Bone mineral densitometry in patients on hemodialysis: difference between genders and what to measure

Figures & data

TABLE 1.  Demographics, clinical, and laboratory parameters of the study group

Variable	Mean ± SD	Range
Male (N = 72)
Age (years)	56.2 ± 12.6	33–83
Dialysis duration (months)	49.7 ± 61	6–300
BMI (kg/m^2)	25.4 ± 3.3	21–34
iPTH (pmol/L)	57.3 ± 59.6*	5–263
Calcium (mmol/L)	2.3 ± 0.2	2.0–2.5
Phosphate (mmol/L)	1.8 ± 0.4	1.0–2.8
Calcium phosphate product (mmol^2/L^2)	4.1 ± 1.0	3.0–6.7
ALP (U/L)	83.4 ± 40.7†	50–325
Female (N = 62)
Age (years)	56.7 ± 11.8	32–83
Dialysis duration (months)	59.5 ± 60.1	6–250
BMI (kg/m^2)	25.0 ± 4.8	17–35
iPTH (pmol/L)	79.8 ± 67.9*	3–260
Calcium (mmol/L)	2.3 ± 0.2	2.0–2.6
Phosphate (mmol/L)	1.8 ± 0.4	1.1–2.8
Calcium phosphate product (mmol^2/L^2)	4.5 ± 2.1	3.0–6.7
ALP (U/L)	116.9 ± 108^†	52–850

Notes: BMI, body mass index; iPTH, intact parathyroid hormone; ALP, alkaline phosphatase.

*p = 0.02; ^†p = 0.02.

TABLE 2.  Mean BMD, T-score, and Z-score in female and male patients

	Female (N = 62)	Male (N = 72)	p
Lumbar spine
PA (total)
BMD (g/cm^2)	0.866 ± 0.158	1.011 ± 0.182
T-score	−1.6 ± 1.4	−0.7 ± 1.7	0.001
Z-score	−0.4 ± 1.5	−0.2 ± 1.7	NS
LL (total)
BMD(g/cm^2)	0.587 ± 0.116	0.799 ± 0.195
T-score	−3.1 ± 1.3	–
Z-score	−0.6 ± 1.3	–
Hip
Neck
BMD(g/cm^2)	0.679 ± 0.130	0.808 ± 0.125
T-score	−1.5 ± 1.2	−0.9 ± 1.0	0.001
Z-score	−0.4 ± 1.1	−0.1 ± 0.9	0.00007
Troch
BMD (g/cm^2)	0.547 ± 0.106	0.692 ± 0.116
T-score	−1.5 ± 1.0	−0.6 ± 0.9	<0.00001
Z-score	−0.7 ± 1.0	−0.3 ± 0.9	<0.00001
Inter
BMD (g/cm^2)	0.893 ± 0.167	1.088 ± 0.163
T-score	−1.3 ± 1.09	−0.6 ± 0.9	<0.00001
Z-score	−0.7 ± 1.2	−0.2 ± 0.9	<0.00001
Total
BMD (g/cm^2)	0.757 ± 0.136	0.941 ± 0.138
T-score	−1.4 ± 1.2	−0.6 ± 0.9	<0.00001
Z-score	−0.6 ± 1.1	−0.3 ± 0.9	<0.00001
Ward's
BMD (g/cm^2)	0.490 ± 0.154	0.597 ± 0.174
T-score	−2.1 ± 1.3	−1.3 ± 1.2	0.04
Z-score	−0.3 ± 1.3	−0.1 ± 1.2	0.002
Forearm
UD
BMD (g/cm^2)	0.311 ± 0.081	0.425 ± 0.097
T-score	−2.0 ± 1.6	−1.6 ± 1.4	NS
Z-score	−1.0 ± 1.5	−0.9 ± 1.5	NS
MID
BMD(g/cm^2)	0.466 ± 0.100	0.613 ± 0.092
T-score	−2.3 ± 1.9	−1.4 ± 1.7	0.01
Z-score	−0.9 ± 1.7	−0.8 ± 1.7	NS
One-third
BMD(g/cm^2)	0.571 ± 0.113	0.745 ± 0.091
T-score	−1.9 ± 1.9	−1.3 ± 1.5	NS
Z-score	−0.6 ± 1.8	−0.5 ± 1.6	NS
Total
BMD(g/cm^2)	0.451 ± 0.096	0.600 ± 0.086
T-score	−2.0 ± 2.1	−1.5 ± 1.6	NS
Z-score	−0.9 ± 1.7	−0.7 ± 1.6	NS

Notes: BMD, bone mineral density; PA, posterior–anterior; LL, lateral–lateral; Troch, trochanter; Inter, intertrochanter; Ward's, Ward's Triangle; UD, ultradistal; MID, middistal; 1/3, one-third; NS, not significant.

