No increased mortality risk in older persons with unexplained anaemia

BACKGROUND

in older persons, anaemia is associated with a number of unfavourable outcomes. In approximately 30% of older persons with anaemia, the cause of the anaemia is unexplained. We assessed the clinical differences between subjects with explained and unexplained anaemia and investigated whether these subjects have different mortality patterns compared with subjects without anaemia.

DESIGN

observational prospective follow-up study.

SETTING

the Leiden 85-plus study.

PARTICIPANTS

four hundred and ninety-one persons aged 86 years.

METHODS

the study population was divided in three groups: (i) no anaemia (reference group, n=377), (ii) explained anaemia (iron deficiency, folate deficiency, vitamin B12 deficiency, signs of myelodysplastic syndrome or renal failure, n=74) and (iii) unexplained anaemia, (n=40). Mortality risks were estimated with Cox-proportional hazard models.

RESULTS

haemoglobin levels were significantly lower in subjects with explained anaemia than in subjects with unexplained anaemia (P<0.01). An increased risk for mortality was observed in subjects with explained anaemia [HR: 1.93 (95% CI: 1.47-2.52), P<0.001], but not in subjects with unexplained anaemia [HR: 1.19 (95% CI: 0.85-1.69), P=0.31]. Adjusted analyses (sex, co-morbidity, MMSE, institutionalised and smoking) did not change the observed associations for both explained and unexplained anaemic subjects.

CONCLUSION

older subjects with unexplained anaemia had similar survival compared with non-anaemic subjects. Increased mortality risks were observed in subjects with explained anaemia compared with non-anaemic subjects.

Effect of cobalt supplementation on serum vitamin B12 levels, weight gain and survival rate in lambs grazing cobalt-deficient pastures

The effect of cobalt supplementation on serum vitamin B12, growth rate and survival rate was measured in controlled field experiments with Texel twin lambs of the same sex, grazing cobalt-deficient pastures. The non-supplemented lambs had lower serum vitamin B12 concentrations than their supplemented brothers or sisters. During the experiments more lambs died in the non-supplemented than in the supplemented group. At the end of the experiments supplemented lambs weighed (mean live weight) 7.2, 9.5, and 11.0 kg more than non-supplemented lambs in 1991, 1992, and 1993, respectively. Sex-related differences in weight gain and survival rate were observed.