Anemia typically develops late in the course of iron deficiency; therefore, patients who are iron deficient but do not yet have anemia are not routinely examined for gastrointestinal bleeding. In these patients, the cause of the iron deficiency is usually unknown. Joosten and associates conducted a prospective study to determine the diagnostic value of upper and lower gastrointestinal tract examination in elderly patients who are iron deficient.

All patients older than 70 years of age with iron deficiency who were admitted to a geriatric department during a 30-month period were prospectively enrolled. Patients were screened with a serum ferritin level at admission. Iron deficiency was defined as a serum ferritin level of less than 50 ng per mL (50 mg per L). Patients were considered anemic if their hemoglobin level was less than 13 g per dL (130 g per L) in men or less than 12 g per dL (120 g per L) in women. Those with a known or obvious cause of blood loss were excluded from the study. Any history of gastrointestinal symptoms or use of nonsteroidal anti-inflammatory drugs (NSAIDs) was recorded. Routine blood studies, a fecal occult blood test and endoscopy of the upper gastrointestinal tract were performed on all patients. When possible, patients were categorized by one of the following causes of blood loss: esophagitis, erosive gastritis, duodenitis, gastric or peptic ulcer, or cancer. Colonoscopy was offered to all patients, with barium enema as an alternative. Lower gastrointestinal causes of bleeding included polyps, inflammatory lesions, vascular lesions and cancer.

Of the 267 patients eligible for the study, 151 were included in the analysis. More than one half of the patients (64 percent) had anemia in addition to iron deficiency. About one half of these patients (49 percent with anemia, 56 percent without) had upper gastrointestinal lesions as well. Erosive gastritis or duodenitis were most common in the latter group. Twenty-three percent of patients with a benign upper gastrointestinal lesion also had a lesion in the colon. Most of the latter were polyps or cancerous lesions. Approximately 60 percent of patients with lesions had no gastrointestinal symptoms. Use of NSAIDs and positive results on a fecal occult blood test were not necessarily predictive of a lesion that could cause blood loss. Similarly, lesions occurred in both sets of patients who were iron deficient, regardless of whether they had anemia.

The authors conclude that a gastrointestinal work-up should be recommended in elderly patients who are iron deficient, regardless of their hemoglobin level.