Remove dotted confidence interval lines and amend legend

Question

How do I remove the confidence interval dotted lines from the plot?

For the legend, why is line 2 dotted while line 1 is solid? Is there a way to make both solid lines? I'm not sure what this code does - lty=1:2, cex=0.8

Graph

I have attached one of my datasets below with the corresponding commands. Thanks!

> km2 <- survfit(Surv(times_start, times_end, type="interval2")~ 1)
> summary(km2)
Call: survfit(formula = Surv(times_start, times_end, type = "interval2") ~ 
    1)

    time n.risk n.event survival std.err lower 95% CI upper 95% CI
    1.31  284.0    2.04    0.993 0.00743       0.9782        1.000
    2.06  282.0    1.03    0.989 0.00856       0.9724        1.000
    2.81  280.9    4.18    0.974 0.01770       0.9395        1.000
    3.56  276.7    2.10    0.967 0.01977       0.9278        1.000
    4.31  274.7    8.42    0.937 0.03557       0.8659        1.000
    5.06  266.2    2.11    0.930 0.03678       0.8556        1.000
    5.81  264.1   13.79    0.881 0.05659       0.7642        1.000
    6.38  250.3    4.24    0.867 0.05838       0.7440        1.000
    7.12  246.1    9.55    0.833 0.06455       0.6940        1.000
    7.88  236.5    7.43    0.807 0.06785       0.6577        0.990
    8.62  229.1    3.18    0.796 0.06866       0.6432        0.984
    9.38  225.9    9.55    0.762 0.07262       0.5963        0.974
   10.12  216.4    4.24    0.747 0.07355       0.5769        0.967
   10.88  212.1   18.03    0.683 0.08015       0.4883        0.957
   11.62  194.1    2.12    0.676 0.08017       0.4793        0.953
   12.56  192.0    8.68    0.645 0.08074       0.4415        0.944
   13.31  183.3    3.33    0.634 0.08069       0.4274        0.940
   14.06  180.0   13.67    0.586 0.08082       0.3690        0.929
   14.81  166.3    2.34    0.577 0.08058       0.3595        0.927
   15.56  164.0   10.33    0.541 0.07952       0.3176        0.921
   16.31  153.6    4.35    0.526 0.07886       0.3005        0.920
   17.06  149.3    3.32    0.514 0.07831       0.2875        0.919
   17.81  146.0    3.89    0.500 0.07761       0.2724        0.919
   18.56  142.1    2.25    0.492 0.07718       0.2638        0.919
   19.31  139.8    5.37    0.473 0.07605       0.2435        0.921
   20.06  134.5    3.36    0.462 0.07530       0.2309        0.923
   20.81  131.1    9.03    0.430 0.07291       0.1983        0.932
   21.56  122.1    5.54    0.410 0.07128       0.1790        0.941
   23.81  116.5   19.40    0.342 0.06341       0.1182        0.990
   24.56   97.1   24.24    0.257 0.05029       0.0575        1.000
 5013.31   72.9   72.88    0.000 0.00000           NA           NA

> plot(km, xmax=50, xlab="Time", ylab="Log cumulative hazard", col="blue", fun="cloglog")
> lines(km2, xlab="Time", ylab="Log cumulative hazard", col="red", fun="cloglog")
> legend("topleft", legend=c("Line 1", "Line 2"), col=c("red", "blue"), lty=1:2, cex=0.8)

`?plot.survfit` and `?lines.survfit` would be useful and also `?par` — rawr, May 19 '20 at 01:42

score 2 · Accepted Answer · answered May 19 '20 at 01:41

I'm not sure which data you're using, but I did this using lung (which should be available after doing library(survival)):

km2 <- survfit(Surv(time, status) ~ 1, data = lung)

plot(km2, xmax=50, xlab="Time", 
     ylab="Log cumulative hazard", 
     col="blue", fun="cloglog", conf.int = FALSE)

So for your example you should be able to add conf.int = FALSE to your plot function to remove the confidence intervals?

The lty=1:2 in your code means that one line is solid (1) and the other is dotted (2). I believe solid is default, so you should remove lty=1:2 if you'd like both to be solid.

Thank you! It works. I did lty=1:1 to make both solid. I tried removing them and no line is being shown in the legend. Nevertheless, much appreciate your help. I have a follow up question - what code should I use to find the slope of that graph? — user2310, May 19 '20 at 02:59

Remove dotted confidence interval lines and amend legend

1 Answers1