though the outcomes have occurred in the past, the basic study design is essentially the same. Thus, the investigator starts with the exposure and other variables at baseline and at follow-up and then measures the outcome during the follow-up period.

Sometimes, the direction may not be as well defined as prospective and retrospective. One may analyze retrospective data on a group of people well as collect prospective data from the same individuals. In a retrospective cohort study, the exposure and the outcome variables are collected before the study has been initiated. Thus, the measurements may not be very accurate or according to our requirements. In addition, the some of the exposures may have been assessed differently for various members of the cohort. Source Link