Loosing anndata .var layer when using sc.concat?

Hi, I am merging my samples, after initial QC, with scanpy.concat and l am loosing my .var layer.

This is my code
adata = sc.concat(adatas, join=‘outer’, index_unique=“_”, keys=sample_ids, label=‘sample_ID’)

Can I provide any other parameter so that concat function keeps the .var layer.
Thank you.