Prevalence and Incidence of Osteoporosis and Osteoporotic Vertebral Fracture in Korea Nationwide Epidemiological Study Focusing on Differences in Socioeconomic Status

EPIDEMIOLOGY

Sung Bae Park, MD, PhD, Jayeun Kim, PhD,y Je Hoon Jeong, MD,z Jung-Kil Lee, MD, PhD,§ Dong Kyu Chin, MD, PhD,{ Chun Kee Chung, MD, PhD,jj Sang Hyung Lee, MD, PhD, and Jin Yong Lee, MD, PhD#

Results. In 2012, the standardized prevalence of OP in the Study Design. A cross-national study. NHI and MA groups was 3968 and 6927 per 100,000, Objective. To determine the prevalence and incidence of respectively (odds ratio, 3.83). The standardized incidence of osteoporosis (OP) and osteoporotic vertebral fracture (OVF) in OP in the MA group was significantly higher than in the NHI Korea and to investigate if socioeconomic status has an effect. group in 2011 and 2012 (odds ratios, 2.34 and 2.19, respect- Summary of Background Data. As life expectancy increases, ively). In addition, the standardized incidence of OVF in the MA OP and related fragility fractures are also increasing. This group in 2011 and 2012 was 408 and 389 per 100,000, presents a serious challenge, not only for health authorities but respectively, and the incidence in the MA group was signifi- also for individuals, their families, and society overall. Determin- cantly higher than in the NHI group (odds ratios, 4.13 and 4.12, ing the prevalence and incidence of OP and related fragility respectively; P < 0.001). fractures is the first step in developing strategies to reduce their Conclusion. We confirmed that the prevalence and incidence increasing disease burdens. Concurrently, we need to confirm of OP and OVF in the MA group were higher than those in the whether people with low socioeconomic status are more NHI group. It showed that low income might be a significant susceptible to these diseases. factor related to OP and OVF. Methods. Using the Health Insurance Review and Assessment Key words: fracture, incidence, osteoporosis, prevalence, Service (HIRA) database from 2008 to 2012, we estimated the socioeconomic status, vertebrae. annual prevalence and incidence of OP and OVF and investi- Level of Evidence: 3 gated the differences according to socioeconomic status by Spine 2016;41:328–336 National Health Insurance (NHI) beneficiaries and Medical Aid (MA) recipients.

t has been estimated that more than 200 million people From the Department of Neurosurgery, Seoul National University Boramae suffer from osteoporosis (OP) across the world1; 27.5 Medical Center, Seoul, Korea; yInstitute of Health and Environment, Seoul National University, Seoul, Korea; zDepartment of Neurosurgery, Soon- million people (22 million women and 5.5 million men) § I 2 3 chunhyang University Bucheon Hospital, Bucheon, Korea; Department of in Europe and at least 10 million in the United States have Neurosurgery, Chonnam National University Research Institute of Medical suffered from OP. OP should be considered a major public Sciences, Chonnam National University Hospital & Medical School, Gwangju, Korea; {Department of Neurosurgery, Yongdong Severance Spine health concern because its prevalence is continuously esca- Hospital, Yonsei University College of Medicine, Seoul, Korea; lating as a result of an increase in the elderly population, and jjDepartment of Neurosurgery, Seoul National University College of Medi- # it is closely associated with fragility fractures, which com- cine, Seoul, Korea; and Public Health Medical Service, Seoul National 1 University Boramae Medical Center, Seoul, Korea. monly occur in the spine, wrist, or hip. For example, in the Acknowledgment date: June 5, 2015. First revision date: August 7, 2015. European Union, it has been estimated that the number of Acceptance date: August 20, 2015. osteoporotic fractures was 3.79 million in 2000 and that 3.5 1,2 The manuscript submitted does not contain information about medical million new fragility fractures were sustained in 2010. device(s)/drug(s). As life expectancy increases, OP and related fragility The Korea Healthcare Technology R&D Project, Ministry for Health and fractures will also increase. This presents a serious chal- Welfare, Republic of Korea (HI10C2020) grant funds were received in support of this work. lenge, not only for health authorities but also for individ- Address correspondence and reprint requests to Jin Y. Lee, MD, PhD, Public uals, their families, and society overall. OP and related Health Medical Service, Seoul National University Boramae Medical fragility fractures have a serious impact on people’s health Center, 20 Boramae-ro 5-gil, Dongjak-gu, Seoul 156–707 Korea; E-mail: and quality of life because they can result in chronic pain, [email protected] morbidity (long-term disability), and mortality.4–7 Accord- DOI: 10.1097/BRS.0000000000001291 ing to the results from the Global Burden of Disease study, 328 www.spinejournal.com February 2016 Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. EPIDEMIOLOGY Osteoporosis and Osteoporotic Vertebral Fracture in Korea Park et al

