diff --git a/R/api_randomize.R b/R/api_randomize.R
index 68e561f..b4884ef 100644
--- a/R/api_randomize.R
+++ b/R/api_randomize.R
@@ -89,7 +89,9 @@ api__randomize_patient <- function(study_id, current_state, req, res) {
     dplyr::select("arm_id" = "id", "name", "ratio") |>
     dplyr::collect()
 
-  randomized_patient <- unbiased:::save_patient(study_id, arm$arm_id)
+  randomized_patient <-
+    unbiased:::save_patient(study_id, arm$arm_id, used = TRUE) |>
+    select(-used)
 
   if (!is.null(randomized_patient$error)) {
     res$status <- 503
diff --git a/R/db.R b/R/db.R
index e169868..9c5da33 100644
--- a/R/db.R
+++ b/R/db.R
@@ -147,15 +147,15 @@ create_study <- function(
   r
 }
 
-save_patient <- function(study_id, arm_id) {
+save_patient <- function(study_id, arm_id, used) {
   r <- tryCatch(
     {
       randomized_patient <- DBI::dbGetQuery(
         db_connection_pool,
-        "INSERT INTO patient (arm_id, study_id)
-                    VALUES ($1, $2)
-                    RETURNING id, arm_id",
-        list(arm_id, study_id)
+        "INSERT INTO patient (arm_id, study_id, used)
+                    VALUES ($1, $2, $3)
+                    RETURNING id, arm_id, used",
+        list(arm_id, study_id, used)
       )
     },
     error = function(cond) {
diff --git a/tests/testthat/test-E2E-study-minimisation-pocock.R b/tests/testthat/test-E2E-study-minimisation-pocock.R
index 556481c..a821a7a 100644
--- a/tests/testthat/test-E2E-study-minimisation-pocock.R
+++ b/tests/testthat/test-E2E-study-minimisation-pocock.R
@@ -68,6 +68,14 @@ test_that("correct request with the structure of the returned result", {
     len = 3,
     type = c("numeric", "numeric", "character")
   )
+
+  checkmate::test_true(
+    dplyr::tbl(db_connection_pool, "patient") |>
+      dplyr::slice_max(id) |>
+      dplyr::collect() |>
+      dplyr::pull(used),
+    TRUE
+  )
 })
 
 test_that("request with one covariate at two levels", {