Not adversely at most carriers. A statin prescription is read as evidence that a diagnosed condition is being managed, and applicants on statins with good ratios routinely reach preferred rates.
This is the most common avoidable mistake in this category: people delay applying, or stop medication, believing the prescription is the problem.
What the prescription tells an underwriter
Two things. That you have diagnosed hyperlipidaemia — which the lab result would show anyway — and that you are doing something about it. The second is what carriers are pricing.
The logic runs through diabetic, hypertensive and cardiac underwriting identically. Someone who sees a doctor, takes what is prescribed and produces improving numbers is a better risk than someone with the same biology and no engagement, and the file shows the difference.
What would actually hurt
A statin in the pharmacy record that is not being refilled. That is a diagnosed condition plus documented non-adherence, and it reads considerably worse than either alone.
The practical instruction
Do not stop or delay medication in order to apply. If anything, the reverse — applying with a treated, well-controlled ratio is close to the best version of this file you can present. Keep taking what has been prescribed and apply on the strength of the result.
The full treatment of this topic is on High cholesterol.