musculoskeletal disorders including OP and fragility All types of healthcare organizations and facilities in fractures ranked as the second largest cause of disability Korea must submit medical claim data to the Health Insur- estimated by the years lost due to disability worldwide.8 ance Review and Assessment Service (HIRA) to receive Furthermore, we should pay more attention to the possib- reimbursement after seeing a Korean patient. HIRA is a ility that socioeconomic status can affect the epidemiology Korean government agency responsible for conducting of OP and related fragility fractures or vice versa because reviews of medical claim data and evaluating the appropri- poverty could be related to osteoporotic fracture, infection, ateness of medical benefits submitted by healthcare organ- and obesity.9,10 If people with low socioeconomic status are izations. Therefore, HIRA accumulates all medical records more susceptible to these diseases, the economic impact on based on medical claim data submitted by medical facili- their families would be more serious than in other groups. ties.15 For example, HIRA gathered 1.3 billion of medical Even if the same medical bills are charged, the proportion of claims from 45.8 million Korean citizens in 2011. the medical costs to the total family income would be higher Finally, the HIRA database from 2008 to 2012 was used in low-income families. to determine the annual prevalence and incidence of OP Korea is one of the most rapidly aging countries; and OVF, and to investigate the differences according to the proportion of the elderly (aged 65) will increase to socioeconomic status. 24.4% (11.7 million) by 2030 and approach 38.8% (15.6 million) in 2050.11 The number of patients with Definition of Diagnosing Osteoporosis OP and related fractures in Korea will increase continu- In Korea, the diagnosis of OP relies on the quantitative ously, and the social and economic burden due to these assessment of bone mineral density (BMD) in the lumbar diseases in the future will also grow rapidly.12 The first step vertebrae or femoral neck. The World Health Organization to deal with this problem effectively and efficiently is working group proposed that osteoporosis should be diag- to determine the prevalence and incidence of OP and nosed in epidemiologic studies when BMD is 2.5 standard related fractures. To do so, we can confirm the size of deviations or more below the mean for healthy young adult problem (i.e., how many people have already had the women in the spine, hip, or wrist (corresponding to a T score diseases and how many people will develop the diseases). 2.5).16 Therefore, after clinicians measure the BMD of Among OP-related fragility fractures, osteoporotic patients, they register information about the patients who vertebral fracture (OVF) tends to occur before other major are diagnosed with osteoporosis, according to the World OP-related fragility fractures, such as hip fractures. There- Health Organization guideline, into the medical system. The fore, it can be used as a single indicator to represent other medical information about the patients with OP is sent and OP-related fragility fractures.13 saved to the HIRA database in Korea. For these reasons, we conducted this study to determine the prevalence and incidence of OP and OVF in Korea from Patient Selection Process 2008 to 2012, and investigated if socioeconomic status Using the HIRA database to access data from 2008 to 2012, affects the prevalence and incidence. we extracted the annual data of patients who had been treated for OP or OVF. In this study, a patient with OP refers MATERIALS AND METHODS to a person who had at least one of the diagnostic codes including M810, M818, M819, M800, M808, or M809, Data Source based on the International Classification of Diseases, 10th Every Korean citizen is covered by the obligated universal Revision (ICD-10). In addition, a patient with OVF refers to healthcare system from birth to death; either National one of the following two cases: one is the case where a Health Insurance (NHI) or Medical Aid (MA). As of person who was diagnosed with at least one of the following 2008, among the entire 51,842,366 (100.0%) members ICD-10 codes: M800, M808, or M809; and the other is the of the Korean population, 50,001,027 (96.4%) were NHI case where a person was diagnosed with at least one of the beneficiaries and 1,841,339 (3.6%) were MA recipients.14 following ICD-10 codes: M810, M818, or M819, and also NHI is operated by NHI premiums gathered from benefi- diagnosed with one of these ICD-10 codes: S220, S221, or ciaries and government subsides. MA is only an option for S32 at the same time (Table 1). members of the Korean population who are unable to pay the NHI premium (e.g., low-income families), which is a Operational Definition of Prevalence and Incidence very similar system to Medicaid in the United States. The of OP and OVF MA system is operated with taxes; the recipients are According to the definition from MeSH (Medical Subject exempted from the premiums and utilize healthcare organ- Headings), prevalence refers to ‘‘The total number of cases izations free of charge or with a reduced amount of medical of a given disease in a specified population at a designated fees. Even though there is secondary or private insurance in time (http://www.ncbi.nlm.nih.gov/mesh/68015995).’’ We Korea, their roles are very limited; NHI and MA cover most adopted period prevalence (usually in the past 12 months) of the medical expenses and private insurance only takes the instead of point prevalence or lifetime prevalence because role of reducing the deductible or out-of-pocket fees, or the the annual prevalence is more applicable to the HIRA costs of services not covered by NHI. database and easily interpretable to changes in time series. Spine www.spinejournal.com 329 Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. EPIDEMIOLOGY Osteoporosis and Osteoporotic Vertebral Fracture in Korea Park et al

