Very Low Rates of Hip Fracture in Beijing, People's Republic of China: The Beijing Osteoporosis Project

American Journal of Epidemiology, Nov 1996

One third of the world's hip fractures are said to occur in Asia, mostly in China. However, there have as yet been no validated studies of hip fracture rates in China. The authors estimated the incidence of hip fractures in Beijing, People's Republic of China, and took several steps to validate the estimates. Ail 76 Beijing hospitals reported ail 1988–1992 admissions that had been coded as 820 (hip fracture) or 821 (other femoral fracture) according to the International Classification of Diseases, Ninth Revision. The authors then compared a random sample of the reports with original medical records, and discovered that 70% of intertrochanteric hip fractures had been miscoded as “other femoral fractures.” The authors retrained all hospital staffs to provide corrected reports. Revised reports missed only 13% of the hip fracture cases recorded in operating room logs of 11 randomly selected hospitals. To validate hospital-based estimates of hip fracture rates, the authors interviewed a random sample of 2, 113 Beijing women aged 50 years or more (97% response rate); all but 4% of past fractures and all seven hip fractures had been treated in hospitals. Finally, the authors surveyed the 27 hospitals in the counties surrounding Beijing. No Beijing residents had been treated for hip fracture outside of the city. Based on the 1990 China census, age-standardized rates of hip fracture (per 100, 000) in Beijing—87 for women, 97 for men—were much lower than those seen in Hong Kong in 1985 (353 for women, 181 for men) or in US Caucasians (510–559 for women, 174–207 for men). From 1988 to 1992, the rates in Beijing increased 34% in women and 33% in men. The authors conclude that hip fracture rates in Beijing are among the lowest in the world but may be rising rapidly. Am J Epidemiol 1996; 144: 901-7.

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Very Low Rates of Hip Fracture in Beijing, People's Republic of China: The Beijing Osteoporosis Project

Am J Epidemiol Very Low Rates of Hip Fracture in Beijing, People's Republic of China The Beijing Osteoporosis Project 3 5 Xu Ling 2 3 5 Lu Aimin 1 3 5 Zhao Xihe 0 3 5 Chen Xiaoshu 0 3 5 Steven R. Cummings 3 5 0 Institute of Nutrition and Food Hygiene, Academy of Preventive Medicine , Beijing , People's Republic of China 1 Department of Medical Records, Peking Union Medical College Hospital , Beijing , People's Republic of China 2 Department of Obstetrics and Gynecology, Peking Union Med- ical College Hospital , Beijing , People's Republic of China 3 Received for publication July 5 , 1995, and in final form May 6, 1996. Abbreviation: ICD-9 , International Classification of Diseases , Ninth Revision 4 Departments of Medicine and Epidemiology and Biostatistics, School of Medicine, University of California , San Francisco, CA 5 Hip Fractures in Beijing , China One third of the world's hip fractures are said to occur in Asia, mostly in China. However, there have as yet been no validated studies of hip fracture rates in China. The authors estimated the incidence of hip fractures in Beijing, People's Republic of China, and took several steps to validate the estimates. All 76 Beijing hospitals reported all 198&-1992 admissions that had been coded as 820 (hip fracture) or 821 (other femoral fracture) according to the International Classification of Diseases, Ninth Revision. The authors then compared a random sample of the reports with original medical records, and discovered that 70% of intertrochanteric hip fractures had been miscoded as "other femoral fractures." The authors retrained all hospital staffs to provide corrected reports. Revised reports missed only 13% of the hip fracture cases recorded in operating room logs of 11 randomly selected hospitals. To validate hospital-based estimates of hip fracture rates, the authors interviewed a random sample of 2,113 Beijing women aged 50 years or more (97% response rate); all but 4 % of past fractures and all seven hip fractures had been treated in hospitals. Finally, the authors surveyed the 27 hospitals in the counties surrounding Beijing. No Beijing residents had been treated for hip fracture outside of the city. Based on the 1990 China census, age-standardized rates of hip fracture (per 100,000) in Beijing-87 for women, 97 for men-were much lower than those seen in Hong Kong in 1985 (353 for women, 181 for men) or in US Caucasians (510-559 for women, 174-207 for men). From 1988 to 1992, the rates in Beijing increased 34% in women and 33% in men. The authors conclude that hip fracture rates in Beijing are among the lowest in the world but may be rising rapidly. Am J Epidemiol 1996; 144:901-7. aged; Asiatic race; diagnosis; hip fractures; hospital records - Approximately one fourth of the world's population lives in the People's Republic of China. Cooper et al. (1) have estimated that one third of the world's hip fractures now occur in Asia and that a majority will occur there by the year 2050. However, these estimates are uncertain, because there have been no population-based studies of the rates of hip fracture in China, the largest country in Asia. Previous studies reported low rates in Singapore in 1960 (2) and low rates in Hong Kong in 1966 that appeared to more than double during the subsequent 20 years (3). It has been difficult to study rates of hip fracture in China, because the International Classification of Diseases, Ninth Revision (ICD-9) (4) system of coding of hospital discharge diagnoses was widely implemented there only recently, and it is not known how accurately hip fractures are being classified. Hospitals have not been required to report hip fractures to public health departments. In addition, it is not known how many hip fractures in China are treated by traditional bonesetters rather than in hospitals. We conducted a population-based study of the rates of hip fracture among men and women living in Beijing. Our study was designed to validate the hip fracture rates reported by hospitals and to assess potential biases that might affect accurate estimation of rates of hip fracture in China. MATERIALS AND METHODS Identification and validation of cases: overview We counted all hip fracture patients discharged between January 1, 1988, and December 31, 1992, from the 76 civilian and military hospitals that serve the 10 urban and suburban districts of Beijing. To find and validate cases of hip fracture, we first surveyed all Beijing hospitals. We then systematically considered potential sources of error in these initial hospital reports (table 1). First, we assessed the completeness of the reports by comparing them with original discharge logs in 34 hospitals. Second, we assessed the accuracy of the coding of cases in the discharge reports by comparing these reports with radiographic and operative reports in the medical records of the same 34 hospitals. Based on the findings of our validation study, we then retrained all medical-records perso (...truncated)


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Xu Ling, Lu Aimin, Zhao Xihe, Chen Xiaoshu, Steven R. Cummings. Very Low Rates of Hip Fracture in Beijing, People's Republic of China: The Beijing Osteoporosis Project, American Journal of Epidemiology, 1996, pp. 901-907, 144/9,