Assessment of fracture risk among postmenopausal Sudanese women: Is the fracture risk assessment score beneficial?

INTRODUCTION

Osteoporosis is characterized by reduced bone quality and density, leading to fragile bones with a high risk of fracture even after a minor fall. The most common bones usually affected are the spine, hip, pelvis, wrist, and upper arm.^[1] Although millions of people worldwide have osteoporosis, it is still underdiagnosed. Hence, it is considered a silent epidemic, as it is relatively pain-free and, unfortunately, leads to serious complications that impact the quality of life of patients and relatives.^[2]

Several studies have addressed osteoporosis and observed the serious risk factors correlated with osteoporosis in the past 15 years.^[3,4] One unfortunate finding is that only a small number of women received appropriate medications even following a fragility fracture.^[5] Moreover, only one out of three vertebral fractures was clinically diagnosed.^[6] This disease has high morbidity, with an estimation of higher than 8.9 million annual fractures.^[7]

Due to the major concern and lack of previous experience in dealing with osteoporosis, as national governments did not prioritize it, the World Health Organization (WHO) fracture risk assessment (FRAX) tool was accredited in about 60 countries. Unfortunately, Sudan is not one of them yet. This tool makes it easier to identify people at risk of fracture, particularly those areas with no facilities to check their bone mineral density (BMD).^[8] Moreover, BMD measures the quantity of bone density, not the quality; thus, it might have low sensitivity to predict fractures.^[9]

The FRAX tool calculates a 10-year probability of a major osteoporotic fracture (MOF) or a hip fracture (HF) with or without considering the BMD. This tool helps improve the prediction of fractures in women even before they develop osteoporosis.^[10] Modifiable risk factors, such as current smoking and alcoholism, and non-modifiable factors, such as age and gender, in addition to several other independent risk factors, are all addressed in its calculation.^[11]

According to different studies, FRAX score calculation with and without BMD provides the same fracture risk prediction.^[12,13] The probability of fracture estimated by the tool is based on the country’s epidemiology; therefore, it differs in various world regions. Furthermore, the International Osteoporosis Foundation (IOF) consolidates its international use to make fracture protection a pressing issue worldwide.^[14] In Sudan, many women tend to increase their weight using dexamethasone tablets, which might increase the risk of osteoporotic fractures. Moreover, we believe that there is irrational use of steroids in rheumatological diseases, which may make Sudan differ in epidemiology.

This study aimed to calculate the risk of postmenopausal Sudanese women developing fractures using the FRAX score to put a set action toward these women.

MATERIALS AND METHODS

A descriptive cross-sectional community-based household study was conducted in a house-to-house survey from January 2020 to June 2020. The population of this study is composed of those who live in Atbara City, north Sudan, where a large number of people have moved in recent years due to mining. A random sampling strategy was used, which was a multistage cluster. First, the study participants were selected from urban locations. North, West, South, and East were the four geographic divisions of the city. Then, two districts were chosen from each geographic area using a simple tossing technique. The number of homes was chosen in proportion to the population size. Starting at house number three on the district’s main street, a survey (house-to-house) was done. Families who declined to participate or vacant homes were replaced by the home next door.

Postmenopausal Sudanese women permanently residing in Atbara City were included in the study. Patients already diagnosed with osteoporosis and receiving treatment, premenopausal women, rural residents, and temporal residents were excluded from the study.

RESULTS

The analysis was based on data from 350 postmenopausal women living in River Nile State to assess screening for osteoporosis with the WHO FRAX score. Participants’ ages ranged from 40 to 90 years (mean: 55.988), of which approximately 33% (n = 118), 36% (n = 127), and 22% (n = 79) were aged between 40–50, 51– 60, and 61–70, respectively [Table 1].

Most participants were overweight, with 61.4% (n = 215) having a BMI above 25, and only 4.9% (n =17) were underweight [Table 1]. The number and proportion of women with a previous fragility fracture were 24 (6.9%) from 350 women. After analyzing the total number of participants, we identified 22 women (6.3%), one of whose parents had a HF.

A total of 40 women (11%) were exposed to oral glucocorticoids. In addition, 53 women (15.1%) were diagnosed with rheumatoid arthritis (RA), and 21 women (6%) complained of insulin-dependent diabetes mellitus (IDDM). Notably, 71 women (20.3%) had premature menopause, representing a clear prevalence of a significant risk factor for osteoporosis [Table 1].

The risk of MOF is highest in approximately 7% (n = 24) of the women, and 18.6% (n = 65) have an intermediate risk. In addition, 16.3% (n = 57) of the women have a high risk of HF, which indicates the need for treatment recommended by the WHO according to the FRAX questionnaire. Furthermore, 83.7% (n = 293) have a mild-to-moderate risk of HF; the mean is 1.98 and SD is 0.11 [Table 2].

With advancing age, the incidence of fractures increased in various fracture sites [Table 1]. As age increases, the risk for HF, vertebral fractures, and all osteoporotic fractures combined increase, especially at the age of 60 and above.

Lower BMI is significantly associated (P = 0.001) with minimal trauma fractures, particularly MOF, while fracture risk decreased with a higher BMI [Table 3].

Moreover, a significant relationship was seen between a previous fragility fracture and the incidence of future fractures, with P=0.004 and 0.000 for HF and MOF, respectively [Table 3]. As demonstrated in above-mentioned tables, a significant P-value regarding the correlation between parent HF and MOF is addressed in our study. More than 30% and 18.2% of participants whose parents had a history of HF have a significant association with 10–19% and >20% of the risk of MOF, respectively.

Regarding systemic glucocorticoid use, the findings revealed a statistically significant difference (P < 0.05) between exposure to systemic glucocorticoids and fragility fracture incidence. Those findings were evident for both HF and MOF [Table 3].

