The prevalence of the metabolic syndrome
7.3.3 Health related quality of life – Quantitative results
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From Figure 7.1 and 7.2, it is evident that transplant candidates on dialysis experienced a lower HRQOL across all HRQOL domains when compared to transplant recipients. Lowest mean scores were VT domain for candidates on dialysis (57.1 ± 19.6 and 60.1 ± 19.7) at both time points. Candidates’ subjective appraisal of their general health, as indicated by the GH score, was also low (59.5 ± 19.6 and 62.3 ± 22.2) at both time points. At six months, the GH domain had the largest significant difference in domain scores between candidates and recipients (d = 4.352, p = 0.000). For candidates, subjective perception of mental health had a score of 74.2 ± 19.3 at baseline, improving to 79.0 ± 14.1 at six months. The differences between MH scores for candidates versus recipients were not significant. Among recipients, HRQOL scores improved by the second assessment, especially in RP, BP, GH and SF. Similar to that of candidates, the low scores of recipients was for VT (73.3 ± 20.2 and 73.6 ± 21.5). GH was also low at baseline (71.3 ± 24.4) but improved considerably by six months (86.2 ± 17.5).
When the study sample was divided according to gender, females had lower scores than males (Figure 7.3 and 7.4). Differences between scores for the two groups were significant either at baseline, six months or both, for all domains (Table 7.5). The significant differences between scores for males and females were in the domain of RP (80.4 ± 35.6 and 49.0 ± 46.1, df = 2.961, p = 0.005), at baseline and at six months (84.5 ± 32.6 and 54.8 ± 48.0, df = 2.785, p = 0.08). The implication of this finding was that compared to males, females were most severely limited in their physical ability to perform daily activities.
For the physical and mental composite scores, the PCS for candidates was 47.4 ± 8.6 and 47.7 ± 9.5, while MCS was 47.6 ± 10.3 and 51.5 ± 8.7 at each time point. The PCS for transplant recipients was 53.8 ± 10 and 56.6 ± 6.5, while MCS was 51.3 ± 11.5 and 54.2 ± 8.5 at baseline and six months respectively. Differences between the two groups were significant for PCS only at baseline and six months (df = 2.708, p = 0.009 and df = 4.464, p = 0.000). There was no significant difference between candidates and recipients at either time point for MCS.
Over the six month period, SF-36 scores in each HRQOL domain increased, signalling improvements in HRQOL from baseline to six months for the study sample. Statistically significant differences between baseline and six months for all participants were GH: (t = - 2.351, p = 0.022), SF: (t = -2.139, p = 0.036), RE: (t = -2.230, p = 0.029), MH: (t = -2.327, p = 0.023), MCS: (t = -3.213, p = 0.002).
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Correlations of HRQOL with socio-demographic, nutritional status and clinical variables
Table 7.6 shows HRQOL correlations with clinical and nutritional variables. The association between HRQOL and albumin was demonstrated in both candidates and recipients in the overall PCS at the six month assessment, but not the MCS. For the candidates, there was a significant association with low albumin levels and low HRQOL scores in the physical domains of RP (r = 0.304, p = 0.038) and BP (r= 0.358, p = 0.014). This finding illustrated that candidates with lower albumin levels experienced more limitations in daily activities and were in more pain.
Transplant recipients were also influenced by albumin at six months in the physical domains of PF (r = 0.514, p = 0.017) and RP (r = 0.543, p = 0.011), but were also limited in daily activities by emotions (RE) at lower levels of albumin (r = 0.492, p = 0.024). There was a lack of correlation with CD4+ count or significant differences in HRQOL between the VL categories.
In transplant recipients only, MCS (r = - 0.451, p = 0.040) was negatively associated with treatment duration, with the implication being that mental health deteriorated in accordance with a greater time lapse since transplantation.
In candidates, indicators of nutritional status such as pre- albumin and BMI, correlated with GH at baseline (prealbumin: r = 0.401, p = 0.031 and BMI: r = 0.338, p = 0.025). Among transplant recipients on the other hand, indicators of nutritional status were significantly associated with more HRQOL domains at six months i.e. RP (r = 0.493, p = 0.038), RE (r = 0.493, p 0.038) and the MCS (r = 0.495, p = 0.037). Correlations of MAMC, a proxy of muscle mass, with HRQOL scores was evident in the transplant group, but not the dialysis group. There was a strong positive relationship between MAMC and the PCS (r = 0.821, p = 0.000) at baseline. MAMC also correlated with individual domains of physical; PF, RP, BP, and GH. There was a weak negative association with MAMC and MCS (r = - 0.484, p = 0.042).
