Katz index: a test that evaluates daily activities

We are active beings. As with other animals, humans need to carry out multiple actions in order to survive.

We need to eat, move to avoid dangers, protect ourselves from the cold... and we usually do all of this almost without thinking, day by day and continuously. However, these actions are more complex than they appear, and although most of us we have automated require learning and can be lost in certain circumstances.

In many cases, due to medical or psychiatric problems (for example, an accident, a disabling illness, or a dementia) It is possible that basic and fundamental activities that we used to carry out without problem by ourselves become a problem, requiring external help to carry them out. And knowing whether or not we are independent in the most basic functions can be useful to provide the help we need, or to analyze rehabilitation processes.

• Related article: "The 6 types of disability and their characteristics"

In order to assess our situation there are different indexes or scales, such as the Katz index or scale. It is about this instrument that we are going to talk throughout this article.

The Katz scale / index: what is it and what is it for?

The Katz Index (sometimes also called the Katz Functional Scale) It is an assessment instrument that allows to assess the degree of physical dependence of a subject to carry out the so-called basic activities of daily life.

With this concept we refer to the set of essential and most relevant skills for the survival, self-care, and self-preservation without relying on supports external.

It is a scale that allows evaluating the degree of dependence or independence of a subject in six large basic skills: washing, dressing, using the toilet, moving / getting around, toilet training and feeding. These skills are organized in a hierarchical way, ordered according to the progression that a child would carry out in its development.

This is relevant given that when the most fundamental activities require external support, it is common for the rest of the basic functions to also require help. In other words, if a person has difficulty feeding, it is likely that he also has difficulties dressing or doing any of these activities. Its use allows both assessing the current situation of the subject and evaluating the progress made in rehabilitation processes.

Originally, the Functional Scale or Katz index was developed with the purpose of contributing to assess the rehabilitation carried out by people with fractures of the hip, although with the passage of time its function has come to be used to assess the degree of dependence that patients present with various types of conditions.

It is one of the most used in the functional assessment of geriatric patients or in palliative care, since it allows obtaining information on the degree of help or dependence that the person needs in their day by day and better adjust the aid that is provided or the rehabilitations to which it is submit. It is possible to fill it in based on the observation of the patient by the professionals, or through the information provided by the subject himself or by the caregivers.

Items included

The Katz scale or index It is an assessment instrument that includes a total of six items to assess, each referred to one of the basic skills of daily life. Specifically, the items that are scored on this scale are the following.

1. Washed

Bathing or washing is considered a basic activity of daily life, although one of the most complex. The person capable of washing a single part or completely without assistance will be assessed as independent, while they will be in situation of dependency that person who needs help to wash, enter or exit the bathtub or wash more than one part of the Body.

2. Dress

Getting dressed is a complex basic activity, which requires some coordination, planning skills and motor skills. Independence or autonomy in this skill implies being able to take the necessary clothes, put them on or take it off and use items such as buttons and zippers in order to get dressed completely. Dependency will be considered in all those cases in which the person cannot dress alone or does so partially.

3. Use of toilet

A basic activity but somewhat more complex than those that follow, independent use of the toilet implies the ability to access and exit the toilet., use it correctly, clean and fix clothes by himself and without the need for external support. When there is dependence, help is required to use this element or it requires wedges or urinals.

4. Mobilization

Mobilization refers to the ability to move through the environment or perform acts such as getting up, sitting down, or lying down in a chair or bed.. This in turn allows other fundamental basic activities to be carried out. A person dependent on this ability will require aids to move, sit or lie down, or use elements such as beds or chairs.

5. Continence

One of the most fundamental basic skills, we understand by continence the ability to control urination and defecation processes. That is, it implies the ability to contain feces and urine and to expel them voluntarily. Habitual incontinence, whether total or partial, would be assessed as dependence on this ability.

6. Feeding

It is considered the most basic and relevant of all the basic activities of daily life. The ability to feed expresses the possibility for the subject to move food to his mouth and eat it without the need for external help.

It is important to note that this does not include more complex processes such as cutting or spreading food with silverware. If there is dependence on this basic ability, support will be required to be able to feed or the use of enteral or parenteral tube feeding.

Assessment of the information provided by the scale

The Katz index does not provide a numerical score and does not require complex calculations. To evaluate an individual with this scale, it will be noted for each of the basic activities of daily life if the subject is independent or dependent on external aids (including these aids mechanical guidance, direction of action or the need for supervision).

In previous versions there was the possibility of marking a partial dependency for each of the activities, although at present they only consider the condition of independence and that of dependence.

Once all the items have been evaluated, the number of activities for which the person is independent and a letter is given, which will be the total assessment of the dependence / independence of the subject for these activities.

Thus we can find an independent person in all functions (A), independent in all except one (B), independent in all except bathing and another function (C), independent in all except bathing, dressing and another function (D), independent for all except bathing, dressing, using the toilet and one more function (E), independent for all except bathing, dressing, using the toilet, moving and another function (F), dependent for the six functions (G) or dependent on at least two functions but not classifiable as C, D, E or F (H).

Bibliographic references:

• Cruz, A.J. (1991). The Katz index. Rev Esp Geriatr Gerontol, 26: 338-48.

• Trigás-Ferrín, M., Ferreira-González, L and Meijide-Míguez, H. (2011). Functional assessment scales in the elderly. Galicia Clin., 72 (1): 11-16.