US fastfood chain McDonald’s has posted its first worldwide increase in comparable sales in 15 months, as its new product offerings strengthened US sales.

McDonald’s said US sales at restaurants open more than a year rose 6.3% in May, the largest increase in four years. Worldwide same-store sales increased 2.2%.

Chief executive Jim Cantalupo attributed much of the sales improvement to the company’s US menu changes. In an attempt to turn around months of poor sales performances, McDonald’s has been slowing its expansion and focusing instead on improving sales at existing outlets.

The company has added new items such as salads to its menu in a bid to win back customers in the US, where it has around 13,500 fastfood outlets.

McDonald’s said it would incur around US$50m in pre-tax expenses in the second quarter in order to better automate its restaurant operations, close underperforming stores and boost billboard advertising.

Same-store sales in Europe, the company’s second-largest market after the US, fell 1%, while comparable sales in McDonald’s Asia, Pacific, Middle East and Africa region fell 6.1%.