Risk of Arrhythmia Among New Users of Hydroxychloroquine in Rheumatoid Arthritis and Systemic Lupus Erythematosus: A Population-Based Study.

OBJECTIVES: We assessed the association between hydroxychloroquine (HCQ) initiation and risk of arrhythmia among patients with incident rheumatoid arthritis (RA) or with incident systemic lupus erythematosus (SLE). METHODS: All patients with incident RA or SLE and no arrhythmic events, not receiving antiarrhythmic medications, and not receiving HCQ prior to the index date of disease in British Columbia, Canada, between January 1996 and December 2014 were identified from administrative databases. We identified patients who were dispensed HCQ prescriptions (HCQ initiators) or were not dispensed HCQ prescriptions (HCQ noninitiators) during each study year; groups were matched 1:1 by propensity scores using baseline confounders on demographics, comorbidities, medications, and health care utilization. Outcomes were any new arrhythmias, atrial fibrillation, abnormal electrocardiograms, including long QT syndrome and conduction disorder, and other unspecified arrhythmias during follow-up. We used cause-specific Cox proportional hazards models with death as a competing event to assess the association between HCQ initiation and the outcomes. RESULTS: We identified 11,518 propensity score-matched patients with RA or SLE in each group. Over the mean follow-up of 8 years, there were 1,610 and 1,646 incident arrhythmias in the HCQ initiator group and the noninitiator group, respectively, with crude incidence rates of arrhythmia of 17.5 and 18.1 in 1,000 persons per year, respectively. The adjusted cause-specific hazard ratio (cHR) for patients who received HCQ was 0.96 (95% confidence interval [95% CI] 0.89-1.03) compared with HCQ noninitiators, and the cHRs for patients who took HCQ and had arrhythmia subtypes of atrial fibrillation, abnormal electrocardiograms, and other unspecified arrhythmias were 0.93 (95% CI 0.83-1.04), 0.98 (95% CI 0.87-1.11), and 0.95 (95% CI 0.84-1.07), respectively. CONCLUSION: Risk of any type of arrhythmia was not increased among new users of HCQ.

Predictors of disease relapse in IgG4-related disease following rituximab.

OBJECTIVE: IgG4-related disease (IgG4-RD) is a relapsing-remitting condition responsible for fibroinflammatory lesions that can lead to organ damage and life-threatening complications at nearly any anatomical site. The duration of remission following treatment varies and predictors of relapse are unclear. The objectives of this study were to review our experience with rituximab as remission induction in IgG4-RD, to clarify the duration of efficacy and to identify predictors of flare following treatment. METHODS: In this retrospective cohort study, all patients were treated with two doses of rituximab (1 g) separated by 15 days. Clinical, radiographic and laboratory data pertaining to rituximab response and disease relapse were collected from the electronic medical record. Kaplan-Meier curves were constructed to estimate the time to disease relapse. Log-rank analyses were performed to compare times to relapse among subgroups. Potential relapse predictors were evaluated with Cox regression analysis. RESULTS: Fifty-seven of 60 patients (95%) had clinical responses to rituximab. Forty-one patients (68%) were treated without glucocorticoids. Twenty-one patients (37%) experienced relapses following treatment at a median time from the first infusion of 244 days. Baseline concentrations of serum IgG4, IgE and circulating eosinophils predicted subsequent relapses, with hazard ratios of 6.2 (95% CI: 1.2, 32.0), 8.2 (95% CI: 1.4, 50.0) and 7.9 (95% CI: 1.8, 34.7), respectively. The higher the baseline values, the greater the risk of relapse and the shorter the time to relapse. Only 10% of the patients had elevations of all three major risk factors, underscoring the importance of measuring all three at baseline. CONCLUSION: Baseline elevations in serum IgG4, IgE and blood eosinophil concentrations all predict IgG4-RD relapses independently.

The Toll-Like Receptor 4 (TLR4) Variant rs2149356 and Risk of Gout in European and Polynesian Sample Sets.

