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Evaluation of IScore validity in a Greek cohort of patients with type 2 diabetes.

Dragoumanos V, Tzirogiannis KN, Panoutsopoulos GI, Krikonis K, Fousteris E, Vourvou M, Elesnitsalis G, Melas N, Kourentzi KT, Melidonis A - BMC Neurol (2013)

Bottom Line: Baseline population characteristics and mortality rates did not differ significantly for both cohorts.Based on ROC curves analysis IScore's predictive ability for 30 day mortality was excellent, without statistically significant difference, for both cohorts.Calibration of the model was good for both groups of patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nursing, Faculty of Human Movement and Quality of Life Science, University of Peloponnese, Sparta, Lakonia, Greece. gpanouts@uop.gr.

ABSTRACT

Background: Diabetes constitutes a risk factor for stroke that also aggravates stroke prognosis. Several prognostic models have been developed for the evaluation of neurologic status, severity, short-term functional outcome and mortality of stroke patients. IScore is a novel tool recently developed in order to predict mortality rates within 30 days and 1 year after ischemic stroke and diabetes is not included in the scoring scale of IScore. The aim of the present study was to evaluate and compare IScore validity in ischemic stroke patients with and without diabetes.

Methods: This prospective study included 312 consecutive Caucasian patients with type 2 diabetes and 222 Caucasian patients without diabetes admitted for ischemic stroke in a tertiary Greek hospital. Thirty-day and 1-year IScores were individually calculated for each patient and actual mortality was monitored at the same time intervals. IScore's predictive ability and calibration was evaluated and compared for ischemic stroke patients with and without diabetes. The performance of IScore for predicting 30 and 1-year mortality between patients with and without diabetes was assessed by determining the calibration and discrimination of the score. The area under the receiver operating characteristic curve was used to evaluate the discriminative ability of IScore for patients with and without diabetes, whereas the calibration of IScore was assessed by the Hosmer-Lemeshow goodness-of fit statistic.

Results: Baseline population characteristics and mortality rates did not differ significantly for both cohorts. IScore values were significantly higher for patients with diabetes at 30 days and 1 year after ischemic stroke and patients with diabetes presented more frequently with lacunar strokes. Based on ROC curves analysis IScore's predictive ability for 30 day mortality was excellent, without statistically significant difference, for both cohorts. Predictive ability for 1 year mortality was also excellent for both groups with significantly better ability for patients with diabetes especially at high score values. Calibration of the model was good for both groups of patients.

Conclusions: IScore accurately predicts mortality in acute ischemic stroke Caucasian patients with and without diabetes with higher efficacy in predicting 1 year mortality in patients with diabetes especially with high scores.

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Related in: MedlinePlus

ROC curves for IScore regarding a) 30-day and b) 1-year actual mortality rates. Receiver operating characteristic (ROC) curves for IScore regarding 30-day and 1-year actual mortality rates for acute ischemic stroke diabetic (n = 312) and non diabetic patients (n = 222). The area under the ROC curve was 0.87 (95% CI, 0.80-0.93) for diabetic and 0.85 (95% CI, 0.79-0.91) for non-diabetic at 30 days and 0.93 (95% CI, 0.90-0.97) and 0.87 (95% CI, 0.82-0.91) at 1 year.
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Figure 1: ROC curves for IScore regarding a) 30-day and b) 1-year actual mortality rates. Receiver operating characteristic (ROC) curves for IScore regarding 30-day and 1-year actual mortality rates for acute ischemic stroke diabetic (n = 312) and non diabetic patients (n = 222). The area under the ROC curve was 0.87 (95% CI, 0.80-0.93) for diabetic and 0.85 (95% CI, 0.79-0.91) for non-diabetic at 30 days and 0.93 (95% CI, 0.90-0.97) and 0.87 (95% CI, 0.82-0.91) at 1 year.

Mentions: Discrimination, or predictive accuracy, was assessed by building receiver operating characteristic (ROC) curves for mortality both in diabetic and non-diabetic population for 30-day and 1 year mortality and the area under the curves (AUC) was used to evaluate and compare the predictive accuracy of risk classifications. Based on AUC analysis the discriminative ability of IScore was excellent for patients with diabetes with a value of 0.87 (95% CI, 0.80-0.93) and patients without diabetes with a value of 0.85 (95% CI, 0.79-0.91) at 30 days without significant difference between groups (Chi = 0.17, p = 0.68) (Figure 1). Respectively discriminative ability was also excellent for diabetic group with a value of 0.93 (95% CI, 0.90-0.97) and non-diabetic group with a value of 0.87 (95% CI, 0.82-0.91) at 1 year with significantly higher discriminative ability (Chi = 5.23, p < 0.05) for IS patients with diabetes especially located in high risk (IScore >160) diabetic subgroups (Figure 1).


