Hemoglobin concentration variations over time in general medical inpatients

A decrease in hemoglobin concentration [Hb] with no apparent cause is frequently observed in critically ill patients. Scarce information is available about this situation in general ward-admitted patients (GWAP).

To describe [Hb] variation with no obvious cause in GWAP, and to estimate the prevalence and predictors of patients with [Hb] decreases > or =1.5 g/dL.

Prospective, observational study in internal medicine GWAP, carried out at two teaching hospitals in Buenos Aires, Argentina. Patients with a history of, or admitted for diseases associated with decreases in [Hb], as well as those with length of stay less than three days, were excluded.

Upon hospitalization, complete personal and clinical data were recorded. Furthermore, Katz index, APACHE II acute physiology score (APS) and Charlson score were calculated. [Hb] and hematocrit (HCT) were also assessed during hospitalization.

A total of 338 patients were evaluated, 131 were included. A mean [Hb] decrease of 0.71 g/dL was observed between admission and discharge (P < 0.001; 95% CI, 0.47-0.97). Forty-five percent of the included patients had decreases in [Hb] > or = 1.5 g/dL. This was associated with a higher APS, a higher [Hb] at admission, and a discharge diagnosis of infectious or gastrointestinal disease. No bleeding episodes were observed.

An [Hb] decrease was frequently observed during GWAP hospitalization with no evident blood loss. Even though this decrease has multiple causes, the severity of the acute illness seems to play a major role.