Gout increases risk of fracture: A nationwide population-based cohort study

Association between gout and the risk of osteoporosis and fractures: a meta-analysis

OBJECTIVE

The relationship between gout and osteoporosis is poorly clarified, and the association between gout and fractures incidence remains controversial. Hence, in the present study, we aimed to comprehensively evaluate the available literature to elucidate whether gout is associated with an increased risk of both osteoporosis and fractures.

MATERIALS AND METHODS

We conducted an exhaustive search of pertinent literature published until 20 March 2023, in well-recognized databases, namely Medline, Embase and Cochrane Library, focusing on examining the association between gout and the risk of osteoporosis or fracture. Meta-analysis was performed to aggregate the relative risks (RR) using random- or fixed-effects models. Sensitivity analyses were conducted iteratively, whereby each study was removed sequentially to gauge its impact on the overall outcome. Publication bias was assessed using Egger's and Begg's tests. This study was registered with PROSPERO (registry number: CRD42022376822).

RESULTS

Herein, we included 10 observational studies comprising a total of 1,606,095 participants. An independent population sample of four studies validated the significant association between gout and osteoporosis (RR = 1.25, 95% confidence interval [CI] 1.05-1.48), with the results demonstrating robustness. However, our analysis did not detect any association between gout and fracture risk when compared with the control group (RR = 1.09, 95%CI 0.99-1.19), along with high heterogeneity (p for heterogeneity = 0.000; I2 = 79.7%). Further subgroup analysis revealed that gout is positively associated with fracture risk in the Chinese population (RR = 1.17, 95%CI 1.14-1.21), with no evidence of heterogeneity (p for heterogeneity = 0.420; I2 = 0.00%).

CONCLUSION

Our meticulous evaluation of the available literature indicates that gout has no discernible impact on fracture incidence, although it is positively associated with an enhanced risk of osteoporosis. Therefore, it is imperative to prioritize preventive measures to prevent osteoporotic complications in individuals diagnosed with gout.

Risk of gout attack not increased in patients with thalassemia: a population-based cohort study

The incidence of gout arthritis in patients with thalassemia and the association between them was indefinite. We aimed to give epidemiological evidence regarding the association between thalassemia and gout arthritis. This retrospective cohort study extracted data relating to the risk of gout arthritis from patients diagnosed with thalassemia between 2000 and 2013. We selected the control group at a ratio of 1:4 by propensity score matching (PSM). Univariable and multivariable Cox proportional hazard regression models were performed to analyze the association between thalassemia and gout arthritis and to evaluate the hazard ratio (HR) of gout arthritis after exposure with thalassemia. The sensitivity analysis was performed to avoid the mislabeled thalassemia disease, the transfusion-dependent thalassemia was classified to compare the risk of gout arthritis. The secondary outcome for the risk of gout arthritis with antigout drugs treatment was also evaluated between study groups. In the age and sex matched cohort, the majority of thalassemia patients were women (62.03%) and aged younger than 30 years old (44.79%). There were 138 (4.2%) and 500 (3.8%) incident cases of gout arthritis in the thalassemia and non-thalassemia group. After PSM, the incidence rate, per 100 person-years, of gout arthritis was 0.48 (95% CI 0.42 to 0.56) and 0.60 (95% CI 0.51 to 0.72) in non-thalassemia individuals and patients with thalassemia, respectively. In the Cox proportional hazard regression, patients with thalassemia had no significant increase in the risk of gout arthritis (adjusted HR, 1.00; 95%CI: 0.80 to 1.25) after adjusting demographic variables and comorbidities. The Kaplan-Meier curve showed that the cumulative incidence of gout arthritis was not a significant difference in the thalassemia group than in the comparison group (p > 0.05). The sensitivity analysis showed the consistent results about the risk of gout arthritis in patients with thalassemia. Our study indicated that there was no significant increase in the risk of gout arthritis in subjects with thalassemia.Future research needs to clarify the biological mechanisms behind this connection.

