Hemoglobin concentration variations over time in general medical inpatients

Abstract

BACKGROUND: 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). OBJECTIVES: 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. DESIGN, SETTING AND PATIENTS: 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. MEASUREMENTS: 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. RESULTS: 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. CONCLUSIONS: 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.