Effects of protein and omega-3 supplementation, provided during regular dialysis sessions, on nutritional and inflammatory indices in hemodialysis patients

Figures & data

Table 1 Selected fatty acid composition of omega-3 and placebo capsule

	Omega-3 (g/100 g as FA)	Placebo (g/100 g as FA)
C16:0	0.96	13.86
C16:1	0.35	1.44
C17:0	0.14	0.07
C17:1	–	0.11
C18:0	4.66	2.73
C18:1n9	8.88	66.64
C18:2n6	2.00	11.42
C18:3n3	0.77	0.69
C20:0	0.50	0.43
C20:1n9	–	0.26
C20:5n3	35.36	–
C21:5n3	1.70	–
C22:5n3	4.95	–
C22:6n3	24.31	–
SAFA	7.02	17.26
MUFA	15.21	70.63
PUFA	77.77	12.11
Omega-3	67.08	0.69

Abbreviations: FA, fatty acids; SAFA, saturated fatty acids; MUFA, monounsaturated fatty acids; PUFA, polyunsaturated fatty acids.

Figure 1 Study’s flow chart.

Notes: All patients at the Great Lake Dialysis clinic (n = 105) were screened for eligibility. Sixty-nine patients met the inclusion criteria but six of them declined to participate. The remaining 63 patients were randomized into omega-3 and placebo groups and underwent intervention for 6 months. Seven additional subjects (placebo, n = 4; omega-3, n = 3) were excluded from data analysis due to death (n = 4, 2 from each group) or hospitalization (n = 3). Two patients voluntarily dropped out as they were unable to swallow the capsules but their data were included in the analysis (intent to treat).
Abbreviation: MIS, malnutrition-inflammation score.

Table 2 Clinical and demographic characteristics of the study population

	Omega-3 (n = 31)	Placebo (n = 32)	P-value
Demographics
Age (years)	59 ± 13	58 ± 13	0.845
Ethnicity
African American (n, %)	30 (97)	32 (100)	–
Caucasian (n, %)	1 (3)	0 (0)	–
Gender (males, %)	20 (62.5)	12 (38.7)	0.059
Income ($ per month)	1015 ± 576	1148 ± 761	0.552
Clinical
Time on dialysis (years)	3.6 ± 2.9	3.3 ± 3.8	0.784
BMI (kg/m^2)	28.4 ± 8.3	26.9 ± 7.8	0.468
Diabetes mellitus (n, %)	20 (62.5)	20 (64.5)	0.868
Kt/v	1.58 ± 0.29	1.63 ± 0.32	0.536
Statin usage (n, %)	11 (35.5)	9 (28.1)	0.530
CRP (mg/dL)	5.8 ± 9.2	4.9 ± 5.6	0.134

Notes: Differences in age, time on dialysis, BMI, Kt/v and income were tested using independent t-test. Baseline CRP levels are reported in median ± interquartile range. Differences were tested using Mann–Whitney rank-sum test. Differences in gender, diabetes mellitus, and statin treatment were tested using chi-square. P < 0.05 is considered significant.

Abbreviations: BMI, body mass index; Kt/v, index of dialysis adequacy; CRP, C-reactive protein.

Table 3 Means and standard deviations of lipid profiles (TC, HDLC, LDLC, and TAG) at baseline and month-6

	Placebo (n = 26)				Omega-3 (n = 28)				P overall
	Baseline	Month-6	Diff	P	Baseline	Month-6	Diff	P
Lipid profiles
TC (mg/dL)	159 ± 49	138 ± 42	−21 ± 26	0.000	176 ± 36	139 ± 29	−37 ± 32	0.000	0.057
HDLC (mg/dL)	44 ± 13	49 ± 11	+5 ± 8	0.004	41 ± 14	47 ± 16	+6 ± 8	0.000	0.531
LDLC (mg/dL)	94 ± 42	69 ± 35	−25 ± 27	0.000	108 ± 34	71 ± 29	−39 ± 33	0.000	0.092
TAG (mg/dL)	104 ± 69	96 ± 68	−7 ± 61	0.561	123 ± 60	102 ± 53	−20 ± 55	0.064	0.405
LDL-HDL ratio	2.2 ± 1.0	1.5 ± 0.9	−0.7 ± 0.8	0.000	3.0 ± 1.6	1.7 ± 1.0	−1.3 ± 1.1	0.000	0.043

Notes: All values are presented as mean ± SD. P values for each group derived from paired t-test between baseline versus month-6 comparison. Overall P values derived using independent t-test, tested for mean differences of lipid profiles parameters between omega-3 and placebo groups (bold face). Data excludes values from 7 subjects (placebo, n = 4; omega-3, n = 3) who died (n = 4, 2 from each group), or were hospitalized (n = 3), during the course of the study. One subject (placebo) was excluded due to extremely high TAG levels (478 mg/dL) as the Friedwald equation is not reliable when TAG levels exceed 400 mg/dL.

