Clinical Factors Associated with Serum Magnesium Concentration in Patients Undergoing Peritoneal Dialysis: A Single-Center Observational Study

Figures & data

Table 1 Clinical Characteristics of the Patients (n = 60)

Variable	Mean ± SD or Median [IQR]	Number (%)
Age (years)	62.5 [51.5−72.5]
Male sex		44 (73)
Body mass index (kg/m^2)	23.2 [20.8−25.3]
Diabetes mellitus		23 (38)
Hepatic disease		2 (3)
Cardiac disease		24 (40)
Surgical history of parathyroidectomy		1 (2)
PD period (months)	24 [12−45]
Treatment by hybrid PD		13 (22)
Administration of phosphate binders		51 (85)
Administration of calcium-sensing receptor activator		14 (23)
Administration of magnesium oxide		1 (2)
Administration of proton pump inhibitor		25 (42)
Administration of diuretics		36 (60)
Administration of vitamin D		32 (53)
PD method: CAPD		21 (35)
PD method: APD		39 (65)
PD dialysate Mg concentration: 1.5mEq/L		10 (17)
PD dialysate Mg concentration: 0.5 mEq/L		45 (75)
PD dialysate Mg concentration: combination of 1.5 mEq/L and 0.5mEq/L		5 (8)
Total Kt/V urea	1.6 [1.4−1.8]
Peritoneal Kt/V urea	1.1 [0.8−1.4]
Renal Kt/V urea	0.4 [0.2−0.8]
Four-hour D/P Creatinine	0.7 ± 0.1
White blood cells (10^3/µL)	6.2 [5.1−7.4]
Red blood cells (10^4/µL)	350.1 ± 46.2
Hemoglobin (g/dL)	10.8 ± 1.3
Platelets (×10^4/µL)	22.9 ± 7.5
Total protein (g/dL)	6.3 ± 0.5
Albumin (g/dL)	3.3 ± 0.5
Blood urea nitrogen (mg/dL)	53.0 [48.0−62.8]
Creatinine (mg/dL)	10.9 ± 3.2
C-reactive protein (mg/dL)	0.2 [0.0−0.5]
Uric acid (mg/dL)	5.9 [5.0−7.2]
Sodium (mEq/L)	138.2 ± 4.0
Potassium (mEq/L)	4.4 [3.8−5.1]
Chloride (mEq/L)	99.8 ± 5.0
Corrected calcium (mg/dL)	9.1 ± 0.6
Phosphorus (mg/dL)	5.5 ± 1.1
Magnesium (mg/dL)	2.1 [1.8−2.5]
Zinc (µg/dL)	60.5 [52.0−68.0]
Iron (µg/dL)	74.5 [52.0−95.8]
Ferritin (mg/mL)	134.2 [85.4−254.5]
Transferrin saturation (%)	44.8 [26.9−64.4]
Blood sugar (mg/dL)	108.0 [99.0−130.8]
HbA1c (%)	5.6 [5.0−6.1]
Total cholesterol (mg/dL)	178.3 ± 47.4
HDL cholesterol (mg/dL)	46.5 [35.3−54.8]
LDL cholesterol (mg/dL)	97.1 ± 36.0
Triglycerides (mg/dL)	124.0 [87.0−181.5]
Intact-parathormone (pg/dL)	224.0 [140.8−320.5]

Abbreviations: SD, standard deviation; IQR, interquartile range; PD, peritoneal dialysis; HD, hemodialysis; CAPD, continuous ambulatory peritoneal dialysis; APD, automated peritoneal dialysis; D/P Creatinine, dialysate/plasma creatinine ratio; HbA1c, hemoglobin A1c; HDL, high-density lipoprotein; LDL, low-density lipoprotein.

Table 2 Clinical Factors Associated with Serum Mg Concentration (n = 60)

Variable	Univariate Analysis		Multivariate Analysis
	Β	P	β	P
Age	−0.127	0.34
Male sex	0.062	0.63
Body mass index	0.027	0.83
Diabetes mellitus	−0.082	0.53
Hepatic disease	0.051	0.70
Cardiac disease	−0.124	0.34
Surgical history of parathyroidectomy	−0.071	0.59
PD period	0.203	0.12
Treatment by hybrid PD	0.264	0.04	0.143	0.26
Administration of phosphate binders	0.294	0.02	0.118	0.35
Administration of calcium-sensing receptor activator	−0.069	0.60
Administration of magnesium oxide	−0.193	0.14
Administration of proton pump inhibitor	0.032	0.81
Administration of diuretics	−0.179	0.17
Administration of vitamin D	−0.064	0.63
PD modality: CAPD	0.003	0.98
PD modality: APD	−0.003	0.98
PD dialysate Mg concentration: 1.5mEq/L	−0.117	0.37
PD dialysate Mg concentration: 0.5 mEq/L	0.115	0.38
PD dialysate Mg concentration: combination of 1.5 mEq/L and 0.5mEq/L	−0.022	0.87
Total Kt/V urea	−0.044	0.74
Peritoneal Kt/V urea	−0.127	0.33
Renal Kt/V urea	0.227	0.08
Four-hour D/P Creatinine	−0.243	0.06
White blood cells	−0.208	0.12
Red blood cells	0.090	0.50
Hemoglobin	0.168	0.20
Platelets	−0.093	0.48
Total protein	−0.133	0.31
Albumin	0.221	0.09
Blood urea nitrogen	0.122	0.35
Creatinine	0.169	0.20
C-reactive protein	−0.318	0.01	−0.137	0.31
Uric acid	0.102	0.44
Sodium	0.045	0.73
Potassium	0.451	< 0.01	0.388	0.01
Chloride	0.094	0.47
Corrected calcium	0.064	0.63
Phosphorus	0.237	0.07
Zinc	−0.056	0.67
Iron	0.121	0.36
Ferritin	−0.203	0.12
Transferrin saturation	−0.158	0.23
Blood sugar	−0.136	0.30
HbA1c	−0.232	0.08
Total cholesterol	−0.232	0.08
HDL cholesterol	0.030	0.82
LDL cholesterol	−0.191	0.14
Triglycerides	−0.201	0.12
Intact-parathormone	−0.333	0.01	−0.221	0.08

Abbreviations: SD, standard deviation; PD, peritoneal dialysis; HD, hemodialysis; CAPD, continuous ambulatory peritoneal dialysis; APD, automated peritoneal dialysis; D/P Creatinine, dialysate/plasma creatinine ratio; HbA1c, hemoglobin A1c; HDL, high-density lipoprotein; LDL, low-density lipoprotein.

Figure 1 Significant correlation between serum magnesium concentration and serum potassium concentration in patients undergoing peritoneal dialysis.