Really, you should change the way you store your data in the spreadsheet. As it is you're losing most of the benefit of the spreadsheet format. Even in excel, you wouldn't be able to use those numbers as they're stored as text.
One of the many ways of extracting the numbers from the text:
t = readtable('book1.xlsx');
t.patient = cellfun(@str2double, regexp(t.patient, '\d+', 'match'), 'UniformOutput', false)
If you didn't have those brackets [] around the text and the numbers had beens separated by spaces, it would have been easier.
