[Mathematical model for the predictive value of a test in critically ill patients studies according to APACHE II score and pathology at admission].
OBJECTIVE
To find a predictive model for mortality at four different days from the admission for critically ill patients.


METHODS
Retrospective study on two consecutive series of critically ill patients admitted in ICU.


METHODS
1254 critically ill patients, subdivided into two series of 813 (561 survivors and 252 non survivors) and 441 patients (291 survivors and 150 non survivors), respectively.


METHODS
None.


METHODS
All patients had APACHE II calculated within the first 24 hours from the admission in ICU and, if the patient was still in ICU, also at the 5th, 10th and 15th day from the admission. Casistics was subdivided into two unequal series, ratio 2:1, with a random selection made on each of the 6 considered years. On the 1st series, in 1st, 5th, 10th and 15th day, for mathematical predictive models were made, using stepwise logistic regression (BMDP, Los Angeles). In the 1st day the following independent variables were utilized: APACHE II score, the specific diagnosis at admission, fitted following Knaus' diagnostic criteria, united in 6 principal categories, while for the other 3 days the variation % of APACE II score as regards the previous day.


RESULTS
For each of the considered day four mathematical models have been made. These models have been validated in both series in calibration from the Hosmer-Lemeshow Goodness-of-fit test and in discrimination from the ROC curves. For each day Y (Prob.% to die) = eLogit/1 + eLogit, where Logit = beta 0 (constant) + beta 1*APACHE II + beta 2*Variat.%APACE II (difference between actual APACHE II - APACHE II of the previous day/actual APACHE II) + beta k, (coefficient pertinent to pathology).


CONCLUSIONS
The mathematical model, as other models do, stratifies enough the casistics according to the risk of death. Waiting for further studies to make more precise prognostic mathematical models, this one and others can help the clinical assessment in single patient evaluation.
Istituto delle Emergenze Medico-Chirurgiche, Università degli Studi, Ancona.
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Donati
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Valente
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Münch
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Gabbanelli
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Montozzi
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Pietropaoli
D018806:APACHE; D000328:Adult; D003422:Critical Care / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011237:Predictive Value of Tests
Modello matematico per la predizione dell'esito nei pazienti degenti in terapia intensiva articolato sul trend dell'APACHE II score e sulla patologia causa del ricovero.