Hyperhomocysteinemia in ankylosing spondylitis: prevalence and association with clinical variables

Association of homocysteine with ankylosing spondylitis: a systematic review and meta-analysis

Background

Hyperhomocysteinemia is associated with autoimmune diseases such as ankylosing spondylitis (AS), systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA). Current findings regarding plasma/serum homocysteine (HCY) levels in AS patients are inconsistent. This study aims to systematically evaluate the association between circulating HCY levels and AS.

Methods

Online electronic databases (PubMed, Web of Science, Embase, ScienceDirect, China National Knowledge Infrastructure (CNKI), and Wanfang data) were used to retrieve all relevant articles published up to May 7, 2020. The pooled standardized mean difference (SMD) with 95% confidence interval (CI) was calculated using the random-effect model, Stata16 software.

Results

Nine articles containing 778 AS patients and 522 controls were included in this meta-analysis. No significant differences in HCY levels were found between AS and control groups (pooled SMD = 0.46, 95% CI = − 0.30 to 1.23, P = 0.23). However, subgroup analysis suggested that HCY levels were significantly higher (P < 0.05) in the AS group treated with methotrexate (MTX) compared with the control group. In contrast, HCY levels were significantly (P < 0.05) lower in the AS group receiving anti-TNF-α treatment compared with the control group. No significant differences were detected between HCY levels and disease activity scores (Bath AS disease activity index, BASDAI), and methylenetetrahydrofolate reductase (MTHFR) C677T genotype.

Conclusion

This meta-analysis indicates that HCY levels are similar between AS and controls, and do not correlate with disease activity. However, different medical treatments cause fluctuations of circulating HCY levels in AS patients. Further and larger-scale studies are needed to confirm these findings.

Trial registration

This study was registered at international prospective register of systematic reviews (PROSPERO), registration number: CRD42020184426.

Comorbidities in Spondyloarthritis

Comorbidities in spondyloarthritis (SpA) add to the burden of disease by contributing to disease activity, functional and work disability, and mortality. Thus, awareness of comorbidities in SpA is crucial to improve their screening and management and to ultimately improve outcomes in those affected. Osteoporosis has been reported to be the most prevalent comorbidity in SpA, and its risk is increased in these patients, compared with the general population; the risk of vertebral fractures requires further evaluation. Cardiovascular risk is also increased in this population, both due to an increase of the traditional cardiovascular risk factors in these patients, but also due to the presence of inflammation. The role of non-steroidal anti-inflammatory drugs in this increased risk needs further elucidation, but there is consensus on the need to encourage smoking cessation and to perform periodic evaluation of cardiovascular risk in these patients, particularly in the case of change in treatment course. Concerning the risk of cancer, no increased risk inherent to SpA seems to exist. However, an increased neoplastic risk can occur due to SpA treatments, e.g., P-UVA. Data are sparse on the risk of infections compared with rheumatoid arthritis, but there appears to be no risk in the absence of TNF-inhibitor exposure. Regardless of which comorbidity, a gap exists between recommendations for their management and actual implementation in clinical practice, suggesting that there is still a need for improvement in this area. Systematic screening for these comorbidities should improve both short- and long-term outcomes in SpA patients.

Cardiovascular profile in ankylosing spondylitis: a systematic review and meta-analysis

OBJECTIVE

Rheumatoid arthritis is associated with increased cardiovascular risk. In ankylosing spondylitis (AS), there is a paucity of information concerning this risk. Our objective was to assess the incidence of myocardial infarction (MI) or strokes and the cardiovascular risk profile in AS patients.

METHODS

We performed a systematic literature review using PubMed, EMBase, and the Cochrane Library up to August 2009. Incidence of MI or stroke was calculated by metaproportion. For cardiovascular risk factors, differences between AS patients and controls were expressed by standardized mean differences using inverse of variance method.

RESULTS

For MI, 8 longitudinal studies were included. In controls (n=82,745), 1,318 MI cases were observed (4.6%; 95% confidence interval [95% CI] 1.2%, 10.0%). In AS patients (n=3,279), 224 MI cases were reported (incidence 7.4%; 95% CI 5.2%, 10.0%). The increase in MI cases in AS patients was not significant (risk ratio 1.88; 95% CI 0.83, 4.28). For stroke, 7 longitudinal studies reported 327 strokes in AS patients (n=31,949), which is an incidence of 2.2% (95% CI 1.3%, 3.4%). In controls (n=7,372), one study reported 170 strokes (2.3%; 95% CI 2.0%, 2.7%). For cardiovascular risk factors, 15 case-control studies and 9 abstracts were included (n=1,214 for patients and n=1,000 for controls). AS patients were characterized by a higher weighted mean intima-media thickness and higher risk of metabolic syndrome. In AS patients, there was a significant decrease in triglycerides, total cholesterol, and high-density lipoprotein (HDL) cholesterol.

CONCLUSION

AS patients appear to be at higher risk of MI, which could be due to low HDL cholesterol levels or to systemic inflammation. Management of cardiovascular risk factors and control of systemic inflammation should be taken into account in AS.

Mortality in spondylarthritis

Ankylosing spondylitis (AS) is a chronic inflammatory joint disease that can lead to chronic pain in axial and peripheral joints and to functional impairments after several years. Excess mortality has been reported in patients with AS. We reviewed recent studies of patients with AS who were treated and monitored according to the improved methods developed in the past few years, without radiation therapy. Our results do not support excess mortality in these patients. Long-term follow-up data from patients enrolled in biologics registries will provide additional information. Cardiovascular disease is the leading cause of death in patients with AS, as in the general population. However, the cardiovascular mortality rate may be slightly increased in patients with AS, probably as a result of dyslipidemia and early endothelial dysfunction. Similarly, and as expected, there is excess mortality related to the spinal disease itself and to renal and gastrointestinal disease. More surprisingly, alcohol abuse and injury or suicide cause excess mortality compared to the general population. In the absence of radiation or radium-224 therapy, and regardless of the other treatments used, the evidence does not support an increased rate of lymphoma or other malignancies compared to the general population. In this review, we discuss the causes and rates of mortality in patients with AS.