Anemia in cystic fibrosis: incidence, mechanisms, and association with pulmonary function and vitamin deficiency.

BACKGROUND Anemia is associated with increased morbidity and mortality in many chronic diseases. Little is known about anemia in cystic fibrosis (CF). Because the majority of patients with CF die of lung disease, the objective of this study was to identify the frequency, severity, and mechanisms of anemia in CF and to determine if there was an association between anemia and poor lung function in these patients. Vitamin deficiency was used to assess the association of malabsorption and anemia. METHODS Charts of 218 CF patients (ages >1 month to 61 years) were reviewed. Information extracted included medical history, complete blood counts, iron studies, pulmonary function tests, vitamin levels, serum creatinine levels, and medications. RESULTS As patients aged, anemia increased from 12% in those < 16 to 58.3% > or = age 40. Anemic patients had poorer lung function than nonanemic patients. Mean forced expiratory volume (FEV(1)) and forced vital capacity (FVC) were 51.6% (SEM +/- 10.3) and 69.7% (SEM +/- 9.3) in anemic and 82.5% (SEM +/- 9.2) and 95% (SEM +/- 8.3) in nonanemic patients, respectively (P < .001). Of vitamin-deficient patients, 90% were anemic whereas only 59.5% of nonvitamin-deficient patients were anemic (P = .02). Complete iron studies were only available in 17 of 48 anemic patients and 11 were diagnosed with iron deficiency. CONCLUSIONS Anemia in CF is associated with poor lung function and vitamin deficiency. Although anemia was often incompletely evaluated, iron deficiency was common. Recognition and complete evaluation of anemia might be important for continued improvement of care in CF.