Elsevier

Bone

Volume 53, Issue 2, April 2013, Pages 430-436
Bone

Original Full Length Article
Osteoporotic hip fractures: Bisphosphonates sales and observed turning point in trend. A population-based retrospective study

https://doi.org/10.1016/j.bone.2012.12.014Get rights and content

Abstract

The aim is to examine the temporal trends of hip fracture incidence in Portugal by sex and age groups, and explore the relation with anti-osteoporotic medication.

From the National Hospital Discharge Database, we selected from 1st January 2000 to 31st December 2008, 77,083 hospital admissions (77.4% women) caused by osteoporotic hip fractures (low energy, patients over 49 years-age), with diagnosis codes 820.x of ICD 9-CM. The 2001 Portuguese population was used as standard to calculate direct age-standardized incidence rates (ASIR) (100,000 inhabitants). Generalized additive and linear models were used to evaluate and quantify temporal trends of age specific rates (AR), by sex.

We identified 2003 as a turning point in the trend of ASIR of hip fractures in women. After 2003, the ASIR in women decreased on average by 10.3 cases/100,000 inhabitants, 95% CI (− 15.7 to − 4.8), per 100,000 anti-osteoporotic medication packages sold. For women aged 65–69 and 75–79 we identified the same turning point. However, for women aged over 80, the year 2004 marked a change in the trend, from an increase to a decrease. Among the population aged 70–74 a linear decrease of incidence rate (95% CI) was observed in both sexes, higher for women: − 28.0% (− 36.2 to − 19.5) change vs − 18.8%, (− 32.6 to − 2.3).

The abrupt turning point in the trend of ASIR of hip fractures in women is compatible with an intervention, such as a medication. The trends were different according to gender and age group, but compatible with the pattern of bisphosphonates sales.

Highlights

► Identification of a turning point, compatible with an intervention on osteoporotic hip fracture incidence rates, nationwide. ► Identification of different trend patterns of osteoporotic hip fracture incidence rates by sex and age-groups. ► Identification of bisphosphonates as plausible intervention related to the abrupt decrease in the osteoporotic hip fracture incidence rates trend.

Introduction

Identifying and understanding trends of hip fracture incidence is important, not only as a way for planning future medical resources and treating patients but also in planning effective preventive measures [1]. Costs related to hip fractures are not only restricted to hospitalization but also to the long recovery time and assistance that these patients require [2], [3]. Public health interventions can be taken using knowledge gathered from epidemiologic studies using secondary data. These studies can provide valuable information with the use of reliable data on a national basis [4], [5].

The bone quality impairment is associated to aging and elevates the risk of osteoporotic fractures, particularly in post-menopausal women. Furthermore, an excessive pathologic decrease in bone strength can be prevented either by the use of medicaments or by changing activity and nutritional behaviour [6]. Osteoporotic hip fractures are more common among women over the age of 49 years and grows exponentially with aging. With the increase of life expectancy the range of population at risk is considerable, enhancing the need to analyze trends by age groups. In 2008, life expectancy at age 65 in the European Union (27 member states) was 17.2 and 20.7 years for males and females respectively [7]. In Portugal, the same indicator with data from 2009 to 2011 was 16.9 and 20.2 respectively (last available data) [7], [8]. Moreover, the elderly form the fastest growing age group in most western countries thus aggravating the burden of osteoporosis.

In Portugal there are no national studies addressing the trend of hip fractures. However, internationally several studies have been conducted reporting trends of age-standardized incidence rates of hip fractures [1]. Nevertheless the results are not consensual: increasing, decreasing and stable trends have been reported, which may reflect different stages in the epidemic curve. The results regarding the shape of the trends as well an existing pattern in men have also differ. Studies in Finland [9] and Australia [10], [11] have reported rates of hip fractures compatible with a non-linear trend. However in Finland the decrease pattern was observed in both genders, whereas in Australia only women presented a decreasing pattern. Rates presenting linear decreases have been reported by studies in Belgium [12], Denmark [13], Canada [14], United States [15] for both genders and Spain just for women [16]. Unique causes are impossible to assess, nevertheless studies have pointed out different plausible reasons, according to their results, namely medication for osteoporosis [10], [11], [16] or other interventions [13], [14].

It is important to explore time trends of age-standardized incidence rates of hip fractures although they may hide different underlying trends by age groups thus leading to incorrect conclusions. And since hip fractures affect a wide range of ages, these studies may help uncover unequal patterns and meaningful associations with the preventive procedures undertaken by different countries.

The aim of this work is to examine the temporal trends of hip fracture incidence in Portugal by sex and age group, and explore its relation with anti-osteoporotic medication.

Section snippets

Study area

The study area was Continental Portugal with a population of 10,135,309 inhabitants in 2008. In 2000 there were 3,298,922 inhabitants aged 50 years or over, increasing by 11.9% in 2008 (n = 3,691,104) [8], in contrast with a decrease of − 0.6% in the population aged under 50 in the same period.

Data

Population data was the annual official estimates, per sex and 5-year age groups, except for 2001, which was a census year.

We used data from the National Hospital Discharge Register (NHDR). The use of this

Results

During the study period we identified 77,083 hip fractures, 77.4% in women (mean age (standard deviation (SD)) at admission 81.1 (SD 8.5) years old versus 78.3 (SD 10.1) and (p-value < 0.0001) for women and men respectively. Table 1 shows number of admissions and mean age at admission, according to the year of admission whereas Table 2 shows the ASIR and age-specific rates during the period of study.

The age groups where the smooth function of time was statistically significant, indicating a

Discussion

In this population-based retrospective study, the year 2003 appeared as a turning point in the time trend of age-standardized incidence rate (ASIR) of hip fracture in women. The observed trend from 2000 to 2008 with a clear and abrupt decrease change in 2003, is compatible with an intervention on national level. When analysing by sex, the anti-osteoporotic medication packages sold, in each of the years within the study period, had the same impact on the trend of ASIR for women, with the same

Disclosure statement

All authors declare no competing interest.

Role of funding source

The funder Foundation for Science and Technology has no role in this paper.

Acknowledgements

This work was financed byFEDER funds through the Programa Operacional Factores de Competitividade — COMPETE and by Portuguese funds through FCT — Fundação para a Ciência e a Tecnologia within the framework of the project PEst-C/SAU/LA0002/2011 and by PTDC/SAU-EPI/113424/2009 grant and SFRH/BD/40978/2007 fellowship.

We would like to acknowledge the Central Administration of Health Services (ACSS) for the data from the National Hospital Discharge Register, and National Authority of Medicines and

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