Acta Medica Mediterranea, 2015, 31: 127

STUDY OF EFFECTIVENESS OF THE SAPS II-III, APACHE II-IV AND MPM II SCORES IN THE DETERMINATION OF PROGNOSIS OF THE PATIENTS IN REANIMATION

INCE ILKER1, KIZILKAYA MEHMET1, AKSOY MEHMET1, DOSTBIL AYSENUR1, KARA FESIH2, SUMERCOSKUN AYSENUR3, AHISKALIOGLU ALI1 1Ataturk University School of , Department of and Reanimation - 2Erzurum Sifa Hospital Department of Anesthesiology and Reanimation - 3Denizli Cal Hospital Department of Anesthesiology and Reanimation

ABSTRACT

Introduction: Acute Physiology and Chronic Health Evaluation (APACHE), Simplified Acute Physiology Score (SAPS) and Mortality Probability Models (MPM) are the most commonly used mortality prediction scores. In this study, we aimed to research effectiveness of SAPS II-III, APACHE II-IV and MPM II in the evaluation of prognosis in the patients hospitalized in the intensive care unit. Materials and methods: The files of the patients hospitalized in the Reanimation Intensive Care Unit between January 2008 and June 2010 were examined retrospectively. 466 patients who stayed at least 24 hours in the intensive care unit were enrolled in the study. Results: The mortality rate was determined as 53.93%. The estimated mortality rate was determined as 60.62% for APACHE II, 48.96% for APACHE IV, 57.52% for SAPS II, 58.94% for SAPS III and 46.89% for MPM II. ROC curve analysis results were 0.734 for APACHE II, 0.740 for APACHE IV, 0.717 for SAPS II, 0.720 for SAPS III and 0.700 for MPM II. Conclusion: In our study, the mortality prediction results of SAPS II-III, APACHE II-IV and MPM II scores were found to be statistically significant between the deceased and living patients. When these scoring systems were compared in ROC curve analysis for the mortality prediction rank, it was found that APACHE IV was the best mortality predictive score system and the others were APACHE II, SAPS III, SAPS II, MPM II, respectively.

Key words: SAPS II, SAPS III, APACHE II, APACHE IV, MPM II.

Received May 18, 2014; Accepted September 02, 2014

Introduction APACHE is the first scoring system used to determine the prognosis of the patients. The SAPS During 1970-80s, many studies were conduct- scoring system was developed later. SAPS II is the ed to predict severity and prognosis of a disease and most widely used scoring system in European provide a comparison of the results between inten- intensive care units(4). The SAPS III prognostic sys- sive care units and standardize patients during eval- tem was recently developed by a worldwide cohort uation of new treatments(1, 2). As a result of these operation(5). In this study, we aimed to compare the studies, several scoring systems have been devel- efficiency of SAPS II-III, APACHE II-IV and MPM oped. There are two different groups; those evaluat- II scores. ing mortality expectations [APACHE (Acute Physiology and Chronic Health Evaluation), SAPS Material and method (Simplified Acute Physiology Score), MPM (Mortality Probability Models), TISS (Therapeutic In this study, with the approval of the local Intervention Scoring System)] and those evaluating ethics committee, from January 2008 to June 2010, organ dysfunctions [LODS (Logistic Organ files of patients hospitalized in Atatürk University, Dysfunction System), MODS (Multiple Organ Faculty of Medicine, Department of Anesthesiology Dysfunction Score), SOFA (Sequential Organ and Reanimation, Intensive Care Unit (ICU) were Failure Assessment)](3). retrospectively analyzed. 128 Ince Ilker, Kizilkaya Mehmet et Al

