«Declared quality of life»: new perspectives for assessing patients’ quality of life in clinical medicine

In modern patient-oriented medical care, quality of life is an important criterion for a comprehensive assessment of the patient's health and evaluation of treatment effectiveness. This article is devoted to the current methodological issues of assessing quality of life and other patient-reported outcomes (PRO) and attempts to reveal the difficulties of interpreting PRO data obtained in real-world clinical practice. A new concept for identifying significant changes in the patient's general health condition in clinical practice is presented, and a new model of quality of life outcomes before and after treatment is considered. The concepts of “declared quality of life”, “index of achieved quality of life” and “declared clinical effect” have been declared. Assessment of the declared quality of life of the patient and determination of the index of the achieved quality of life can be used for practical purposes to implement the principle of patient-oriented care in clinical practice.