I believe you can do this safely. However, if you can I would recommend a sandbox strategy to allow you to get back to your existing configuration. If your vCenter server and DB are on the same server and it is a physical server, I would make myself a sandbox by virtualizing the system using converter. If it is already a VM, clone it. If your database is on another host, see if you can create a new instance of the same data and connect a cloned copy of your vCenter server to the new DB. Keeping your vCenter server offline or on different IPs (obviously necessary for an external DB), do the uninstall and reinstall of vCenter and attempt to connect the new installation to the sandbox DB. This should be an effective test and if you like the results, and don't mind running vCenter in a VM, you can simply switch to the new vCenter instance. You can also repeat the process on the production vCenter host instead.
In any case a sandbox is a very handy tool to have here.