Fracture diagnoses were based on ICD-9 CM Code. On a regular basis, the NHI Bureau randomly assigned senior orthopedic

surgeons to inspect the original contents of patients’ charts and ICD-9 CM Code to ensure the validity of ICD-9 CM Code. The inspectors do not have any conflict of interest with the patients’ hospitals. For these reasons, we infer that the validity of fracture diagnoses is very high. This study analyzed two outcomes: (a) annual mortality and standardized mortality ratio (SMR) after hip fractures; as well as (b) mortality and SMR at different time periods after hip click here fractures, and the effects of risk factors on survival. Time to death was defined as the duration from the index date to death. Subjects alive or lost to follow up were treated as censored. The comorbidities of a subject were retrieved before or at the time of the index date based on the Charlson Comorbidity Index (CCI) [30]. For each cohort year, we calculated the incidence as the number of inpatients

with hip fracture divided by the mid-population of that cohort year and stratified them by gender. We calculated the annual mortality as the number of death divided by the number of newly-diagnosed cases of that cohort year and stratified them by gender. We calculated follow-up mortality and SMR at different time periods (one-month to ten-year for mortality and one-year to ten-year for SMR) after fracture, and stratified them by age and gender. Follow-up mortality was estimated by using the Kaplan–Meier method. We compared hip fracture mortality with that of the general selleck population using annual and follow-up SMR. SMR was estimated based on the following definition: the number of deaths among inpatients with hip fracture divided by the expected number of death cases according to age-specific, sex-specific, and calendar-year-specific death rates obtained from the Taiwan national death registry. We compared the effects of risk factors such as age, gender, type of hip fracture, and number of comorbidities on survival using the log-rank test. All analyses were performed using the SAS System (version 9.2; SAS Institute, Cary, NC) and the

Statistical Package for the Social Sciences (version 10.0; SPSS Inc, Chicago, IL). Between 1999 and 2009, 143,595 subjects were Isotretinoin admitted for the first time with a primary diagnosis of hip fracture and underwent an operation. Among these patients, 56,403 (39.28%) were male, 87,192 (60.72%) were female, 69,882 had cervical fracture, and 73,713 had trochanteric fracture (Table 1). The annual incidence rate of hip fracture gradually increased from 405/100,000 to 471/100,000 from 1999 to 2005 (Table 2). Incidence then dropped to 446/100,000 in 2006 and fluctuated between 451/100,000 and 476/100,000 after 2006. From 1999 to 2009, the male-to-female ratio of annual incidence increased from 0.60 to 0.66, annual mortality rate of hip fracture gradually decreased from 18.10% to 13.