Risk factors associated with incident fractures in Japanese men with rheumatoid arthritis: a prospective observational cohort study

Incidence and predictors of fragility fracture in postmenopausal rheumatoid arthritis patients receiving oral bisphosphonates: a longitudinal observational study

Background

Although many studies have reported the predictors of fractures in patients with rheumatoid arthritis (RA) who are not receiving anti-osteoporotic treatments or who are receiving unspecified treatments, studies focusing on the predictors of fracture in patients with RA who are currently being treated with oral bisphosphonates (BP) are quite scarce. This study aims to investigate the incidence and predictors of fragility fracture in postmenopausal patients with RA receiving oral BP.

Methods

This retrospective longitudinal observational study comprised 98 postmenopausal RA patients receiving oral BP for a minimum of 6 months between April 2015 and December 2020. The cumulative incidence of fragility fractures including vertebral and nonvertebral fractures was investigated using the Kaplan–Meier method. Cox proportional hazards analysis was used to analyze baseline predictors of future fragility fractures. To determine a cutoff value of continuous predictors, the receiver-operating characteristic curve was applied.

Results

Twenty patients developed fractures during the study period, with a cumulative incidence of 6.1% at 12 months, 10.5% at a median follow-up of 28 months, and 14.4% at 36 months. Multivariable Cox hazards analysis showed a history of prior vertebral fracture (hazard ratio [HR] 6.26, 95% confidence interval [CI] 1.99‒19.68, P = 0.001) and dose of methotrexate (HR 0.87, 95% CI 0.76‒0.99, P = 0.041) to be independent predictors. The cutoff value for methotrexate dose was 4 mg/week.

Conclusions

We found a cumulative incidence of any fractures of 10.5% at 28 months in patients with RA currently being treated with oral BP. A history of prior vertebral fractures and methotrexate dose were positive and negative predictors for fractures, respectively. Practitioners should consider selecting another anti-osteoporotic drug in patients with RA who remain at risk despite receiving oral BP.

THE RISK OF OSTEOPOROTIC FRACTURES IN PATIENTS WITH RHEUMATOID ARTHRITIS: RESULTS OF THE PROGRAM «OSTEOSCREENING RUSSIA»

Rheumatoid arthritis (RA) and the use of glucocorticoids (GCs) are proven risk factors for osteoporosis (OP) and osteoporotic fractures (OPF). There are also other reasons for increased fracture risk in RA.

Objective: to determine the rate of RA in an epidemiological sample of persons aged 50 years and older and to identify those in need of antiosteoporotic therapy among the patients with RA in order to prevent OPF.

Subjects and methods. The epidemiological sample included 18,018 people aged 50 years and older (13,941 women and 4,077 men; mean age, 62±10 years). The survey consisted of a unified questionnaire, measurement of daily dietary calcium intake, and calculation of a 10-year fracture risk using the FRAX® algorithm.

Results and discussion. The prevalence of RA in the epidemiological population sample aged 50 years and older was 1.7% (1.9% in women and 1.2% in men; p=0.0047). The mean FRAX® values for major OPF in RA patients were significantly higher than those in non-RA individuals: 18.4±10 and 13.2±7.9%, respectively (p=0.0001) for women and 8.9±6.4 and 6.2±3.7%, respectively (p=0.0001) for men. 42% of the patients with RA were at high risk for OPF. Thus, 48% of the women with RA had FRAX® values above the therapeutic intervention threshold; and the non-RA group needed antiosteoporotic therapy significantly less (31%; p=0.00001). At the same time, the detection rate of high-risk OPF in men with and without RA did not differ significantly (8 and 5%, respectively; p>0.05). The most common risk factors (RFs) for OP and OPF in RA patients included previous fractures (33%), secondary causes of OP (30%), GC use (18%), and, additionally, smoking (33%) in male patients with RA. The female patients with RA significantly more frequently took GCs (17%) and had other secondary causes of OP and OPF (33%) than those without RA (7.7% (p=0.0001) and 23% (p=0.0004, respectively). The male patients with RA versus to the population-based control showed significant differences when they only used GCs (20 and 5%, respectively; p = 0.0001); the remaining RFs were encountered at the same frequency. Less than half of the normal daily calcium intake was observed in 20% of men and 16% of women (p=0.53).