Patients who stayed at least 24 hours in the exerted on identifying which scoring system better intensive care unit were enrolled in the study. predicted the results. Patients younger than 18 years, burn patients and patients who had undergone coronary were Results not included. The variables used for SAPS II, SAPS III, 466 patients hospitalized in the Reanimation APACHE II, APACHE IV and MPM II scoring sys- Intensive Care Unit between January 2008 and June tems were shown in Table 1(5-11). 2010 were retrospectively evaluated. 271 (58.2%) were male and 195 (41.8%) were female. The mean age was 58.2 ± 18.78 and the average length of stay in intensive care was 8.54 ± 7.89 days. The mortali- ty rate in our intensive care unit was found to be 54.93%. 62.5% of patients who died were male and 37.5% were female. The difference between the mortality rates of patients by gender was found to be statistically significant (P=0.036). When diagnoses for introduction to the inten- sive care unit were analyzed, COPD (Chronic obstructive pulmonary disease) was in first place with 34.8%. Cardiac arrest (8.15%) and acute myocardial infarction (7.08%) were established as Table 1: The variables used for SAPS II, SAPS III, APA- 2nd and 3rd place, respectively. CHE II, APACHE IV, MPM II scoring. Data obtained from deceased and living ICU: intensive care unit, GCS: Glasgow Score, SBP: patients for variables in APACHE II, APACHE IV, systolic blood pressure, HR: heart rate, BUN: blood urine SAPS II, SAPS III and MPM II scoring systems nitrogen, MAP: Mean arterial pressure, RR: respiratory rate, were statistically analyzed. Distribution of variables DBP: diastolic blood pressure, BUN: blood urea nitrogen, Hct: with respect to mortality and p values are shown in hematocrit, UOP: urine output Tables 2 to 6. All data obtained for SAPS II-III, APACHE II- IV and MPM II was entered into an already pre- pared computer program for all 5 scoring systems and projected mortality rates were expressed as a percentage. In line with the results obtained, esti- mated mortality rates for APACHE II-IV, SAPS II- III and MPM II were compared with each other. Statistical analyses were performed using SPPS software (version 18.0, SPSS, Chicago,İllinois, USA). The patients were divided into 2 groups according to death (after 24 hours later) as the end point and the difference between quantitative and qualitative variables of the patient Table 2: Comparison of statistical parameters of APA- groups with and without mortality was evaluated by CHE II between living and deceased patients. student t test and chi-square test, respectively. *p < 0.05, SD:Standart deviation, n: Number of patients, GCS: P<0.05 was considered to be significant. Glasgow Coma Score, HR: Heart rate, RR: Respiratory rate Continuous variables are represented as "mean Mortality estimates of scoring systems were ± standard deviation". Multivariate analyses in compared by conducting ROC curve analyses. The which ICU scoring systems APACHE II-IV, SAPS calculation is based on calculating the area under II-III and MPM are used were conducted. the curve. Accordingly, it can be said that a scoring ROC (Receiver Operating Characteristic) system with maximum area under the curve is the curve analysis was used to determine scoring sys- best predictor of mortality. ROC curve analysis tems’ estimation of mortality. The area (AUC) results for APACHE II, APACHE IV, SAPS II, under plotted ROC curves was calculated. Effort is SAPS III, and MPM II were 0.734, 0.740, 0.717, Study of effectiveness of the Saps Ii-Iii, Apache Ii-Iv And Mpm Ii Scores in the determination... 129

0.720 and 0.700, respectively. Their order accord- ing to the results are APACHE IV > APACHE II > SAPS III > SAPS II > MPM II. The situation creat- ed by the results of scoring systems in ROC curve analysis are shown in Figure 1.

Table 6: Comparison of statistical parameters of MPM II between living and deceased patients. *p < 0.05, SD:Standart deviation, n: Number of patients, GCS: Glasgow Coma Score,UOP: urine output, PT: Prothrombin Time

Table 3: Comparison of statistical parameters of APA- CHE IV between living and deceased patients. Fig. 1: ROC curve analysis of scoring systems. *p < 0.05, SD:Standart deviation, n: Number of patients, ROC curve analysis results for APACHE II, APACHE IV, SAPS Temp: Temperature, SBP: systolic blood pressure, DBP: diasto- II, SAPS III, and MPM II were 0.734, 0.740, 0.717, 0.720 and lic blood pressure, HR: heart rate, BUN: blood urea nitrogen, 0.700, respectively. Their order according to the results are UOP: urine output, Hct: hematocrit, GCS: Glasgow Coma APACHE IV > APACHE II > SAPS III > SAPS II > MPM II. Score, Pre-ICU LOS: Length of stay Discussion

In our study, we compared mortality estimation results of SAPS II-III, APACHE II-IV and MPM II, which are intensive care scoring systems. What makes our study important is that 5 different scoring systems were evaluated with 466 patients. Many studies have been conducted on intensive care scoring systems’ estimation of mortality(16,17,18). Table 4: Comparison of statistical parameters of SAPS II Studies have reported different results(16,17,18). Scoring between living and deceased patients. *p < 0.05, SD:Standart deviation, n: Number of patients, GCS: systems can be valuable tools, although they are full Glasgow Coma Score, SBP: Systolic blood pressure, HR: heart of potential random and systematic errors. How, rate, Temp: Temperature, UOP: urine output, BUN: blood urea when and by whom they were evaluated are all criti- nitrogen, Pre-ICU LOS: Length of stay cal details(12). Ulus et al.(13) investigated efficiency of APACHE II on estimation of mortality in 100 patients in respiratory intensive care unit and report- ed that it can be successfully used in determining mortality rate. Daley et al.(14) did not find disease-spe- cific use of the APACHE II system appropriate. However, there are also studies in which APACHE II was used in specific patient groups(15). In our study, Table 5: Comparison of statistical parameters of SAPS III between living and deceased patients. similar to the above work, we concluded that *p < 0.05, SD:Standart deviation, n: Number of patients, Pre- APACHE II may be used successfully for prediction ICU LOS: Length of stay, GCS: Glasgow Coma Score, Temp: of mortality. Temperature, HR: heart rate, SBP: systolic blood pressure 130 Ince Ilker, Kizilkaya Mehmet et Al

