TY - JOUR
T1 - Health status as a potential mediator of the association between hemodialysis vascular access and mortality
AU - Grubbs, Vanessa
AU - Wasse, Haimanot
AU - Vittinghoff, Eric
AU - Grimes, Barbara A.
AU - Johansen, Kirsten L.
N1 - Funding Information:
This project was sponsored by the USRDS Nutrition Special Studies Center (N01-DK-7-0005). The interpretation and reporting of the data presented here are the responsibility of the authors and in no way should be seen as an official policy or interpretation of the US government. V.G. was supported by grant 1K23DK093710-01A1 from the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) and by the Harold Amos Medical Faculty Development Program of the Robert Wood Johnson Foundation. K.L.J. was supported by contract N01-DK-7-0005 and grant 1K24DK085153 from NIDDK.
PY - 2014/4
Y1 - 2014/4
N2 - BackgroundIt is unknown whether the selection of healthier patients for ateriovenous fistula (AVF) placement explains higher observed catheter-associated mortality among elderly hemodialysis patients.MethodsFrom the United States Renal Data System 2005-2007, we used proportional hazard models to examine 117 277 incident hemodialysis patients aged 67-90 years for the association of initial vascular access type and 5-year mortality after accounting for health status. Health status was defined as functional status at dialysis initiation and number of hospital days within 2 years prior to dialysis initiation.ResultsPatients with catheter alone had more limited functional status (25.5 versus 10.8% of those with AVF) and 3-fold more prior hospital days than those with AVF (mean 18.0 versus 5.4). In the unadjusted model, the likelihood of death was higher for arteriovenous grafts (AVG) Hazard ratio (HR) 1.20 [95% CI (1.16-1.25)], catheter plus AVF [HR 1.34 (1.31-1.38)], catheter plus AVG [HR 1.46 (1.40-1.52)] and catheter only [HR 1.95 (1.90-1.99)], compared with AVF (P < 0.001). The association attenuated -23.7% (95% CI -22.0, -25.5) overall (AVF versus all other access types) after adjusting for the usual covariates (including sociodemographics, comorbidities and pre-dialysis nephrology care) AVG [HR 1.21 (1.17-1.26)], catheter plus AVF [HR 1.27 (1.24-1.30)], catheter plus AVG [HR 1.38 (1.32-1.43)] and catheter only [HR 1.69 (1.66-1.73)], P < 0.001. Additional adjustment for health status further attenuated the association by another -19.7% (-18.2, -21.3) overall but remained statistically significant <AVG [HR 1.18 (1.13-1.22)], catheter plus AVF [HR 1.20 (1.17-1.23)], catheter plus AVG HR 1.38 [1.26 (1.21-1.31)] and catheter only [HR 1.54 (1.50-1.58)], P < 0.001>.ConclusionsThe observed attenuation in mortality differences previously attributed to access type alone suggests the existence of selection bias. Nevertheless, the persistence of an apparent survival advantage after adjustment for health status suggests that AVF should still be the access of choice for elderly individuals beginning hemodialysis until more definitive data eliminating selection bias become available.
AB - BackgroundIt is unknown whether the selection of healthier patients for ateriovenous fistula (AVF) placement explains higher observed catheter-associated mortality among elderly hemodialysis patients.MethodsFrom the United States Renal Data System 2005-2007, we used proportional hazard models to examine 117 277 incident hemodialysis patients aged 67-90 years for the association of initial vascular access type and 5-year mortality after accounting for health status. Health status was defined as functional status at dialysis initiation and number of hospital days within 2 years prior to dialysis initiation.ResultsPatients with catheter alone had more limited functional status (25.5 versus 10.8% of those with AVF) and 3-fold more prior hospital days than those with AVF (mean 18.0 versus 5.4). In the unadjusted model, the likelihood of death was higher for arteriovenous grafts (AVG) Hazard ratio (HR) 1.20 [95% CI (1.16-1.25)], catheter plus AVF [HR 1.34 (1.31-1.38)], catheter plus AVG [HR 1.46 (1.40-1.52)] and catheter only [HR 1.95 (1.90-1.99)], compared with AVF (P < 0.001). The association attenuated -23.7% (95% CI -22.0, -25.5) overall (AVF versus all other access types) after adjusting for the usual covariates (including sociodemographics, comorbidities and pre-dialysis nephrology care) AVG [HR 1.21 (1.17-1.26)], catheter plus AVF [HR 1.27 (1.24-1.30)], catheter plus AVG [HR 1.38 (1.32-1.43)] and catheter only [HR 1.69 (1.66-1.73)], P < 0.001. Additional adjustment for health status further attenuated the association by another -19.7% (-18.2, -21.3) overall but remained statistically significant <AVG [HR 1.18 (1.13-1.22)], catheter plus AVF [HR 1.20 (1.17-1.23)], catheter plus AVG HR 1.38 [1.26 (1.21-1.31)] and catheter only [HR 1.54 (1.50-1.58)], P < 0.001>.ConclusionsThe observed attenuation in mortality differences previously attributed to access type alone suggests the existence of selection bias. Nevertheless, the persistence of an apparent survival advantage after adjustment for health status suggests that AVF should still be the access of choice for elderly individuals beginning hemodialysis until more definitive data eliminating selection bias become available.
KW - elderly
KW - hemodialysis
KW - mortality
KW - vascular access
UR - http://www.scopus.com/inward/record.url?scp=84897400820&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84897400820&partnerID=8YFLogxK
U2 - 10.1093/ndt/gft438
DO - 10.1093/ndt/gft438
M3 - Article
C2 - 24235075
AN - SCOPUS:84897400820
SN - 0931-0509
VL - 29
SP - 892
EP - 898
JO - Proceedings of the European Dialysis and Transplant Association - European Renal Association. European Dialysis and Transplant Association - European Renal Association. Congress
JF - Proceedings of the European Dialysis and Transplant Association - European Renal Association. European Dialysis and Transplant Association - European Renal Association. Congress
IS - 4
ER -