‘Screen and Treat for Anaemia Reduction (STAR)’ strategy: study protocol of a cluster randomised trial in rural Telangana, India

Haemoglobin diagnostic cut-offs for anaemia in Indian women of reproductive age

BACKGROUND

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.

METHOD

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.

RESULTS

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).

CONCLUSION

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.

Childhood and Adolescent Anemia Burden in India: The Way Forward

The burden of anemia in Indian children, based on capillary blood sampling, is believed to be profound and worsening (67.1%) according to the successive National Family Health Surveys (NFHS). This might be an overestimate. The recent Comprehensive National Nutrition Survey of Indian children, that used venous blood sampling, found only less than half (30.7%) the NFHS prevalence, of which only one third was due to iron deficiency (ID). Unfortunately, the apparently worsening NFHS anemia burden estimate has been interpreted as an inadequacy of the present iron supplementation policy. This has led to additional iron supply through mandatory rice fortification. However, the lack of efficacy of iron supplementation appears inevitable, if the true prevalence of iron deficiency anemia is only about 10%. Thus, etiology is a critical consideration when devising appropriate and effective prevention policies. Future policies must focus on precision, thoughtfulness, restraint, and community engagement.