TABLE 1. Diagnostic Codes and Their Related Descriptions Used in this Study 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 Value < < < < < < < < According to ICD-10 P P P P P P P P P Code Description M800 Postmenopausal osteoporosis with pathologic fracture ice through the year 2011–2012. M808 Osteoporotic compression fracture, other osteo- 95% CI porosis with pathologic fracture, senile osteoporosis with pathologic fracture M809 Osteoporosis with pathologic fracture y

M810 Postmenopausal osteoporosis tistical Office and the information of Odds M818 Other osteoporosis, secondary osteoporosis, Ratio senile osteoporosis, transient osteoporosis M819 Male osteoporosis, osteoporosis, osteoporosis

spine nce Review & Assessment Serv S220 Bursting fracture of thoracic spine, chance — — fracture of thoracic spine, compression frac- No.

ture of thoracic spine, fracture and dis- Standardized location of thoracic spine, fracture of thoracic spine S221 Compression fracture of multiple thoracic spine, multiple fracture of thoracic spine (96.8) (97.1) ormation Service in the Korea National Sta ance Service, Health Insura N(%)

S32 Bursting fracture of lumbar spine, compression 49,299,165 49,662,097 fracture of lumbar spine, compression fracture re. of multiple lumbar spine, compression fracture of sacral spine, fracture and dislocation of

lumbar spine, fracture of coccyx, fracture of — — lumbar apophysis, fracture of lumbar spine, No.

fracture of lumbar spine, fracture of lumbosa- Standardized

cral spine, multiple fractures of lumbar spine om the Korean Statistical Inf and pelvis ICD-10, International Classification of Disease, 10th Revision. OVF, osteoporotic vertebral fractu N(%)

Incidence is defined by MeSH as ‘‘The number of new cases 1,609,481 (3.2) 1,507,044 (2.9)

of a given disease during a given period in a specified popu- Yearbook published by the National Health Insur lation (http://www.ncbi.nlm.nih.gov/mesh/68015994).’’ We — —

adopted the concept of the annual incidence, which is the No.

