Marton et al developed a discriminant function in 1981 which can help identify those patients with involuntary weight loss who are likely to have a physical explanation for the weight loss, from those who do not have a physical explanation for the weight loss.
Parameters used for score:
(1) duration of cigarette smoking in pack years
(2) decrease in activity due to fatigue
(3) nausea or vomiting
(4) improvement in appetite
(5) cough which has changed in character recently
(6) physical cause for weight loss found on physical examination
|
Parameter |
Finding |
Points |
|
less than 20 pack years of cigarette smoking |
yes |
+3 |
|
|
no (>= 20 pack years) |
0 |
|
no decrease in activity due to fatigue |
yes |
+5 |
|
|
no (decrease in activity due to fatigue) |
0 |
|
patient complains of nausea or vomiting |
yes |
-3 |
|
|
no |
0 |
|
patient has had improvement in appetite |
yes |
-2 |
|
|
no |
0 |
|
patient has a cough that has recently changed |
yes |
-1 |
|
|
no |
0 |
|
patients has findings on physical examination suggesting a physical cause of weight loss |
yes |
-1 |
|
|
no |
0 |
discriminant function score =
= SUM(values for the 6 parameters) + 8
where:
• 8 is a correction factor
Interpretation:
• minimum score: 1
• maximum score: 16
|
Discriminant Function Score |
Estimated Probability of a Physical Explanation for the Weight Loss |
|
1 - 6 |
100% |
|
7 - 8 |
78% |
|
9 - 11 |
14% |
|
12 - 16 |
0% |
Table 5, page 572
Purpose: To separate patients with involuntary weight loss who are likely to have a physical cause from those without a physical cause.
Specialty: Nutrition, Hematology Oncology
Objective: clinical diagnosis, including family history for genetics, other testing
ICD-10: R63.4,