Conclusion. 42% of the RA patients aged 50 years and older were at high risk for OPF and needed antiosteoporotic therapy. Every third woman with RA had at least one other comorbidity or condition associated with the increased risk of OPF. In the male patients with RA, the FRAX® algorithm could reveal only 8% of persons at high risk for fractures, while 58% of them had two or more additional RFs that can negatively affect bone mineral density and increase the risk of fracture. To identify those who require prevention and treatment of OP and OPF, it is preferable to perform bone densitometry of the axial skeleton among male patients with RA. 

Evaluating osteoporotic fracture risk with the Fracture Risk Assessment Tool in Chinese patients with rheumatoid arthritis

This study aims to evaluate the discriminative and predictive capacity of the Fracture Risk Assessment Tool (FRAX) to determine the 10-year risk of osteoporotic fracture in Chinese rheumatoid arthritis (RA) patients.This study included 168 RA patients and 168 healthy individuals as controls. The Chinese mainland FRAX model was applied to calculate the 10-year risk of osteoporotic fractures, defined as fracture of the spine, forearm, hip, or shoulder.The incidence of osteoporosis was significantly increased in RA patients compared to controls (P < .05). Bone mineral density (BMD), lumbar vertebra T-score, and femoral neck T-score were significantly lower in RA patients compared to controls (P < .05). BMD, disease duration, DAS28, and glucocorticoid use were important risk factors for osteoporotic fractures in Chinese RA patients. Ten-year osteoporotic fracture risk in Chinese RA patients was higher when BMD was incorporated in FRAX.There was a higher incidence of osteoporosis and reduced BMD in RA patients compared to controls. The FRAX model should integrate femoral neck BMD with other risk factors to evaluate osteoporotic fracture risk in RA patients, making it a valuable screening tool.

Body mass index and the risk of low bone mass-related fractures in women compared with men: A PRISMA-compliant meta-analysis of prospective cohort studies

BACKGROUND

Body mass index (BMI) is inconsistently associated with the progression of low bone mass-related fractures. We conducted a systematic review and meta-analysis to summarize the evidence regarding the relationship between BMI and the risk of fracture in men and women separately. Furthermore, we analyzed the association between BMI and fracture risk in women compared with men.

METHODS

PubMed, EmBase, and the Cochrane Library were searched up to November 2015 to identify prospective cohort studies of low bone mass-related fractures. Prospective cohort studies that reported effect estimates of fracture risk for different BMI categories compared to normal weight were included. Relative risk (RR) and the ratio of relative risk (RRR) were calculated using a random-effect model to measure the relationship between BMI and fracture risk.

RESULTS

We analyzed 37 cohorts (32 articles), which included a total of 506,004 women and 118,372 men; overall, 38,200 incident cases were reported. Overall, a lower BMI was not associated with fracture risk in men (RR: 1.50, 95% confidence interval [CI]: 1.00-2.26; P = 0.051) or women (RR: 1.25, 95% CI: 0.97-1.62; P = 0.083). Although a higher BMI might play a beneficial impact in men (RR: 0.80, 95% CI: 0.69-0.93; P = 0.003), it has little effect in women (RR: 0.91, 95% CI: 0.74-1.11; P = 0.343). In addition, an increase in BMI by 5 kg/m decreased the risk of fractures in men (RR: 0.90, 95% CI: 0.83-0.98; P = 0.017) and women (RR: 0.85, 95% CI: 0.81-0.89; P < 0.001). Finally, there was no evidence of a sex difference in the RR for fractures between participants with different BMI categories compared with those with normal BMI. Finally, gender did not affect the risk of fracture for any category of BMI values.

CONCLUSION

Higher BMI may affect the risk of fractures regardless of the sex. This association may be due to the interaction between the participants' BMI and their bone mass density.