Fifty-three (15.1%) patients were diagnosed with RA, leading to a marked increase in the possibility of fractures; 24 (45.3%) out of 53 were eligible for osteoporosis treatment, as they were at high risk for HF, even without the DEXA scan evaluation for BMD [Table 3].

A statistically significant difference (P < 0.05) between HF/MOF and IDDM, premature menopause, malabsorption, and osteoporotic fractures are addressed in our study [Table 3].

A small number of participants, 2% (n = 7), had chronic liver disease (CLD), which is insignificantly correlated with osteoporotic fractures. In addition, five women (1.4%) were diagnosed with osteogenesis imperfecta, and again P-value was insignificant regarding the correlation between it and osteoporotic fracture.

DISCUSSION

Osteoporosis is the most common metabolic bone disease,^[16] affecting more than a third of postmenopausal women.^[17] This study’s results show that the FRAX tool is helpful for the assessment of osteoporosis, and this is consistent with a Palestinian study done to evaluate FRAX performance in predicting fracture risk.^[18]

A major strength of the tool is that it can predict fracture risk for 10 years. Therefore, the results provide an index of the usefulness of this prognostic model. To the best of our knowledge, our study is the first to use the FRAX tool prediction in Sudan.

The survey results of 350 women (done without a DEXA scan) revealed a significant association between increasing age and increased risk of both HF and MOF. This has been established in the previous studies.^[19-21]

The age effect was most evident in the 70s–90s age group. Due to the increase in age, estrogen levels, calcium, and vitamin D are reduced. Thus, bone density naturally decreases, which is a serious risk for fragility fractures. Loss of estrogen results in favor of osteoclasts relative to osteoblasts because estrogen normally induces apoptosis of osteoclasts.^[22]

As addressed in Vestergaard’s study,^[23] the BMI is an observed risk factor for future fractures. Our data which is consistent with the previously mentioned study showed a significant link between a low basal index and a high risk of fragility fracture. This may be due to muscle weakness and associated reduction in vitamin D and protein levels, all contributing to the increased liability of falling.^[24] In addition to the above clinical risk factors, it also found a significant link between previous HF and the risk of minimal trauma fracture. Our data has shown substantial agreement with a previous retrospective observational cohort study.^[25] These findings revealed that special attention should be given after any fragility fracture in postmenopausal women to reduce the risk of subsequent fractures.

Our study has a positive association between parenteral HF and MOF; this is supported by cohort studies as well as a survey by Yang et al.^[26] conducted in Canada. This study showed that patients treated with glucocorticoids have a significantly higher risk of osteoporotic fracture. Thus, a prescription should be given to them to prevent future fractures, not only with calcium supplements and vitamin D but also with antiresorptive therapy, which can be discontinued after cessation of glucocorticoids if there are no other risk factors. A similar study indicated that premenopausal women with a history of fractures or receiving a high dose of glucocorticoids should use bone protective agents.^[27] For example, the IOF-European Calcified Tissue Society framework recommends that the FRAX score be used to decide the lifelong bone protective agents used for postmenopausal women and men aged 50 years or older who are on oral glucocorticoids for at least 3 months.^[28]

Our study reported a significant association between RA and HF and MOF. Inflammation leads to bone loss near the affected joint. Several studies have also demonstrated bone loss in areas distant from the affected joint. This could be explained by the systemic effects of the disease, reduced mobility, nutritional deficiencies, and weight loss.^[29]

The study examined the effect of IDDM on bone quality, and it was found that this disease is significantly associated with weak bones. This may be due to increased calcium loss in the urine and negative calcium balance when the blood glucose level is high. In addition, in diabetes, there is resistance to the parathyroid hormone, leading to low calcium levels and increased fracture risk. Moreover, the glycosylation of collagen and its end products alters the bone structure.^[30] Prior studies correlated the complications of IDDM and increased fracture risk. These complications include retinopathy, neuropathy, kidney disease, and cardiovascular diseases.^[31]

We also found a significant correlation between malabsorption (which causes low calcium absorption) and an increased risk of fracture, particularly HF. It is well known that osteomalacia, which is due to vitamin D depletion, is a leading cause of the decrease in BMD.^[32] Our results show a weak correlation between chronic malnutrition, CLD, and osteogenesis imperfecta. A possible reason for this is the small sample size in comparison to cohort studies.

Our study has limitations, as it is a cross-sectional observational study. Therefore, a cohort study with a larger sample size is needed. In addition, this study had few participants, which masks the relationships between some factors and fragility fractures. Furthermore, there is a lack of detail on some risk factors, for example, the duration of oral glucocorticoids, the smoking dose, and how many previous fractures. Moreover, the FRAX tool did not contain all risks of falls and must not replace clinical judgment.

CONCLUSION

According to the FRAX tool, 16.3% and approximately 7% of our participants have a risk for HF and MOF, respectively. In addition, our study identified multiple risk factors significantly correlated with osteoporotic fractures. These factors include low body weight, previous fragility fractures, parent HF, glucocorticoid use, IDDM, and premature menopause. Therefore, we conclude that the FRAX tool is useful in predicting 10-year fracture risk.

AUTHORS’ CONTRIBUTIONS

SKN: Concepts, design, data analysis, manuscript editing and review. MSM: Literature search, data acquisition, data analysis, manuscript preparation, manuscript editing and review. AMF: Manuscript preparation, manuscript editing and review. SIF: Manuscript editing and review. FBM: Manuscript editing and review. SOB: Manuscript editing and review. All authors have critically reviewed and approved the final draft and are responsible for the manuscript’s content and similarity index.