Hi Folks, Trying to fit a nested (shared or joint) frailty model using Penalized Likelihood estimation on the hazard function. Dataset is a multi-year clustered RCT Variables: Treatment: 0-placebo, 1-Intervention riv: 0-no exposure to illness, 1-exposure to illness tte: time to event of exposure (days) community: cluster id subject_id: participant id year: study year {1,2,3,4} At each year, participants across 36 communities (varying in size ~100 to 150 people) are followed from April to October, monitored for exposure to illness. For the most part subjects re-enroll each year , and Treatment remains the same for all years. Exposure variable (riv) is set 0 at the beginning of each year. Each year I obtain the HR 95% CI from Analysis of Maximum Likelihood Estimates with Sandwich Variance Estimate using proc phreg data=rivdata covs(aggregate) covm ; id community; model tte*riv(0)=Treatment /ties=EFRON rl; by year; run; But would like to fit all years together and see HR 95% CI. The two approaches I have tried are - One: proc phreg data=rivdata covs(aggregate) covm ; class community subject_id; model tte*riv(0)=Treatment /ties=EFROM rl; /* strata year; */ random community; run; Two: proc surveyphreg data=rivdata; class Treatment; cluster community; /* cluster community subject_id; */ model tte*riv(0)=Treatment /ties=EFRON rl; hazardratio Treatment; /* strata year; */ run; Any help would be appreciated to get correct HR 95% CI for all years combined. I've tried frailtypack in R, package is unstable, even after being re-released Oct 20, 2020. Thanks
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