Mortality among Male Veterans with Hip Fractures

摘要

Objective: To study the mortality rate among male veterans with hip fractures. Methods: This is a retrospective observational study of all male veterans who were admitted to one of the 7 Veterans Affairs (VA) Medical Centers of the Great Lakes Health Care System during the period from January 1st, 1998 to Dec 30th, 2000 with an International Classification of Diseases (ICD)-9 code of a hip fracture. Demographic, medical and mortality data were abstracted from the VA electronic medical records by a trained abstractor. Patients were followed until May 1st, 2002 (follow up period from 4 to 40 months). Descriptive statistics were used to describe population demographics. Mortality rates were estimated using the Kaplan & Meier product-limit method. One-year mortality ratio was calculated based on the U.S. life table for men. Student's t-test was used to compare two independent population means. The Taylor's approximation for the variance of a ratio method was used to compare the one year morality rate among subjects in this study to that reported among male patients with hip fractures who were not treated in the VA system. Results: A total of 226 subjects were included in the study. Subjects' age ranged between 56 and 106 years (mean + SD = 79+9 years). By the end of the follow up period, 94 subjects have died (42%). Using the Kaplan & Meier product-limit method, the estimated proportion + SD surviving at 6 months was .77+.03 (mortality rate of 23%), at one year was .71+.03 (mortality rate of 29%), at 2 years was .66+.03 (mortality rate of 34%), and at 3 years was .57+.04 (mortality rate of 43%). Median duration to death was (M+SD) 326.6+37 days (range 1-1194 days). The mortality ratio of subjects at 1 year compared to that of men aged 79 years (which was equal to the mean age of subjects) from the U.S. life table for men was 4.4 (95% CI 3.32 to 5.48). In addition, the mortality rate among subjects in this study was significantly greater than that reported men with hip fractures who were not treated in the VA system. The mean age + SD (at time of hospital admission for an acute hip fracture) of subjects who died was greater than those who did not (82+9 vs. 77+ 9, p<.001).Conclusion: Male veterans with hip fractures had excess mortality compared to U.S. men in general as well as to other men with hip fractures who were not treated in the VA system. Further work is needed to identify possible causes for this observation and to test interventions aimed at minimizing mortality and morbidity among male veterans who sustain hip fractures. Osteoporosis formerly thought of as a disease of women, has recently gained recognition as an important public health issue in men. Approximately 30% of hip fractures occur in men aged 65 years or older. The incidence of hip fracture begins to increase when men reach their late 60s, and it parallels the increase that begins in women in their early 60s.1 The estimated lifetime risk of hip fracture in a 50-year-old Caucasian man is 11% compared with a 23% risk for a 50-year-old woman, based on predicted mortality.2 Hip fractures have been linked to increased mortality. In a study of 300 elderly patients with hip fractures, Sexson and Lehner reported a one year mortality rate of 12.7% in patients who were cognitively intact.4 Magaziner and colleagues reported three months, six months, and one year mortality rates of 8.2%, 12.6%, and 17.4%, respectively, in a series of 814 home-dwelling hip fracture patients.5 Aharonoff and others followed 612 elderly patients who sustained a non-pathologic hip fracture and reported one year mortality rate of 12.7%.6 Male sex has been reported to be an independent risk factor for increased mortality after hip fracture.5,6,8 An Australian study reported an age standardized mortality rate one year after hip fracture of 2.18 (95% CI 2.03-2.32) for women and 3.17 (2.9-3.44) for men.9 Only a small body of the literature addressed hip fractures among male veterans. Our prior work