<qa>  What is the GDS scale?1. - Life expectancy less than 6 months for any clinical reason we considered criteria of a life expectancy less than 6 months 7 c-7 d global deterioration degree on GDS Global Deterioration Scale-FAST Functional Assessment Staging scale in patients with dementia; severe disabilities considered as score less than 15 points in Barthel index and left ventricular ejection fraction equal or less than 20 