[Predictive evaluation and efficient management of medical examinations using Mahalanobis Taguchi System Method].
The Mahalanobis-Taguchi System (MTS), an evaluative technique used in quality engineering, was utilized in a system analysis of medical examinations to determine practicability, to differentiate cost reduction benefits of specific components for increasing efficiency, and to determine possibility of utility on forecasting of future health condition of individuals.


METHODS
1. Medical examination date over a two year period were utilized to differentiate subject into two groups: Group A--Healthy or normal; and Group C--Patient group requiring treatment or currently undergoing treatment. The Mahalanobis distance for Group C from the Mahalanobis space of Group A was calculated for each subject to determine differentiability. 2. Utilizing the MTS method specific components of the examination system were selected and analyzed for effectiveness in diagnosis and screening to enhance efficiency of the examination. 3. Group A subjects (determined from the two year data), were analyzed using the data at the end of 1 year to develop the Mahalanobis space and the Mahalanobis distance at the 2nd year point was calculated and analyzed.


RESULTS
1. Subjects who were classified as group A at both 1st and 2nd year points numbered 159. With a cutoff point of 2.0 for Mahalanobis distance 98.1% of the healthy subjects (Group A) were classified as belonging to the healthy group, and 91.9% of C group as belonging to the patient group. 2. Blood pressure, GOT, GPT, gamma-GTP, T Chol, TG, UA, Cr, BS, HbA1c, Hb, and MCH were found to be effective components in the examination. Based on this result the items included in the examination can be reduced by approximately 60%. 3. With cutoff value of 1.5, the results of 90% of subjects 1 year later could be predicted. The prediction that 15% of Group C subjects would improve to join Group A could be made. Overall, the results 1 year later could be predicted at a level of 90% accuracy.


CONCLUSIONS
These results suggest that the Mahalanobis-Taguchi System technique can accurately assess medical examination quality and can also be used, with reasonable accuracy, to predict the condition of individuals one year later. Therefore, the MTS can be used to help determine which patients should be receiving the examination 1 year later. In addition, components of the examination can be assessed using the MTS for benefits and costs to determine levels of essentiality of components. As a result, it can be used an effective tool for development and improvements in the examination system. With further development in the technique, it may become possible for use as a tool in disease diagnosis and treatment.
Makajima
H
H
Department of Internal Medicine I, Jikei University School of Medicine.
Takada
K
K
Yano
H
H
Takagi
I
I
Shibamoto
Y
Y
Yamauchi
M
M
Toda
G
G
D003362:Cost-Benefit Analysis; D006801:Humans; D008962:Models, Theoretical; D010808:Physical Examination / Q000191:economics / Q000379:methods; D011237:Predictive Value of Tests; D013997:Time Factors