Broad is captain of England's Twenty20 team and admitted that he was sorry to be without Pietersen for the ultimately unsuccessful defence of their title in Sri Lanka this month.
"It's hard to tell if the results would have been different had he been there," said Broad.
"Obviously he's a fantastic Twenty20 cricketer, who did wonders for us when we won the World Cup in 2010.
"In June, when I found out he'd retired from the white-ball format, as captain I was hugely disappointed, because I thought he'd be an integral part of our World Cup defence.
"It would be hard for me to say we didn't miss someone of his experience at the top of the order, so I was disappointed when he did pull out.
"But the situation went towards the management side of things and it turned out he couldn't be there."