Deposition of crystallized monosodium urate (MSU) in joints as a result of hyperuricemia is a central risk factor for gout. However other factors must exist that control the progression from hyperuricaemia to gout. A previous genetic association study has implicated the toll-like receptor 4 (TLR4) which activates the NLRP3 inflammasome via the nuclear factor-κB signaling pathway upon stimulation by MSU crystals. The T-allele of single nucleotide polymorphism rs2149356 in TLR4 is a risk factor associated with gout in a Chinese study. Our aim was to replicate this observation in participants of European and New Zealand Polynesian (Maori and Pacific) ancestry. A total of 2250 clinically-ascertained prevalent gout cases and 13925 controls were used. Non-clinically-ascertained incident gout cases and controls from the Health Professional Follow-up (HPFS) and Nurses Health Studies (NHS) were also used. Genotypes were derived from genome-wide genotype data or directly obtained using Taqman. Logistic regression analysis was done including age, sex, diuretic exposure and ancestry as covariates as appropriate. The T-allele increased the risk of gout in the clinically-ascertained European samples (OR = 1.12, P = 0.012) and decreased the risk of gout in Polynesians (OR = 0.80, P = 0.011). There was no evidence for association in the HPFS or NHS sample sets. In conclusion TLR4 SNP rs2143956 associates with gout risk in prevalent clinically-ascertained gout in Europeans, in a direction consistent with previously published results in Han Chinese. However, with an opposite direction of association in Polynesians and no evidence for association in a non-clinically-ascertained incident gout cohort this variant should be analysed in other international gout genetic data sets to determine if there is genuine evidence for association.

Statin use and mortality in rheumatoid arthritis: a general population-based cohort study.

BACKGROUND: Dual lipid-lowering and anti-inflammatory properties of statins may lead to survival benefits in patients with rheumatoid arthritis (RA). However, data on this topic are limited, and the role of statins in RA remains unclear. OBJECTIVES: To examine the association of statin use with overall mortality among patients with RA in a general population context. METHODS: We conducted an incident user cohort study with time-stratified propensity score matching using a UK general population database. The study population included individuals aged ≥20 years who had a diagnosis of RA and had used at least one disease-modifying antirheumatic drug (DMARD) between January 2000 and December 2012. To closely account for potential confounders, we compared propensity score matched cohorts of statin initiators and comparators (non-initiators) within 1-year cohort accrual blocks. RESULTS: 432 deaths occurred during follow-up (mean 4.51 years) of the 2943 statin initiators for an incidence rate of 32.6/1000 person-years (PY), while the 513 deaths among 2943 matched comparators resulted in an incidence rate of 40.6/1000 PY. Baseline characteristics were well-balanced across the two groups. Statin initiation was associated with a 21% lower risk of all-cause mortality (HR=0.79, 95% CI 0.68 to 0.91). When we defined RA by its diagnosis code alone (not requiring DMARD use), the corresponding HR was 0.81 (95% CI 0.74 to 0.90). CONCLUSIONS: Statin initiation is associated with a lower risk of mortality among patients with RA. The magnitude of association is similar to that seen in previous randomised trials among the general population.

The Interaction Between Like-Charged Nanoparticles Mediated by Rod-Like Ions.

We present a brief review of recent studies of the interaction between charged nanoparticles immersed in a solution of oppositely charged rod-like counterions. To analyze these systems, we extend and employ an approximate field theory for point charges that has been shown to be accurate from the weak to the intermediate through to the strong coupling regimes. The resulting theory compares well with simulation data. We find that in the weak coupling limit, the interactions between the plates in the rod system are only repulsive. In the intermediate coupling regime, the multivalent rod-like counterions can mediate attractive interactions between the nanoparticles through two mechanisms. Charge correlations between different counterion rods lead to attractions between the plates, as in the case for the point charge counterions. For sufficiently long rods, however, bridging contributes to the attractive interaction, where the correlation of the charges within the rods is important. In the strong coupling limit, the inter-ionic charge correlations dominate the attractive interactions at short separations between the charged nanoparticles.