An overview can help you understand the general topic and help you find more specific ideas to explore.
The Institute of Medicine defines Clinical Practice Guidelines as "statements that include recommendations intended to optimize patient care that are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options" (see https://www.ncbi.nlm.nih.gov/books/NBK209546/.)
The best place to find clinical practice guidelines used to be the National Guideline Clearinghouse from the U.S. Agency for Healthcare Research and Quality, but the site was discontinued in mid-2018 due to lack of funding. As an alternative, you can create a free account to search the ECRI Guidelines Trust below, or try a web search for: Clinical Practice Guidelines [insert your topic here].
Some "best bets" for getting started with health statistics & data:
State Statistics & Data
National Statistics & Data
Global Statistics & Data
Interested in finding more?
Remember that it takes a lot of time and effort to collect data. Who would be interested enough in your topic to collect that data? (For example, the American Cancer Society collects a lot of data about cancer research and patients). It's possible that no one has collected data for your exact population or year of interest, but if you think broadly you can usually find related data.