Original Article

Osteoporosis International

, Volume 9, Issue 3, pp 242-253

First online:

International Variation in the Incidence of Hip Fractures: Cross-National Project on Osteoporosis for the World Health Organization Program for Research on Aging

  • A. V. SchwartzAffiliated withDivision of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California, USA
  • , J. L. KelseyAffiliated withDivision of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California, USA
  • , S. MaggiAffiliated withProgram on Aging, National Research Council (CNR), Padua, Italy (formerly at the World Health Organization Program for Research on Aging)
  • , M. TuttlemanAffiliated withDivision of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA (formerly at the Office of Prevention, Epidemiology, and Clinical Applications, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH)
  • , S. C. HoAffiliated withDepartment of Community and Family Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
  • , P. V. JónssonAffiliated withDepartment of Medicine, Reykjavik City Hospital, University of Iceland, Reykjavik, Iceland
  • , G. PoórAffiliated withDepartment for Rheumatology and Metabolic Bone and Joint Diseases, National Institute of Rheumatology and Physiotherapy, Budapest, Hungary
  • , J. A. Sisson de CastroAffiliated withDepartment of Internal Medicine and Endocrinology, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
  • , L. XuAffiliated withDepartment of Obstetrics and Gynecology, Peking Union Medical College Hospital, Beijing, People’s Republic of China
    • , C. C. MatkinAffiliated withDivision of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California, USA
    • , L. M. NelsonAffiliated withDivision of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California, USA
    • , S. P. HeyseAffiliated withDivision of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA (formerly at the Office of Prevention, Epidemiology, and Clinical Applications, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH)

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Abstract:

A cross-national study of hip fracture incidence was carried out in five geographic areas – Beijing, China; Budapest, Hungary; Hong Kong; Porto Alegre, Brazil; and Reykjavik, Iceland – during the years 1990–1992. Cases of hip fracture among women and men of age 20 years and older were identified using hospital discharge data in conjunction with medical records, operating room logs, and radiology logs. Estimated incidence rates varied widely, with Beijing reporting the lowest rates (age-adjusted rate per 100 000 population for men 20 years and older = 45.4; women = 39.6) and Reykjavik the highest rates (men = 141.3; women = 274.1). Rates were higher for women than for men in every area except Beijing. In every area except Budapest, review of the operating room or radiology logs identified additional cases that were not reported in the discharge list, increasing the estimated number of hip fractures by 11% to 62%, depending on the area. Review of medical records identified miscoding of hip fractures (ICD9 820) as ‘shaft of femur and other femur fractures’ (ICD9 821) in the discharge lists of every area except Budapest, increasing the estimated number of hip fractures by 1% to 30%. The final estimates of hip fracture incidence taking into account all investigated sources of undercount and overcount ranged from 15% lower to 89% higher than an estimate based on the discharge diagnoses alone. Although these results indicate substantial limitations in relying on hospital discharge data alone to estimate hip fracture incidence rates, the extent of errors found in the discharge lists is smaller than the large international variation found here and previously reported in incidence rates. The findings support the conclusion that the differences reported among countries mainly reflect genuine variation in the hip fracture incidence rates.

Key words:Hip fracture – Hospital discharge data – Incidence rates – International comparison – Osteoporosis