Trend, seasonality and geographical distribution of the incidence of hip fracture in an Health authority area of the Valencian Community (1994-2000)

Abstract

Background. Hip fracture incidence has been estimated in our country over short time periods without evaluating the changes in trend and seasonality over the course of time. This study is aimed at estimating hip fracture incidence in a Health District in the Autonomous Community of Valencia throughout a seven-year period (1994-2000), delving into its trend, seasonality and the geographical changes by health districts and whether a rural or urban population is involved. Methods. Descriptive study of the cases of HF among individuals over 45 years of age. The patients not residing within the District, the pathological fractures and those due to traffic accidents were not included. The time-related and geographical changes in the incidence were estimated by Poisson regression. Results. The overall incidence of hip fractures among individuals over 45 years of age was 274 cases/100000 inhabitants/year (CI 95% 259 - 288). The incidence among males was 149 cases/100,000 inhabitants/year; being 383 cases/100,000 inhabitants/year for females. The time-related distribution show a positive, although non-significant trend, with an average 0.04% monthly increase in the incidence. This trend was greater among males than among females. A clear seasonality, with relatively lower incidences during the spring and summer months, were found to exist. The incidences did not vary significantly among health districts nor by the type of urban or rural population involved. Conclusions. HF incidence is similar to although somewhat higher than that of other Spanish provinces. A discreet positive trend and a clear seasonality were found, without any significant geographical changes.