Potential Association of Osteoporosis and Not Osteoporotic Fractures in Patients with Gout: A Longitudinal Follow-Up Study

Health issues associated with gout and increased occurrence of osteoporosis or fractures have been raised; however, the results are elusive. Herein, we explored the possible link between gout and incident osteoporosis/osteoporotic fractures based on long-term follow-up nationwide data. This study enrolled 16,305 patients with gout and 65,220 controls who were matched by propensity score at a 1:4 ratio on the basis of sex, age, income, and residence from the Korean National Health Insurance Service-Health Screening Cohort database (2002−2015). A Cox proportional hazard model was employed to identify the relevance between gout and incident osteoporosis/fractures, following adjustment for various covariates. In the follow-up period, osteoporosis developed in 761 individuals with gout and 2805 controls (incidence rates: 8.0 and 7.3/1000 person-years, respectively), and each osteoporotic fracture in the distal radius (2.8 vs. 2.7/1000 person-years), hip (1.3 vs. 1.3/1000 person-years), and spine (4.5 vs. 4.5/1000 person-years) occurred in gout and control groups, respectively. After adjustment, the gout group presented an 11% higher development of osteoporosis (95% confidence interval = 1.02−1.20) than the controls (p = 0.011). Subgroup analyses maintained the augment of incident osteoporosis in sufferers with gout, particularly in either men or <60 years. However, no such relevance was identified between gout and incident osteoporotic fractures at any site. In conclusion, gout may result in a slightly elevated likelihood of developing osteoporosis, and not osteoporotic fractures, in the Korean population.

Gout as a risk factor for osteoporosis: A Korean population-based study

Uric acid acts as both an antioxidant and a pre-oxidant that induces oxidative stress; thus, it plays a paradoxical role in inflammation. However, the effect of gout, a hallmark of hyperuricemia, on osteoporosis remains unclear. Therefore, this study aimed to investigate the association between gout and osteoporosis. This retrospective cohort study used data from the Korean National Health Insurance Service Database. In total, 628,565 participants who were diagnosed with gout and prescribed medications for gout for at least 90 days were selected. The control cohort included patients with no history of gout or use of gout medication. Age and sex 1:1 propensity score matching and Cox proportional hazards models were used to investigate risk factors for osteoporosis. In total, 305,810 patients with gout met the inclusion criteria. Compared with the control group, both men and women with gout showed an increased incidence rate ratio of osteoporosis. In the stratified analysis by age, patients with gout showed an increased incidence rate ratio for osteoporosis in all age groups, except for those over 80 years of age (P < .001). Gout showed an increased hazard ratio of 1.48 (95% CI: 1.45-1.51, P < .001). The female sex has also been identified as a risk factor for osteoporosis. Patients in their 70s had the highest HR. Gout is significantly associated with the risk of osteoporosis. In particular, the results of this study showed that the incidence of osteoporosis increased up to four times in male patients in their 20s with gout compared to without gout.

Alternate Warm and Cold Therapy (AWCT) on Uricemia, Sleep, Pain, Functional Ability, and Quality of Life (USPFQoL) in Patients with Gout: A Path Forward

Objective

To understand the impact of alternate warm and cold therapy (AWCT) on uricemia, sleep, pain, functional ability, and quality of life in gout patients.

Methods

A quasiexperimental, nonequivalent control group, pre and posttest design was adopted among 120 gout patients. The data were collected on demographics, comorbidities, pain level, joint swelling/joint tenderness, patient global assessment of response to treatment (PGART), health-related quality of life (HRQoL) with SF-36, sleep quality by Pittsburgh Sleep Quality Index (PSQI), and serum uric acid and assessed. Descriptive and inferential statistics were used to analyze the data.

