Atorvastatin can rarely cause new onset diabetes mellitus and increase the blood glucose levels. But this is a very rare side effect of long term use of statins. Gemfibrozil usually does not have this side effect. I would recommend you to undergo investigations to determine your glycemic status that includes HbA1c measurements. As diabetes has many risk factors, even if the results are confirming of diabetes; it is difficult to pinpoint on atorvastatin. Medications may be initiated based on the test results. Please take the medications as prescribed by your physician. Hope the above information helps you. Thanks.