diff --git a/lib/Doctrine/DBAL/Connection.php b/lib/Doctrine/DBAL/Connection.php
index 55ee3412eda..f487ce0cfbd 100644
--- a/lib/Doctrine/DBAL/Connection.php
+++ b/lib/Doctrine/DBAL/Connection.php
@@ -98,13 +98,6 @@ class Connection implements DriverConnection
     /** @var ExpressionBuilder */
     protected $_expr;
 
-    /**
-     * Whether or not a connection has been established.
-     *
-     * @var bool
-     */
-    private $isConnected = false;
-
     /**
      * The current auto-commit mode of this connection.
      *
@@ -192,8 +185,7 @@ public function __construct(
         $this->params  = $params;
 
         if (isset($params['pdo'])) {
-            $this->_conn       = $params['pdo'];
-            $this->isConnected = true;
+            $this->_conn = $params['pdo'];
             unset($this->params['pdo']);
         }
 
@@ -356,7 +348,7 @@ public function getExpressionBuilder()
      */
     public function connect()
     {
-        if ($this->isConnected) {
+        if ($this->_conn !== null) {
             return false;
         }
 
@@ -364,8 +356,7 @@ public function connect()
         $user          = $this->params['user'] ?? null;
         $password      = $this->params['password'] ?? null;
 
-        $this->_conn       = $this->_driver->connect($this->params, $user, $password, $driverOptions);
-        $this->isConnected = true;
+        $this->_conn = $this->_driver->connect($this->params, $user, $password, $driverOptions);
 
         $this->transactionNestingLevel = 0;
 
@@ -524,7 +515,7 @@ public function setAutoCommit($autoCommit)
         $this->autoCommit = $autoCommit;
 
         // Commit all currently active transactions if any when switching auto-commit mode.
-        if ($this->isConnected !== true || $this->transactionNestingLevel === 0) {
+        if ($this->_conn === null || $this->transactionNestingLevel === 0) {
             return;
         }
 
@@ -689,7 +680,7 @@ public function fetchOne(string $query, array $params = [], array $types = [])
      */
     public function isConnected()
     {
-        return $this->isConnected;
+        return $this->_conn !== null;
     }
 
     /**
@@ -771,8 +762,6 @@ public function delete($tableExpression, array $identifier, array $types = [])
     public function close()
     {
         $this->_conn = null;
-
-        $this->isConnected = false;
     }
 
     /**