PRO

Initialism.

PRO (countable and uncountable, plural PROs)

1. Initialism of pressure retarded osmosis.
2. (medicine) Initialism of patient-reported outcome.
   • 2022 August 30, Ricardo Ruiz-Villaverde, Lourdes Rodriguez Fernandez-Freire, Pilar Font-Ugalde, Manuel Galan-Gutierrez, “Tildrakizumab: Efficacy, Safety and Survival in Mid-Term (52 Weeks) in Three Tertiary Hospitals in Andalucia (Spain)”, in Journal of Clinical Medicine‎^[1], volume 11, number 17, →DOI, page 5:

     In the bivariate analysis carried out by subgroups, we did not find statistically significant differences (p < 0.05) between bionaïve or bioexperienced patients, patients with BMI < 30 or BMI > 30 in relation to the efficacy variables (PASI and BSA) and analyzed PROs (VAS pruritus and DLQI).

• RED

From the term pronoun.

English Wikipedia has an article on:

PRO (linguistics)

Wikipedia

• As big pro.

PRO

1. (syntax) A theoretical phonologically null pronoun

• pro ("little pro")

• RPO, opr., ROP, orp, OPr., POR