Some drug manufacturing companies claim that their drugs makes the treatment better for the patient and also help in improving the standard of treatment the patient receives. Such a claim is possible only by analyzing the patient’s feedback in using the drug. This is done by the PRO instruments in identifying all aspects of well being of the patient. The quality of life measurements are used not only to identify the physical effects caused by the disease, but also to identify how much has it influenced on the emotional aspects of the person, his well being, his social activities, feelings and his ability to fight the risks. In spite of evaluating a drug effect on the quality of life, the FDA rarely accepted a claim stating that the drug has been the reason for patient’s effective improved quality of life. This is because; it is very hard to achieve the broader aspects of the quality of life to be satisfied by drugs that are targeted specific to certain symptoms.

However, usually with the Health related Quality of life aspects, a claim on improving the patient’s aspects of health can be accepted since it is much easier to capture the important features of the HQRL than the QoL. HQRL measures the patient’s knowledge of how a treatment affects their illness or well-being, at least the effect on their physical, mental and social behavior. For example, the Asthma Quality of Life instrument shortly termed as the AQLQ has proven to capture the behavior of the drug on asthma patients, which was accepted by the FDA.

The most commonly used PRO instruments help to assess on the following constructs:

Symptoms are the effects before a disease or infection is caused. They are also termed as impairments.

1.    Functioning: This is done to test how the treatment functions well in the patient’s point of view. It determines the disability of the drug or the patient.

2.    Health related Quality of life: This includes the previous two instruments, the impairments and the disability and allows patients to report its outcome on the healthy life.

3.    Quality of life: This is a step far beyond the health related quality of life. The quality of life allows users to fulfill their needs, physical and emotional without any restriction and report the outcome.

The instruments that are used to identify the impairments or the symptoms of a disease within a patient are more commonly used in all clinics. This makes the physician to identify the problem more clearly. Instruments that involve assessment of personal care, use of locomotives and routine life activities are the disability instruments. The health related quality of life (HQRL) is generally multi-dimensional instrument with combing the aspects of the impairments and the disability questionnaires and allowing person to report its outcome on the personal life status. The Quality of life is done by asking the patient’s ability to fulfill their needs and requirements both physical and emotional without any emotional restrictions. The needs-based model is often used for QoL.

Sometimes the approval of drug by the FDA or the regulatory authorities is based on the PRO instruments. Evidences show that six cancer drugs were approved just because of the PRO instruments. Out of which one was accepted truly because of the relief in pain, suppression of symptoms that the patients reported. The instrument used to identify it was called as pain intensity scale. The other five drugs were seen attacking the cancer itself. By instruments assessment, even the drug functioning within the patient is well identified and this would help FDA to decide on approving the drug. In some cases, where the person is potentially not satisfied with the drug and find that the drug causes more pain than the normal treatment, he can report it in the PRO questionnaire, which will be used in deciding further about the drug in the market.