34.05 Cognitive Impairment and Graft Loss in Kidney Transplant Recipients

J. M. Ruck¹, A. G. Thomas¹, A. A. Shaffer^1,2, C. E. Haugen¹, H. Ying¹, F. Warsame¹, N. Chu², M. C. Carlson^3,4, A. L. Gross^2,4, S. P. Norman⁵, D. L. Segev^1,2, M. McAdams-DeMarco^{1,2  1}Johns Hopkins University School Of Medicine,Department Of Surgery,Baltimore, MD, USA ²Johns Hopkins School Of Public Health,Department Of Epidemiology,Baltimore, MD, USA ³Johns Hopkins School Of Public Health,Department Of Mental Health,Baltimore, MD, USA ⁴Johns Hopkins University Center On Aging And Health,Baltimore, MD, USA ⁵University Of Michigan,Department Of Internal Medicine, Division Of Nephrology,Ann Arbor, MI, USA

Introduction:  Cognitive impairment is common in patients with end-stage renal disease and impairs adherence to complex treatment regimens. Given the complexity of immunosuppression regimens following kidney transplantation, we hypothesized that cognitive impairment might be associated with an increased risk of all-cause graft loss among kidney transplant (KT) recipients. 

Methods:  Using the Modified Mini-Mental State (3MS) examination, we measured global cognitive function in a prospective cohort of 864 KT candidates (8/2009-7/2016). We estimated the association between pre-KT cognitive impairment and graft loss, using hybrid registry-augmented Cox regression to adjust for confounders precisely estimated in the Scientific Registry of Transplant Recipients (N=101,718). We compared the risk of graft loss between KT recipients with vs. without any cognitive impairment (3MS<80) and those with vs. without severe cognitive impairment (3MS<60), stratified by the type of transplant (living donor KT (LDKT) or deceased donor KT (DDKT)). We extrapolated estimates of the prevalence of any cognitive impairment and of severe cognitive impairment in the national kidney transplant recipient population using predictive mean matching and multiple imputation by chained equations.

Results: The prevalence of any cognitive impairment in this 864-patient multicenter cohort was 6.7% among LDKT recipients and 12.4% among DDKT recipients, extrapolating nationally to 8.1% among LDKT recipients and 13.8% of DDKT recipients. LDKT recipients with any cognitive impairment had higher graft loss risk than recipients without any cognitive impairment (5-year graft loss: 45.5% vs. 10.6%, p<0.01; aHR: _1.263.28_8.51, p=0.02); those with severe impairment had a risk of similar magnitude that was not statistically significant (_0.742.79_10.61, p=0.1). DDKT recipients with any cognitive impairment had no increase in graft loss vs. those without any cognitive impairment, but those with severe cognitive impairment had higher graft loss risk (5-year graft loss: 53.0% vs. 24.0%, p=0.04; aHR: _1.382.97_6.29, p<0.01). 

Conclusion: Cognitive impairment is common among both LDKT and DDKT recipients in the United States. Given these associations between cognitive impairment and graft loss, pre-KT screening for impairment is warranted to identify and more carefully follow higher-risk KT recipients.