Association between renal function and memory-related disease: evidence from the China Health and Retirement Longitudinal Study

Previous studies have reported that renal function is associated brain structure and cognitive dysfunction. However, the association between renal function and memory-related disease was not well characterized. Altogether, 5,282 individuals were included in this study based on China Longitudinal Study of Health and Retirement. Four estimated glomerular filtration rate indicators (eGFR), including CG, CKD-EPIscr, CKD-EPIscr-cys, and CKD-EPIcys were used to evaluate the association between renal function and memory-related disease. The multivariable-adjusted HRs (95% CIs) of the memory-related disease in the low eGFR group (eGFR 2) were 1.56 (1.13–2.16) for CG, 1.56 (1.19–2.06) for CKD-EPIscr, 1.45 (1.06–1.99) for CKD-EPIscr-cys and 1.27 (0.91–1.77) for CKD-EPIcys, respectively. Similarly, each SD increase of eGFR was associated with reduced risk of memory-related disease on continuous analyses. Subgroup analyses further confirmed these associations. Moreover, the addition of eGFR to conventional risk factors improved the predictive power for memory-related disease (net reclassification improvement: 13.90% for CG, 19.83% for CKD-EPIscr and 30.65% for CKD-EPIscr-cys). In conclusion, impaired renal function was associated with the increasing risk of memory-related disease, indicating that renal function may be a potential indicator for memory-related disease. Further studies from other races and populations are needed to replicate our findings and to clarify the potential mechanisms.既往研究已证实，肾功能与脑结构及认知功能障碍存在关联。然而，肾功能与记忆相关疾病之间的关联尚未得到充分阐明。本研究基于中国健康与养老追踪调查（China Longitudinal Study of Health and Retirement），共纳入5282名研究对象。本研究采用四种估算肾小球滤过率（estimated glomerular filtration rate, eGFR）指标，即CG、CKD-EPIscr、CKD-EPIscr-cys及CKD-EPIcys，用以评估肾功能与记忆相关疾病的关联。低eGFR组（eGFR分层2）中，记忆相关疾病的多变量校正风险比（Hazard Ratio, HR）及95%置信区间（Confidence Interval, CI）分别为：CG指标对应1.56（1.13~2.16）、CKD-EPIscr对应1.56（1.19~2.06）、CKD-EPIscr-cys对应1.45（1.06~1.99）、CKD-EPIcys对应1.27（0.91~1.77）。同样，在连续性分析中，eGFR每增加1个标准差（standard deviation, SD），记忆相关疾病的发病风险均有所降低。亚组分析进一步验证了上述关联。此外，将eGFR加入传统危险因素模型后，记忆相关疾病的预测效能得到提升（净重新分类改善率：CG组为13.90%，CKD-EPIscr组为19.83%，CKD-EPIscr-cys组为30.65%）。综上，肾功能受损与记忆相关疾病的发病风险升高存在关联，提示肾功能或可成为记忆相关疾病的潜在预测指标。未来仍需在其他种族及人群中开展研究，以重复本研究结论并阐明其潜在机制。