Results

Patients had mean age of 58 and 61 years, mean number of comorbidities was 1.8 and 1.4, as well as presence of arthritic comorbidities except gout was 1.1 and 0.8 among study and control group participants, respectively. Pain (p < 0.001), PGART (p=−0.01), HRQoL, sleep quality, and level of SUA (mg/dl) improved significantly (p < 0.01) among the study group over study periods. It affirms that the AWCT is effective in reducing pain, functional disability, and SUA, as well as improving the sleep quality and HRQoL of the gout patients. There was a reduced incidence of gout flares (p < 0.001), and taking additional medicines for pain (p < 0.01) was statistically significant among study participants. Except social functioning, other domains of health were significantly (p < 0.05) affected by the comorbidities like hypertension, diabetes, heart disease, renal disease, and asthma/chronic obstructive pulmonary disease.

Conclusions

Gout is independently associated with higher medical and arthritic comorbidity, and AWCT can be better and cost-effective alternative therapy for gout patients. In addition, it may lead to improved cardiac function, hypertension, and renal insufficiency.

Risk of Non-Vertebral Fracture in Gout Compared to Rheumatoid Arthritis

Objective: To evaluate the risk of non-vertebral fractures in patients with gout compared with those with rheumatoid arthritis (RA). Methods: Using claims data from Medicare (2008–2015), we conducted a cohort study of patients with gout versus RA matched on age, sex, and index date with a 1:1 ratio. The primary outcome was a composite endpoint of non-vertebral fractures including hip, pelvis, humerus, and wrist identified with the validated algorithms. We also assessed hip fractures separately. Multivariable Cox proportional hazards regression estimated the hazard ratio (HR) for the outcomes in gout versus RA adjusted for 45 covariates. Results: We included a total of 134,157 matched pairs of gout and RA patients (mean age: 73.7 years). Risk factors for fracture were more prevalent in RA, while other comorbidities including obesity, coronary heart disease, hypertension, and diabetes were more common in gout. Over the mean 2.8 years follow-up, the incidence rate (IR)/1000 person-year (PY) of non-vertebral fractures was 10.42 in gout and 15.01 in RA. For hip fractures, the IR/1000 PY was 4.86 in gout and 7.73 in RA. The multivariable HR associated with gout versus RA was 0.84 (95% confidence interval (CI) 0.80–0.88) for non-vertebral fractures and 0.76 (95% CI 0.71–0.82) for hip fractures. Stratified analyses by age, sex, prior fractures, steroid use, and TNF inhibitor use showed similar results. Conclusions: In this large cohort of older patients, gout was associated with a modestly decreased risk of non-vertebral or hip fractures versus RA. However, non-vertebral fractures occurred frequently in both gout and RA.

Effect of hyperuricemia on functional outcomes and complications in patients with elbow stiffness after open arthrolysis combined with hinged external fixation: a retrospective study

BACKGROUND

Hyperuricemia is considered a risk factor for increased postoperative complications and adverse functional outcomes in a variety of orthopedic surgeries. The purpose of this retrospective study was to investigate the clinical efficacy of patients with different uric acid levels after elbow arthrolysis.

METHODS

The study included 131 patients with post-traumatic elbow stiffness who underwent arthrolysis between March 2014 and March 2016. All patients were divided into 4 groups based on the preoperative serum level of uric acid (UA). The quartile method was used for grouping patients, including 33 in Q1 (UA <293 μmol/L), 34 in Q2 (293-348 μmol/L), 32 in Q3 (348-441 μmol/L), and 32 in Q4 (441-710 μmol/L). At baseline and each time point of follow-up, functional performance, Mayo Elbow Performance Score, visual analog scale for pain, and complications were evaluated.

RESULTS

Preoperative data were not significantly different among the 4 groups (Q1, Q2, Q3, and Q4). At the final follow-up, the following data showed significant differences among the 4 groups: extension (P = .031), flexion (P = .008), range of motion (P = .003), Mayo Elbow Performance Score (P = .011), and visual analog scale (P = .032). Interestingly, patients in the Q4 group had the poorest clinical outcomes. However, no significant differences were found among the 4 groups in new onset or exacerbation of nerve symptoms (P = .919), reduced muscle strength (P = .536), instability (P = .567), or infection (P = .374) at the last follow-up.

