Safety and Efficacy of Empagliflozin (BI 10773) and Sitagliptin Versus Placebo Over 76 Weeks in Patients With Type 2 Diabetes

Inclusion criteria: 1. Patients completing the entire treatment period of the preceding double-blind trial 1245.19, 1245.20 or 1245.23 with or without rescue therapy. 2. Signed and dated written informed consent by date of Visit 1 in accordance with Good Clinical Practice and local legislation. Exclusion criteria: 1. Patient who meet one or more of the withdrawal criteria of the treatment period of the previous trial 1245.19, 1245.20 or 1245.23. 2. Indication of liver disease, defined by serum levels of either alanine aminotransferase , aspartate aminotransferase, or alkaline phosphatase above 3 x upper limit of normal as determined during last visit of preceding trial. 3. Impaired renal function defined as glomerular filtration rate\<30 ml/min (severe renal impairment, Modification of Diet in Renal Disease formula) as determined during last visit of preceding trial. 4. Contraindications to sitagliptin, pioglitazone, metformin or sulfonylurea according to local label, which started during trial participation in 1245.19, 1245.20 or 1245.23 5. Pre-menopausal women (last menstruation \< or = 1 year prior to informed consent) who are nursing or pregnant or are of child-bearing potential and are not practicing an acceptable method of birth control, or do not plan to continue using this method throughout the study and do not agree to submit to periodic pregnancy testing during participation in the trial. Acceptable methods of birth control include tubal ligation, transdermal patch, intra uterine devices/systems, oral, implantable or injectable contraceptives, sexual abstinence (if acceptable by local authorities), double barrier method and vasectomised partner. 6. Alcohol or drug abuse within the 3 months prior to informed consent that would interfere with trial participation or any ongoing condition leading to a decreased compliance to study procedures or study drug intake. 7. Participation in another trial with an investigational drug within 30 days prior to informed consent (except 1245.19, 1245.20 and 1245.23). 8. Any other clinical condition that would jeopardize patient's safety while participating in this clinical trial.