Nitrates Do Not Affect Bone Density or Bone Turnover in Postmenopausal Women: A Randomized Controlled Trial

Organic nitrates have been reported to have significant effects on bone mineral density (BMD) and bone turnover in previous clinical trials. However, results are inconsistent and some trials with strikingly positive results have been retracted because of scientific misconduct. As preparation for a potential fracture prevention study, we set out to determine the lowest effective dose and the most effective and acceptable nitrate preparation. We undertook a 1-year, double-blind, randomized, placebo-controlled trial of three different nitrate preparations and two different doses in osteopenic postmenopausal women, with a planned 1-year observational extension. The primary endpoint was change in BMD at the lumbar spine, and secondary endpoints included BMD changes at other sites, changes in bone turnover markers, and adverse events. A total of 240 eligible women who tolerated low-dose oral nitrate treatment in a 2-week run-in period were randomized to five different treatment groups or placebo. Over 12 months, there were no statistically significant between-group differences in changes in BMD at any site and no consistent differences in bone turnover markers. When the active treatment groups were pooled, there were also no differences in changes in BMD or bone turnover markers between nitrate treatment and placebo. Eighty-eight (27%) women withdrew during the run-in phase, with the majority because of nitrate-induced headache, and 41 of 200 (21%) women randomized to nitrate treatment withdrew or stopped study medication during the 1-year study compared with 1 of 40 (2.5%) in the placebo group. In summary, organic nitrates do not have clinically relevant effects on BMD or bone turnover in postmenopausal women and were poorly tolerated. These results call into question the validity of previous clinical research reporting large positive effects of nitrates on BMD and bone turnover. © 2020 American Society for Bone and Mineral Research.

Minimal Important Difference in Voice Handicap Index-10

Importance

The minimal important difference (MID) on patient-reported outcome measures can indicate how much of a change on that scale is meaningful.

Objective

To use an anchor-based approach to estimate MID in the Voice Handicap Index-10 (VHI-10) total score.

Design, Setting, and Participants

In this cohort study, a volunteer sample of adult patients visiting the voice clinic at the University of Minnesota from April 7, 2013, through July 3, 2016, completed the VHI-10 (range, 0-40, with higher scores indicating greater voice-related handicap) at baseline and 2 weeks later in conjunction with a global rating of change. An anchor-based approach was used to identify an MID. The association between the global change score and change in VHI-10 score was analyzed using Pearson rank correlation. A distribution-based method was used to corroborate the findings.

Main Outcome and Measures

Global rating of change on the VHI-10.

Results

Of the 273 participants, 183 (67.0%) were women and 90 (33.0%) were men (mean [SD] age, 54.3 [15.6] years); 259 (94.9%) were white. Participants had a variety of voice disorders, most commonly muscle tension dysphonia, irritable larynx, benign vocal fold lesions, and motion abnormalities. Among patients reporting no change on the global change score, the mean (SD) change in VHI-10 score was 1 (5). Among those reporting a small change, the mean (SD) change in VHI-10 was also 1 (5). Among those reporting a moderate change in voice symptoms, the mean (SD) change in VHI-10 score was 6 (8). Among those with a large change, the mean (SD) change in VHI-10 score was 9 (13). The correlation between the global change score and the change in VHI-10 score was 0.32 (95% CI, 0.12-0.49). Distribution-based analyses identified effect sizes comparable to those of the anchor-based categories.

Conclusions and Relevance

These findings suggest that a difference of 6 on the VHI-10 may represent an MID. This difference was associated with a moderate change on the global rating scale, and the small-change and no-change categories were indistinguishable. Given the lack of differentiation between small and no change and the modest correlation between the global change score and change in the VHI-10 score, additional studies are needed.

Factors associated with change in radiographic damage scores in gout: a prospective observational study

BACKGROUND/AIMS

Radiographic damage is frequently observed in patients with longstanding gout. The aim of this prospective observational study was to determine factors associated with change in radiographic damage scores in gout.