CONCLUSION

This study confirms that in patients with post-traumatic elbow stiffness, abnormal serum uric acid metabolism was a risk factor for poor performance and postoperative pain after arthrolysis. Therefore, detecting the preoperative serum uric acid levels of the patients would be helpful for evaluating the postoperative outcomes.

Global epidemiology of gout: prevalence, incidence, treatment patterns and risk factors

Gout is the most common inflammatory arthritis and occurs when hyperuricaemia, sustained elevation of serum urate levels resulting in supersaturation of body tissues with urate, leads to the formation and deposition of monosodium urate crystals in and around the joints. Recent reports of the prevalence and incidence of gout vary widely according to the population studied and methods employed but range from a prevalence of <1% to 6.8% and an incidence of 0.58-2.89 per 1,000 person-years. Gout is more prevalent in men than in women, with increasing age, and in some ethnic groups. Despite rising prevalence and incidence, suboptimal management of gout continues in many countries. Typically, only a third to half of patients with gout receive urate-lowering therapy, which is a definitive, curative treatment, and fewer than a half of patients adhere to treatment. Many gout risk factors exist, including obesity, dietary factors and comorbid conditions. As well as a firmly established increased risk of cardiovascular disease and chronic kidney disease in those with gout, novel associations of gout with other comorbidities have been reported, including erectile dysfunction, atrial fibrillation, obstructive sleep apnoea, osteoporosis and venous thromboembolism. Discrete patterns of comorbidity clustering in individuals with gout have been described. Increasing prevalence and incidence of obesity and comorbidities are likely to contribute substantially to the rising burden of gout.

Bone microstructure and volumetric bone mineral density in patients with hyperuricemia with and without psoriasis

We analyzed volumetric bone mineral density (vBMD) and bone microstructure using HR-pQCT in subjects with normouricemia (NU) and subjects with hyperuricemia (HU) with and without psoriasis (PSO). HU was associated with higher cortical vBMD and thickness. Differences in average and trabecular vBMD were found between patients with PSO + HU and NU.

INTRODUCTION

Hyperuricemia (HU) and gout are co-conditions of psoriasis and psoriatic arthritis. Current data suggest a positive association between HU and areal bone mineral density (BMD) and a negative influence of psoriasis on local bone, even in the absence of arthritis. However, the influence of the combination of HU and psoriasis on bone is still unclear. The aim of this study was to assess the impact of HU with and without psoriasis on bone microstructure and volumetric BMD (vBMD).

METHODS

Healthy individuals with uric acid levels within the normal range (NU), with hyperuricemia (HU), patients with hyperuricemia and psoriasis (PSO + HU), and patients with uric acid within the normal range and psoriasis (PSO + NU) were included in our study. Psoriasis patients had no current or past symptoms of arthritis. Average, trabecular, and cortical vBMD (mgHA/cm³); trabecular number (Tb.N, 1/mm) and thickness (Tb.Th, mm); inhomogeneity of the network (1/N.SD, mm); and cortical thickness (Ct.Th., mm) were carried out at the ultradistal radius using high-resolution peripheral quantitative computed tomography. In addition, bone turnover markers such as DKK-1, sclerostin, and P1NP were analyzed.

RESULTS

In total, 130 individuals were included (44 NU participants (34% female), 50 HU (24%), 16 PSO + HU (6%), 20 PSO + NU (60%)). Subjects were aged: NU 54.5 (42.8, 62.1), HU 57.5 (18.6, 65.1), PSO + HU 52.0 (42.3, 57.8), and PSO + NU 42.5 (34.8, 56.8), respectively. After adjusting for age, sex, BMI, and diabetes, patients in the HU group revealed significantly higher values of cortical vBMD (p < 0.001) as well as cortical thickness (p = 0.04) compared to the NU group. PSO + NU showed no differences to NU, but PSO + HU demonstrated both lower average (p = 0.03) and trabecular vBMD (p = 0.02). P1NP was associated with average, cortical, and trabecular vBMD as well as cortical thickness while sclerostin levels were related to trabecular vBMD.