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Domains of HRQOL
Figure 7.1: HRQOL domain scores for transplant candidates and recipients at baseline
Domains of HRQOL
Figure 7.2: HRQOL domain scores for transplant candidates and recipients at six months 0
10 20 30 40 50 60 70 80 90 100
PF RP BP GH VT SF RE MH
SF-36 Scores
Dialysis Transplant
0 10 20 30 40 50 60 70 80 90 100
PF RP BP GH VT SF RE MH
SF-36 Scores
Dialysis Transplant
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Figure 7.3: HRQOL domain scores for males and females at baseline
Figure 7.4: HRQOL domain scores for males and females at six month 0
10 20 30 40 50 60 70 80 90
PF RP BP GH VT SF RE MH
SF-36 scores
Domains of HRQOL
Male Female
0 10 20 30 40 50 60 70 80 90 100
PF RP BP GH VT SF RE MH
SF 36 scores
Domains of HRQOL
Male Female
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Table 7.5: SF-36 scores with significant differences according to treatment group and gender expressed as means ± SD
Domains All Candidates Recipients d P Male Female d p
PF (B) 80.4 ± 21.2 74.6 ± 19.7 93.6 ± 18.7 3.726 0.000 84.0 ± 20.1 74.6 ± 22.0 - -
PF (6 M) 81.1 ± 21.3 76.2 ± 20.5 92.1 ± 19.0 3.123 0.003 85.8 ± 18.2 73.5 ± 23.8 2.414 0.019
RP (B) 68.4 ± 42.5 61.7 ± 43.9 83.3 ± 35.6 2.147 0.037 80.4 ± 35.6 49.0 ± 46.1 2.961 0.005
RP (6 M) 73.2 ± 41.5 64.9 ± 44.4 91.7 ± 26.6 3.076 0.007 84.5 ± 32.6 54.8 ± 48.0 2.785 0.008
BP (B) 77.8 ± 27.2 76.0 ± 28.2 81.9 ± 24.9 - - 84.6 ± 23.3 66.8 ± 30.0 2.747 0.008
BP (6 M) 85.3 ± 24.5 81.6 ± 26.7 93.5 ± 16.3 2.258 0.028 92.0 ± 15.0 74.5 ± 32.4 2.595 0.014
GH (B) 63.2 ± 21.7† 59.5 ± 19.6 71.3 ± 24.4 2.113 0.038 69.0 ± 20.1 54.2 ± 21.5 2.857 0.006
GH (6 M) 69.8 ± 23.7† 62.3 ± 22.2 86.2 ± 17.5 4.352 0.000 71.0 ± 24.9 67.7 ± 21.5 - -
VT (B) 62.1 ± 21.0 57.1 ± 19.5 73.3 ± 20.2 3.135 0.003 66.4 ± 20.8 55.2 ± 19.7 2.210 0.031
VT (6 M) 64.3 ± 21.1 60.1 ± 19.7 73.6 ± 21.5 2.528 0.014 67.3 ± 20.5 59.4 ± 21.6 - -
SF (B) 75.6 ± 27.6† 71.8 ± 26.1 83.9 ± 29.6 79.2 ± 27.1 69.7 ±27.9 - -
SF (6 M) 82.9 ± 24.6† 78.2 ± 25.5 93.5 ± 19.2 2.725 0.009 88.4 ± 20.0 74.0 ± 28.9 2.223 0.032
RE (B) 73.5 ± 42.5† 70.2 ± 43.5 81.0 ± 40.2 - - 82.5 ± 36.2 59.0 ± 48.4 2.140 0.038
RE (6 M) 85.8 ± 31.2† 83.7 ± 31.8 90.5 ± 30.0 - - 88.1 ± 28.3 82.1 ± 35.6 - -
MH (B) 76.2 ± 20.2† 74.2 ± 19.3 80.6 ± 22.1 - - 80.3 ± 18.4 70.0 ± 21.7 2.188 0.032
MH (6 M) 80.8 ± 14.3† 79.0 ± 14.1 85.0 ± 14.2 - - 82.5 ± 13.8 78.2 ± 14.8 - -
Composite
PCS (B) 49.4 ± 9.5 47.4 ± 8.6 53.8 ± 10.0 2.708 0.009 51.8 ± 8.0 45.5 ± 10.5 2.786 0.007
PCS (6 M) 50.4 ± 9.6 47.7 ± 9.5 56.6 ± 6.5 4.464 0.000 53.1 ± 6.3 46.1 ± 12.2 2.744 0.010
MCS (B) 48.7 ± 10.8† 47.6 ± 10.3 51.3 ± 11.5 - - 50.9 ± 9.9 45.4 ± 11.4 2.095 0.040
MCS (6 M) 52.3 ± 8.7† 51.5 ± 8.7 54.2 ± 8.5 - - 53.0 ± 8.2 51.4 ± 9.4 - -
B: baseline, 6 M: six months, PF: physical functioning, RP: role physical, BP: bodily pain, GH: general health, VT: vitality, SF: social function, RE: role emotional, MH: mental health, d:difference, p (p value)
†Statistically significant difference between baseline and six month follow up for all participants, paired samples t-test:
GH: (t = -2.351, p = 0.022), SF: (t = -2.139, p = 0.036), RE: (t = -2.230, p = 0.029), MH: (t = -2.327, p = 0.023), MCS: (t = -3.213, p = 0.002).
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Table 7.6: Correlations of SF- 36 scores with clinical and nutritional variables for transplant candidates and recipients
Transplant candidates Transplant recipients
Prealbumin r (p)
Albumin r (p)
BMI r (p)
Prealbumin r (p)
Albumin r (p)
MAMC
PF 0.514* (0.017) [6M] 0.675**(0.003) [B]
RP 0.304* (0.038) [6M] 0.493* (0.038) [6M] 0.543* (0.011) [6M] 0.558* (0.020) [B]
BP 0.358* (0.014) [6M] 0.757** (0.000) [B]
GH 0.401* (0.031) [B] 0.338* (0.025) [B] 0.608** (0.010) [B]
VT SF
RE 0.493* (0.038) [6M] 0.492* (0.024) [6M]
MH
MCS 0.495* (0.037) [6M] -0.484*(0.042) [6M]
PCS 0.329* (0.024) [6M] 0.464* (0.034) [6M] 0.821**(0.000) [B]
B: baseline, 6 M: six months
PF: Physical functioning, RP: Role physical, BP: bodily pain, GH: general health, VT: vitality, SF: social function, RE: role emotional, MH: mental health, MCS:
mental component score, PCS: physical component score r (p): Correlations using Pearson’s coefficient r ( p value)
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