Socio-demographic characteristics, medical history and clinical characteristics of study participants
In this study we found that, those patients with age greater than 50 year, those with family history of hypertension, those who were on calcium supplement and/or phosphate binder, those who were on calcium rich diet and/or low phosphate diet, those who had a duration of CKD for more than 2 year and those who were on maintenance hemodialysis were more predominant in the CKD-MBD arm and this was statistically significant (Table 1).
Table 1: Socio-demographic characteristics, medical history and clinical characteristics of study participants, N=300
Variable
|
|
CKD-MBD
|
p-value
|
|
|
Presence
|
Absence
|
|
Age (above 50)
|
214 (71.3%)
|
149 (69.6%)
|
65 (30.4%)
|
0.001
|
Gender (Male)
|
198 (66.0%)
|
150 (75.8%)
|
48 (24.2%)
|
0.673
|
Hypertensive
|
285 (95.0%)
|
213 (74.7%)
|
72 (25.3%)
|
0.646
|
Diabetic
|
77 (25.7%)
|
60 (77.9%)
|
17 (22.1%)
|
0.492
|
Hypercholesterolemia
|
16 (5.3%)
|
14 (87.5%)
|
2 (12.5%)
|
0.235
|
FHx Hypertension
|
65 (21.7%)
|
61 (93.8%)
|
4 (6.2%)
|
<0.001
|
FHx Diabetes
|
27 (9.0%)
|
22 (81.5%)
|
5 (18.5%)
|
0.415
|
FHx Hypercholesterolemia
|
9 (3.0%)
|
8 (88.9%)
|
1 (11.1%)
|
0.329
|
Ca supplements
|
106(35.3%)
|
67(63.2%)
|
39(36.8%)
|
<0.001
|
Phosphate binders
|
90(30.0%)
|
51(56.7%)
|
39(43.3%)
|
<0.001
|
RRT (Dialysis)
|
129 (43.0%)
|
125 (96.9%)
|
4 (3.1%)
|
<0.001
|
CKD duration (above 2yrs)
|
149 (49.7%)
|
122 (81.9%)
|
27 (18.1%)
|
0.006
|
Duration dialysis (> 2yrs)
|
33 (25.6%)
|
33 (100.0%)
|
0 (0.0%)
|
0.234
|
Ca rich diet
|
160(53.3%)
|
90(56.3%)
|
70(43.7%)
|
<0.001
|
Low phosphate diet
Mean PTH±SD
Mean Calcium±SD
Mean Phosphate±SD
Mean albumin±SD
|
149(49.7%)
|
75(50.3%)
583±310.4
1.5±0.4
3.5±0.9
36±5.7
|
74(49.7%)
48±5.7
2.5±0.5
1.3±0.7
37±3.2
|
<0.001
<0.001
<0.001
<0.001
0.523
|
Distribution of perticipants with CKD-MBD by their CKD stages
Among patients with CKD-MBD, those who were on CKD stage 3A, 3B, 4, 5 and 5D were 7(3.1%), 3(1.3%),5 (2.2%), 85(37.8%) and 125 (55.6%) respectively (Figure 1).
Distribution of abnormalities in serum calcium, phosphate and parathyroid hormone levels by CKD stages
CKD-MBD was defined based on an abnormality of serum calcium, phosphate or parathyroid hormone level. More than half of patients with hypocalcemia 91(52.3%) were on CKD stage 5D; 36(43.9%) of patients with hyperphosphatemia were on CKD stage 5D while 113 (57.7%) of patients with hyperparathyroidism were on CKD stage 5D (Figure 2).
Proportion of patients with CKD-MBD using calcium supplements, phosphate binders, calcium rich diet and low phosphate diet
Among the patients with CKD-MBD, 67 (29.8%) were taking calcium supplements, 51 (22.7%) were taking phosphate binders, 90 (40.0%) were on a calcium rich diet and 75 (33.7%) were on low phosphate diet (Figure 3).
Factors associated with CKD-MBD
In a univariate analysis, age >50years, use of calcium supplements and/or phosphate binders, being on dialysis, duration of CKD >2years and use of calcium rich diet and/or low phosphate diet were associated with CKD-MBD. Participants aged above fifty years had three fold high risk of developing CKD-MBD as compared to their younger counterparts [OR 3.32, (95% C.I 1.61-6.82), p=0.001]; participants who were on calcium supplements were two times more likely to have CKD-MBD [OR 2.56, (95% C.I 1.50-4.37), p=0.001]; participants who were on phosphate binders were three times more likely to have CKD-MBD [3.70, (95% C.I 2.13-6.41), p=<0.001]; participants who were on hemodialysis had more than sixty fold high risk of developing CKD-MBD [OR 61.78, (95% C.I 12.60-302.91), p=<0.001] and participants who had a duration of CKD for more than two years had two fold high risk of developing CKD-MBD [OR 2.11, (95% C.I 1.22-3.61), p=0.007].
In a multivariate analysis, all of these associations remained significant, although the odds ratios were smaller (Table 2).
Table 2: Factors associated with CKD-MBD
Variable
|
|
Crude Odds ratio (95% CI)
|
P-value
|
Adjusted odds ratios (95% CI)
|
P-value
|
Age >50years
|
3.32 (1.61-6.82)
|
0.001
|
1.54(0.53-4.44)
|
0.428
|
|
Male
|
1.125 (0.651-1.944)
|
0.673
|
|
|
|
Hypertension
|
1.352 (0.371-4.927)
|
0.647
|
|
|
|
Diabetes
|
0.806 (0.435-1.492)
|
0.493
|
|
|
|
Ca++ supplements
|
2.56 (1.50-4.37)
|
0.001
|
1.29(1.11-1.51)
|
0.001
|
|
Phosphate binders
|
3.70 (2.13-6.41)
|
<0.001
|
1.46(1.09-21.00)
|
0.001
|
|
On dialysis
|
61.78(12.60-302.91)
|
<0.001
|
13.39(5.02-35.71)
|
<0.001
|
|
CKD-Duration (>2years)
|
2.11 (1.22-3.61)
|
0.007
|
1.18(0.37-3.73)
|
0.776
|
|
Ca++ rich diet
|
21.00(8.16-54.07)
|
<0.001
|
1.83(1.60-2.11)
|
0.001
|
|
Low phosphate diet
|
148(20.18-1085.45)
|
<0.001
|
1.97(1.68-2.32)
|
0.001
|
|