number of new cases of OP or OVF within 1 year by each ard population in the year 2012 fr Standardized consecutive year. In this study, annual incidence rates of OP and OVF in 2011 and 2012 were only calculated to obtain an Total MA NHI

accurate incidence rate. That is, we established the washing- Health Insurance; OP, osteoporosis; out period from 2008 to 2010. Therefore, for example, the (100.0) (100.0) incidence rate of OP in 2011 means the proportion of patients who were first diagnosed in 2011 without any treatment or

diagnosis history of OP from 2008 to 2010; and the incidence was calculated using the stand rate in 2012 means the proportion of newly diagnosed 2012 117,346 232 12,956 389 104,390 224 4.12 4.04–4.20 2012 588,377 1165 36,203 1628 552,174 1150 2.19 2.17–2.21 2012 243,054 481 30,377 849 212,677 458 4.78 4.73–4.84 2012 2,018,236 4120 197,865 6927 1,883,371 3968 3.83 3.82–3.85 20112012 50,908,646 51,169,141 patients in 2012 without any records from 2008 to 2011. nce was based on the Health Insurance Statistical In this article, prevalence and incidence were calculated two ways; resulting in crude numbers and standardized numbers. Crude prevalence or crude incidence means the OVF 2011 118,541 247 14,013 408 104,528 237 4.13 4.06–4.21 calculation results without any adjustment, whereas stand- OVF 2011 230,296 480 30,862 846 199,434 454 4.81 4.76–4.87 ardized prevalence or standardized incidence means the calculation results after adjusting for sex and age. To do ized number per 100,000 population

so, population data from the Korea National Statistics Summary of Prevalence andPopulation) Incidence of OP and OVF by the Type of Health Insurance (Standardized Per 100,000 Office and information on subpopulations grouped by the type of health insurance were obtained from the Health Insurance Statistical Yearbook published by the National

Health Insurance Service. Values from the HIRA database population by type ofinsurance health TABLE 2. The overall standard Odds ratios were calculated using the total number of each population grouped by the type of health insurance. Incidence OP 2011 658,952 1352 46,010 1936 612,942 1330 2.34 2.32–2.36 Prevalence OP 2011 2,018,437 4158 207,066 7037 1,811,371 3985 3.87 3.85–3.89 Variable Year N (%) The composition of the Korean CI indicates confidence interval; MA indicates Medical Aid; NHI, National y for 2008 to 2012 were used to yield the annual crude subpopulations grouped by the type of health insura

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TABLE 3. Prevalence of OP and OVF From 2008 to 2012 in Korea Variable Crude Prevalence Standardized Prevalence Disease Year Populations Total Male Female Total Male Female OP 2008 Total 1,648,043 157,410 1,490,633 3850 772 6941 NHI beneficiaries 1,443,726 134,008 1,309,718 3644 698 6603 MA recipients 204,317 23,402 180,915 6637 2280 11,013 2009 Total 1,821,722 185,367 1,636,405 4091 863 7332 NHI beneficiaries 1,609,632 159,898 1,449,734 3880 786 6988 MA recipients 212,140 25,469 186,671 7224 2520 11,947 2010 Total 1,961,831 204,725 1,757,106 4186 894 7491 NHI beneficiaries 1,755,226 179,082 1,576,144 4014 825 7216 MA recipients 206,605 25,643 180,962 6926 2470 11,400 2011 Total 2,018,437 213,983 1,804,454 4158 894 7436 NHI beneficiaries 1,811,371 188,066 1,623,305 3985 826 7158 MA recipients 207,066 25,917 181,149 7037 2,485 11,608 2012 Total 2,018,236 218,788 1,862,448 4120 864 7389 NHI beneficiaries 1,883,371 193,702 1,689,669 3968 803 7145 MA recipients 197,865 25,086 172,779 6927 2427 11,447 OVF 2008 Total 204,763 20,595 184,168 492 103 881 NHI beneficiaries 171,333 17,424 153,909 457 94 823 MA recipients 33,430 3171 30,259 889 294 1487 2009 Total 217,526 22,445 195,081 499 106 893 NHI beneficiaries 184,146 19,217 164,929 465 97 835 MA recipients 33,380 3228 30,152 926 303 1552 2010 Total 233,078 204,725 208,289 505 110 903 NHI beneficiaries 200,460 21,546 178,914 478 101 856 MA recipients 32,618 3243 29,375 880 295 1467 2011 Total 230,296 25,141 205,155 480 106 855 NHI beneficiaries 199,434 22,066 177,368 454 98 811 MA recipients 30,862 3075 27,787 846 278 1417 2012 Total 243,054 26,897 216,157 481 106 858 NHI beneficiaries 212,677 23,800 188,877 458 99 819 MA recipients 30,377 3097 27,280 849 279 1421 MA indicates Medical Aid; NHI, National Health Insurance; OP, osteoporosis; OVF, osteoporotic vertebral fracture. The overall standardized number per 100,000 population was calculated using the standard population in the year 2012 from the Korean Statistical Information Service in the Korea National Statistical Office and the information of subpopulations grouped by the type of health insurance was based on the Health Insurance Statistical Yearbook published by the National Health Insurance Service, Health Insurance Review & Assessment Service through the year 2008–2012.

