Fix #4674
diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index c6f84e0..c27607e 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -126,7 +126,10 @@
 	 */
 	public function db_connect($persistent = FALSE)
 	{
-		$this->options[PDO::ATTR_PERSISTENT] = $persistent;
+		if ($persistent === TRUE)
+		{
+			$this->options[PDO::ATTR_PERSISTENT] = TRUE;
+		}
 
 		try
 		{