Anaemia among subjects with chronic renal insufficiency

Sir, We read with interest the report by Jungers et al. [1] in the September issue of NDT. The authors compared their results with our earlier publication [2]. Jungers et al. stated that ‘With respect to the influence of gender, our observations are in agreement with data from the USRDS registry report, with a higher proportion of anaemia in female patients [6], but at variance with those of Hsu et al. [3], who report that at any given level of renal function men had a larger decrease in Hct (haematocrit) than women.’ We would like to clarify that although we found that the drop in haematocrit is larger in women than men for every decrement in creatinine clearance (CrCl), because men started with a higher haematocrit, the absolute haematocrit is still higher among men at any given CrCl. Our results have since been reproduced using a nationally representative, non-referral sample [3]. Jungers et al. also stated that we ‘did not provide the mean values of Hct with respect to the various degrees of renal dysfunction.’ While this is true, these can be inferred easily. For example, the mean haematocrit of all the women in our study was 38.7% (Table 1 in reference [2]). Since the majority of our study subjects had normal renal function, 38.7% is close to the haematocrit of our reference group (CrCl )80 mlumin). In a population with mean age of 49 years and 27% blacks (what was observed), the mean haematocrit of women with CrCl 20–30 mlumin can be estimated to be (38.7 2.9) %s35.8%. In a similar manner, the mean haematocrit values for all other gender and CrCl combinations can be derived from the multivariate regression coefficients provided in Table 2 of reference [2]. It is clear that anaemia is common among patients with chronic renal insufficiency. Further studies, however, are needed to define the most appropriate therapeutic response [4].