CONCLUSION

Hyperuricemia in otherwise healthy subjects was associated with a better cortical vBMD and higher cortical thickness. However, patients with both psoriasis and hyperuricemia revealed a lower vBMD.

Risk of fragility fracture among patients with gout and the effect of urate-lowering therapy

BACKGROUND

Previous studies that quantified the risk of fracture among patients with gout and assessed the potential effect of urate-lowering therapy have provided conflicting results. Our study aims to provide better estimates of risk by minimizing the effect of selection bias and confounding on the observed association.

METHODS

We used data from the Clinical Practice Research Datalink, which records primary care consultations of patients from across the United Kingdom. We identified patients with incident gout from 1990 to 2004 and followed them up until 2015. Each patient with gout was individually matched to 4 controls on age, sex and general practice. We calculated absolute rate of fracture and hazard ratios (HRs) using Cox regression models. Among patients with gout, we assessed the impact of urate-lowering therapy on fracture, and used landmark analysis and propensity score matching to account for immortal time bias and confounding by indication.

RESULTS

We identified 31 781 patients with incident gout matched to 122 961 controls. The absolute rate of fracture was similar in both cases and controls (absolute rate = 53 and 55 per 10 000 person-years, respectively) corresponding to an HR of 0.97 (95% confidence interval 0.92-1.02). Our finding remained unchanged when we stratified our analysis by age and sex. We did not observe statistically significant differences in the risk of fracture among those prescribed urate-lowering therapy within 1 and 3 years after gout diagnosis.

INTERPRETATION

Overall, gout was not associated with an increased risk of fracture. Urate-lowering drugs prescribed early during the course of disease had neither adverse nor beneficial effect on the long-term risk of fracture.

The Paradoxical Role of Uric Acid in Osteoporosis

Because of its high prevalence worldwide, osteoporosis is considered a serious public health concern. Many known risk factors for developing osteoporosis have been identified and are crucial if planning health care needs. Recently, an association between uric acid (UA) and bone fractures had been explored. Extracellular UA exhibits antioxidant properties by effectively scavenging free radicals in human plasma, but this benefit might be disturbed by the hydrophobic lipid layer of the cell membrane. In contrast, intracellular free oxygen radicals are produced during UA degradation, and superoxide is further enhanced by interacting with NADPH oxidase. This intracellular oxidative stress, together with inflammatory cytokines induced by UA, stimulates osteoclast bone resorption and inhibits osteoblast bone formation. UA also inhibits vitamin D production and thereby results in hyper-parathyroidism, which causes less UA excretion in the intestines and renal proximal tubules by inhibiting the urate transporter ATP-binding cassette subfamily G member 2 (ABCG2). At normal or high levels, UA is associated with a reduction in bone mineral density and protects against bone fracture. However, in hyperuricemia or gout arthritis, UA increases bone fracture risk because oxidative stress and inflammatory cytokines can increase bone resorption and decrease bone formation. Vitamin D deficiency, and consequent secondary hyperparathyroidism, can further increase bone resorption and aggravated bone loss in UA-induced osteoporosis.

Gout is not associated with the risk of fracture: a meta-analysis

BACKGROUND

Numerous quantitatively based studies measuring the association between gout and the risk of fractures remain inconclusive. In order to determine whether gout could increase the risk of fractures, a meta-analysis was performed systematically.

METHODS

Electronic databases, MEDLINE/PubMed, Embase, and Cochrane Library were systematically searched to identify studies evaluating the association of gout and the risk of fractures. No restrictions on language, publication date, or journal of publication were imposed. Meta-analysis was performed to pool the outcome estimates of interest such as fracture incidence, fracture risk, and fracture risk in different sites and at different time points in the follow-up period.

