title: Making a ggsurvplot with a coxph
body: <p>I've coded the following <code>coxph</code>object</p>
  <pre><code>cox &lt;- coxph(Surv(INTERVAL, PX_STAT_CODE) ~ TX_NUM, data = outcomes_1and2above, robust = TRUE, weights = weights, cluster=subclass)
  </code></pre>
  <p>from a propensity score matched dataset and would like to create a KM plot that delineates by <code>TX_NUM</code>. I'm using the following code</p>
  <pre><code>fit &lt;- survfit(cox, data=outcomes_1and2above)
  ggsurvplot(fit, data=outcomes_1and2above)
  </code></pre>
  <p>which returns</p>
  <p><a href="https://i.stack.imgur.com/3QK4p.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3QK4p.png" alt="enter image description here" /></a></p>
  <p>I was able to do this previously with the unmatched dataset using the following code</p>
  <pre><code>outcomes_1and2above_Surv &lt;- Surv(time = outcomes_1and2above$INTERVAL, event = outcomes_1and2above$PX_STAT_CODE)
  km_fit_txnum_12a &lt;- survfit(outcomes_1and2above_Surv ~ outcomes_1and2above$TX_NUM, data = outcomes_1and2above)
  ggsurvplot(fit = outcomes_1and2above_Surv, data = outcomes_1and2above)
  </code></pre>
  <p>but am unable to replicate this with the matched data since the <code>Surv</code> function doesn't have a <code>weights</code> argument.</p>