From a personal perspective, I believe physicians should be more careful when prescribing BP meds as patients get older or when multiple complex diagnosis and polypharmacy are in the mix.
I suffer from moderate hypertensive heart disease, LVH, mild nephropathy and adrenal insufficiency all caused by hypertention. Recently, my Renin value was found to be 1532.60 and the Dr blamed my meds Candesartan/HCT 16/12.5mg, recently reduced from Candesartan/HCT 32/25mgs. No action was taken and I was left trying to manage this situation plus multiple other diagnosis e.g. PA, hypothyroid, hyperinsulinaemia, insulin resistance and to top it all, last month diabetes Mellitus was added to the list. Obviously, there are more factors to consider for an increased Renin value than simply an unwanted side effect of BP medication, however, it has been my experience that Dr's are not equipped to deal with complex diagnoses and resultant polypharmacy.
Perhaps a study into the course of hypertension and its effects on the body would shed light on how to manage medications in consideration of other illnesses.
In my case organ damage began at the age of 40 years old so in my opinion monitoring of medications in terms of age was not appropriate rather medication alterations and adjustments to meet the needs of failing organs and systems might be better.
One thing I have noticed is that since my cortisol dropped significantly, so has my BP therefore baseline cortisol might be a useful variable to measure particularly in patients with hypothyroidism and associated (diagnosed or undiagnosed) adrenal dysfunction.