The company is already burdened with increased health care costs due to medical cost inflation and increased health care enrollments in the U.S. Currency is also expected to hurt profitability in the to-be reported quarter. Wal-Mart expects U.S. comp sales growth of around 1% for the 13-week period ending Jul 31 as against relatively flat comps last year. Sam's Club comp sales, without the impact of fuel sales, are expected to be flat to up 2% as against flat comps last year.