A review of the methods used to define glucocorticoid exposure and risk attribution when investigating the risk of fracture in a rheumatoid arthritis population

BACKGROUND

Glucocorticoid therapy is used widely in patients with rheumatoid arthritis (RA) with good efficacy but concerns about safety including fractures. Estimates of fracture risk for any given patient are complicated by the dynamic pattern of glucocorticoid use, where patients vary in their dose, duration and timing of glucocorticoid use.

OBJECTIVE

To investigate which methods are currently used to attribute fractures to glucocorticoid exposure and investigate whether such methods can consider individual treatment patterns.

RESULTS

Thirty-eight studies used five common definitions of risk attribution to glucocorticoid exposure: "current use", "ever use", "daily dose", "cumulative dose" and "time variant". One study attempted to combine multiple definitions where "cumulative dose" was nested within "daily dose", covering the effects of dose and duration but not timing. The majority of results demonstrated an equivocal or increased risk of fracture with increased exposure, although there was wide variation, with odds ratios, hazard ratios and relative risks ranging from 0.16 to 8.16. Within definitions there was also variability in the results with the smallest range for "time variant", 1.07 to 2.8, and the largest for "cumulative dose", ranging from risk estimates of 0.88 to 8.12.

CONCLUSION

Many studies have looked into the effect of glucocorticoids on fracture risk in patients with RA. Despite this, there is no clear consensus about the magnitude of risk. This is a consequence of the varied analysis models and their different assumptions. Moreover, no current analysis method allows consideration of dose, duration and timing of glucocorticoid therapy, preventing a clear understanding of fracture risk for patients and their individual treatment patterns.

Ten-year incidences of self-reported non-vertebral fractures in Japanese patients with rheumatoid arthritis: discrepancy between disease activity control and the incidence of non-vertebral fracture

Despite improvements in rheumatoid arthritis disease activity of in the past 10 years, the incidence of self-reported non-vertebral fractures did not decrease in our cohort of 9,987 patients. This study may indicate that osteoporosis treatment and non-vertebral fracture prevention remain important regardless of the rheumatoid arthritis disease activity.

INTRODUCTION

Although rheumatoid arthritis (RA) is a risk factor for osteoporosis and fractures, few studies have described the association between disease activity and the fracture incidence in patients with RA. This study aimed to investigate changes in the non-vertebral fracture incidence between 2001 and 2010 in our Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort.

METHODS

The IORRA is a prospective observational cohort study of Japanese RA patients. A total of 9,987 patients with RA were enrolled in this cohort from 2000 to 2010. The clinical parameter and non-vertebral fracture occurrence data were collected biannually through self-reported questionnaires. Incidences of self-reported non-vertebral fractures were also analyzed via standardization according to gender, age, and disease activity during each 2-year period.

RESULTS

From 2001 to 2010, the percentage of patients with 28-joint disease activity score remission increased from 7.8 to 39.7%, prednisolone intake decreased from 51.4 to 41.3%, and bisphosphonate intake increased from 5.0 to 23.4%. The non-vertebral fracture incidence rates were 24.6/1,000 person-years in 2001 and 35.5/1,000 person-years in 2010, with no apparent change even after standardization. The overall non-vertebral fracture incidence was significantly higher in the autumn/winter than in the spring/summer (p = 0.02).

CONCLUSION

Despite improvements in disease activity and functional disability, the non-vertebral fracture incidence exhibited no apparent change between 2001 and 2010 in our patients with RA. Osteoporosis treatment and non-vertebral fracture prevention remain important regardless of the disease control in patients with RA.

