Slum area has hospital within reach (6)
I believe the answer is:
ghetto
'slum area' is the definition.
(I've seen this before)
'hospital within reach' is the wordplay.
'hospital' becomes 'h'.
'within' is an insertion indicator.
'reach' becomes 'getto' (getting to is a kind of reaching**).
'h' inserted into 'getto' is 'GHETTO'.
'has' is the link.
(Other definitions for ghetto that I've seen before include "Densely populated slum area" , "Densely populated city slum" , "Needy part of city" , "(Often slum) area occupied by minority group" , "Racially distinct quarter" .)