03 - First we carried out two univariate analysis as to determine whether OPN level is a significant predictor for survival(a the Kaplan-Meier

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Unformatted text preview: First, we carried out two univariate analysis as to determine whether OPN level is a significant predictor for survival: (a) the Kaplan-Meier method was used to calculate overall survival for the whole group (n = 94), as well as for patients with ‘‘high’’ and ‘‘low’’ osteopontin levels (above or below the group’s median). (b) using the continuous values of the OPN levels, we applied the log-transform as to make its distribution Gaussian in good approximation; then we carried out a correlation analysis w.r.t. 1-year survival (n = 89 patients). Second, we calculated creatinine clearance (Cockcroft-Gault formula) from gender, age, weight and serum creatinine levels, and considered the product of OPN level and creatinine clearance (i.e., its log-transform), which we correlated with 1-year survival. Results: Overall 1-year survival for the whole group (n = 94) was 56%, calculated using the Kaplan Meier method. The median survival was 14.5 months. In both univariate analyses of OPN levels, no significant relationship to survival was found: (a) median survival times of patients with high or low osteopontin levels were 10.0 and 16.1 months, respectively; the log-rank test applied to the Kaplan-Meier curves resulted in a statistically insignificant p-value of 0.11. (b) the correlation analysis with 1-year survival (n = 89 patients) also resulted in an insignificant p-value, namely 0.18. However, the product of OPN level and creatinine clearance showed a negative correlation with 1-year-survival, with a significant p-value of 0.03, confirming our hypothesis. Conclusions: OPN level together with creatinine clearance is a significant predictor for 1-year survival. Elevated OPN levels do not necessarily reduce the probability of 1-year survival, especially when creatinine clearance is low. Conversely, low OPN levelsnot necessarily reduce the probability of 1-year survival, especially when creatinine clearance is low....
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This note was uploaded on 05/24/2010 for the course MD 23 taught by Professor Tarc during the Spring '10 term at Anadolu University.

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