Information on any ARs, laboratory tests, and other measurements, especially of renal function and serum calcium, was collected. In association with the use of ZOL, the following conditions were included as the known, important risks: predefined acute-phase reaction (APR: pyrexia, malaise, arthralgia, myalgia, nausea, vomiting, influenza-like illness, headache, diarrhea, bone pain, pain in an extremity, and acute-phase reaction as reported by the attending physician), renal function-related ARs, hypocalcaemia, osteonecrosis of the jaw, and atypical femoral fracture. Any events were classified according to MedDRA ver. 23.0.