Alterations of bone density, microstructure, and strength of the distal radius in male patients with rheumatoid arthritis: a case-control study with HR-pQCT

In this cross-sectional study, we investigated volumetric bone mineral density (vBMD), bone microstructure, and biomechanical competence of the distal radius in male patients with rheumatoid arthritis (RA). The study cohort comprised 50 male RA patients of average age of 61.1 years and 50 age-matched healthy males. Areal BMD (aBMD) of the hip, lumbar spine, and distal radius was measured by dual-energy X-ray absorptiometry. High-resolution peripheral quantitative computed tomography (HR-pQCT) of the distal radius provided measures of cortical and trabecular vBMD, microstructure, and biomechanical indices. aBMD of the hip but not the lumbar spine or ultradistal radius was significantly lower in RA patients than controls after adjustment for body weight. Total, cortical, and trabecular vBMD at the distal radius were, on average, -3.9% to -23.2% significantly lower in RA patients, and these differences were not affected by adjustment for body weight, testosterone level, or aBMD at the ultradistal radius. Trabecular microstructure indices were, on average, -8.1% (trabecular number) to 28.7% (trabecular network inhomogeneity) significantly inferior, whereas cortical pore volume and cortical porosity index were, on average, 80.3% and 63.9%, respectively, significantly higher in RA patients. RA patients also had significantly lower whole-bone stiffness, modulus, and failure load, with lower and more unevenly distributed cortical and trabecular stress. Density and microstructure indices significantly correlated with disease activity, severity, and levels of pro-inflammatory cytokines (interleukin [IL] 12p70, tumor necrosis factor, IL-6 and IL-1β). Ten RA patients had focal periosteal bone apposition most prominent at the ulnovolar aspect of the distal radius. These patients had shorter disease duration and significantly higher cortical porosity. In conclusion, HR-pQCT reveals significant alterations of bone density, microstructure, and strength of the distal radius in male RA patients and provides new insight into the microstructural basis of bone fragility accompanying chronic inflammation.

Risk factors associated with the occurrence of hip fracture in Japanese patients with rheumatoid arthritis: a prospective observational cohort study

Risk factors associated with the occurrence of hip fracture in Japanese patients with rheumatoid arthritis (RA) were evaluated in a prospective, observational cohort study. Physical disability, advanced age, history of total knee replacement (TKR), and low body mass index (BMI) appear to be associated with the occurrence of hip fracture.

INTRODUCTION

This study seeks to evaluate the association between potential risk factors and the occurrence of hip fractures in Japanese RA patients.

METHODS

A total of 9,720 patients (82.1% female; mean age, 55.7 years) with RA were enrolled in a prospective observational study from 2000 to 2010. Self-reported hip fractures were verified using patient medical records. Cox proportional hazards models were used to analyze independent contributions of various risk factors to hip fracture occurrence.

RESULTS

During a mean follow-up of 5.2 years, 152 patients reported 152 hip fractures. Among these patients, 97 hip fractures in 97 patients (15 males, 82 females) were verified with medical records. Japanese version of the Health Assessment Questionnaire (J-HAQ) disability score [per 1 score, hazard ratio (HR), 2.64; 95% confidence interval (CI), 1.94-3.58], age (per 10 years; HR, 1.53; 95% CI, 1.25-1.87), history of TKR (HR, 3.75; 95% CI, 1.57-8.96), and BMI (per 1 kg/m2, HR, 0.92; 95% CI, 0.86-0.99) were significantly associated with hip fractures. Among the scores on the eight domains of the J-HAQ, J-HAQ (arising) (HR, 1.74; 95% CI, 1.28-2.36) and J-HAQ (hygiene) (HR, 1.58; 95% CI, 1.11-2.24) were significantly correlated with the occurrence of hip fracture.

CONCLUSIONS

High J-HAQ disability score, advanced age, history of TKR, and low BMI appear to be associated with the occurrence of hip fractures in Japanese RA patients. Among the eight domains of the J-HAQ, arising and hygiene disabilities appear to be correlated with the occurrence of hip fractures in this patient population.

Sites, frequencies, and causes of self-reported fractures in 9,720 rheumatoid arthritis patients: a large prospective observational cohort study in Japan

Sites, frequencies, and causes of self-reported fractures in Japanese patients with rheumatoid arthritis (RA) were evaluated in a prospective, observational cohort study. The incidence and cause of fracture differ by anatomical site, sex, and age. These differences may be considered in establishing custom strategies for preventing fractures in RA patients in the future.

PURPOSE

The literature contains limited data describing the details of fractures at different skeletal sites in patients with RA.

