

Cox regression plots for interaction ... 

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lamjas posted on Tuesday, July 30, 2019  8:57 am



Hi, I am new to cox regression. Is it possible to plot the survival curves for a significant interaction in Mplus, using model constraint and loop function? If so, could you please show me the formula I should put in? I appreciate your help. Variable: Days tc x1 x2; Survival = Days; Timecensored = tc (0 = RIGHT 1 = NOT); Usevariables are Days tc x1 x2 INT; DEFINE: INT = x1 * x2; Model: Days on x1 (p1) x2 (p2) INT (p1xp2); 

lamjas posted on Wednesday, July 31, 2019  8:31 am



It is a followup of my post. If I can use model constraint and loop function to plot survival curve, is the following code correct? !say x1 is sex, 0=male, 1=female !say x2 is age Model constraint: Plot (ML MH FL FH); Loop (Time,0,50,1); ML = Time x EXP(p1*0 + p2*20 + p1xp2*0*20); MH = Time x EXP(p1*0 + p2*40 + p1xp2*0*40); FL = Time x EXP(p1*1 + p2*20 + p1xp2*1*20); MH = Time x EXP(p1*1 + p2*40 + p1xp2*1*40); 


I don't see how loop can help. Instead follow these directions. 1. Add plot:type=plot3; to your input file 2. Click the "view plots" button. 3. Click "Curves for specific covariate values / estimated survival curve" 4. click Next 5. Enter ML in the "name a set of values" 6. Click X1 and in "specify a value for variable" enter 0 7. Click X2 and in "specify a value for variable" enter 20 8. Click INT and in "specify a value for variable" enter 0 9. Enter MH in the "name a set of values" 10. Click X1 and in "specify a value for variable" enter 0 11. Click X2 and in "specify a value for variable" enter 40 12. Click INT and in "specify a value for variable" enter 0 13. Repeat those 4 steps for FL and MH changing the values accordingly 14. Click Finish and you should get the 4 survival curves you need. 

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