RESULTS

Screening determined that seven studies involving a total of 684,964 participants (151,002 in the gout group and 533,962 in the control group) were deemed viable for inclusion in the meta-analysis. The results of the analysis showed that gout would not significantly have a relatively higher risk of any fracture (RR = 1.11, 95% CI 0.98-1.26). Subgroup analysis showed consistent results for sexuality (female: RR = 1.13, 95% CI 0.93-1.37; male: RR = 0.99, 95% CI 0.91-1.07) and several occurring sites (humerus, wrist, vertebra, hip, upper limbs, and lower limbs). Additionally, the results demonstrated that urate-lowering drugs prescribed early during disease had neither adverse nor beneficial effect on the long-term risk of fractures (RR = 0.89, 95% CI 0.76-1.05).

CONCLUSIONS

This meta-analysis confirmed that gout was not associated with an increased risk of fractures. Urate-lowering drugs prescribed early during the course of disease had neither adverse nor beneficial effect on the long-term risk of fractures.

Bone mineral density and serum osteocalcin levels in patients with gout

Objective: The objective of the study is to evaluate the relation of gout with osteoporosis and serum osteocalcin (OC) levels. Material and methods: Seventy-five patients diagnosed with gout and 55 controls were included in the study. Comorbid conditions and drugs associated with osteoporosis were excluded. The T and Z scores from lumbar spine (L2-L4) and femur (neck, ward, trochanter, total) were determined by dual-energy X-ray absorptiometry (DXA). OC levels were measured by enzyme-linked immunosorbent assay. Results: Osteoporosis according to T scores of lumbar vertebrae L2-L4 was found to be significantly higher in patients with gout compared to the control group (p = 0.02). Lumbar spine T-score was -1.6 in gout group and -1.0 in controls. OC level was 7.9 ng/mL in the gout group and 18.9 ng/mL in the control group. There was a significant difference (p < 0.001). In addition, mean OC level was 12.4 ± 6.9 ng/mL in the patients diagnosed with osteoporosis and 17.2 ± 10.6 ng/mL in the patients that were classified as normal and a significant difference was established between the two groups (p = 0.03). A significant negative correlation was found between OC level and body mass index, age, and age at first attack. Similarly, femoral T-score established a negative correlation with parathyroid hormone, age, age at first attack, and allopurinol dose. Conclusion: Serum OC level can be a useful marker in the assessment of bone turnover and clinicians should keep osteoporosis in mind in gout patients.

Association of gout with osteoporotic fractures

PURPOSE

Previous studies have shown that serum uric acid levels and inflammation are associated with bone mineral density. Gout, a disease characterized by hyperuricemia and inflammation, contributes to the risk of osteoporotic fractures. However, this association is controversial. Therefore, this study investigated whether gout in older people (age > 55 years) is associated with osteoporotic fracture risk.

METHODS

This population-based, cross-sectional study included 2674 participants (147 cases of gout and 388 fractures). Standardized and self-administered questionnaires were employed and physical examinations, blood tests, and bone mineral density examinations were performed; multivariate-adjusted logistic regression models were used to evaluate associations between gout and osteoporotic fracture risk.

RESULTS

The data were adjusted for age; smoking status; alcohol status; physical activity; body mass index; waist circumference; hypertension; cardiovascular events; diabetes mellitus; rheumatoid arthritis; serum levels of total cholesterol (TC), triglycerides, and high- and low-density lipids; and T-scores. We found a significant association between gout and osteoporotic fracture risk in women (odds ratio [OR], 2.00; 95% confidence interval [CI], 1.12-3.56; P = 0.019), but no such association in men (OR, 1.30; 95% CI, 0.58-2.88; P = 0.525). Further stratified analyses showed a significant association between gout and osteoporotic fracture risk in women without rheumatic arthritis and in those with high TC levels or with osteoporosis (all, P < 0.05).

CONCLUSIONS

In older Chinese adults, gout is significantly associated with the risk of osteoporotic fractures in women, especially those without rheumatic arthritis and in those with high TC levels or with osteoporosis.