prevalence and incidence rates. In addition, all prevalence examine the difference in utilization patterns of medical and incidence rates were standardized by sex and age using institutions and the difference in the possibility of under- these two datasets and finally computed as the annual going surgery because of OVF, according to types of health number per 100,000 of the population. We evaluated the insurance coverage (NHI vs. MA). All analyses were per- difference in medical utilization according to the type of formed using SAS Enterprise Guide (SAS Institute, Inc., health insurance in 2011 and 2012. The types of medical Cary, NC) and figure descriptions were conducted using institutions comprised tertiary teaching hospitals, general R 3.1.1 (The Comprehensive R Archive Network: http:// hospitals, hospitals, and clinics. We compared the number cran.r-project.org). All statistical tests were two-sided and of surgeries performed in the NHI and MA groups. results with P < 0.05 were considered significant. Ethics Statement Statistical Analysis This study was exempted from approval by the institutional Frequency analyses were conducted to describe the distri- review board (IRB No. 07–2014–7). bution of prevalence and incidence of OP and OVF from 2008 to 2012 (only 2011 and 2012 in the case of incidence). RESULTS We calculated odds ratios to identify the relative risk of prevalence and incidence in MA recipients compared with Prevalence NHI beneficiaries. In addition, 95% confidence intervals As of 2012, there were 2,018,236 persons with OP and were calculated. Pearson’s chi-square test was performed to 243,054 persons with OVF in Korea, which represented Spine www.spinejournal.com 331 Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. EPIDEMIOLOGY Osteoporosis and Osteoporotic Vertebral Fracture in Korea Park et al

Figure 1. Crude prevalence of osteoporosis and osteoporotic vertebral fracture by sex and age group from 2008 to 2012 in Korea. 3.94% and 0.48%, respectively, of the entire Korean popu- OP and OVF, respectively, compared with NHI beneficia- lation (51,169,141). After adjusting for age and sex, the ries (P < 0.0001) (Table 2). standardized prevalence of OP and OVF was estimated to be The standardized prevalence of OP per 100,000 4120 and 481 per 100,000 of the population, respectively. increased from 3850 to 4120 over the 5-year period, In particular, the prevalence of OP and OVF was much whereas the prevalence for OVF has stabilized to around higher in people with a low socioeconomic status; MA 480 to 500 for the same period. MA recipients had a higher recipients had a 3.83 times and 4.78 times higher risk of prevalence than NHI beneficiaries (Table 3).

Figure 2. Standardized prevalence of osteoporosis and osteoporotic vertebral fracture by the type of health insurance from 2008 to 2012 in Korea.

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TABLE 4. Incidence of OP and OVF in 2011 and 2012 According to the Type of Insurance in Korea Variable Crude Incidence Standardized Incidence Disease Year Populations Total Male Female Total Male Female OP 2011 Total 658,952 119,266 539,686 1352 497 2211 NHI beneficiaries 612,942 108,136 504,806 1330 473 2191 MA recipients 46,010 11,130 34,880 1936 1107 2769 2012 Total 588,377 112,102 476,275 1162 443 1890 NHI beneficiaries 552,174 102,422 449,752 1150 424 1880 MA recipients 36,203 9680 26,523 1628 980 2279 OVF 2011 Total 118,541 17,310 101,231 247 73 421 NHI beneficiaries 104,528 15,370 89,158 237 69 406 MA recipients 14,013 1940 12,073 408 173 644 2012 Total 117,346 17,768 99,578 232 70 395 NHI beneficiaries 104,390 15,870 88,520 224 66 382 MA recipients 12,956 1898 11,058 389 172 608 MA indicates Medical Aid; NHI, National Health Insurance; OP, osteoporosis; OVF, osteoporotic vertebral fracture. The overall standardized number per 100,000 population was calculated using the standard population in the year 2012 from the Korean Statistical Information Service in the Korea National Statistical Office and the information of sub-populations grouped by the type of health insurance was based on the Health Insurance Statistical Yearbook published by the National Health Insurance Service, Health Insurance Review & Assessment Service through the year 2011–2012.

