Rewrite

<?php
class News
{

  private $host = 'localhost';
  private $dbname = 'mvc_site';
  private $user = 'root';
  private $password = '';
  private $db;


    public function __construct()
    {
      $this -> db = new PDO("mysql:host = $host; dbname = $dbname", $user, $password);
    }

    public function getNewsItemById($id)
    {
       $id = intval($id);

        if($id)
        {

        $newsList = [];

        $result = $this -> db->query('SELECT * FROM news WHERE id='.$id) -> fetchAll()[0];

        return $newsItem;

        }

    }


    public static function getNewsList()
    {

        $newsList = [];

        $result = $this -> db->query('SELECT id, title, date, short_content'
                             .'FROM news'
                             .'ORDER BY date DESC'
                             .'LIMIT 10') -> fetchAll();

        return array_merge($result,$newList);
    }
}
?>