METHODS

People with gout and disease duration <10 years were recruited into this prospective observational study. At the baseline visit, structured assessment was undertaken in 290 participants including detailed clinical examination and plain radiographs (XR) of the hands and feet. Participants were invited to attend a further study visit with repeat XR 3 years after the baseline visit. XR were scored for erosion and joint space narrowing according to the gout-modified Sharp/van der Heijde XR damage score.

RESULTS

Age, subcutaneous tophus count and tender joint count were independently associated with XR damage score at the baseline visit. Paired serial XR were available for 140 participants. In stepwise linear regression analysis, change in total damage score over 3 years was positively associated with change in subcutaneous tophus count and baseline XR damage score, and inversely associated with baseline subcutaneous tophus count (model R²=0.39, p<0.001). Change in subcutaneous tophus count contributed most to the change in erosion score (partial R² change=0.31, p<0.001), and baseline XR damage score contributed most to the change in narrowing score (partial R² change=0.31, p<0.001).

CONCLUSIONS

Development of new subcutaneous tophi and baseline radiographic damage are associated with progressive joint damage scores in people with gout. These data provide further evidence that the tophus plays a central role in bone erosion in gout.

Body mass index modulates the relationship of sugar-sweetened beverage intake with serum urate concentrations and gout

Introduction

Both sugar-sweetened beverage (SSB) intake and body mass index (BMI) are associated with elevated serum urate concentrations and gout risk. The aim of this study was to determine whether the associations of SSB intake with serum urate and gout are moderated by BMI.

Method

The effects of chronic SSB intake on serum urate and gout status were analysed in a large cross-sectional population study. The effects of an acute fructose load on serum urate and fractional excretion of uric acid (FEUA) were examined over 180 minutes in a short-term intervention study. In all analyses, the responses were compared in those with BMI <25 mg/kg² (low BMI) and ≥25 mg/kg² (high BMI).

Results

In the serum urate analysis (n = 12,870), chronic SSB intake was associated with increased serum urate in the high BMI group, but not in the low BMI group (P_difference = 3.6 × 10⁻³). In the gout analysis (n = 2578), chronic high SSB intake was associated with gout in the high BMI group, but not in the low BMI group (P_difference = 0.012). In the acute fructose loading study (n = 76), serum urate was increased in the high BMI group at baseline and throughout the observation period (P_{BMI group} <0.0001), but there were similar acute serum urate increases in both BMI groups in response to the fructose load (P_interaction = 0.99). The baseline FEUA was similar between the two BMI groups. However, following the fructose load, FEUA responses in the BMI groups differed (P_interaction <0.0001), with increased FEUA at 120 minutes and 180 minutes in the low BMI group and reduced FEUA at 60 minutes in the high BMI group.

Conclusions

These data suggest that BMI influences serum urate and gout risk in response to chronic SSB intake, and renal tubular uric acid handling in response to an acute fructose load. In addition to many other health benefits, avoidance of SSBs may be particularly important in those with overweight/obesity to prevent hyperuricaemia and reduce gout risk.

Trials registration

Australian Clinical Trials Registry ACTRN12610001036000. Registered 24 November 2010.

Urate crystal deposition in asymptomatic hyperuricaemia and symptomatic gout: a dual energy CT study

BACKGROUND

The aim of this study was to compare the frequency and volume of dual energy CT (DECT) urate deposits in people with asymptomatic hyperuricaemia and symptomatic gout.

METHODS

We analysed DECT scans of the feet from asymptomatic individuals with serum urate ≥540 µmol/L (n=25) and those with crystal proven gout without clinically apparent tophi (n=33).

RESULTS

DECT urate deposits were observed in 6/25 (24%) participants with asymptomatic hyperuricaemia, 11/14 (79%) with early gout (predefined as disease duration ≤3 years) and 16/19 (84%) with late gout (p<0.001). DECT urate deposition was observed in both joints and tendons in the asymptomatic hyperuricaemia group, but significantly less frequently than in those with gout (p≤0.001 for both joint and tendon sites). The volume of urate deposition was also significantly lower in those with asymptomatic hyperuricaemia, compared with the early and the late gout groups (p<0.01 for both comparisons). Similar urate volumes were observed in the early and late gout groups.