The crude prevalence of OP and OVF has been increasing difference in the possibility of receiving an operation for 5 years, regardless of sex and age. In men, the prevalence between the NHI (18.1%) and MA (17.8%) groups in of OP and OVF was highest in the 70s age group, whereas in 2011 (P ¼ 0.37) (Table 5). females, the prevalence of OP was highest in the 60s age group and OVF was highest in the 70s age group (Figure 1); DISCUSSION however, after standardizing the date, female MA recipients From the results, the prevalence and incidence of OP and OVF in the 70s age group had the highest prevalence of OP, among MA recipients were significantly higher than those of whereas female MA recipients in the 80s age group had the NHI beneficiaries. We believe that our study provides more highest prevalence of OVF (Figure 2). accurate information about the prevalence and incidence of OP and OVF in Korea, even though there have been several Incidence epidemiological studies regarding OP and related fragility As of 2012, there were 588,377 persons (1165 per 100,000) fractures conducted in Korea.5,7,13,17 Firstly, we used NHI newly diagnosed with OP in Korea; the incidence in the MA data containing the whole medical records of the entire group was 36,203 persons (1628) and in the NHI group it Korean population (about 50 million people) from 2008 to was 552,174 persons (1150). MA recipients were two times 2012. Secondly, we established 3-year washing-out periods to more likely to suffer from OP than NHI beneficiaries calculate more accurate incidence rates. Lastly, no previous (P < 0.0001). In 2012, 117,346 persons (232) were newly study has investigated the differences in the prevalence and diagnosed with OVF in Korea; the incidence in the MA incidence of OP and OVF according to socioeconomic status group was 12,956 persons (389), and in the NHI group it using a national database. was 104,390 persons (224). MA recipients were four times There have been three studies regarding descriptive epi- more likely to suffer from OVF than NHI beneficiaries demiology of OP and OP-related vertebral fracture in (P < 0.0001) (Table 2). Korea.5,12,13 Comparing our results and the three related The data showed that females in the MA group had the studies, two studies showed that prevalence of OP increased highest incidence rates for OP and OVF (Table 4). Female by older age, lower education level, lower monthly income, MA recipients in the 60s age group had the highest incidence and residence in a rural area.5,13 Similarly, the present study of OP, whereas female MA recipients in the 80s age group also showed that the socioeconomic status might be a had the highest incidence of OVF (Figure 3). significant factor related OP and OVF. Nevertheless, the order of the prevalence of OP according The Difference in Medical Utilization According to to age group was different. In our study, the order of the Socioeconomic Status standardized prevalence of OP was 70s, 80s, 60s, and then MA recipients with OP and OVF were less likely to utilize the 50s age groups and the highest age group in the male and tertiary teaching hospitals than NHI beneficiaries female groups were the 80s and 60s age groups, respectively. (P < 0.0001). Instead, the proportion utilizing general hos- These results can mean that OP in males might be mainly pitals was higher for the MA group than the NHI group; influenced by aging and OP in females might be mainly however, there was no difference in utilizing hospitals and influenced by menopause. Because we used the entire clinics between the NHI and MA groups. There was no medical records in HIRA, whereas the other two studies Spine www.spinejournal.com 333 Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. EPIDEMIOLOGY Osteoporosis and Osteoporotic Vertebral Fracture in Korea Park et al

Figure 3. Standardized incidence of osteoporosis and osteoporotic vertebral fracture by the type of health insurance from 2008 to 2012 in Korea. used sampled and self-reported data, Korean National fractures,13 the incidence in the present study was lower. Health and Nutrition Examination Survey, the present study This difference could result from the difference in calculat- could be more accurate and precise compared with other ing the incidence. two studies. Compared with one study that used the HIRA In addition, there are many risk factors affecting OP and database in calculating the incidence of OP-related vertebral associated fragility fractures such as age, sex, geographical