METHODS

We evaluated the details of fractures in Japanese RA patients on the basis of our Institute of Rheumatology Rheumatoid Arthritis cohort study in 9,720 RA patients (82 % women; mean age, 56 years) who were enrolled from 2000 to 2010. The details of fractures were obtained through biannual patient self-report questionnaires.

RESULTS

Over a mean duration of 5.2 years, 1,317 patients (13.5 %) reported 2,323 incident fractures comprising 563 (24.2 %) clinical vertebral fractures and 1,760 (75.8 %) nonvertebral fractures. Rib fractures were the most common fractures in men, followed by clinical vertebral and hip fractures; the most common fractures in women were clinical vertebral fractures, followed by rib, foot, and hip fractures. There was a significant difference between sexes in the rates of rib, clavicle, shoulder, and ankle fractures. Spontaneous event was the primary cause of clinical vertebral fracture (65.4 %), whereas falls were the primary cause of upper extremity (76.5 %) and lower extremity (57.8 %) fractures. Rates of clinical vertebral and hip fractures increased, while those of rib and foot fractures decreased with increasing age. Incidence of falls, as causes of nonvertebral fractures, also increased in older age groups.

CONCLUSION

Our results suggest that the causes of fractures may differ depending on anatomical site and that prevention of falls may be the most effective way to reduce upper and lower extremity fractures, especially in older patients with RA.

Clinical review. Risk factors for low bone mass-related fractures in men: a systematic review and meta-analysis

CONTEXT

Testing men at increased risk for osteoporotic fractures has been recommended.

OBJECTIVE

The aim of this study was to estimate the magnitude of association and quality of supporting evidence linking multiple risk factors with low bone mass-related fractures in men.

DATA SOURCES

We searched MEDLINE, EMBASE, Web of Science, SCOPUS and Cochrane CENTRAL through February 2010. We identified further studies by reviewing reference lists from selected studies and reviews.

STUDY SELECTION

Eligible studies had to enroll men and quantitatively evaluate the association of risk factors with low bone density-related fractures.

DATA EXTRACTION

Reviewers working independently and in duplicate determined study eligibility and extracted study description, quality, and outcome data.

DATA SYNTHESIS

Fifty-five studies provided data sufficient for meta-analysis. The quality of these observational studies was moderate with fair levels of multivariable adjustment and adequate exposure and outcome ascertainment. Statistically significant associations were established for age, low body mass index, current smoking, excessive alcohol use, chronic corticosteroid use, history of prior fractures, history of falls, history of hypogonadism, history of stroke, and history of diabetes. Statistical heterogeneity of the meta-analytic estimates of all associations was significant except for chronic corticosteroid use. None of these associations were of large magnitude (i.e. adjusted odds ratios were generally <2). No evidence supporting a particular effective testing or screening strategy was identified.

CONCLUSIONS

Multiple risk factors for fractures in men were identified, but their usefulness for stratifying and selecting men for bone density testing remains uncertain.

Official Positions for FRAX® clinical regarding rheumatoid arthritis from Joint Official Positions Development Conference of the International Society for Clinical Densitometry and International Osteoporosis Foundation on FRAX®

Rheumatoid arthritis is the only secondary cause of osteoporosis that is considered independent of bone density in the FRAX(®) algorithm. Although input for rheumatoid arthritis in FRAX(®) is a dichotomous variable, intuitively, one would expect that more severe or active disease would be associated with a greater risk for fracture. We reviewed the literature to determine if specific disease parameters or medication use could be used to better characterize fracture risk in individuals with rheumatoid arthritis. Although many studies document a correlation between various parameters of disease activity or severity and decreased bone density, fewer have associated these variables with fracture risk. We reviewed these studies in detail and concluded that disability measures such as HAQ (Health Assessment Questionnaire) and functional class do correlate with clinical fractures but not morphometric vertebral fractures. One large study found a strong correlation with duration of disease and fracture risk but additional studies are needed to confirm this. There was little evidence to correlate other measures of disease such as DAS (disease activity score), VAS (visual analogue scale), acute phase reactants, use of non-glucocorticoid medications and increased fracture risk. We concluded that FRAX(®) calculations may underestimate fracture probability in patients with impaired functional status from rheumatoid arthritis but that this could not be quantified at this time. At this time, other disease measures cannot be used for fracture prediction. However only a few, mostly small studies addressed other disease parameters and further research is needed. Additional questions for future research are suggested.