Abbreviations: TC, total cholesterol; HDLC, high density lipoprotein cholesterol; LDLC, low density lipoprotein cholesterol; TAG, triacylglycerides; Diff, mean difference of month-6 minus baseline.

Table 4 Means and standard deviations of nutritional status indicators (Ser alb, Hgb, MIS score, nPNA, and BMI) at baseline and month-6

	Placebo (n = 27)				Omega-3 (n = 28)				P overall
	Baseline	Month-6	Diff	P	Baseline	Month-6	Diff	P
Nutritional status
Ser alb (g/dL)	3.7 ± 0.2	3.8 ± 0.4	0.0 ± 0.3	0.756	3.6 ± 0.3	3.7 ± 0.3	0.1 ± 0.3	0.070	0.295
Hgb (g/L)	11.0 ± 1.0	11.3 ± 1.7	0.2 ± 1.7	0.471	10.4 ± 1.1	10.8 ± 1.5	0.3 ± 1.4	0.282	0.866
MIS score	7.6 ± 3.6	8.1 ± 4.0	0.6 ± 4.0	0.215	9.0 ± 3.6	9.1 ± 3.4	0.4 ± 2.2	0.408	0.730
nPNA	0.96 ± 0.38	0.91 ± 0.22	−0.01 ± 0.23	0.810	0.99 ± 0.29	0.87 ± 0.25	−0.07 ± 0.45	0.471	0.598
BMI (kg/m^2)	25.4 ± 5.6	25.1 ± 6.1	0.3 ± 1.8	0.327	28.1 ± 7.0	28.1 ± 7.2	0.1 ± 1.0	0.699	0.500

Notes: All values are presented as mean ± SD. P values for each group derived from paired t-test between baseline versus month-6 comparison. Overall P values derived using independent t-test, tested for mean differences of nutritional parameters between omega-3 and placebo groups (bold face). Data excludes values from 7 subjects (placebo, n = 4; omega-3, n = 3) who died (n = 4, 2 from each group) or were hospitalized (n = 3), during the course of the study.

Abbreviations: Ser alb, serum albumin; Hgb, hemoglobin; MIS, malnutrition inflammation score; nPNA, normalized protein equivalence of nitrogen appearance; BMI, body mass index; Diff, mean difference of month-6 minus baseline.

Table 5 Means and standard deviations of inflammatory indicators (NFκB, CRP) at baseline and month-6

	Placebo (n = 27)			Omega-3 (n = 28)			P overall
	Baseline	Month-6	P	Baseline	Month-6	P
NFκB (μg/mL)	2.48 ± 1.03	2.54 ± 1.14	0.703	2.52 ± 1.19	2.15 ± 0.4	0.129	0.134
CRP (mg/dL)*	6.6 ± 8.3	11.0 ± 13.9	0.040	13.1 ± 17.5	14.6 ± 19.7	0.565	0.259
CRP (mg/dL)**	4.9 ± 5.6	4.6 ± 12.0	0.034	5.8 ± 9.2	6.1 ± 14.0	0.412	0.326

Notes: NFκB value is presented as mean ± SD. CRP value is presented as *mean ± SD and **median ± IQR. P values for each group derived from either paired t-test (NFκB)/Wilcoxon rank sum test (CRP) between baseline versus month-6 comparison. Overall P values derived using either independent t-test/Mann–Whitney rank sum test, tested for mean differences of inflammatory parameters between omega-3 and placebo groups (bold face). Data excludes values from 7 subjects (placebo, n = 4; omega-3, n = 3) who died (n = 4, 2 from each group) or were hospitalized (n = 3), during the course of the study.

Abbreviations: NFκB, Nuclear factor kappa-light-chain enhancer of activated B cells; CRP, C-reactive protein.