How can I add more text into a plot using ggplot2 in R?

Question

I have this graph that I made using this code:

df3 <- data.frame(outcome=c("Any complication", "Cardiac complication",
                            "Vascular Complication","Vascular complication",
                            "Respiratory complication", "Infectious complication",
                            "Neurological complication"),
                 index=1:7,
                 effect=c(-.4, -.25, -.1, .1, .15, .2, .3),
                 lower=c(-.43, -.29, -.17, -.02, .04, .17, .27),
                 upper=c(-.37, -.21, -.03, .22, .24, .23, .33))

plot2 <- ggplot(data=df3, aes(y=index, x=effect, xmin=lower, xmax=upper))+
  geom_point(shape="diamond", colour="royalblue4", size=5) + 
  geom_errorbarh(height=.2, colour="royalblue4") +
  scale_y_continuous(breaks=1:nrow(df3), labels=df3$outcome) +
  labs(title="Adjusted Relative Risk for Complications", x="Relative Risk", y = "Type of complication") +
  geom_vline(xintercept=0, color='gray', linetype='dashed', alpha=.5) +
  theme_minimal()+
  plots_theme

But I would like to add the RR, the 95% confidence interval and some other things there, as shown here:

I could really use some help! Quite new in R here :(

Zhiqiang Wang · Accepted Answer · 2022-11-10 03:49:25Z

1

To make it easier, I would borrow one of several R packages which can make forest plots. As a quick start, I use forestplot package here as an example:

library(tidyverse)
library(forestplot)
df3 %>%
  mutate(ci = paste0(" (", lower, ",  ", upper, ")")) %>%
  arrange(-index) %>%
  forestplot::forestplot(
    labeltext = c(outcome, effect, ci),
    mean = effect, 
    low = lower,
    upper = upper,
    size = 0.1,
    graph.pos = 2,
    vertices = TRUE,
    xlab = "Relative Risk", 
    title="Adjusted Relative Risk for Complications") %>% 
  fp_add_header(
    outcome = c("Outcome"),
    effect = c("Estimate"), 
    ci = "95% (CI)") %>% 
  fp_set_style(box = "royalblue4", line = "royalblue4")

Edit

Just something different from your question, the Estimate values shown in the graph may not be relative risk but regression coefficient. If you would like to present relative risk, you could take an advantage of meta package:

library(meta)
df3 <- df3 %>% arrange(-index)
forest_df <-metagen(lower = lower, 
              upper = upper, 
              TE = effect,
              data = df3, 
              sm = "RR")

forest(forest_df,
       studlab = paste0(outcome), 
       layout = "JAMA", 
       common = FALSE, 
       hetstat = FALSE, 
       overall = FALSE)

Get work done with less code and journal format.

edited Nov 10, 2022 at 3:49

answered Nov 10, 2022 at 2:30

Zhiqiang Wang

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1 Comment

Darla Carvallo Over a year ago

OMG I just realized this! How silly hahaha of course RR can't be negative! Thank you so much for your input, highly appreciated!!!!

Ric · Accepted Answer · 2022-11-10 01:34:08Z

1

Here a way with geom_rect, geom_text and annotate.

library(ggplot2)
df3 <- data.frame(outcome=c("Any complication", "Cardiac complication",
                            "Vascular Complication","Vascular complication",
                            "Respiratory complication", "Infectious complication",
                            "Neurological complication"),
                 index=1:7,
                 effect=c(-.4, -.25, -.1, .1, .15, .2, .3),
                 lower=c(-.43, -.29, -.17, -.02, .04, .17, .27),
                 upper=c(-.37, -.21, -.03, .22, .24, .23, .33))

ggplot(data=df3, aes(y=index, x=effect, xmin=lower, xmax=upper))+
  geom_point(shape="diamond", colour="royalblue4", size=5) + 
  geom_errorbarh(height=.2, colour="royalblue4") +
  scale_y_continuous(breaks=1:nrow(df3), labels=df3$outcome) +
  labs(title="Adjusted Relative Risk for Complications", x="Relative Risk", y = "Type of complication") +
  geom_vline(xintercept=0, color='gray', linetype='dashed', alpha=.5) +
  annotate("rect",  xmin=.5, xmax= 1, ymin=0, ymax= 8, fill = "white")+
  geom_text(aes(label = paste(effect, "(", lower, ",", upper,")")) ,
            x= 0.5, hjust="left") +
  scale_x_continuous(limits = c(-0.5, 1.0))+
  annotate("text", label = "Estimate  - 95% CI", x = 0.5, hjust="left", y= 8)+
  theme_minimal() + theme()

answered Nov 10, 2022 at 1:34

Ric

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1 Comment

Darla Carvallo Over a year ago

This was super helpful to understand annotate and geom_text! Thank you so much!!!!

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