CONCLUSIONS

Although subclinical urate deposition can occur in people with asymptomatic hyperuricaemia, these deposits occur more frequently and at higher volumes in those with symptomatic gout. These data suggest that a threshold of urate crystal volume may be required before symptomatic disease occurs.

Development of a patient-reported outcome measure of tophus burden: the Tophus Impact Questionnaire (TIQ-20)

Background

Tophus burden is currently measured using physical examination and imaging methods. The aim of this study was to develop a patient-reported outcome (PRO) tool to assess tophus burden in people with gout.

Methods

The responses from interviews with 25 people with tophaceous gout were used to generate items for a preliminary PRO tool. Following cognitive testing of each item, a preliminary 34-item questionnaire was administered to 103 people with tophaceous gout. Rasch analysis generated a 20-item Tophus Impact Questionnaire (TIQ-20). Test-retest reproducibility and construct validity of the TIQ-20 were assessed.

Results

The TIQ-20 responses fit the Rasch model and demonstrated unidimensionality, adequate precision, absence of differential item functioning and adequate person separation index. The TIQ-20 included items related to pain, activity limitation, footwear modification, participation, psychological impact and healthcare use due to tophi. In the 103 patients with tophaceous gout, floor effects were observed in 4.9% and ceiling effects in 1%. The TIQ-20 test-retest intraclass correlation coefficient was 0.76 (95% CI 0.61 to 0.85). All predicted correlations for construct validity testing were observed, including weak correlation with serum urate concentrations (r<0.30), moderate correlation with subcutaneous tophus count and dual energy CT urate volume (r=0.30–0.50), and stronger correlation with Health Assessment Questionnaire scores (r>0.50).

Conclusions

We have developed a tophus-specific PRO in patients with tophaceous gout. The TIQ-20 demonstrates acceptable psychometric properties. Initial results show internal, face and construct validity, reproducibility and feasibility. Further research is required to determine responsiveness to change.

Influence of the ABCG2 gout risk 141 K allele on urate metabolism during a fructose challenge

INTRODUCTION

Both genetic variation in ATP-binding cassette sub-family G member 2 (ABCG2) and intake of fructose-containing beverages are major risk factors for hyperuricemia and gout. This study aimed to test the hypothesis that the ABCG2 gout risk allele 141 K promotes the hyperuricaemic response to fructose loading.

METHODS

Healthy volunteers (n = 74) provided serum and urine samples immediately before and 30, 60, 120 and 180 minutes after ingesting a 64 g fructose solution. Data were analyzed based on the presence or absence of the ABCG2 141 K gout risk allele.

RESULTS

The 141 K risk allele was present in 23 participants (31%). Overall, serum urate (SU) concentrations during the fructose load were similar in those with and without the 141 K allele (PSNP = 0.15). However, the 141 K allele was associated with a smaller increase in SU following fructose intake (PSNP <0.0001). Those with the 141 K allele also had a smaller increase in serum glucose following the fructose load (PSNP = 0.002). Higher fractional excretion of uric acid (FEUA) at baseline and throughout the fructose load was observed in those with the 141 K risk allele (PSNP <0.0001). However, the change in FEUA in response to fructose was not different in those with and without the 141 K risk allele (PSNP = 0.39). The 141 K allele effects on serum urate and glucose were more pronounced in Polynesian participants and in those with a body mass index ≥25 kg/m².

CONCLUSIONS

In contrast to the predicted responses for a hyperuricemia/gout risk allele, the 141 K allele is associated with smaller increases in SU and higher FEUA following a fructose load. The results suggest that ABCG2 interacts with extra-renal metabolic pathways in a complex manner to regulate SU and gout risk.

CLINICAL TRIALS REGISTRATION

The study was registered by the Australian Clinical Trials Registry (ACTRN12610001036000).

Reduced creatinine clearance is associated with early development of subcutaneous tophi in people with gout

Background

Although typically a late feature of gout, tophi may present early in the course of disease. The aim of this study was to identify factors associated with the presence of early tophaceous disease.

