St. John's Medical College, Sarjapur Road, Bengaluru, Karnataka, 560 034, India.
ICMR-National Institute of Nutrition, Jamai-Osmania, Hyderabad, Telangana, 500007, India.
Eur J Clin Nutr. 2023 Oct;77(10):966-971. doi: 10.1038/s41430-023-01308-5. Epub 2023 Aug 3.
The persistent high prevalence of anaemia among Indian women of reproductive age (WRA) despite aggressive long-term iron supplementation could be related to over-diagnosis from an inappropriately high haemoglobin (Hb) diagnostic cut-off. To develop an appropriate cut-off for Indian WRA, we hypothesized that during iron-folic acid (IFA) supplementation to a mixed (anaemic/non-anaemic) WRA population, the positive slope of the Hb-plasma ferritin (PF) response in anaemic women would inflect into a plateau (zero-response) as a non-anaemic status is reached. The 2.5th percentile of the Hb distribution at this inflection point will be the diagnostic Hb cut-off for iron-responsive anaemia.
A hierarchical mixed effects model, with a polynomial mean and variance model to account for intraclass correlation due to repeated measures, was used to estimate the response curve of Hb to PF, or body iron stores, in anaemic and non-anaemic WRA (without inflammation), who were receiving a 90-day IFA supplementation.
The Hb response curve at low PF values showed a steep increase, which inflected into a plateau at a PF of 10.1 µg/L and attained a steady state at a PF of 20.6 µg/L. The Hb distribution at the inflection was a normal probability distribution, with a mean of 12.3 g/dL. The 2.5th percentile value of this distribution, or the putative diagnostic Hb cut-off for anaemia, was 10.8 g/dL (~11 g/dL).
The derived Hb cut-off is lower than the current adult values of 12 g/dL and could partly explain the persistently high prevalence of anaemia.
尽管长期积极补铁，印度育龄妇女（WRA）的贫血患病率仍然居高不下，这可能与血红蛋白（Hb）诊断截止值过高导致过度诊断有关。为了为印度 WRA 制定合适的诊断截止值，我们假设在向混合（贫血/非贫血）WRA 人群补充铁叶酸（IFA）时，贫血女性的 Hb-血浆铁蛋白（PF）反应的正斜率在达到非贫血状态时会变为平坦（无反应）。在这个拐点处，Hb 分布的第 2.5 个百分位数将是缺铁性贫血的诊断 Hb 截止值。
使用分层混合效应模型，采用多项式均值和方差模型来解释由于重复测量引起的类内相关性，估计贫血和非贫血（无炎症）WRA 接受 90 天 IFA 补充时，Hb 对 PF 或体铁储存的反应曲线。
低 PF 值时的 Hb 反应曲线呈陡峭上升，在 PF 值为 10.1 µg/L 时变为平坦，在 PF 值为 20.6 µg/L 时达到稳定状态。拐点处的 Hb 分布呈正态概率分布，均值为 12.3 g/dL。该分布的第 2.5 个百分位数值，即假设的贫血诊断 Hb 截止值为 10.8 g/dL（~11 g/dL）。
得出的 Hb 截止值低于当前成人值 12 g/dL，这可能部分解释了贫血患病率居高不下的原因。
