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An updated hip fracture projection in Asia: The Asian Federation of Osteoporosis Societies study

Objectives Hip fracture is a major public health problem. Earlier studies projected that the total number of hip fracture will increase dramatically by 2050, and most of the hip fracture will occur in Asia. To date, only a few studies provided the updated projection, and none of them focused on the hip fracture projection in Asia. Thus, it is essential to provide the most up to date prediction of hip fracture in Asia, and to evaluate the total direct medical cost of hip fracture in Asia. Methods We provide the updated projection of hip fracture in 9 Asian Federation of Osteoporosis Societies members using the most updated incidence rate and projected population size. Results We show that the number of hip fracture will increase from 1,124,060 in 2018 to 2,563,488 in 2050, a 2.28-fold increase. This increase is mainly due to the changes on the population demographics, especially in China and India, which have the largest population size. The direct cost of hip fracture will increase from 9.5 billion United State dollar (USD) in 2018 to 15 billion USD in 2050, resulting a 1.59-fold increase. A 2%–3% decrease in incidence rate of hip fracture annually is required to keep the total number of hip fracture constant over time. Conclusions The results show that hip fracture remains a key public health issue in Asia, despite the available of better diagnosis, treatment, and prevention of fracture over the recent years. Healthcare policy in Asia should be aimed to reduce the burden of hip fracture.


Introduction
Osteoporotic fracture is a major public health problem that is known to be associated with increased dependency, morbidity, and mortality. Among all osteoporotic fracture, hip fracture incurs the greatest morbidity, mortality, and costs. Studies by Cooper et al. [1] and Gullberg et al. [2] in 1990s projected that approximately 4.50e6.26 million of hip fractures will occur worldwide by 2050, where half of them will occur in Asia. Thus, a huge effort, including improve diagnosis and medications, various fracture prevention programmes, and research, has been undertaken to reduce the incidence of fracture worldwide.
Multiple studies have shown that incidence of hip fracture has been stabilized or reduced slightly in many countries or cities, such as Spain [3], Japan [4], United States [5], France [6], Taiwan [7], and Hong Kong [8]. However, this might not be the case for some countries, such as China [9,10] and Korea [11,12]. On the other hand, life expectancy worldwide has increased by 5 years in the last 15 years, according to the World Health Organization [13]. This implies that the total number of hip fracture may be continue to rise with the changing demographics, despite the decrease in the incidence of hip fracture reported in some countries. Therefore, we aim to provide the best estimate of hip fracture in Asia using the most updated information, and to evaluate the total direct medical cost of hip fracture in Asia.

Data sources
Data on incidence rate of hip fracture was obtained from 9 Asian Federation of Osteoporosis Societies (AFOS) members, including China [14,15], Hong Kong [16], India [17], Japan [18,19], Korea [20], Malaysia [21], Singapore [21], Taiwan [22,23], and Thailand [24] (Table 1). For Taiwan, we noted that a large difference in the incidence of hip fracture were estimated by two studies, due to Chie et al. [22] and Wang et al. [23] used International Classification of Diseases (ICD), 9th revision (ICD-9) of 820.XX (proximal femur fracture) and 820.XX to 821.XX (other femur fracture) to define hip fracture, respectively. To be conservative, we included both studies in the estimation of the total number of hip fracture. Only publications using nationwide or big databank that provided age-specific incidence of hip fracture between ages 50 and 80 years were included. Such decision provides a more accurate projection and accounts for a more realistic impact on total numbers of hip fractures due to change in the population demographics. Since 2 sets of hip fracture data were available for China, Japan, and Taiwan, the mean of the two estimates was used.
Similarly, direct costs of hip fracture were obtained from publications and available government data (    Hong Kong [26], India [27], Japan [28], Korea [13], Malaysia [27], Singapore [29], Taiwan [30], and Thailand [31]. The projection of direct medical cost was calculated assuming there was no secular change in incidence of hip fracture and unit cost.

