Department of Clinical Sciences Malmö, Clinical and Molecular Osteoporosis Research Unit, Lund University, Malmö, Sweden.
Department of Geriatrics, Skåne University Hospital, Malmö, Sweden.
Nephron. 2020;144(6):290-298. doi: 10.1159/000507256. Epub 2020 May 11.
BACKGROUND/AIMS: Prospective data on age-related changes in kidney function are required, especially since the current Kidney Disease Improving Global Outcomes (KDIGO) definition has been suggested to classify a large number of elderly people with CKD.
This study, a complement to our previous Cr-based study in the same cohort, is aimed at evaluating cystatin C (cysC)-based changes in kidney function during aging in older women and analyzing the association between CKD and mortality through 10 years of follow-up.
cysC was available in 981 women from the Osteoporosis Prospective Risk Assessment (OPRA) cohort, all aged 75 years on entry. Reinvestigations were made after 5 (n = 685) and 10 years (n = 365). Kidney function was estimated (estimated glomerular filtration rate [eGFR]) using Chronic Kidney Disease Epidemiology Collaboration cysC and Caucasian, Asian, Pediatric, and Adult cysC equations and the change in function calculated. Women were staged equivalent to CKD stage 1, 2, 3a, or 3b-5 according to the KDIGO classification. Mortality risk was estimated for 5-year or 10-year follow-up time using Cox proportional hazard analyses (reference category, CKD stages 1 and 2).
Mortality risk for women with the worst kidney function (CKD stages 3b-5) increased during both 5-year follow-up times compared to that for women in stages 1 and 2 (age 75-80 years: adjusted Hazard Ratio [HRadj] 3.9, 95% confidence interval [CI] 2.3-6.5; age 80-85 years: HRadj 1.7, 95% CI 1.0-2.7). In contrast, women in stage 3a had increased risk only in the first 5-year follow-up (HRadj 1.7, 95% CI 1.0-3.0, age 75-80 years). Change in kidney function amounted to a loss of 1.9 (±1.4) mL/min/1.73 m2 per year during the 10-year follow-up, and at age 85 years, 4 of every 5 women had an eGFR equivalent to CKD.
In the future, an age-adapted definition of CKD, lowering the threshold for CKD in the elderly, may be beneficial to avoid overdiagnosis of CKD.
背景/目的：需要前瞻性数据来了解肾功能随年龄变化的情况，尤其是因为目前的肾脏病改善全球结局（KDIGO）定义被认为将大量老年慢性肾脏病（CKD）患者归类。
本研究是对我们之前在同一队列中基于 Cr 研究的补充，旨在评估老年女性中胱抑素 C（cysC）在肾功能随年龄变化中的作用，并通过 10 年随访分析 CKD 与死亡率之间的关系。
OPRA 队列中的 981 名女性年龄均为 75 岁，在入组时可获得 cysC 数据。在 5 年（n = 685）和 10 年（n = 365）时进行了复查。使用慢性肾脏病流行病学合作组 cysC 和高加索、亚洲、儿科和成人 cysC 方程估算（估算肾小球滤过率[eGFR]），并计算功能变化。根据 KDIGO 分类，女性按 CKD 1 期、2 期、3a 期或 3b-5 期分期。使用 Cox 比例风险分析（参考类别为 CKD 1 期和 2 期）估计 5 年或 10 年随访时间的死亡率风险。
与 CKD 1 期和 2 期的女性相比，肾功能最差（CKD 3b-5 期）的女性在 5 年随访期间死亡率风险增加（年龄 75-80 岁：调整后的风险比[HRadj]为 3.9，95%置信区间[CI]为 2.3-6.5；年龄 80-85 岁：HRadj 为 1.7，95%CI 为 1.0-2.7）。相反，仅在第一个 5 年随访中，3a 期女性的风险增加（HRadj 为 1.7，95%CI 为 1.0-3.0，年龄 75-80 岁）。在 10 年随访期间，肾功能下降了 1.9（±1.4）mL/min/1.73 m2/年，85 岁时，每 5 名女性中就有 4 名 eGFR 相当于 CKD。
未来，适应年龄的 CKD 定义，降低老年人 CKD 的门槛，可能有助于避免 CKD 的过度诊断。