TABLE 3.  Correlation between BMD of measurement sites laboratory and clinical parameters, expressed as a coefficient of correlation (r) in male patients

	Lumbar spine		Hip					Forearm
	PA total	LL total	Neck	Troch	Inter	Total	Ward's	UD	MID	1/3	Total
Age	0.300*	NS	−0.293^†	NS	NS	NS	−0.314*	NS	NS	NS	NS
HD	NS	NS	NS	NS	NS	NS	NS	−0.295^†	−0.390^‡	−0.351*	−0.388^‡
BMI	NS	NS	NS	NS	0.322*	0.294^†	NS	0.279^†	0.284^†	NS	0.271^†
iPTH	NS	NS	NS	−0.277^†	−0.263^†	−0.280^†	NS	−0.286^†	−0.340*	−0.306*	−0.346*
Ca	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
P	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
Ca × P	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
ALP	−0.254^†	−0.281^†	NS	−0.261^†	−0.248^†	−0.256^†	NS	−0.232^†	−0.385^‡	−0.377^‡	−0.378^‡

Notes: BMD, bone mineral density; PA, posterior–anterior; LL, lateral–lateral; Troch, trochanter; Inter, intertrochanter; Ward's, Ward's Triangle; UD, ultradistal; MID, middistal; 1/3, one-third; BMI, body mass index; iPTH, intact parathyroid hormone; Ca, calcium; P, phosphorus; ALP, alkaline phosphatase; NS, not significant.

*p < 0.01; ^†p < 0.05; ^‡p < 0.001; (r = 0.302, p < 0.01), (r = 0.232, p < 0.05), (r = 0.372, p < 0.001).

TABLE 4.  Correlation between PTH and BMD in measurement sites expressed as a coefficient of correlation (r) in female patients

	Lumbar spine		Hip					Forearm
	PA total	LL total	Neck	Troch	Inter	Total	Ward's	UD	MID	1/3	Total
Age	NS	0.273	−0.277	NS	NS	NS	−0.366^†	−0.326^†	−0.381^†	−0.384^†	−0.380^†
HD	−0.453^‡	NS	−0.436^‡	−0.315	−0.356^†	−0.384^†	−0.280	−0.394^†	−0.426^‡	−0.422^‡	−0.425^‡
BMI	0.328^†	0.328^†	0.406^‡	0.356^†	0.383^†	0.421^‡	0.310	NS	NS	NS	NS
iPTH	−0.384^†	NS	−0.369^†	−0.359^†	−0.390^†	−0.400^‡	NS	−0.342^†	−0.414^‡	−0.371^†	−0.398^‡
Ca	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
P	0.272	NS	NS	0.300	NS	NS	NS	NS	NS	NS	NS
Ca × P	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
ALP	−0.360^†	−0.274	−0.463^‡	−0.480^‡	−0.508^‡	−0.527^‡	−0.385^†	−0.349^†	−0.349^†	−0.375^†	−0.331^†

Notes: PA, posterior–anterior; LL, lateral–lateral; Troch, trochanter; Inter, intertrochanter; Ward's, Ward's Triangle; UD, ultradistal; MID, middistal; 1/3, one-third; BMI, body mass index; iPTH, intact parathyroid hormone; Ca, calcium; P, phosphorus; ALP, alkaline phosphatase; NS, not significant.

*p < 0.05; ^†p < 0.01; ^‡p < 0.001; (r = 0.250, p < 0.05), (r = 0.325, p < 0.01), (r = 0.395, p < 0.001).

TABLE 5.  Correlation between BMD of individual measurement sites expressed as a coefficient of correlation (r) in female patients

	PA total	LL total	Neck	Troch	Inter	Total	Ward's	UD	MID	1/3	Total
PA	1	0.571	0.687	0.709	0.722	0.752	0.620	0.643	0.581	0.568	0.610
LL	0.571	1	0.458	0.513	0.413	0.466	0.413	0.392	0.374	0.319	0.373
Neck	0.687	0.458	1	0.737	0.871	0.911	0.842	0.716	0.740	0.717	0.750
Troch	0.709	0.513	0.737	1	0.799	0.872	0.698	0.700	0.635	0.584	0.653
Inter	0.722	0.413	0.871	0. 799	1	0.980	0.794	0.749	0.769	0.739	0.778
Total	0.752	0.466	0.911	0.872	0.980	1	0.805	0.763	0.761	0.727	0.773
Ward's	0.620	0.413	0.842	0.698	0.794	0.805	1	0.618	0.598	0.581	0.616
UD	0.643	0.392	0.716	0.700	0.749	0.763	0.618	1	0.865	0.792	0.905
MID	0.581	0.374	0.740	0.635	0.769	0.761	0.598	0.865	1	0.792	0.993
1/3	0.568	0.319	0.717	0.584	0.739	0.727	0.581	0.792	0.792	1	0.963
Total	0.610	0.373	0.750	0.653	0.778	0.773	0.616	0.905	0.993	0.963	1

Notes: BMD, bone mineral density; PA, posterior–anterior; LL, lateral–lateral; Troch, trochanter; Inter, intertrochanter; Ward's, Ward's Triangle; UD, ultradistal; MID, middistal; 1/3, one-third.

