Prevalence of Nonalcoholic Fatty Liver Disease in Patients With Rheumatoid Arthritis: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Previous studies have shown a potential association between nonalcoholic fatty liver disease (NAFLD) and some immune-mediated inflammatory diseases, such as rheumatoid arthritis (RA), but this association has not been analyzed systematically. Therefore, we aimed to perform a systematic review and meta-analysis to ascertain a pooled prevalence estimate of NAFLD among patients with RA to fill this gap in knowledge.

METHODS

We conducted a literature search in PubMed, Embase, Web of Science, Scopus, and ProQuest, for observational studies published from inception to August 31, 2022, which reported prevalence of NAFLD in 100 or more adult (age, ≥18 y) patients with RA. To be included, NAFLD diagnosis was based on either imaging or histologic assessment. The results were presented as pooled prevalence, odds ratio, and 95% CI. The I2 statistic was used to measure the heterogeneity between studies.

RESULTS

This systematic review included 9 eligible studies derived from 4 continents comprising 2178 patients (78.8% women) with RA. The pooled prevalence of NAFLD was 35.3% (95% CI, 19.9-50.6; I2 = 98.6%; P < .001) in patients with RA. All studies used ultrasound for the diagnosis of NAFLD, except for 1 study that used transient elastography. The pooled prevalence of NAFLD in men with RA was significantly higher than in women with RA (35.2%; 95% CI, 24.0-46.5 compared with 22.2%; 95% CI, 17.9-26.58; P for interaction = .048). Each 1-unit increase in body mass index was associated directly with a 24% increased risk of NAFLD in RA patients (adjusted odds ratio, 1.24; 95% CI, 1.17-1.31; I2 = 0.0%; P = .518).

CONCLUSIONS

Based on this meta-analysis, 1 in 3 patients with RA had NAFLD, which appears comparable with its overall prevalence among the general population. Clinicians should actively screen for NAFLD in patients with RA.

Transition of Methotrexate Polyglutamate Drug Monitoring Assay from Venipuncture to Capillary Blood-Based Collection Method in Rheumatic Diseases

Objective

Methotrexate (MTX) polyglutamate (MTXPG3) levels from isolated red blood cells (RBCs) collected by venipuncture have clinical utility in guiding MTX dosing for patients with rheumatoid arthritis (RA). Our objective was to transition this RBC-based therapeutic drug monitoring (TDM) assay to dried capillary blood collected by fingerstick.

Methods

Patients with RA treated with MTX were enrolled. Specimens were collected by fingerstick (volumetric absorptive microsampler) and venipuncture to measure MTXPG3 from dried capillary blood, total venous blood, and isolated RBCs. MTXPG3 levels from dried capillary blood were measured using LC-MS/MS, converted to RBC equivalent (nmol/L), and compared with those from isolated RBCs (reference method). Following transition to fingerstick collection, comparability in the distributions of dried capillary and venipuncture-based RBC MTXPG3 levels was assessed using the Kolmogorov–Smirnov (K-S) test.

Results

Intraday and interday precision ranged from 2.0% to 10.9% and 3.1% to 10.8%, respectively, at MTXPG3 concentrations ranging from 5 to 100 nmol/L. In 106 participants treated with MTX, MTXPG3 levels from total venous and dried capillary blood were comparable [slope = 0.97 (95% CI, 0.92–1.03); R2 = 0.92]. Dried capillary blood MTXPG3 converted to RBC equivalent was similar to levels from isolated RBCs (30 ± 18 nmol/L vs 33 ± 19 nmol/L; n = 106). After implementation in the clinical laboratory, RBC equivalents MTXPG3 from the fingerstick method were similar to levels from venipuncture [39 ± 22 nmol/L (n = 825) vs 39 ± 24 nmol/L (n = 47935)] (K-S test P = 0.09). Underexposure to MTX (MTXPG3 ≤5 nmol/L RBCs) was detected in 7.0% and 8.5% patient specimens collected using the fingerstick and venipuncture methods, respectively.

Conclusion

Capillary blood MTXPG3 levels can be used to guide MTX dosing in TDM practice.

Capillary blood collected on volumetric absorptive microsampling (VAMS) device for monitoring hydroxychloroquine in rheumatoid arthritis patients

A novel technique for collection of capillary blood, termed volumetric absorptive microsampling (VAMS), has been recently cleared by the FDA for collection of human blood. VAMS absorbs a fixed volume of blood (10μl) and overcomes area bias and homogeneity issues associated with dried blood spot (DBS). This study is the application of VAMS for therapeutic drug monitoring (TDM) in human capillary blood. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) workflow for analysis of VAMS sample was developed and validated. Concentration of hydroxychloroquine (HCQ) and its metabolites, desethylhydroxychloroquine (DHCQ), desethylchloroquine (DCQ), and bisdesethylchloroquine (BDCQ), in capillary blood on VAMS sampler were compared to those in venous blood in rheumatoid arthritis patients. Feasibility of capillary blood collected on both VAMS and DBS card were evaluated on patients. Stability of dried capillary blood on VAMS was also examined. Our results established that VAMS is a simple and accurate sampling technique that delivers the benefits of DBS sampling while overcoming the issues associated with hematocrit and homogeneity. It requires a small blood volume, simplifies sample logistics management, and may allow sample collection in the patient's home setting.

