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Clinical Trials: CLASSIF1 Individual Patient Classification

Günter Valet



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1. Presence: Data of clinical trials with large patient groups are typically statistically evaluated to reveal advantages of new therapies. This is fundamental for medical progress, but ultimately individual patients are treated and not patient groups. Personalised, individualized, outcome oriented or precision medicine crucially depend of individually discriminating molecular parameter patterns for precise diagnosis and outcome prediction to optimally apply therapies..

2. Standardized CLASSIF1 percentile classification uses only measured patient parameter values like weight, size, erythrocyte counts etc after transformation according to their position above (+), below (.) or in between (0) upper and lower percentile threshold pairs (5/95, 10/90, 15/85, 20/80, 25/75, 30/70%) of the value distributions for example of patients prior to therapy as reference. As parameter values increasse or decrease during therapy, more (+) or (-) values emerge in the triple matrix value representation. The classification program iteratively maximizes the sum of sensitivity plus specificity (fig.1) for the discrimination of diseases states by stepwise temporary removal of individual parameter columns of the database from consideration by the classification process. It is calculated whether the removal has improved or deteriorated the classification result, followed by reinsertion of the parameter column and continuation of the classification process without the values of the next parameter.column until all parameter columns have been processed in this way. Only parameter columns having improved sensitivity and specificity of the classification above the initial level are retained at the end as inherently standardized classification masks, since the masks directly represent measured parameter values. Missing parameter values do not have to be reconstituted. Patients are classified with the available information until a predetermined cut-off level of less than 50% or 40% availibility of the required classification mask parameters. Although not required for classification, means, standard deviations, statistical significance and parameter correlations were calculated to better characterizate analyzed data sets.

In case the relevant percentile thresholds and classification masks are publicly available for exmple from clinical trial studies or other quality controlled sources, individual patients can be manually classified everywhere. The number of provided data columns is in principle unlimited with data matrices of so far more than 50.000 analyzed parameter columns. Data pattern classification was in these cases superior in discriminiation to correlation or external link statistical analysis.

3. Classification strategy proceeds from "low accuracy" with the 30/70% percentile pair to "high accuracy" with the 5/95% pair. While high accuracy parameter patterns are required for reliable patient classifications, low accuray classifiers with only borderline significant parameters are useful for the identification of metabolic processes underlying treated diseases (parameter fishing). Once low accuracy knowledge has been aquired, more discriminant parameters can be searched within the identified metabolic context.

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  SAIS1  Sitagliptin versus Glimepiride
external link PROLOGUE  Sitagliptin in Carotid Artery Atherosclerosis (soon)


4. Example of Manual Individual Patient Classification: external link SAIS1


CLASSIF1
selected
mask parameters


using
percentile thresholds
25%    75%

generate
reference
classif. masks
contr(0w)    ther(26w)
for:
manual individual patient
classification

example: pat85 validation set
values(0w) mask values(26w) mask

 -HbA1c (%)
 -CPept Index
 -HDL (mg/dl)
 -SOD (U/ml)
 -BAP Index

 <7.06      >7,76
 <1.01      >1.66
 <43.45      >58.46
 <2.55      >5.83
 <21.23     >28.06

  0 +    -
- 0       +
- 0       +
- 0       +
- 0       +

  7.10   0         6.90    -
  2.00   +        2.40    +
39.00    -      47.00    0
  3.10    0        3.30    +
24.73    0       20.75    -

  mask coincidence (n/n,%)
  Contr_0w:     4/5  80   2/5 40
  Ther_26w:    1/5  20   3/5 60
  classific:      C        T
  which is correct, see database
  records nr.30,78


5. Future: As datasets of clinical trials become available in EXCEL format, molecular parameter patterns can be established to reveal molecular characteristics of individual patients in different diagnostic and therapeutic situations. They are a prerequisite for the development of molecular classifiers concerning disease diagnosis or individualized outcome predictions in case of a single or several applicable therapies.


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© 2025 G.Valet
Internet: https://www.classimed.de/health1.html
gval24 last update: Jan 15,2025
first display: Dec 18,2024