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Characterizing the relationship between health utility and renal function after kidney transplantation in UK and US: a cross-sectional study.

Neri L, McEwan P, Sennfält K, Baboolal K - Health Qual Life Outcomes (2012)

Bottom Line: The adjusted median disutility associated to CKD stage 5 compared to CKD stage 1-2 for the whole sample was 0.18 (p<0.01, quantile regression).Center effect was not statistically significant.Impaired renal function is associated with reduced health-related quality of life independent of possible confounders, center-effect and analytic framework.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dipartimento di Scienze Mediche e di Comunità, Università degli Studi di Milano, Milano, Italy. luca.neri@unimi.it

ABSTRACT

Background: Chronic allograft nephropathy (CAN) occurs in a large share of transplant recipients and it is the leading cause of graft loss despite the introduction of new and effective immunosuppressants. The reduction in renal function secondary to immunologic and non-immunologic CAN leads to several complications, including anemia and calcium-phosphorus metabolism imbalance and may be associated to worsening Health-Related Quality of Life. We sought to evaluate the relationship between kidney function and Euro-Qol 5 Dimension Index (EQ-5Dindex) scores after kidney transplantation and evaluate whether cross-cultural differences exist between UK and US.

Methods: This study is a secondary analysis of existing data gathered from two cross-sectional studies. We enrolled 233 and 209 subjects aged 18-74 years who received a kidney transplant in US and UK respectively. For the present analysis we excluded recipients with multiple or multi-organ transplantation, creatinine kinase ≥200 U/L, acute renal failure, and without creatinine assessments in 3 months pre-enrollment leaving 281 subjects overall. The questionnaires were administered independently in the two centers. Both packets included the EQ-5Dindex and socio-demographic items. We augmented the analytical dataset with information abstracted from clinical charts and administrative records including selected comorbidities and biochemistry test results. We used ordinary least squares and quantile regression adjusted for socio-demographic and clinical characteristics to assess the association between EQ-5Dindex and severity of chronic kidney disease (CKD).

Results: CKD severity was negatively associated with EQ-5Dindex in both samples (UK: ρ= -0.20, p=0.02; US: ρ= -0.21, p=0.02). The mean adjusted disutility associated to CKD stage 5 compared to CKD stage 1-2 was Δ= -0.38 in the UK sample, Δ= -0.11 in the US sample and Δ= -0.22 in the whole sample. The adjusted median disutility associated to CKD stage 5 compared to CKD stage 1-2 for the whole sample was 0.18 (p<0.01, quantile regression). Center effect was not statistically significant.

Conclusions: Impaired renal function is associated with reduced health-related quality of life independent of possible confounders, center-effect and analytic framework.

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Relationship between estimated Glomerular Filtration Rate and Health Related Quality of Life.
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Figure 2: Relationship between estimated Glomerular Filtration Rate and Health Related Quality of Life.

Mentions: Since the interaction between CKD severity and center of enrollment was not significant, we tested the association between renal impairment and EQ-5Dindex with quantile regression in the pooled sample. Results from quantile regression are summarized in Figures 1 and 2. The adjusted median disutility associated to CKD stage 5 compared to CKD stage 1–2 for the whole sample was 0.18 (Wald test for trend across categories, p<0.01), slightly smaller than the adjusted mean disutility estimated from GLM (0.22, Wald test for trend across categories, p<0.01) (Figure 1). According to the results obtained evaluating the quantile process (τ being evaluated: 0.15, 0.30, 0.50, 0.70, 0.85) the association between eGFR (entered as a continuous variable) and EQ-5Dindex was slightly stronger in the upper tail of the outcome distribution. Parameter estimates ranged from 0.02 (τ=0.15) to 0.06 (τ=0.85) and were not significant at τ<0.30 (Figure 2a). In the upper half of the outcome distribution (τ>0.50) the relationship between eGFR and EQ-5Dindex was non-linear: the coefficient estimate for eGFR2 ranged from −0.003 to −0.004 and was statistically significant at the 5% confidence level (Figure 2b). The interaction term between the indicator variable denoting the center of enrollment and eGFR was not significant at any percentile of the outcome variable.