Statistical analysis
For ease of comparison, we provided the incidences of hip fracture based on the following stratified age groups: 50e54, 55e59, 60e64, 65e69, 70e74, 75e79, and 80 years. In cases where published data included incidence of hip fracture for age groups beyond 80 years (e.g., 80e84, 85e89, and 90 years), the incidence of hip fracture for the group 80 years was estimated based on the population structure of the study populations in the study year.
Projections for hip fractures was done in the year of 2025, 2030, 2035, 2040, 2045, and 2050 based on the most recent available sexand age-specific incidence of hip fracture and the predicted population size in these years by the Worldbank (available at http:// www.worldbank.org/), except the predicted population size of Taiwan was from the United Nations (http://data.un.org/Default. aspx), since such data was unavailable in the Worldbank. We multiplied the incidence of hip fracture for each of the 5-year age groups for each sex by the predicted number of population in each group to calculate the projected total numbers of hip fractures. The same method was used to calculate the projected direct medical cost. The projected total number of hip fracture was further estimated assuming 1%, 2%, and 3% increase or decrease of incidence rate in involved AFOS members since the study year of the published data in the respective country or region.

Results
We identified hip fracture incidence in 9 AFOS members that were suitable for analysis. The total population of 9 AFOS members in 2018 was 3.19 billion, which accounts for 70.3% and 42.0% of the Asia and World population, respectively. Table 1 shows the incidences of hip fracture based on previously published data in 9 AFOS members, graph showing the difference in hip fracture incidence between the countries is provided as Fig. 1.
Assuming there was no substantial change in hip fracture incidence since the study year, the projected number of hip fracture in the study areas will be 1.12 million in 2018, and it will reach 2.56 million by 2050 (Table 3), equivalent to 2.28-fold increase when compared to 2018. Malaysia and Japan are projected to have the highest (3.55 fold) and the lowest (1.36 fold) increase in the total number of hip fractures by 2050, respectively. The absolute number increase in projected hip fracture in 2050 will be 0.515 million in male, 0.925 million in female, and 1.44 million in overall population for all AFOS members. The increase will be mainly contributed by China (0.681 millions) and India (0.460 millions), which explains 79% of the total increase.
Assuming there is a 1%, 2%, and 3% increase in hip fracture incidence annually calculated from the study year, the total numbers of hip fractures are expected to reach 3.8, 5.6, and 8.3 million in 2050, respectively (Table 4). On the other hand, if there were a 1%, 2%, and 3% decrease in hip fracture incidence annually since the study year, the total number of hip fractures will then be 1.7, 1.2, and 0.77 million, respectively (Table 5).
For the direct medical cost of hip fractures, the projected cost in 2018 will be USD 9.5 billion, and the projected cost increasing to USD 15 billion by 2050.

