Can patient characteristics predict the outcome of endoscopic evaluation of iron deficiency anemia: a multiple logistic regression analysis

Gastrointest Endosc. 2004 Jun;59(7):766-71. doi: 10.1016/s0016-5107(04)00348-7.


Background: The purpose of this study was to identify clinical and biochemical variables that predict the outcome of upper/lower endoscopy in outpatients with iron deficiency anemia and to determine which endoscopic procedure should be performed first.

Methods: Ninety-eight patients (74 women, 24 men; mean age 55 years) with iron deficiency anemia referred from the hematology department were interviewed and responded to a questionnaire that included clinical and biochemical variables, and underwent EGD (with biopsies) and colonoscopy. The endoscopic findings were recorded as presence/absence of GI cancer, upper/lower GI tract lesions and bleeding/non-bleeding-associated GI lesions. A multiple logistic regression analysis was applied to identify variables significantly related with the outcome of the investigations. Multiple analyses were performed so that a Bonferroni correction for multiple testing removed significance except where p<0.01.

Results: A likely cause of iron deficiency anemia was found in 86.7% of patients. The risk factors for GI malignancies were: male gender (OR 7.5: 95% CI[1.7, 31.9]; p<0.01), advanced age (OR 1.1/y: 95% CI[1, 1.2]; p<0.01), and lower mean corpuscular volume (OR 1.1/unit: 95% CI[1, 1.2]; p<0.002). The risk factors for bleeding-related diseases were the following: greater age (OR 1.1/y: 95% CI[1.1, 1.2]; p<0.001), absence of lower-GI tract symptoms (OR 4.7: 95% CI[1.3, 16.6]; p<0.05), and a positive fecal occult blood test (OR 4.1: 95% CI[1.2, 14.3]; p<0.05). The risk factors for non-bleeding-related GI tract diseases were the following: negative fecal occult blood test (OR 4.5: 95% CI[1.16, 20]; p<0.05) and higher Hb level (OR 1.4/unit: 95% CI[1.1, 1.8]; p<0.05).

Conclusions: For non-hospitalized patients with iron deficiency anemia, colonoscopy should be the initial investigation in those greater than 50 years of age, particularly men, and those without upper-GI tract symptoms and with lower values for mean corpuscular volume and Hb. EGD should be performed first in younger patients, particularly those with a mild decrease in Hb and a negative fecal occult blood test.

MeSH terms

  • Age Factors
  • Anemia, Iron-Deficiency / blood
  • Anemia, Iron-Deficiency / etiology*
  • Biopsy
  • Colonoscopy
  • Duodenum / pathology
  • Endoscopy, Gastrointestinal*
  • Erythrocyte Indices
  • Female
  • Gastrointestinal Diseases / complications
  • Gastrointestinal Diseases / diagnosis
  • Gastrointestinal Hemorrhage / diagnosis*
  • Gastrointestinal Hemorrhage / etiology
  • Gastrointestinal Neoplasms / complications
  • Gastrointestinal Neoplasms / diagnosis*
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Occult Blood
  • Odds Ratio
  • Regression Analysis
  • Risk Factors
  • Stomach / pathology