Doing a cox regression, how do I analyze a continuous variable in which a lower result is worse?
With a simple linear regression you have a dependent and independent variable, with an outcome model of:
y = - mx + c

If I understand your problem, y would be mortality, and x would be your clinical variable (i.e. when x increases y decreases). And it would be the same if you want to do your other example, because there is an inverse relationship between the two (i.e. when you decrease x, y increases).
It sounds like your hazard ratio is m (i.e. the relationship between the clinical variable and the mortality)
m = (y - c )/x

So to getting a HR&gt;1 will depend on your data.