Wang 2013.

Study characteristics
Methods	Recruitment period: July 2008 to March 2010 Outcomes: Bone PFS, overall survival, bone mineral density, SREs, VAS scores for pain relief, analgesic use, toxicity and adverse events Pain assessment tool: VAS Randomization: "eligible patients are randomly divided into two groups"
Participants	Eligibility criteria: patients’ > 18 years with life expectancy of > 6 months patients with histologically confirmed prostate cancer, with at least 2 radiographic (ECT and CT or MRI) evidences of bone metastases patients were required to have castrated level of PSA (< 2 ng/mL), achieved by bilateral orchidectomy or administration of a luteinizing‐hormone releasing hormone agonist Exclusion criteria: patients with significant renal, hepatic, or non‐malignant‐related diseases previous radical prostatectomy, chemotherapy, or radiotherapy previous use of bisphosphates and calcium supplement Paget’s diseases, primary hyperparathyroidism, or osteoporosis Participants randomized: 137 randomized, 69 zoledronic acid, 68 clodronate Mean age: 71.3 zoledronic acid group 73.6 clodronate group Country of participants: China
Interventions	Previous interventions: not mentioned Interventions during study period: all participants received a calcium supplement of 500 mg and vitamin D of 400 IU daily; participants received either 4 tablets of clodronate (1600 mg) once daily, at least 1 h before breakfast, or zoledronic acid 4 mg over a 30 min IV infusion) every 1 month
Outcomes	Reported and analyzed in this review: SREs adverse events overall survival pain relief
Funding sources	Funding sources: Wenzhou science technology bureau (Y20100023)
Declarations of interest	Conflicts of interest: all authors state that they have no conflict of interest
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information on sequence generation
Allocation concealment (selection bias)	Unclear risk	Insufficient information on allocation concealment
Blinding of participants and personnel (performance bias) Blinding of participants	Unclear risk	Insufficient information on blinding of participants and personnel
Blinding of participants and personnel (performance bias) Blinding of personnel	Unclear risk	Insufficient information on blinding of participants and personnel
Blinding of outcome assessment (detection bias) Outcomes subjective to participants	Unclear risk	Insufficient information on blinding of participants and personnel
Blinding of outcome assessment (detection bias) Outcomes subjective to outcome assessors	Unclear risk	Insufficient information on blinding of outcome assessors
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	No known reason for bias
Incomplete outcome data (attrition bias) Time‐to‐event data	Low risk	"All the recruited patients were evaluated for the efficacy and safety every 1 month until death." Intention‐to‐treat‐analysis was used.
Incomplete outcome data (attrition bias) Patient‐reported outcomes (other than safety data)	Unclear risk	"All the recruited patients were evaluated for the efficacy and safety every 1 month until death." No information on discontinuation
Incomplete outcome data (attrition bias) Safety data	Unclear risk	"All the recruited patients were evaluated for the efficacy and safety every 1 month until death." No information on discontinuation
Incomplete outcome data (attrition bias) Other outcomes	Unclear risk	"All the recruited patients were evaluated for the efficacy and safety every 1 month until death." No information on discontinuation
Selective reporting (reporting bias)	Unclear risk	No protocol available.
Other bias	Low risk	None identified