Table 1. Characteristics of the included studies (n = 8).

CRF: chronic renal failure; DM: diabetes mellitus; ESRD: end-stage renal disease; GIT: gastrointestinal tract; HD: hemodialysis; INR: international normalized ratio; KT/V: K is the urea clearance (mL per minute), T is the treatment duration (minutes), and V is the volume of urea distribution (mL); NSAIDS: non-steroidal anti-inflammatory drugs; PD: peritoneal dialysis; PTH: parathyroid hormone

Study	Location	Inclusion criteria	Exclusion criteria
Peck et al. [12,13]	United States	ESRD patients	DM; age <18 or >78 years; beta-adrenergic blocking drugs or L-carnitine; malabsorption or other conditions affecting fatty acid metabolism; concurrently involved in other research studies
Begum et al. [31]	United States	Patients on maintenance HD of both sexes; age ≥20 years, with symptoms of dry and/or itchy skin	Patients with DM, malabsorption problems, or other conditions that may affect fatty acid metabolism
Ghanei et al. [32]	Iran	Patients with ESRD who were under intermittent HD and had pruritus for >3 months with no response to antipruritic drugs	Pruritus because of other skin diseases; malignancies; hepatic cholestasis; hepatitis B and C; steroid treatment; hemoglobin <10g/dL and KT/V index <1.2; warfarin treatment; allergy to fish oil
Lahiji et al. [33]	Iran	Age >18 years undergoing CAPD for ≥1 month complaining of pruritus for >8 weeks	Poor compliance; current pruritus treatment; other skin disorders; malignancy; malabsorption; kidney transplantation; INR >1.1; PTH >300 pg/mL or phosphorus levels >7 mg/dL; hemoglobin <10 g/dL
Shayanpour et al. [34]	Iran	Age >18 years old with HD duration >3 months	Liver diseases; skin diseases; malignancy; allergy to omega-3 supplements; kidney transplantation
Heydarbaki et al. [35]	Iran	>18 years; no drinking alcohol; conscious; diagnosis of CRF ≥4 weeks; HD for ≥2 sessions per week; chronic itching ≥4 weeks	Taking other antipruritics; death during study, other skin diseases causing itching; contraindication of antihistamines; taking any anti-itching drug except cetirizine; topical treatments which can induce itching; sensitivity to omega-3; digestive problems
Forouhari et al. [36]	Iran	ESRD patients; age >18 years; intermittent HD >3 months; pruritus >8 weeks; no history of pruritic skin disease before renal failure	Other skin diseases; hepatic cholestasis; hepatitis B/C; steroid treatment; current treatment for uremic pruritus; malabsorption; malignancy; kidney transplantation; anemia; phosphorus level >7 mg/dL; PTH >300 μg/L); anticoagulants; allergic reaction; GIT problems
Rafieipoor et al. [37]	Iran	Consent; age >20 years; KT/V higher than the standard range; no omega-3 fatty acid supplement during the last three months; no history of PD; no surgery in the previous six months; no allergy to omega-3, medium chain triglycerides oil, or fish and fish products; not pregnant	Psychiatric conditions; intellectual disability; active inflammatory, infection, pulmonary, cardiac, hemoglobinopathies and coagulopathy conditions; malignancy; recent use of immunosuppressant, chemotherapeutics or anticoagulants; NSAIDs; corticosteroids; non-compliance with omega-3 supplementation or HD; disease aggravation; hospitalization/surgery