TABLE 6.  Correlation between BMD of individual measurement sites expressed as a coefficient of correlation (r) in male patients

	PA	LL	Neck	Troch	Inter	Total	Ward's	UD	MID	1/3	Total
PA	1	0.659	0.298	0.559	0. 449	0.480	0.211	0.371	0.311	0.289	0.358
LL	0.659	1	0.416	0.529	0.470	0.513	0.361	0.435	0.353	0.261	0.394
Neck	0.298	0.416	1	0.633	0.727	0.795	0.821	0.286	0.281	0.194	0.287
Troch	0.559	0.529	0.633	1	0.800	0.873	0.460	0.478	0.443	0.331	0.466
Inter	0.449	0.470	0.727	0.800	1	0.976	0.555	0.512	0.534	0.345	0.540
Total	0.480	0.513	0.795	0.873	0.976	1	0.621	0.527	0.537	0.365	0.548
Ward's	0.211	0.361	0.821	0.460	0.555	0.621	1	0.184	0.152	0.100	0.153
UD	0.371	0.435	0.286	0.478	0.512	0.527	0.184	1	0.758	0.394	0.802
MID	0.311	0.353	0.281	0.443	0.534	0.537	0.152	0.758	1	0.842	0.991
1/3	0.289	0.261	0.194	0.331	0.345	0.365	0.100	0.394	0.842	1	0.838
Total	0.358	0.394	0.287	0.466	0.540	0.548	0.153	0.802	0.991	0.839	1

Notes: BMD, bone mineral density; PA, posterior–anterior; LL, lateral–lateral; Troch, trochanter; Inter, intertrochanter; Ward's, Ward's Triangle; UD, ultradistal; MID, middistal; 1/3, one-third.

TABLE 7.  Osteoporosis and reduced bone mass compared to T-score

	Normal N (%)	Reduced bone mass N (%)	Osteoporosis N (%)
Lumbar spine
PA
Male	38 (53)	24 (33)	10 (14)
Female	22 (35)	21 (34)	19 (31)
LL
Male	–	–	–
Female	4 (6)	16 (26)	42 (68)
Hip
Neck
Male	36 (50)	34 (47)	2 (3)
Female	17 (27)	34 (55)	11 (18)
Troch
Male	43 (60)	29 (40)	0 (0)
Female	16 (26)	34 (55)	12 (19)
Inter
Male	43 (60)	28 (39)	1 (1)
Female	24 (39)	28 (45)	10 (16)
Total
Male	43 (60)	29 (40)	0 (0)
Female	20 (32)	31 (50)	11 (18)
Ward's
Male	22 (30)	35 (49)	15 (21)
Female	9 (14)	29 (47)	24 (39)
Forearm
UD
Male	22 (30)	30 (42)	20 (28)
Female	16 (26)	25 (40)	21 (34)
MID
Male	26 (36)	25 (35)	21 (29)
Female	13 (21)	27 (44)	22 (35)
1/3
Male	30 (42)	27 (37)	15 (21)
Female	18 (29)	25 (40)	19 (31)
Total
Male	26 (36)	27 (37)	19 (26)
Female	16 (26)	24 (39)	22 (35)

Notes: PA, posterior–anterior; LL, lateral–lateral; Troch, trochanter; Inter, intertrochanter; Ward's, Ward's Triangle; UD, ultradistal; MID, middistal; 1/3, one-third.

TABLE 8.  Z-score in female and male patients

	Z < −1 N (%)	Z < −2 N (%)
Lumbar spine
PA
Male	28 (39)	8 (11)
Female	18 (29)	5 (8)
LL
Male	–	–
Female	26 (42)	6 (10)
Hip
Neck
Male	12 (17)	3 (5)
Female	20 (32)	3 (5)
Troch
Male	24 (33)	4 (6)
Female	27 (43)	6 (10)
Inter
Male	16 (22)	3 (5)
Female	21 (34)	6 (10)
Total
Male	13 (18)	3 (5)
Female	19 (31)	6 (10)
Ward's
Male	11 (15)	3 (5)
Female	14 (23)	4 (6)
Forearm
UD
Male	35 (49)	15 (21)
Female	35 (56)	16 (26)
MID
Male	36 (50)	16 (22)
Female	28 (45)	14 (23)
1/3
Male	28 (39)	13 (18)
Female	25 (40)	12 (19)
Total
Male	35 (49)	13 (18)
Female	27 (43)	14 (23)

Notes: PA, posterior–anterior; LL, lateral–lateral; Troch, trochanter; Inter, intertrochanter; Ward's, Ward's Triangle; UD, ultradistal; MID, middistal; 1/3, one-third.

Z < −1, low bone density, Z < −2 bellow the expected range for age.