Confidence intervals for Hazard ratio - sas weibull AFT

I have a doubt with Weibull Accelerated failure time model Hazard ratio's confident intervals interpret from SAS output, thake this as an example:

 Standard 95% Confidence Chi- Parameter DF Estimate Error Limits Square Pr > ChiSq Intercept 1 0.4258 0.8463 -1.2329 2.0845 0.25 0.6148 hodgkins 1 -1.3746 0.6465 -2.6417 -0.1075 4.52 0.0335 Scale 1 1.2733 0.2044 0.9297 1.7440 Weibull Shape 1 0.7854 0.1260 0.5734 1.0757 

for the variable hodgkins the hazard ratio is: HR= exp(-BETA_hodgkins/Scale_est) = exp(-(-1.3746)/1.2733) = 2.943

the confidence interval can be calculated in the same manner as:

exp(-1_conf/Scale_IC) = exp(-(-2.6417)/0.9297)

exp(-2_conf/Scale) = exp(-(-0.1075)/1.7440)

?

Example reference: http://www4.stat.ncsu.edu/~dzhang2/st745/chap5.pdf

• "If the Weibull model is a reasonable model for your data and you use Proc Lifereg and Proc Phreg to fit the data, then the regression coefficient estimates not only have opposite signs (except possibly for the intercept) but also have different magnitude" which procedure are you using? – Deep North Jan 7 '18 at 23:05
• Thank you for your interest, i had using proc lifereg (dist=Weibull) – Surv Jan 8 '18 at 6:40