Subgroup Analysis & Meta-Regression

library(meta)

# Copy and paste the entire code below into your Console.
# Then hit Enter.
thirdwave <- 
  structure(
     list(
            study = c("Call", "Cavanagh", "Danitz-Orsillo", 
                      "de Vibe", "Frazier", "Frogeli", 
                      "Gallego", "Hazlett-Stevens", "Hintz", 
                      "Kang", "Kuhlmann", "Lever Taylor", 
                      "Phang", "Rasanen", "Ratanasiripong", 
                      "Shapiro", "Song", "Warnecke"), 
            es = c(0.70, 0.35, 1.79, 0.18, 0.42, 0.63, 
                   0.72, 0.52, 0.28, 1.27, 0.10, 0.38, 
                   0.54, 0.42, 0.51, 1.47, 0.61, 0.60), 
            se = c(0.260, 0.196, 0.345, 0.117, 0.144, 
                   0.196, 0.224, 0.210, 0.168, 0.337, 
                   0.194, 0.230, 0.244, 0.257, 0.351, 
                   0.315, 0.226, 0.249), 
            rob = c("high", "low", "high", "low", "low", 
                    "low", "high", "low", "low", "low", 
                    "high", "low", "low", "low", "high", 
                    "high", "high", "low"),
            fu.weeks = c(4, 10, 2, 8, 5, 6, 6, 7, 
                         12, 1, 3, 4, 5, 6, 3, 2, 5, 2)), 
     row.names = c(NA, -18L), class = "data.frame")

# Run REM meta-analysis
rem <- metagen(es, se, study, thirdwave)

# Subgroup analysis
update.meta(rem, by = rob)

# Run meta-regression on follow-up in weeks
metareg(rem, ~ fu.weeks)