Usefulness of the scales measuring pain, disability and quality of life

Cases studies Usefulness of the scales Back pain and physical disability Scales shown; criteria for selection, meaning and use of the provided information Scales to measure pain intensity Scales to measure degree of physical disability Scales to measure quality of life

These scales serve to provide valid and reliable measures of patients' pain intensity, degree of physical disability and quality of life.

They are useful in determining the intensity of the ailment within the parameter measured at a given time and in reliably following its evolution in the patient. Most of these scales are not useful for comparing the degree of illness among different patients.

Determining pain intensity, degree of physical disability and quality of life, reliably and validly, is useful both in a clinical setting and for research.

In a clinical setting, these scales are useful for:

1. Making a reliable follow-up of a patient's evolution. It has been shown that the value of each scale correlates better to the aspect measured (whether it is specifically pain, disability of quality of life) than any other kind of test, such as the simple radiograph, Computerized Axial Tomography (CAT scan), Magnetic Resonance Imaging (MRI) or electromyography (EMG).
2. Determining the therapeutic objective and priority in each instance and consequently, choosing the most indicated treatment strategy. For example, in a patient with very intense pain and little disability, analgesic treatment should be applied first. In a patient with little pain and greater disability, physical rehabilitation should be applied. The priorities can vary over time according to the patient's evolution.

In a research setting, these scales are indispensable for any kind of study in which the degree of a patient's illness or its evolution over time must be determined in a reliable manner. These studies include, among others:

• Studies on the efficacy or effectiveness of a given treatment. If the instrument chosen for measuring the symptom's intensity (for example, pain or disability) is not reliable, the effect of the evaluated treatment could be jeopardized. Conversely, improvements over time resulting from a treatment could go undetected if the measuring instruments are not sufficiently sensitive.
• Studies on risk factors of prognostic aspects. For example, in order to determine the possible influence of pain intensity, degree of physical disability or disturbance in the quality of life on the patient's evolution or his or her risk of suffering work disability due to back pain, each one of these aspects must be evaluated in a reliable manner.