n class="r-out co"><span class="r-pr">#&gt;</span>   ..$ study_id            : chr [1:5] "A" "A" "A" "A" ...</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>   ..$ site_id             : chr [1:5] "S0001" "S0002" "S0003" "S0004" ...</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>   ..$ max_visit           : num [1:5] 27 27 28 27 25</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>   ..$ n_pat               : int [1:5] 20 20 20 20 20</span>
<span class="r-out co"><span c