These drugs could possibly cause more problems than the high blood pressure if the patient is experiencing high blood pressure due to syndrome X. They can worsen insulin resistance.
Enter (diuretics OR beta blockers) AND mortality into PubMed. It might take a month of Sundays just to read the abstracts. Diuretics can have similar adverse metabolic effects, yet these older drugs are still advocated as first line therapies. It's too bad, but medicine is not simple.
Mechanism of differential effects of antihypertensive agents on serum lipids.
" beta-Blockers and diuretics tend to negatively affect both glucose tolerance and plasma lipids."