Speculation has been growing about the future of the 54-year-old chain following a raft of closures by other high street brands across the UK casual dining sector last year.
Accounts for the 52 weeks to 30 December 2018 show EBITDA for the group, which operates over 600 restaurants worldwide, dropped 15% to £80.2m
Overall revenue grew 1.6% but like-for-like sales in the UK and Ireland declined 0.9%.
Pre-tax losses widened from £28.7m in 2017 to £55m, which the company says was driven by falling profits and net interest charges of £93.1m.
Earnings were also hit by a 7.5% drop in like-for-like sales in its international business, which has been growing in Asia since PizzaExpress was bought by Chinese private equity group Hony Capital for £900m in 2014.
The group opened 26 restaurants overseas in 2018, 20 in mainland China, and international markets now make up almost 20% of its total sales.
PizzaExpress' CEO Jinlong Wang blamed "sector-wide labour and property cost increases in the UK combined with more challenging conditions in some of [the] less mature international markets" for the decline in EBITDA.
Writing in its accounts he acknowledged that the brand needed to ‘remain relevant’ in a challenging market.
In March PizzaExpress began trialling an overhaul of its design and menu at its restaurant in London’s Oxford Circus and it is also angling for a cut of the grab and go sector with the launch of pizza by the slice concept Za in the City.
The company has also developed new concepts overseas, and opened ‘fine casual dining’ Italian restaurant Meanwhile in Shanghai in 2018.
“Looking forward, whilst we expect both the UK and International markets to remain competitive we are confident that our focus on customer-led innovation and investment in our brand and our people will put us in a strong position to succeed in this environment and continue to deliver a resilient performance,” says Wang.
PizzaExpress has debts of £1.12bn, £655.6m of which is due for repayment in 2021. The company previously said around £400m is a loan from its parent company.