Influence of acute inflammation on iron and nutritional status indexes in older inpatients.

OBJECTIVE

To investigate the relations between acute inflammation, as shown by high C-reactive protein (CRP) serum levels, and laboratory indexes of iron and nutritional status and to ascertain whether the presence of acute inflammation affects the diagnostic reliability of these indexes.

DESIGN

Cross-sectional study.

SETTING

Geriatric ward for rehabilitation.

PARTICIPANTS

A total of 163 patients, 77 men and 86 women aged 60 years or older.

MEASUREMENTS

CRP values > 1 mg/dL were considered to indicate the presence of acute inflammation. Iron status was explored by measuring erythrocyte mean cell volume (MCV), hemoglobin (Hb), serum iron (Fe), TIBC, percent transferrin saturation (% TS) and ferritin (SF). Nutritional status was determined by albumin (Alb) and prealbumin (pre-Alb) serum levels.

MAIN RESULTS

In the whole series, CRP correlated significantly with all iron status variables except erythrocyte MCV (directly with SF, inversely with the others) and correlated inversely with Alb and pre-Alb. Mean values of iron status variables were significantly different in patients with inflammation and those without: SF was higher and the other variables lower. Patients with low % TS (< 16%) showed a pattern consistent with iron deficiency. Compared to the group with normal values, they had more severe anemia, lower MCV, Fe, and SF, and higher TIBC; mean Alb, pre-Alb, and CRP values were not significantly different. The prevalence of inflammation was 50% (39.5% in the group with normal % TS). A similar pattern was observed in patients with microcytosis (MCV < 84 fL) associated with low % TS; dividing this subgroup according to SF values (low, < 30 micrograms/L) did not provide more information because patients with acute inflammation were excluded.

CONCLUSIONS

Patients with acute inflammation present altered iron status indexes that resemble those observed in the anemia of chronic disease. Fe, TIBC and SF lose diagnostic value. The concomitant presence of microcytosis and low % TS, and to a lesser extent the presence of one of these alterations, is suggestive of iron deficiency associated with inflammation and may warrant gastrointestinal tract investigations and ferrous salt treatment. Protein-calorie malnutrition seems to enhance the effects of inflammation on iron status indexes.