Standard treatment in daily clinical practice for early rheumatoid arthritis improved disease activity from 2001 to 2006

We aimed to clarify the degree of improvement in disease control following early treatment of rheumatoid arthritis (RA) in daily clinical practice in 2006 compared to that in 2001. Using a large observational Japanese RA cohort (IORRA), we analyzed changes in clinical parameters, including disease activity assessed by the disease activity score 28 (DAS28) and physical disability assessed by the Japanese version of the Health Assessment Questionnaire (J-HAQ), which occurred within 2 years of cohort inception. All patients had enrolled in the IORRA cohort within 1 year of RA onset, in either 2001 (2001-cohort) or 2006 (2006-cohort). For both cohorts, changes in clinical features over 2 years were compared by Fisher's exact test or the Wilcoxon test. The 2001-cohort included 71 patients and the 2006-cohort included 56 patients. Over the 2-year period for each cohort, DAS28 significantly decreased from 3.9 to 3.5 in the 2001-cohort (p < 0.001) and from 4.1 to 3.1 in the 2006-cohort (p < 0.0001), and J-HAQ significantly decreased from 0.62 to 0.49 (p < 0.02) in the 2001-cohort and from 0.71 to 0.41 (p < 0.001) in the 2006-cohort. Greater improvement in disease activity over 2 years occurred in the 2006-cohort than in the 2001-cohort (p < 0.05). Better disease control was obtained following changes in RA treatment strategy that occurred in Japan between 2001 and 2006.

Studies of the efficacy and safety of methotrexate at dosages over 8 mg/week using the IORRA cohort database

The maximum dosage of methotrexate (MTX) for treatment of rheumatoid arthritis (RA) formally approved in Japan is 8 mg/week. We intended to examine the efficacy and safety of MTX at dosages over 8 mg/week in Japanese rheumatoid arthritis patients using the large Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort database. Among 9,122 patients registered in the IORRA database from the October 2000 survey to the October 2007 survey, 5,201 patients who had been treated with MTX were selected. We attempted to overcome the drawbacks innate to nonrandomized studies by using longitudinal analyses and multifactorial logistic regression analyses. Cross-sectional analysis of data obtained from the October 2007 survey indicated that dosages of MTX higher than 8 mg/week were used in 27.5% of patients treated with MTX. Longitudinal analyses based on data from three consecutive phases showed that final Disease Activity Score-28 (DAS28) values were significantly lower [n = 260, mean difference 0.563, 95% confidence interval (CI) 0.438-0.688, P < 2.2 × 10(-22), two-sided paired t test] than initial values when MTX was increased from 8 mg/week or lower to over 8 mg/week. In addition, longitudinal analyses based on data from two consecutive phases indicated decreases in DAS28 values of 0.26 ± 1.04 (n = 690, P = 6.78 × 10(-11), two-sided paired t test) when MTX dosages were increased from 8 mg/week or lower to over 8 mg/week, compared with decreases of 0.07 ± 0.89 (n = 2,125, P = 0.000307) when the dosage was maintained at 8 mg/week. The decreases in DAS28 values were significantly larger in the former than the latter (P = 2.27 × 10(-6), two-sided unpaired t test). Concerning safety of MTX at dosages over 8 mg/week, we performed logistic regression analysis in which the objective variable was the existence or nonexistence of self-reported side-effects and the explanatory variable was the MTX dosage in the former phase, with adjustments made for age, sex, body mass index (BMI), steroid administration, folic acid administration, concomitant pulmonary diseases, and renal dysfunction. The results indicated that MTX dosages over 8 mg/week did not have any association with either severe or severe + moderate side-effects. These data regarding both efficacy and safety of MTX at dosages over 8 mg/week in Japanese RA patients would provide the basis for use of the drug at dosages currently not formally approved by the Japanese government.

