I view the HD-PROP as participating in what is a strong industry...

I view the HD-PROP as participating in what is a strong industry trend and direction. It was simply participating in the latest trend of including Patient Reporting Outcomes for trials. Industry groups in pharma have developed around this and I believe that Rudy Tanzi is also serving in a leadership capacity on one of those groups. I'll try to find it an share.

So HD-PROP was not developed after-the-fact in reaction to anything in-determinant.

Here is a helpful article, and represents more on the purpose behind HD-PROP, which is a PRO and not a PCO.

By Teja Thorat, MSc. MPH

Each time I attend a health economics conference, I come away confused by the same question: What’s the difference between “patient-reported outcomes,” and “patient-centered outcomes?” I don’t think I’m the only young researcher confused by these terms. So I decided to sort it out. Here’s what I learned:
For many years, clinical outcomes such as a reduction in the number of cardiac events, fractures, or other measurable physiological events have been used as end points in clinical trials to interpret the effect of a medical treatment/procedure on patients. Now, however, there is a growing awareness of the importance of including patients and their perspectives in evaluating medical treatments.

Patient-reported outcomes (PROs). PROs are typically defined as health states or reports directly obtained from the patient.[1] PRO questionnaires collect data on patients’ views on treatment effects rather than clinical evaluation of the treatment. PROs include patient satisfaction with a treatment, adherence to a treatment, non-clinical symptoms, and health perception after undergoing treatment.[2] It is important to note that PROS may differ for every patient even if they have the same outcomes on other metrics. For example, the ability to drive a car may be more important to someone who lives in the suburbs than someone who lives in the city near public transportation. This raises important questions about what indicators should be measured and how large a change is significant. Many PRO measurement scales— generic and disease-specific — are being developed but validation and interpretation are crucial factors. Research on these issues is underway.

Patient-centered outcomes (PCOs). Patient-centered outcomes include patient-reported outcomes but can also include information from sources other than the patient. Donald L. Patrick, Professor at University of Washington, explained PCOs at the ISPOR 2013 meeting this way, “PCOs are outcomes important to patients’ survival, function, or feelings, as identified or affirmed by patients themselves, or judged to be in patients’ best interest by clinicians and caregivers when patients cannot report for themselves” [2]. The Patient-Centered Outcomes Research Institute (PCORI) defines patient-centered outcomes research (PCOR) as research that helps people and their caregivers communicate and make informed health care decisions, allowing their voices to be heard in assessing the value of health care options.[3] Essentially, a patient-centered outcome might be thought of as the union of patient-reported outcomes and patient-relevant, clinical outcomes.