We used it in all patient groups admitted to our units and sampling frequency of physiological vari- intensive care unit in general, rather than in specific ables. It was observed that medical personnel record- patients. ing patients’ medical values recorded normal ranges In a multi-center study, Zimmerman et al.(16) and disregarded extreme values. Such data causes a found that APACHE IV is quite good in predicting lower mortality score. They suggested that extreme mortality. In another multi-center study, Brinkman et values can be better determined by increasing the al.(17) identified that APACHE IV is better than frequency of sampling of physiological variables. In APACHE II and SAPS II in predicting mortality. our study, we did not conduct a more extensive sam- Similar to the above studies, APACHE IV was also pling, except for routine tests. There are studies established as the scoring system that best predicted demonstrating that more accurate results are obtained mortality among 5 different scoring systems com- when sampling frequency is increased as well as pared in our study. studies demonstrating that sampling frequency is Park et al.(18) found that the prediction of mortal- insignificant in the determination of mortality. ity by APACHE II and SAPS II was higher than Suistomaa et al.(21) found a higher mortality score observed mortality in neurosurgical intensive care when they increased the sampling frequency of patients. In that study, observed mortality was hemodynamic and laboratory values in intensive 24.8%, while APACHE II expected mortality was care. Conversely, in a study carried out in pediatric 37.7% and SAPS II expected mortality was 38.4%. intensive care, Pollack et al.(22) did not conclude that In our study, the actual mortality rate was 54.93%, better expected mortality rates are obtained by while the mean potential mortality rate was found as increasing frequency of sampling. 60.62%, 48.96%, 46.89%, 57.52%, and 58.94% for Due to the improving quality of intensive care APACHE II, APACHE IV, MPM, SAPS II and units in recent years, ability to predict mortality of SAPS III, respectively. In our investigation, we did APACHE, SAPS II, MPM II scoring systems not detect significant differences between the actual declines. All three of these systems were developed mortality rate and expected mortality rates according as a result of studies performed on patient groups at to the available data. least 10 years ago. During this time, innovations in Khwannimit et al.(24) compared the estimation of intensive care units have greatly reduced the mortali- mortality by APACHE II and SAPS II in 2040 cases ty rate(23). Therefore, intensive care scoring systems and identified APACHE II as more efficient. In our should be updated to reflect current developments. study, we also identified APACHE II as more effi- When faced with a patient in need of intensive cient than SAPS II in line with the current study. care, it is impossible for us to refuse admission of the In a multi-center study covering 39617 cases, patient into the intensive care unit, even if hospital Glance et al.(19) reached the conclusion that SAPS II mortality is 100%. Therefore, intensive care mortali- and MPM II models are successful in prediction of ty scores are rather used to get an idea about a mortality. However, Eroğlu at al.(20) reported that patient’s mortality when they first arrive in the clinic, SAPS II and MPM II were incapable of predicting inform the patient’s relatives and determine progno- mortality in intensive care patients. In our study, the sis by daily calculations. For all these reasons, it ability to predict the mortality of individual SAPS II- becomes necessary to use scoring systems and record III, APACHE II-IV and MPM II scoring systems was resulting scores on a regular basis in order to deter- found to be statistically significant. When scoring mine the severity of disease and the possibility of systems were evaluated by ROC curve analyses, the mortality. order of ability to predict mortality was found as Limitation of our study be done on small num- APACHE IV > APACHE II > SAPS III > SAPS II > bers of patients because we done this study in a sin- MPM II. gle center. When the studies are evaluated carefully, the As a result, in our study, the mortality predic- scoring systems used give different results in differ- tion results of SAPS II-III, APACHE II-IV and MPM ent intensive care units. Although the parameters II scores were found to be statistically significant used are the same, different results can be obtained between deceased and living patients. When these when the same scoring systems are compared in two scoring systems were compared with each other different intensive care units. In order to investigate based on the area under the curve in ROC curve the reasons for this, Bosman et al.(25) examined the analysis, the mortality prediction order was found effects of data collection process in intensive care that APACHE IV was the best mortality predictive Study of effectiveness of the Saps Ii-Iii, Apache Ii-Iv And Mpm Ii Scores in the determination... 131 score system and the others were APACHE II, SAPS today’s critically ill patients. 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