Incidence of falls and fear of falling in Japanese patients with rheumatoid arthritis

The objective of this study is to determine the incidence of falls and fear of falling by gender and age in Japanese patients with rheumatoid arthritis (RA). Among the Japanese patients who participated in a single-institute-based prospective observational cohort study of patients with RA, namely the Institute of Rheumatology Rheumatoid Arthritis, 765 men (median age 63 years) and 4,231 women (median age 60 years) with RA responded to questions related to falls. Eight percent of men and 11% of women reported one or more falls during the previous 6 months. At least one fall and multiple falls were significantly more frequent in men (p < 0.05) and in women (p < 0.001) with RA over age 65 and age 75 years, respectively, although there was no significant linear increase in risk with age. Sixteen percent of men and 22% of women reported fear of falling. More men over age 65 tended to report fear of falling than those under age 65 (p < 0.001), although the incidence of women with fear of falling increased with advancing age. Japanese patients with RA over age 65 and age 75 appeared to have a high risk of at least one fall and multiple falls, respectively.

Associations between methotrexate treatment and methylenetetrahydrofolate reductase gene polymorphisms with incident fractures in Japanese female rheumatoid arthritis patients

Several case reports have described associations between pathological nonvertebral fractures and low-dose methotrexate (MTX) in rheumatoid arthritis (RA) patients. Furthermore, a significant association between the C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene and incident fractures has been reported in postmenopausal women. We attempted to determine whether MTX use and MTHFR polymorphisms are associated with incident fracture risk in Japanese female RA patients. DNA samples, laboratory data, and clinical data were obtained from 731 female RA patients more than 50 years old as part of the Institute of Rheumatology Rheumatoid Arthritis (IORRA) observational cohort study. Genotyping of the MTHFR polymorphisms C677T and A1298C was performed using TaqMan SNP Genotyping Assays. MTX use, MTHFR polymorphisms, and other potential risk factors predictive of fracture were analyzed by Cox proportional hazards regression models, including time-dependent covariates. During 78 months from October 2000 to March 2007, 25 and 90 patients developed vertebral and nonvertebral fractures, respectively. Patients with nonvertebral fractures were more likely to take MTX (P = 0.011; odds ratio, 1.77; 95% confidence interval, 1.13-2.76) compared to patients without fractures. Although the C677T and A1298C polymorphisms were not significantly associated with incident fracture risk, MTX use, age, disease duration, and Japanese health assessment questionnaire score were significantly (P < 0.05) and independently associated with nonvertebral fracture incidence. Our results suggest that MTX use is associated with a nonvertebral fracture risk, whereas MTHFR polymorphism status does not appear to be a clinically useful marker for predicting fracture risk in Japanese female RA patients.

A1330V polymorphism of low-density lipoprotein receptor-related protein 5 gene and self-reported incident fractures in Japanese female patients with rheumatoid arthritis

We attempted to determine whether the A1330V polymorphism of the low-density lipoprotein receptor-related protein 5 (LRP5) gene is associated with a risk of self-reported incident fractures and hypercholesterolemia in Japanese patients with rheumatoid arthritis (RA). DNA samples, laboratory data, and clinical data were obtained from 563 female RA patients who participated in the Institute of Rheumatology Rheumatoid Arthritis (IORRA) observational cohort study. A1330V genotyping was performed using a custom TaqMan assay. Multiple logistic regression analyses showed that any incident fracture was significantly associated with older age (P = 0.000000036), high Japanese Health Assessment Questionnaire (J-HAQ) score (P = 0.016), and high daily prednisolone dose (P = 0.031), but not with the A1330V polymorphism, while serum total cholesterol levels >or=220 mg/100 mL were independently correlated with baseline older age (P = 0.00011), low J-HAQ score (P = 0.0098), high body mass index (P = 0.024), 1330VV genotype (P = 0.027), and high daily prednisolone dose (P = 0.031). Our results suggest that this LPR5 polymorphism does not appear to be a clinically useful marker for the prediction of fracture risk in Japanese female RA patients, although it is associated with increased serum total cholesterol levels.