Cell-bound complement activation products in systemic lupus erythematosus: comparison with anti-double-stranded DNA and standard complement measurements

OBJECTIVE

To compare the performance characteristics of cell-bound complement (C4d) activation products (CBCAPS) on erythrocyte (EC4d) and B cells (BC4d) with antibodies to double-stranded DNA (anti-dsDNA) and complement C3 and C4 in systemic lupus erythematosus (SLE).

METHODS

The study enrolled 794 subjects consisting of 304 SLE and a control group consisting of 285 patients with other rheumatic diseases and 205 normal individuals. Anti-dsDNA and other autoantibodies were measured using solid-phase immunoassays while EC4d and BC4d were determined using flow cytometry. Complement proteins were determined using immunoturbidimetry. Disease activity in SLE was determined using a non-serological Systemic Lupus Erythematosus Disease Activity Index SELENA Modification. A two-tiered methodology combining CBCAPS with autoantibodies to cellular and citrullinated antigens was also developed. Statistical analyses used area under receiver operating characteristic curves and calculations of area under the curve (AUC), sensitivity and specificity.

RESULTS

AUC for EC4d (0.82±0.02) and BC4d (0.84±0.02) was higher than those yielded by C3 (0.73±0.02) and C4 (0.72±0.02) (p<0.01). AUC for CBCAPS was also higher than the AUC yielded by anti-dsDNA (0.79±0.02), but significance was only achieved for BC4d (p<0.01). The combination of EC4d and BC4d in multivariate testing methodology with anti-dsDNA and autoantibodies to cellular and citrullinated antigens yielded 80% sensitivity for SLE and specificity ranging from 70% (Sjogren's syndrome) to 92% (rheumatoid arthritis) (98% vs. normal). A higher proportion of patients with SLE with higher levels of disease activity tested positive for elevated CBCAPS, reduced complement and anti-dsDNA (p<0.03).

CONCLUSIONS

CBCAPS have higher sensitivity than standard complement and anti-dsDNA measurements, and may help with the differential diagnosis of SLE in combination with other autoantibodies.

Long-term effects of combination treatment with fludarabine and low-dose pulse cyclophosphamide in patients with lupus nephritis

OBJECTIVES

To determine the safety and efficacy of a short course of fludarabine combined with cyclophoshamide in lupus nephritis.

METHODS

A phase I/II open label pilot study. Thirteen patients with active proliferative lupus nephritis received monthly oral boluses of low-dose cyclophoshamide (0.5 gm/m(2) on day 1) and subcutaneous fludarabine (30 mg/m(2) on days 1-3) for 3-6 cycles. Concomitant prednisone was aggressively tapered from 0.5 mg/kg/day to a low-dose, alternate-day schedule. Patients were followed for at least 24 months after therapy. The primary outcome was the number of patients achieving renal remission defined as stable creatinine, proteinuria <1 gm/day and inactive urine sediment for at least 6 months.

RESULTS

The study was terminated early because of bone marrow toxicity. Eleven patients who received at least three cycles were evaluated for efficacy. Ten patients improved markedly with seven patients achieving complete remission and three patients achieving partial remission. There were three serious haematological adverse events during the treatment with one death due to transfusion-associated graft vs host disease. Profound and prolonged CD4 (mean CD4: 98/microl at 7 months and 251/microl at 12 months) and CD20 lymphocytopenia was noted in most patients. Three patients developed Herpes zoster infections.

CONCLUSIONS

A short course of low-dose fludarabine and cyclophoshamide can induce long-lasting remissions in patients with proliferative lupus nephritis, but severe myelosuppression limits its widespread use.

Dominant unc-37 mutations suppress the movement defect of a homeodomain mutation in unc-4, a neural specificity gene in Caenorhabditis elegans

The unc-4 gene of Caenorhabditis elegans encodes a homeodomain protein that defines synaptic input to ventral cord motor neurons. unc-4 mutants are unable to crawl backward because VA motor neurons are miswired with synaptic connections normally reserved for their sister cells, the VB motor neurons. These changes in connectivity are not accompanied by any visible effects upon neuronal morphology, which suggests that unc-4 regulates synaptic specificity but not axonal guidance or outgrowth. In an effort to identify other genes in the unc-4 pathway, we have devised a selection scheme for rare mutations that suppress the Unc-4 phenotype. We have isolated four, dominant, extragenic, allele-specific suppressors of unc-4(e2322ts), a temperature sensitive allele with a point mutation in the unc-4 homeodomain. Our data indicate that these suppressors are gain-of-function mutations in the previously identified unc-37 gene. We show that the loss-of-function mutation unc-37(e262) phenocopies the Unc-4 movement defect but does not prevent unc-4 expression or alter VA motor neuron morphology. These findings suggest that unc-37 functions with unc-4 to specify synaptic input to the VA motor neurons. We propose that unc-37 may be regulated by unc-4. Alternatively, unc-37 may encode a gene product that interacts with the unc-4 homeodomain.