Methods

People with gout for <10 years were prospectively recruited, and had a comprehensive clinical assessment including examination for subcutaneous tophi. The clinical factors independently associated with the presence and number of tophi were analyzed using regression models.

Results

Of the 290 participants, there were 47 (16.2%) with clinically apparent tophi. In univariate analysis, those with tophi were older, were more frequently taking diuretics and colchicine prophylaxis, and had lower creatinine clearance. The association between the presence of tophi and creatinine clearance was strongest in those with creatinine clearance ≤30 ml/min. In logistic regression analysis, creatinine clearance ≤30 ml/min was associated with the presence of tophi, even after adjusting for ethnicity, corticosteroid use, colchicine use and diuretic use (multivariate adjusted odds ratio 7.0, p = 0.005). Participants with tophi reported higher frequency of gout flares, pain scores, patient global assessment scores, and HAQ scores.

Conclusions

The presence of tophi is associated with more symptomatic disease in people with gout for <10 years. Creatinine clearance is independently associated with early presentation of subcutaneous tophi.

No reduction in circulating preosteoclasts 18 months after treatment with zoledronate: analysis from a randomized placebo controlled trial

The conventional model that bisphosphonates bind to the bone surface and inhibit mature osteoclasts does not convincingly explain the prolonged duration of action of zoledronate. We hypothesized that zoledronate on the bone surface adjacent to marrow cells impairs osteoclastogenesis, contributing to sustained inhibition of resorption. In this case, numbers of circulating preosteoclasts may be reduced after zoledronate treatment. This study assessed this possibility in subjects from a clinical trial. Twenty-two osteopenic women participating in a randomized, controlled trial comparing zoledronate 5 mg with placebo were recruited, 18 months after administration of study drug. Peripheral blood mononuclear cells were analyzed for the presence of osteoclast precursors using flow cytometry for preosteoclast markers and the ability to form osteoclast-like cells in culture with RANKL and M-CSF. There was no difference in the percentage of CD14(+)/CD11b(+) cells in peripheral blood between the two groups. The numbers of TRAP(+) multinucleated cells in cultures in the absence of RANKL and M-CSF were very low in both groups, but a significantly higher number of these cells was observed in the zoledronate group compared with the placebo group (p = 0.01). The number of TRAP(+) multinucleated cells and resorption pits following culture with RANKL and M-CSF did not differ between the two groups. Serum P1NP was reduced 53 % at 18 months in the zoledronate group but unchanged in the placebo group. These results do not support the hypothesis that the inhibitory action of zoledronate contributes to its prolonged action on preosteoclasts within bone marrow.

Prescription and dosing of urate-lowering therapy, rather than patient behaviours, are the key modifiable factors associated with targeting serum urate in gout

Background

Long term serum urate (SU) lowering to a target of <0.36 mmol/l (6 mg/dl) is recommended for effective gout management. However, many studies have reported low achievement of SU targets. The aim of this cross-sectional study was to examine the clinical and psychological factors associated with SU targets in patients with gout.

Methods

Patients with gout for <10 years were recruited from primary and secondary care settings. SU target was defined as SU concentration <0.36 mmol/L at the time of the study visit. Both clinical and psychological factors associated with SU target were analysed. The relationship between SU target and measures of gout activity such as flare frequency, tophi, work absences, and Health Assessment Questionnaire-II was also analysed.

Results

Of the 273 patients enrolled into the study, 89 (32.6%) had SU concentration <0.36 mmol/L. Urate-lowering therapy (ULT) use was strongly associated with SU target (p < 0.001). In those patients prescribed ULT (n = 181), allopurinol dose, patient confidence to keep SU under control, female sex, and ethnicity were independently associated with SU target. Other patient psychological measures and health-related behaviours, including adherence scores, were not independently associated with SU target in those taking ULT. Creatinine clearance, diuretic use, age, and body mass index were not associated with SU target. Patients at SU target reported lower gout flare frequency, compared with those not at target (p = 0.03).

Conclusions

ULT prescription and dosing are key modifiable factors associated with achieving SU target. These data support interventions focusing on improved use of ULT to optimise outcomes in patients with gout.