Lobbyists first lobby to pass legislation favorable to their client/employer, such as laws affecting pharmaceutical companies or manufacturers of medical devices etc. They will often use financial incentives to convince politicians that their bills are in the best interests of their clients.
Lobbyists can also work against laws that may be detrimental to their constituencies, such as those regarding insurance or pricing. It allows them to stop unfavorable bills from becoming law while making sure that changes are beneficial for those paying.
These examples show how powerful lobbyists are in influencing health policy and highlight the need to tighten regulations around lobbying so that all decisions made by the government and industry will be based on the best interests of patients.