Hello all, I am working with a dataset in long format, where each row represents a specific month for a patient (e.g., row 1 = month 1, row 2 = month 2, etc.). Patients become censored (censor=0 -> censor=1) at the month they deviate from their assigned treatment strategy (or by month=12 if they do not start their assigned treatment). I am performing an inverse probability of censoring weighting (IPCW) analysis to estimate the probability of remaining uncensored. For the denominator model, I have included the variables month, baseline covariates (cov1, cov2) and time-varying covariates (cov3, cov4).  However, I am unsure about the appropriate specification for the numerator model. Should it include only baseline covariates (cov1, cov2) (option 1) or should it just be the month variable (option 2)?    numerator - option 1 proc genmod data=example descending; class id month (ref='12'); model censor = month / dist=binomial link=logit; repeated subject = id; output out=censor_num p=num; run; numerator - option 2 proc genmod data=example descending; class id cov1 cov2; model censor = cov1 cov2 / dist=binomial link=logit; repeated subject = id; output out=censor_num p=num; run; denominator proc genmod data=example descending; by exposure_final; class id month (ref='12') cov1 cov2; model censor = month cov1 cov2 / dist=binomial link=logit; repeated subject = id; output out=censor_den p=den; run; ... View more

Dear all,   I am trying to run a target trial emulation comparing drug A to drug B using the clone censor weight approach. each individual is cloned twice and assigned to either drug A or drug B. they are censored if they deviate from their assigned strategy. grace period to start either drug is 6 months from date of diagnosis (time 0). individuals are followed up for up to 2 years after date of diagnosis. the dataset is structured so that each row represents one month.   i am stuck on the inverse probability of censoring weight step. I am finding the two groups are not balanced at month=12 (exposure_final=0 -> drug B, exposure_final=1 -> drug A) with SMD >0.1. Could someone advise if there is an error in my SAS coding?  *denominator model;   proc genmod data=example descending; by exposure_final; class month (ref=”6”); model censor = covariate1 covariate2 covariate3 covariate4 covariate5 / dist=binomial link=logit; output out=censor_den p=den; run;   *numerator model;   proc genmod data=censor_den descending; by exposure_final; class month (ref=”6”); model censor = month / dist=binomial link=logit; output out=censor_num p=num; run;   proc sort data=censor_num; by id;  run;   data example_final; set censor_num; retain n d; by id; if first.id then do; n=1; d=1; end;   n=num*n; d=den*d; wt=n/d; run; ... View more