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region, race, lifestyle, bone quality, and medical history.6,18–20 One study evaluated 1139 ambulatory post- Value 0.0001 0.0001 menopausal women aged 50 years or older to establish an < < P association between poverty and OP-related fracture.9 In this study, MA recipients (as an indicator of low socio-

2 economic status) had a significantly higher prevalence of X OP and incidence of OVF per 100,000 people than those in the NHI group. Therefore, early identification of increased risk for OVF and preventive or therapeutic intervention of OP in MA recipients might succeed in suppressing the increased prevalence of OP and incidence of OVF. Previous studies have reported that the mean age of occurrence of OVF was earlier than that of femoral neck fracture13,21,22; however, in the present study, the prevalence and incidence of OVF in people in their 80s was higher than in other age groups. This study had several limitations. First, patients with asymptomatic OVF might not visit medical institutions in Korea. For this reason, the incidence and prevalence of OVF might have been underestimated. In this study, we used national data obtained from HIRA. If a patient with Value NHI (%) MA (%) 0.0001 60,079 (10.9) 1489 (4.1) 1935.14 0.0001 8888 (8.5) 338 (2.6) 802.76 OVF was only registered as having OP, the number of < < P patients with OVF might also have been underestimated in this study; however, because we evaluated the entire

2 population of South Korea using the HIRA data set, the X results of the present study might provide the best representation of the incidence of OP and OVF. Second, a possible critique of this study is that comparing MA (very poor families) and NHI (everyone else) recipients is a crude

2011 2012 measure of socioeconomic status. Even though this type of comparison is a very common study method,23–25 we should consider that there might be some vulnerable individuals in NHI groups (e.g., lowest 20 percentile). Therefore, in future research, we need to consider more detailed segmentations to represent economic class. Lastly, we did not provide a concrete finding about the risk factors related to OP and OVF among MA recipients. Therefore, future studies are needed to reveal several risk factors associated with low economic status and to provide detailed preventive strategies for OP and OVF. In summary, we confirmed that the prevalence and incidence of OP and OVF in the MA group were higher than those in the NHI group. Low income might be a significant factor related to OP and OVF. Therefore, we should pay more attention to low socioeconomic classes and should reduce their socioeconomic burdens. In addition, we should develop a strategy that includes prevention, activities for Tertiary teaching hospitalGeneral hospital 57,103 (9.3)HospitalClinic 1465 (3.2) 98,526 (16.1) 2327.48 Yes 9403 (20.4) 112,929 (18.4) 344,384 8783 (56.2) (19.1) 26,359 (57.3) 18,953 (18.1) 2497 (17.8) 92,569 (16.8) 7738 (21.4) 106,299 (19.3) 293,227 (53.1) 7053 (19.5) 19,923 (55.0) 20,081 (19.2) 2384 (18.4) Tertiary teaching hospitalGeneral hospital 9593 (9.2)HospitalClinic 339 (2.4) 26,962 (25.8) 1170.76 5039early (36.0) 31,004 (29.7) detection 36,969 (35.4) 3868 (27.6) 4767 (34.0) and intervention, 27,124 (26.0) 4379 (33.8) and 31,341 (30.0) rehabilitation. 37,037 (35.5) 3545 (27.4) 4694 (36.2)

Key Points

Differences in Medical Utilization According to the Type of Health Insurance The prevalence and incidence of OP and OVFs in institution institution Type of medical OperationType of medical No 85,575 (81.9) 11,516 (82.2)MA 0.82 recipients 0.3664 84,309 (80.8) were 10,572 (81.6) higher 5.20 0.0226 than those of NHI beneficiaries. Low income might be a significant factor related

TABLE 5. to OP and OVF. Disease Variables Category NHI (%) MA (%) OP Total 612,942 (100.0) 46,010 (100.0) 552,174 (100.0) 36,203 (100.0) OVF Total 104,528 (100.0) 14,013 (100.0) 104,390 (100.0) 12,956 (100.0) MA indicates Medical Aid; NHI, National Health Insurance; OP, osteoporosis; OVF, osteoporotic vertebral fracture.

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