\title{studies on bone-marrow transplantation versus chemotherapy for the treatment of leukemia}
\description{results from controlled and uncontrolled studies on the effectiveness of allogeneic bone-marrow transplantation (bmt) and conventional chemotherapy (cmo) in the treatment of acute nonlymphocytic leukemia.}
\bold{study}      \tab \code{numeric}    \tab study number \cr
\bold{trt}        \tab \code{character}  \tab treatment (bmt or cmo) \cr
\bold{arms}       \tab \code{numeric}    \tab number of arms in the study (1 = uncontrolled studies; 2 = controlled studies) \cr
\bold{yi}         \tab \code{numeric}    \tab 2-year disease-free survival rates \cr
\bold{sei}        \tab \code{numeric}    \tab corresponding standard errors \cr
\bold{vi}         \tab \code{numeric}    \tab corresponding sampling variances
the dataset includes the results from controlled and uncontrolled studies on the 2-year disease-free survival rate in patients with acute nonlymphocytic leukemia receiving either allogeneic bone-marrow transplantation (bmt) or conventional chemotherapy (cmo). in the controlled (two-arm) studies (studies 1-4), a cohort of patients in complete remission and potentially eligible for bmt was assembled, and those who consented and for whom a donor could be found received bmt, with the remaining patients used as controls (receiving cmo). in the uncontrolled (one-arm) studies (studies 5-16), only a single group was studied, receiving either bmt or cmo.
the data in this dataset were obtained from table 1 in begg and pilote (1991, p. 902).
begg, c. b., & pilote, l. (1991). a model for incorporating historical controls into a meta-analysis. \emph{biometrics}, \bold{47}(3), 899--906. \verb{https://doi.org/10.2307/2532647}
begg, c. b., pilote, l., & mcglave, p. b. (1989). bone marrow transplantation versus chemotherapy in acute non-lymphocytic leukemia: a meta-analytic review. \emph{european journal of cancer and clinical oncology}, \bold{25}(11), 1519--1523. \verb{https://doi.org/10.1016/0277-5379(89)90291-5}
### turn trt and arms into factors and set reference levels
### create data frame with the treatment differences for the controlled studies
### dersimonian and laird method using the treatment differences
res <- rma(yi, vi, data=dat2, method="dl", digits=2)
### begg & pilote (1991) model incorporating the uncontrolled studies
res <- rma.mv(yi, vi, mods = ~ trt, random = ~ 1 | study,
### model involving bias terms for the uncontrolled studies
res <- rma.mv(yi, vi, mods = ~ trt + trt:arms, random = ~ 1 | study,
### model with a random treatment effect
res <- rma.mv(yi, vi, mods = ~ trt, random = list(~ 1 | study, ~ trt | study),
struct="un", tau2=c(0,na), rho=0, data=dat, method="ml", digits=2)
### model with a random treatment effect, but with equal variances in both arms
struct="cs", rho=0, data=dat, method="ml", digits=2)
medicine, oncology, single-arm studies, multilevel models