Gout as a risk factor for osteoporosis: epidemiologic evidence from a population-based longitudinal study involving 108,060 individuals

Is gout a risk factor for future osteoporosis? This large population-based study comprising two matched groups of individuals with and without gout demonstrates that patients with gout have a 20% increase in the risk of developing osteoporosis in future through an 8-year follow-up.

INTRODUCTION

To examine if gout is associated with an increased risk of osteoporosis.

METHODS

We conducted a nationwide population-based retrospective matched-cohort study. Two matched cohorts (n = 36,458 with gout and 71,602 without gout) assembled and recruited from the Longitudinal Health Insurance Dataset containing 1 million subjects. Exclusion criteria were missing data, age < 20 years, short follow-up period, and pre-existing osteoporosis. Both cohorts were followed up until incident osteoporosis, death, or the end of the study. Person-year data and incidence rates were evaluated. A multivariable Cox model was used to derive an adjusted hazard ratio (aHR) after controlling for socioeconomic proxy, geographical difference, glucocorticoid and allopurinol exposure, various prespecified medical conditions, and comorbidities.

RESULTS

Men comprised 72.8% of the cohorts. With a follow-up of 183,729 and 359,900 person-years for the gout and non-gout cohorts, 517 and 811 incidents of osteoporosis occurred, respectively, after excluding osteoporosis incidents in the first 3 years of follow-up. The cumulative incidence of osteoporosis was statistically higher in the gout cohort than in the non-gout cohort, at 3.3 versus 2.1% (P = 0.0036, log-rank). Our Cox model showed a 1.2-fold increase in the incidence of osteoporosis in the gout cohort, with an aHR of 1.2 (95% confidence interval, 1.06-1.35).

CONCLUSIONS

This first population-based epidemiologic study supports the hypothesis that compared with individuals without gout; those with gout have a modest increase in the risk of developing osteoporosis in future.

Lack of Evidence that Soluble Urate Directly Influences Bone Remodelling: A Laboratory and Clinical Study

INTRODUCTION

Numerous observational studies have reported that serum urate concentration positively correlates with bone density and reduced risk of fractures. The aim of this study was to examine whether soluble urate directly influences bone remodelling.

METHODS

In laboratory studies, the in vitro effects of soluble urate were examined in osteoclast, osteoblast and osteocyte assays at a range of urate concentrations consistent with those typically observed in humans (up to 0.70 mmol/L). The clinical relevance of the in vitro assay findings was assessed using serial procollagen-1 N-terminal propeptide (P1NP) and Month 12 bone density data from a randomised controlled trial of allopurinol dose escalation in people with gout.

RESULTS

Addition of urate in the RAW264.7 cell osteoclastogenesis assay led to small increases in osteoclast formation (ANOVA p = 0.018), but no significant difference in bone resorption. No significant effects on osteoclast number or activity were observed in primary cell osteoclastogenesis or resorption assays. Addition of urate did not alter viability or function in MC3T3-E1 pre-osteoblast, primary human osteoblast, or MLO-Y4 osteocyte assays. In the clinical trial analysis, reducing serum urate over a 12 month period by allopurinol dose escalation did not lead to significant changes in P1NP or differences in bone mineral density.

CONCLUSION

Addition of soluble urate at physiological concentrations does not influence bone remodelling in vitro. These data, together with clinical trial data showing no effect of urate-lowering on P1NP or bone density, do not support a direct role for urate in influencing bone remodelling.

Pathological Fracture of the Proximal Tibia from an Intraosseous Gouty Tophus: A Rare Presentation of Gout

Intraosseous gouty tophus as the cause of pathological fracture is a seldom encountered condition. Not only does the tophus lesion affect the bone, but recent literature has also demonstrated a correlation between bone health in relation to gout as a disease entity, and showed the importance of medical treatment to improve the bone quality in patients with gout. We present a rare case of a pathological fracture due to an intraosseous gouty tophus as the presentation of gout, which imposed a diagnostic challenge, and illustrates the importance of multidisciplinary management in such conditions.