Feb 23 (Reuters) - German healthcare group Fresenius narrowed down its 2021 sales growth forecast as it reported a slight full-year results beat on Tuesday, saying improvement in its businesses is heavily dependent on levels of vaccination coverage in its markets.

Fresenius said it expected 2021 sales to grow in a low to mid-single-digit percentage range and confirmed its forecast for at least broadly stable net income. In early February, the group said it expected "healthy sales growth."

The company added net income for the group excluding dialysis unit Fresenius Medical Care should grow in a mid-to high single digit percentage range in constant currency.

Fresenius' full-year net income came in at 1.80 billion euros ($2.19 billion) on a currency-adjusted basis, in line with the preliminary announcement that it would decline by as much as 4% and analysts' forecasts.

($1 = 0.8217 euros) ($1 = 0.8218 euros) (Reporting by Zuzanna Szymanska in Gdansk Editing by Tomasz Janowski)