Ahmad 1990.

Study characteristics
Methods	Study characteristics Study design: parallel RCT Study duration: not reported Study follow‐up: 6 months
Participants	Baseline characteristics Country: USA Setting: multicentre (4 sites) Inclusion criteria: stable maintenance HD patients; > 18 years, dialysis duration > 9 months; prognosis to survive for the duration of the study; no imminent prospect of kidney transplant Randomised number (intervention/control): 47/50 Dialysis modality: HD Mean age ± SD (years): intervention group (47.5 ± 15.4); control group (48.0 ± 15.9) Sex (M/F): intervention group (24/14); control group (27/17) Dialysis duration (mean ± SD) years: intervention group (3.47 ± 2.35); control group (3.35 ± 1.9) Exclusion criteria: medical instability; previous unreliable behaviour patterns; diabetes; endocrinopathies known to interfere with lipid metabolism; known genetic defects in lipid metabolism; previous or current carnitine therapy; class IV angina; liver failure; malignant hypertension; lipid‐lowering drug therapy; high likelihood of imminent living donor transplantation; malignancies other than basal cell carcinomas of the skin
Interventions	Intervention group L‐carnitine (IV): 20 mg/kg at each dialysis session for 6 months Control group Placebo
Outcomes	Outcomes relevant to this review Adverse events Muscle symptoms Intradialytic hypotension
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomized separately at each study center into treatment or control groups using a modified 4 × 4 Latin square. Patients were stratified by sex."
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias)	Low risk	Quote: "double‐blind placebo‐controlled" study
Blinding of outcome assessment (detection bias) Adverse events	Low risk	Quote: "double‐blind placebo‐controlled" study
Blinding of outcome assessment (detection bias) Muscle symptoms	Low risk	Quote: "double‐blind placebo‐controlled" study
Blinding of outcome assessment (detection bias) Myocardial function	Low risk	Quote: "double‐blind placebo‐controlled" study
Incomplete outcome data (attrition bias) Adverse events	Low risk	Quote: "These dropouts occurred for the following reasons: transplantation (2 carnitine, 2 placebo); noncompliance (2 carnitine); patient's request (5 carnitine, 4 placebo). Six of the patients requesting dropout did so during the baseline period (3 from each group)." Missing outcome data balanced in numbers across intervention groups
Incomplete outcome data (attrition bias) Muscle symptoms	Low risk	Quote: "These dropouts occurred for the following reasons: transplantation (2 carnitine, 2 placebo); noncompliance (2 carnitine); patient's request (5 carnitine, 4 placebo). Six of the patients requesting dropout did so during the baseline period (3 from each group)." Missing outcome data balanced in numbers across intervention groups
Incomplete outcome data (attrition bias) Myocardial function	Low risk	Quote: "These dropouts occurred for the following reasons: transplantation (2 carnitine, 2 placebo); noncompliance (2 carnitine); patient's request (5 carnitine, 4 placebo). Six of the patients requesting dropout did so during the baseline period (3 from each group)." Missing outcome data balanced in numbers across intervention groups
Selective reporting (reporting bias)	Unclear risk	The study protocol is not available
Other bias	Unclear risk	Insufficient information to permit judgement