Discussion
The current study projected that the total number of hip fractures in the studied Asian countries or geographic regions will increase from 1.12 million in 2018 to 2.56 million in 2050. Similarly, the direct medical cost will increase from USD 9.5 billion in 2018 to USD 15 billion in 2050.
Cooper et al. [1] and Gullberg et al. [2] projected that the total numbers of hip fractures in Asia by 2050 will be 3.25 million and 2.02 million (45% of the total numbers of hip fractures), respectively. Thus, Asia has long been regarded as a "high risk" region with the highest increase in hip fracture number. The projections made by Cooper and Gullberg were only based on incidence data obtained from 1 to 3 countries in Asia and had been outdated since over 20 years had passed after the article had been published. Using the most updated incidence rate and projected population size, our estimation shows that the total number of hip fracture in 9 Asian countries or regions would reach 2.56 million. Notably, this number will be greater if the whole Asia is included in the projection. For instance, if the hip fracture incidence rate for remaining parts of Asia is assumed to be similar to that in 9 AFOS member countries or regions, the total number of hip fracture occurrences would be estimated to about 3.66 million, which is more than that projected by Cooper and Gullberg.
The increase in total number of hip fracture is expected to be highest in Malaysia and the lowest in Japan. According to the data from United Nations (http://data.un.org), the median age in Malaysia and Japan is 26.99 years and 45.53 years in 2012. Thus, the prevalence of hip fracture in Malaysia is expected to be lower than that in Japan. This also explains the greatest increase in total number of hip fracture is in Malaysia, while the lowest increase is expected to be in Japan, a country with the highest proportion of elderly citizens. China and India contribute to the highest absolute number increase in hip fracture, because these 2 countries have the highest population size. Indeed, these 2 countries constitute approximately 37% of the world population. Thus, hip fracture is expected to be a huge burden for Asia. Hip fracture is not only a personal medical issue, but it affects the family, the whole community and by extension the whole nation. The current study estimated that the direct medical cost in 2018 reaches USD 9.5 billion, and the cost will escalate to USD 15 billion by 2050. The increase in direct medical cost in 2050 (1.59 fold) is lower than the increase in number of hip fractures in 2050 (2.28 fold; Table 3). This is due to the direct medical costs of hip fracture for the countries with the highest increase in the number of hip fracture (China and India) are generally lower (Table 2); whereas Japan, the country with the highest direct medical cost, has the lowest increment in the number of hip fractures by 2050 (Table 3). It should be noted that given the burgeoning economic development in China and India, it is expected that the direct medical cost will increase over time. Thus, the projected direct cost from these countries would be underestimated.
It is alarming that the projected number of hip fracture remains very high, even though a great effort in diagnosis, fracture prevention, and research has been undertaken. With the estimation in Table 5, the main target in Asia is to reduce the annual incidence of hip fracture by 2%e3% each year, in order to stabilize the total number of hip fracture over time. To achieve this goal, various stakeholders, including patients, patient families, healthcare professionals, and governments, need to be actively involved. There could be 10 recommendations for the goal-attaining strategy. First, Asian governments should make more resources available for the management of osteoporosis. AFOS has published a declaration on osteoporosis in Asia [32], which is a big step forward to galvanise the stakeholders to focus on the size of osteoporotic fracture and its impact on the populations. This would not only raise the awareness for the health professionals, but also national health policy makers for resource allocation and effective programs to reduce future fractures. Second, increase public awareness of osteoporosis and reduce primary osteoporotic fracture. Third, fall prevention by improving public awareness of its risk factor, such as sarcopenia.  Predicted change in population demographics are included in the calculations, with the number of hip fracture estimated based on the increase in each of the age group for the different countries. Fourth, reducing re-fracture rate by promoting fracture liaison services (FLSs) [33]. Fifth, early detection of osteoporosis by bone densitometry screening under the trained professionals. Sixth, promote the proper use of antiosteoporosis drug with adequate adherence, which is currently underuse. Seventh, use of generic drug as the first line regimen if considering the cost of treatment. Eighth, nationwide reimbursement of FLS should be encouraged. Ninth, supportive patient group and volunteer in promoting osteoporosis prevention and treatment. Tenth, international cooperation should be enhanced to advance the osteoporosis management.
There are several strengths in the study. The last projection or modelling for the number of hip fractures in Asia was more than 20 years ago, thus, using the recent available information of age-and sex-specific incidence of hip fractures provide a more accurate estimate. Second, the study was conducted by the investigators from the 11 Asian regions or countries (members of the AFOS), thus the study represented the current situation and perspective from these Asian regions. Nevertheless, there are limitations. There were only a point incidence of fractures, therefore secular changes in incidence of hip fracture were not accounted for in the current study, and the changes in the total number of fractures are merely based on the changes in population demographics. In addition, the predicted medical cost was estimated based on data published years ago, therefore it was not accounted for the changes in medical cost as well. However, a recent Korean study [13] showing that the average treatment cost decreased slightly by 2% from 2007 (USD 1520.7) to 2011 (USD 1490.1). Therefore, it is expected that the medical cost should not have big changes over time in developed countries.
In conclusion, the number of hip fracture is expected to increase substantially between 2018 and 2050 based on predicted changes in population demographics in Asian countries. Furthermore, more than USD 10 billion will be spent on the direct medical cost of hip fracture each year in Asia by 2050, assuming the cost of hip fracture treatment is unchanged. These data should make reduction of hip fracture being considered as a top health priority in Asian countries, so as to reduce the burden to the individual and healthcare system.

Conflicts of interest
No potential conflict of interest relevant to this article was reported.