Hip fractures in Finland between 1970 and 1997 and predictions for the future

Summary

Background

Hip fractures in elderly people are common worldwide, and the predicted ageing of populations is increasing the burden of these fractures on health-care systems. However, prediction of the true increases in number of patients needing treatment requires exact knowledge of whether the number of hip fractures is rising more rapidly than can be accounted for by demographic changes alone. We aimed to make such a prediction for people aged 50 years or more in Finland.

Methods

All patients aged 50 years or more, who were admitted to hospitals in Finland during 1970–97 for primary treatment of first hip fracture were selected from the National Hospital Discharge Register. The age-specific and age-adjusted fracture incidences were expressed as the number of patients per 100 000 individuals per year, and predicton of the number, and incidence of hip fractures in Finland (population 5 million) until the year 2030 was calculated with a regression model.

Findings

The number of hip fractures in Finnish people aged 50 or more rose during the study period, from 1857 in 1970 to 7122 in 1997. The corresponding fracture incidence (per 100 000 people) increased from 163 to 438. The age-adjusted incidence of hip fractures also showed a steady increase from 1970 to 1997: in women, from 292 to 467, and in men, from 112 to 233. If this trend continues, the number of hip fractures in Finland will be almost three-fold higher in the year 2030 than in 1997.

Interpretation

The number of hip fractures in elderly Finnish men and women is increasing at a rate that cannot be explained merely by demographic changes. The precise reasons for this are not known, but deterioration in ageadjusted bone-mineral density and strength, with accompanying increase in the age-adjusted incidence of injurious falls of the elderly, could partly account for the development.

Introduction

Hip fractures are a major public health burden, not only economically,1, 2 but also on the health of the elderly since hip fractures represent one of the most important causes of disability and death among this population.1, 2, 3 About half of previously independent elderly victims become partly dependent and ultimately a third totally dependent.1, 3, 4 Hip fractures also lead to an overall 12–20% reduction in expected survival with 5–20% excess mortality within the first year after the fracture.4, 5, 6

In the pathogenesis of hip and other osteoporotic fractures (such as fractures of the wrist, proximal humerus, spine, and pelvis), the falling of the older adult, the fall direction and mechanism, the protective neuromuscular responses, the impact of the fall, the energy absorption capacity or thickness of the soft tissues around the impact site, and degree of osteoporosis are the main determinants of fracture.1, 4, 7, 8 Falls, fall-related factors, and osteoporosis are not inevitable and allow possibilities for fracture prevention.1, 4, 8

The incidence of hip fractures increases exponentially with age, especially after age 60 years, and often shows a large country-to-country variation, and within a country, a large region-to-region variation.1, 4 It seems to be generally agreed that the absolute number and crude incidence of the hip fractures are rising in many countries in conjunction with ageing of the population.1, 2, 4, 9 However, very important for the prediction of the true increases in the number of patients requiring treatment for hip fracture in the new millennium is the exact knowledge whether the number of hip fractures is rising more rapidly than can be accounted for by demographic changes alone.2, 4, 9 For example, Hoffenberg and colleagues¹⁰ calculated that population ageing alone will increase the annual number of hip fractures in England and Wales by about 30% between 1985 and 2015, but if the age-adjusted and sex-adjusted incidence rates continue to rise as they did before 1985, then the increase in the number of hip fractures will be as high as 150%.

Many other previous epidemiological studies have indicated that the age-adjusted or age-standardised incidence of hip fracture rose between the 1950s and the 1980s.2, 4, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 But few reliable databases are available from the 1990s and there is no nationwide study investigating the current numbers, incidences, and secular trends of hip fractures, the database exceeding the year 1992. Therefore, we calculated trends in the absolute number of hip fractures and age-specific and age-adjusted hip fracture incidence rates in those 50 years and older in Finland between 1970 and 1997. Our hypothesis was that the number of hip fractures among elderly Finns is increasing at a rate that cannot be explained by demographic changes alone.