title: Predictive value of anemia for tuberculosis in HIV-infected patients in Sub-Saharan Africa: an indication for routine microbiological investigation using new rapid assays.
abstract: BACKGROUND
  The relationship between anemia and undiagnosed tuberculosis (TB) in patients living with HIV in sub-Saharan Africa is incompletely defined. We assessed the prevalence of TB among those with HIV-related anemia and evaluated new means of rapid TB diagnosis.
  
  
  METHODS
  Blood hemoglobin levels were measured in unselected antiretroviral treatment-naive patients in Cape Town, South Africa, and anemia was classified according to World Health Organization criteria. All patients were screened for TB by testing paired sputum samples using liquid culture (reference standard), fluorescence microscopy, and Xpert MTB/RIF. Urine samples were tested for lipoarabinomannan (LAM) using the Determine TB-LAM diagnostic assay.
  
  
  RESULTS
  Of 602 adults screened, 485 had complete results. Normal hemoglobin levels were found in 44.5% (n = 216) of patients, and mild, moderate, or severe anemia were present in 24.9% (n = 121), 25.4% (n = 123) and 5.2% (n = 25) of patients, respectively. Culture-confirmed pulmonary TB was diagnosed in 8.8% (19/216) of those without anemia compared with 16.5% (20/121), 26.0% (32/123), and 40.0% (10/25) among those with mild, moderate, or severe anemia, respectively (P < 0.001). Anemia was a strong independent predictor of TB. The sensitivities of diagnostic assays were much higher among those with moderate/severe anemia compared with those with no/mild anemia using sputum microscopy (42.9% vs 15.4%), urine LAM (54.8% vs 0%), sputum microscopy plus urine LAM (71.4% vs 15.4%), and sputum Xpert (73.8% vs 41.0%) (P < 0.01 for all).
  
  
  CONCLUSIONS
  A very high prevalence of undiagnosed TB was found in patients with moderate or severe anemia. Such patients should be prioritized for routine microbiological investigation using rapid diagnostic assays.
authors.affiliation: *School of Medicine and Health Sciences, The George Washington University, Washington, DC; †Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; and ‡Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Kerkhoff
authors.forename: Robin
authors.initials: R
authors.lastname: Wood
authors.forename: Monica
authors.initials: M
authors.lastname: Vogt
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Lawn
mesh_terms: D000328:Adult; D000349:Africa; D000740:Anemia / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008070:Lipopolysaccharides / Q000652:urine; D008297:Male; D011247:Pregnancy; D015995:Prevalence; D013019:South Africa / Q000453:epidemiology; D013183:Sputum / Q000382:microbiology; D014376:Tuberculosis / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D006454:Hemoglobins; D008070:Lipopolysaccharides; C050016:lipoarabinomannan