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. 2023 Aug 31;2023(8):CD013074. doi: 10.1002/14651858.CD013074.pub2

Biniaz 2015.

Study characteristics
Methods Study design

  • Parallel RCT


Study dates

  • Duration of follow‐up: 8 weeks

  • Time frame: October 2012 to January 2013
Participants Study characteristics

  • Setting: multicentre (2 hospitals in an urban area of Iran)

  • Country: Iran

  • Inclusion criteria: > 18 years who attended regular HD 3 sessions/week; received HD ≥ 3 months; Hb > 80 g/L; did not take vitamin C from at least 3months before the study

  • Exclusion criteria: active infection or active cancer


Baseline characteristics

  • Number (analysed/randomised): overall (57/62); intervention group (30/not reported); control group (27/not reported)

  • Mean age ± SD (years): intervention group (58.3 ± 11.5); control group (57.1 ± 10.7)

  • Sex (M/F): intervention group (19/11); control group (16/11)

  • Dialysis type: HD

  • Mean dialysis vintage ± SD (years): intervention group (4.7 ± 4.5); control group (3.3 ± 2.6)

  • Comorbidities

    • CVD: not reported

    • Diabetes: not reported

    • Hypertension: not reported

    • Depression (clinician diagnosis): not reported
Interventions Intervention classification

  • Pharmacological intervention

  • Indication: study targeting fatigue


Intervention group

  • Vitamin C supplementation (IV): 250 mg


Control group

  • Placebo


Co‐interventions

  • Not reported
Outcomes Outcomes reported

  • Fatigue outcome measures used: validation data available

  • Fatigue

    • MFI‐20 questionnaire: at the start and end of study

      • General fatigue

      • Physical fatigue

      • Intellectual fatigue

  • Hb: at the start and end of study

  • HCT: at the start and end of study

  • Ferritin: at the start and end of study

  • Marital satisfaction score

    • ENRICH questionnaire: at the start and end of study
Notes Additional information

  • Funding: master's degree thesis supported by the Baqiyatallah University of Medical Sciences. This project was supported by a grant from the Nephrology and Urology Research Center of Baqiyatallah University of Medical Sciences

  • Conflicts of interest/disclosures: not reported

  • Trial registration identification number: not reported

  • A priori published protocol: not reported
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Quote: "The samples were randomly distributed by a lottery method into two equal groups (simple random sampling)."
Allocation concealment (selection bias) Unclear risk Method of allocation concealment was not reported in sufficient detail to permit judgement
Blinding of participants and personnel (performance bias)
All outcomes Unclear risk Quote: "Double‐blinded."
Comment: Although author reported that the study used a double‐blind design, information about blinding of participants and investigators were not clearly stated
Blinding of outcome assessment (detection bias)
All outcomes High risk Fatigue was assessed with an appropriate measure, without differences between groups. However, subjective measures were used, it was not stated whether outcomes were assessed without knowledge of treatment allocation, and knowledge of treatment assignment may have influenced reporting. Participant beliefs about the superiority/inferiority of either intervention could have influenced their assessment of the outcome, but there was no evidence that this was likely. However, objective and subjective outcomes were assessed
Incomplete outcome data (attrition bias)
All outcomes High risk Quote: "Only 57 patients completed the study (30 persons in the intervention and 27 persons in the control group)."
Comment: 57/60 participants completed the study (> 5% loss to follow‐up). Reasons for discontinuation were not provided and it was not clear if there was a difference between the two groups
Selective reporting (reporting bias) High risk Information about the protocol and the statistical analysis plan were not reported. Multiple eligible outcome measurements (scales and time points) were pre‐specified. It was unclear if the reported approach to analysing this outcome was pre‐specified or influenced by the results. Fatigue was measured all time points. All outcomes that should be addressed (fatigue, cardiovascular disease, and death) were not reported
Other bias Low risk There was no evidence of different baseline characteristics, or different non‐randomised co‐interventions between groups. Funding did not influence the data analysis and conflicts of interest were not reported. No other source of bias were apparent