Characterizing the relationship between health utility and renal function after kidney transplantation in UK and US: a cross-sectional study.

Neri L, McEwan P, Sennfält K, Baboolal K - Health Qual Life Outcomes (2012)

Relationship between estimated Glomerular Filtration Rate and Health Related Quality of Life.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539915&req=5

Figure 2: Relationship between estimated Glomerular Filtration Rate and Health Related Quality of Life.
Mentions: Since the interaction between CKD severity and center of enrollment was not significant, we tested the association between renal impairment and EQ-5Dindex with quantile regression in the pooled sample. Results from quantile regression are summarized in Figures 1 and 2. The adjusted median disutility associated to CKD stage 5 compared to CKD stage 1–2 for the whole sample was 0.18 (Wald test for trend across categories, p<0.01), slightly smaller than the adjusted mean disutility estimated from GLM (0.22, Wald test for trend across categories, p<0.01) (Figure 1). According to the results obtained evaluating the quantile process (τ being evaluated: 0.15, 0.30, 0.50, 0.70, 0.85) the association between eGFR (entered as a continuous variable) and EQ-5Dindex was slightly stronger in the upper tail of the outcome distribution. Parameter estimates ranged from 0.02 (τ=0.15) to 0.06 (τ=0.85) and were not significant at τ<0.30 (Figure 2a). In the upper half of the outcome distribution (τ>0.50) the relationship between eGFR and EQ-5Dindex was non-linear: the coefficient estimate for eGFR2 ranged from −0.003 to −0.004 and was statistically significant at the 5% confidence level (Figure 2b). The interaction term between the indicator variable denoting the center of enrollment and eGFR was not significant at any percentile of the outcome variable.

Bottom Line: The adjusted median disutility associated to CKD stage 5 compared to CKD stage 1-2 for the whole sample was 0.18 (p<0.01, quantile regression).Center effect was not statistically significant.Impaired renal function is associated with reduced health-related quality of life independent of possible confounders, center-effect and analytic framework.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dipartimento di Scienze Mediche e di Comunità, Università degli Studi di Milano, Milano, Italy. luca.neri@unimi.it

ABSTRACT

Background: Chronic allograft nephropathy (CAN) occurs in a large share of transplant recipients and it is the leading cause of graft loss despite the introduction of new and effective immunosuppressants. The reduction in renal function secondary to immunologic and non-immunologic CAN leads to several complications, including anemia and calcium-phosphorus metabolism imbalance and may be associated to worsening Health-Related Quality of Life. We sought to evaluate the relationship between kidney function and Euro-Qol 5 Dimension Index (EQ-5Dindex) scores after kidney transplantation and evaluate whether cross-cultural differences exist between UK and US.

Methods: This study is a secondary analysis of existing data gathered from two cross-sectional studies. We enrolled 233 and 209 subjects aged 18-74 years who received a kidney transplant in US and UK respectively. For the present analysis we excluded recipients with multiple or multi-organ transplantation, creatinine kinase ≥200 U/L, acute renal failure, and without creatinine assessments in 3 months pre-enrollment leaving 281 subjects overall. The questionnaires were administered independently in the two centers. Both packets included the EQ-5Dindex and socio-demographic items. We augmented the analytical dataset with information abstracted from clinical charts and administrative records including selected comorbidities and biochemistry test results. We used ordinary least squares and quantile regression adjusted for socio-demographic and clinical characteristics to assess the association between EQ-5Dindex and severity of chronic kidney disease (CKD).

Results: CKD severity was negatively associated with EQ-5Dindex in both samples (UK: ρ= -0.20, p=0.02; US: ρ= -0.21, p=0.02). The mean adjusted disutility associated to CKD stage 5 compared to CKD stage 1-2 was Δ= -0.38 in the UK sample, Δ= -0.11 in the US sample and Δ= -0.22 in the whole sample. The adjusted median disutility associated to CKD stage 5 compared to CKD stage 1-2 for the whole sample was 0.18 (p<0.01, quantile regression). Center effect was not statistically significant.

Conclusions: Impaired renal function is associated with reduced health-related quality of life independent of possible confounders, center-effect and analytic framework.

Show MeSH
Related in: MedlinePlus