CST3 and kidney failure: If bisphosphonates use is required, measure cystatin-C before each infusion (risk of renal failure) (expert opinion: 38.5% strongly agree; 38.5% agree). The use of alendronate or oral bisphosphonates is not recommended (Table 3)256(level of evidence: 5D; class of recommendation: D; expert opinion:.1% agree; 38.5% disagree)