INCREASED RATE OF FRACTURES AND SEVERE KYPHOSIS - SEQUELAE OF LIVING INTO ADULTHOOD WITH CYSTIC-FIBROSIS

Background: Osteoporosis occurs in patients with cystic fibrosis as th ey age, but its clinical implications are not well defined. Objective: To determine the clinical effect of decreased bone mineral density in adults with cystic fibrosis and to assess possible clinical predictor s of osteoporosis. Design: Retrospective cohort study. Setting: Academ ic cystic fibrosis center. Patients: 70 adults with late-stage cystic fibrosis who were referred for lung transplantation. Measurements: Bon e mineral density was measured with dual-energy x-ray absorptiometry, patient-reported fracture events were confirmed by radiography, and ky phosis angles were measured by using the Cobb method. Results: Mean bo ne mineral densities for the spine, femur, and total body were severel y depressed in patients with cystic fibrosis, averaging 2 SDs below th ose of age-matched normal controls (P < 0.001). Patient interviews sho wed that 54 fractures had occurred over 1410 patient-years, and chest radiographs showed evidence of 14 additional rib and 62 additional ver tebral compression fractures. The database (which covered 1410 patient -years) showed that fracture rates were approximately twofold greater in women with cystic fibrosis aged 16 to 34 years (P = 0.015) and men with cystic fibrosis aged 25 to 45 years (P = 0.04) than in the genera l population. Vertebral compression and rib fractures were 100- and 10 -fold more common than expected, respectively (P < 0.001 for both comp arisons). The mean kyphosis angle (+/-SD) for this group was markedly abnormal (44 +/- 14 degrees; 62% greater than or equal to 40 degrees) and probably contributed to diminished stature (mean height loss, 5.8 cm in men with cystic fibrosis and 5.9 cm in women with cystic fibrosi s). Cumulative prednisone dose, body mass index, and age at puberty we re the strongest predictors of bone mineral density. Conclusions: Oste oporosis is universal in adults with late-stage cystic fibrosis, and i ts complications include increased fracture rates and severe kyphosis.