FEV % predicted ( rate ratio -LSB- RR -RSB- @ -LSB- @ % CI , @-@ @ -RSB- per @ % lower ) , more previous exacerbations ( RR @ -LSB- @ % CI , @-@ @ -RSB- ) , Standard therapy ( RR @ -LSB- @ % CI , @-@ @ -RSB- ) , and female sex ( RR @ -LSB- @ % CI , @-@ @ -RSB- ) were associated with future severe exacerbations .