Karnofsky Score for Performance Status Calculator

How does this Karnofsky score for performance status calculator work?

This is a health tool that aims to evaluate the ability of a patient to undergo chemotherapy for different types of cancers. This is often used in conjunction with considerations about the tumor size and location.

This performance status was constructed in 1948 and was first introduced in a study that assessed patients receiving nitrogen mustard chemotherapy for primary lung carcinoma. The linear scale looked at symptoms underlying the patient ability to undertake, aided or unaided daily activities.

Several oncology studies have validated the original study and further on, similar performance status scorings were put in place, such as the Zubrod also known as the Eastern Cooperative Oncology Group (ECOG) Score which is nowadays used under WHO. There is also a scale for pediatric use, the Lansky score.

The KPS is used as a prognostic factor in the cancer patient evaluation and describes the patient functional status on a 11 point scale, with items in 10 unit increments.

The interrater reliability and construct validity of the KPS (KPS comes from Karnosfy performance status) have been analyzed and several examinations pointed out the areas of weakness in the physician judgment.

There have been empirically identified seven behaviorally based questions which would allow the clinician to assign a score in a more accurate manner. The seven variables are:

■ Weight loss;

■ Weight gain;

■ Reduced energy;

■ Difficulty walking;

■ Driving;

■ Grooming;

■ Working part time.

One of the criticisms received by the model refers to the fact that it does not account for unwanted treatment effects and how the score changes after the patient starts the proposed therapy.

Score interpretation

This Karnofsky score for performance status calculator scale runs from 100 to 0 where 100 means the patient’s condition is normal and 0 indicates death. While evaluating the patient symptoms with the KPS, each clinician assigns a performance score which describes different symptom stages in increments of 10.

■ 100 - Normal; no complaints; no evidence of disease.

■ 90 - Able to carry on normal activity; minor signs or symptoms of disease.

■ 80 - Normal activity with effort; some signs or symptoms of disease.

■ 70 - Cares for self; unable to carry on normal activity or to do active work.

■ 60 - Requires occasional assistance, but is able to care for most of their personal needs.

■ 50 - Requires considerable assistance and frequent medical care.

■ 40 - Disabled; requires special care and assistance.

■ 30 - Severely disabled; hospital admission is indicated although death not imminent.

■ 20 - Very sick; hospital admission necessary; active supportive treatment necessary.

■ 10 - Moribund; fatal processes progressing rapidly.

■ 0 - Dead.

These are sometimes put in three states which are described as levels of performance and functionality.

■ A (100 – 80);

■ B (70 – 50);

■ C (40 – 0).

Newer studies now look at the possibility of the KPS to be also be used as a tool in the assessment of the Quality of Life in cancer patients but relevant discoveries are yet to be made.

References

1) Schag CC, Heinrich RL, Ganz PA. (1984) Karnofsky performance status revisited: reliability, validity, and guidelines. J Clin Oncol; 2(3):187-93.

2) Sorensen JB, Klee M, Palshof T, Hansen HH. (1993) Performance status assessment in cancer patients. An inter-observer variability study. Br J Cancer; 67(4): 773–775.

3) Péus D, NewPcomb N, Hofer S. (2013) Appraisal of the Karnofsky Performance Status and proposal of a simple algorithmic system for its evaluation. BMC Med Inform Decis Mak; 13: 72.