Yes, and it is a very common combination. Both treated and controlled is routinely written, often at standard rates — but the two together are weighted more heavily than either alone.
These two travel together often enough that carriers have detailed guidance for the combination. That is good news; the weighting is the thing to understand.
They compound rather than add
Hypertension and hyperlipidaemia are both cardiovascular risk factors acting on the same system, so a carrier does not simply stack two mild ratings. It assesses combined cardiovascular risk, and the pair sits worse than either would suggest in isolation.
Add a raised build score or smoking and the effect compounds again. Metabolic risk factors clustering is exactly what underwriting is designed to detect.
Control is what rescues it
Both conditions treated, both sets of numbers in a good range, documented over time, is a file many carriers will write at or near standard. Both diagnosed and neither controlled is where real ratings appear.
What to bring
Several recent blood pressure readings rather than one, a recent lipid panel with the ratio, your current medication list with start dates, and your height and weight. If the numbers have improved since diagnosis, supply the history so the trend is visible.
The cardiovascular picture as a whole is covered on heart and stroke.
The full treatment of this topic is on High cholesterol.