Hello, Yes ,you are right. Steroids can cause blood sugar levels to rise. Also some people who did not have diabetes before may develop diabetes after taking steroids (this is called secondary diabetes and it often resolves after the steroids are stopped). Blood glucose levels rise during steroid treatment because your liver produces more glucose than normal and your body is not able to produce enough insulin to cope with this increase.   Steroids can also cause your body to become resistant to either insulin produced by your own body or insulin you may be injecting to control your diabetes. You may need to increase your insulin dose while taking steroids. If steroids are reduced or stopped your blood glucose may fall and you will  then need to reduce your dose of injection insulin. Thanks