Evaluation of IScore validity in a Greek cohort of patients with type 2 diabetes.

Dragoumanos V, Tzirogiannis KN, Panoutsopoulos GI, Krikonis K, Fousteris E, Vourvou M, Elesnitsalis G, Melas N, Kourentzi KT, Melidonis A - BMC Neurol (2013)

ROC curves for IScore regarding a) 30-day and b) 1-year actual mortality rates. Receiver operating characteristic (ROC) curves for IScore regarding 30-day and 1-year actual mortality rates for acute ischemic stroke diabetic (n = 312) and non diabetic patients (n = 222). The area under the ROC curve was 0.87 (95% CI, 0.80-0.93) for diabetic and 0.85 (95% CI, 0.79-0.91) for non-diabetic at 30 days and 0.93 (95% CI, 0.90-0.97) and 0.87 (95% CI, 0.82-0.91) at 1 year.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3852226&req=5

Figure 1: ROC curves for IScore regarding a) 30-day and b) 1-year actual mortality rates. Receiver operating characteristic (ROC) curves for IScore regarding 30-day and 1-year actual mortality rates for acute ischemic stroke diabetic (n = 312) and non diabetic patients (n = 222). The area under the ROC curve was 0.87 (95% CI, 0.80-0.93) for diabetic and 0.85 (95% CI, 0.79-0.91) for non-diabetic at 30 days and 0.93 (95% CI, 0.90-0.97) and 0.87 (95% CI, 0.82-0.91) at 1 year.
Mentions: Discrimination, or predictive accuracy, was assessed by building receiver operating characteristic (ROC) curves for mortality both in diabetic and non-diabetic population for 30-day and 1 year mortality and the area under the curves (AUC) was used to evaluate and compare the predictive accuracy of risk classifications. Based on AUC analysis the discriminative ability of IScore was excellent for patients with diabetes with a value of 0.87 (95% CI, 0.80-0.93) and patients without diabetes with a value of 0.85 (95% CI, 0.79-0.91) at 30 days without significant difference between groups (Chi = 0.17, p = 0.68) (Figure 1). Respectively discriminative ability was also excellent for diabetic group with a value of 0.93 (95% CI, 0.90-0.97) and non-diabetic group with a value of 0.87 (95% CI, 0.82-0.91) at 1 year with significantly higher discriminative ability (Chi = 5.23, p < 0.05) for IS patients with diabetes especially located in high risk (IScore >160) diabetic subgroups (Figure 1).

Bottom Line: Baseline population characteristics and mortality rates did not differ significantly for both cohorts.Based on ROC curves analysis IScore's predictive ability for 30 day mortality was excellent, without statistically significant difference, for both cohorts.Calibration of the model was good for both groups of patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nursing, Faculty of Human Movement and Quality of Life Science, University of Peloponnese, Sparta, Lakonia, Greece. gpanouts@uop.gr.

ABSTRACT

Background: Diabetes constitutes a risk factor for stroke that also aggravates stroke prognosis. Several prognostic models have been developed for the evaluation of neurologic status, severity, short-term functional outcome and mortality of stroke patients. IScore is a novel tool recently developed in order to predict mortality rates within 30 days and 1 year after ischemic stroke and diabetes is not included in the scoring scale of IScore. The aim of the present study was to evaluate and compare IScore validity in ischemic stroke patients with and without diabetes.

Methods: This prospective study included 312 consecutive Caucasian patients with type 2 diabetes and 222 Caucasian patients without diabetes admitted for ischemic stroke in a tertiary Greek hospital. Thirty-day and 1-year IScores were individually calculated for each patient and actual mortality was monitored at the same time intervals. IScore's predictive ability and calibration was evaluated and compared for ischemic stroke patients with and without diabetes. The performance of IScore for predicting 30 and 1-year mortality between patients with and without diabetes was assessed by determining the calibration and discrimination of the score. The area under the receiver operating characteristic curve was used to evaluate the discriminative ability of IScore for patients with and without diabetes, whereas the calibration of IScore was assessed by the Hosmer-Lemeshow goodness-of fit statistic.

Results: Baseline population characteristics and mortality rates did not differ significantly for both cohorts. IScore values were significantly higher for patients with diabetes at 30 days and 1 year after ischemic stroke and patients with diabetes presented more frequently with lacunar strokes. Based on ROC curves analysis IScore's predictive ability for 30 day mortality was excellent, without statistically significant difference, for both cohorts. Predictive ability for 1 year mortality was also excellent for both groups with significantly better ability for patients with diabetes especially at high score values. Calibration of the model was good for both groups of patients.

Conclusions: IScore accurately predicts mortality in acute ischemic stroke Caucasian patients with and without diabetes with higher efficacy in predicting 1 year mortality in patients with diabetes especially with high scores.

Show MeSH
Related in: MedlinePlus