Left ventricular size and function in patients with systemic lupus erythematosus associate with lupus anticoagulant: An echocardiographic follow-up study

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with increased risk of cardiac dysfunction. The pathophysiological mechanisms are poorly understood, and prognostic markers are warranted.

PURPOSE

We aimed to identify SLE-characteristics associated with measures of cardiac size and function during a five-year follow-up.

METHODS

We included 108 patients with SLE: 90% females, mean age 46 ± 13 years, median disease duration 14 (range 7-21) years. We performed blood sampling for potential biomarkers as well as a standard echocardiography at baseline and at a 5-year follow-up. To investigate associations with baseline and prospective 5-year changes in echocardiographic parameters, we performed multivariate regression analyses of SLE-related baseline variables (clinical disease activity, lupus nephritis, chronic kidney disease, anti-cardiolipin and/or anti-beta-2 glycoprotein I antibodies, and lupus anticoagulant (LAC)) and adjusted for traditional risk factors.

RESULTS

During follow-up, diastolic function regressed in two out of five echocardiographic measures (E/A ratio 1.4 ± 0.5 vs. 1.3 ± 0.5, p = 0.002; tricuspid regurgitation peak velocity 2.0 ± 0.6 vs. 2.2 ± 0.4 mmHg, p < 0.001). Left ventricular (LV) end-diastolic volume index increased (43.7 ± 13.9 vs. 52.5 ± 15.7 mL/m², p < 0.001). Left and right ventricular systolic function remained stationary. LAC was associated with inferior diastolic function: lower E/A ratio (p = 0.04) and higher E/e' ratio at baseline (p = 0.04) and increased left ventricular atrial volume index during follow-up (p = 0.01). LAC was further associated with LV dilatation during follow-up (p = 0.01).

CONCLUSION

Presence of LAC was associated with measures of diastolic function as well as progressive LV dilatation during the 5-year follow-up. Thus, LAC might be a predictor of cardiac dysfunction in SLE patients. LAC is known to have implications for the microvascular circulation, but the clinical significance of the present findings is yet to be elucidated.

Incidence of Systemic Lupus Erythematosus and Lupus Nephritis in Denmark: A Nationwide Cohort Study

Objective.

To determine the incidence of systemic lupus erythematosus (SLE) and SLE with concomitant or subsequent lupus nephritis (LN) in Denmark during 1995–2011, using data from the Danish National Patient Registry (NPR).

Methods.

To assess the incidence of SLE, we identified all persons aged ≥ 18 years in the NPR with at least 1 International Classification of Diseases, 10th ed (ICD-10) code of SLE and at least 365 days of followup under this diagnosis. Identification of LN cases was based on fulfillment of these criteria and ≥ 1 registration under an ICD-10 code of nephritis concomitantly with or after first SLE registration.

Results.

The overall annual incidence rate per 100,000 for SLE was 2.35 (95% CI 2.24–2.49); 0.69 (95% CI 0.60–0.78) for men and 3.96 (95% CI 3.75–4.17) for women. For LN, the mean annual incidence rate per 100,000 was estimated to be 0.45 (95% CI 0.38–0.53); 0.20 (95% CI 0.13–0.28) for men and 0.69 (95% CI 0.57–0.83) for women. The differences in SLE incidence rates between sexes decreased by age, and the incidence did not differ between men and women after the age of 60 years for LN. The estimated incidences showed no trends by calendar time. Estimated overall point prevalence (December 31, 2011) per 100,000 was 45.2 (95% CI 43.3–47.4) and 6.4 (95% CI 5.7–7.2) for SLE and LN, respectively.

Conclusion.

Our Danish population-based data showed a stable incidence of SLE and LN. As expected, we found higher incidence rates among women than among men, particularly in younger persons.

Genetic polymorphisms of dsRNA ligating pattern recognition receptors TLR3, MDA5, and RIG-I. Association with systemic lupus erythematosus and clinical phenotypes

This study aimed to demonstrate possible associations between genetic polymorphisms in Toll-like receptor 3, interferon induced with helicase C domain 1 (IFIH1) and DEAD (Asp-Glu-Ala-Asp) box polypeptide 58 and systemic lupus erythematosus (SLE), including the phenotypes lupus nephritis and malar rash, as well as the presence of autoantibodies against nucleic acid-containing complexes. Genotyping was carried out in two Danish cohorts [Copenhagen (CPH) and Odense (ODE)] totaling 344 patients and was compared with 641 previously genotyped healthy controls. In the ODE cohort, the patients were only genotyped for the rs1990760 polymorphism of IFIH1. Single nucleotide polymorphisms (SNPs) were determined by a multiplex bead-based assay (CPH cohort) or real-time PCR (ODE cohort). Associations were investigated using the Cochran-Armitage trend test. The odds ratio (OR) for minor allele homozygotes versus major allele homozygotes suggested a protective effect of the IFIH1 rs1990760 SNP for SLE in the ODE cohort [OR 0.52, 95 % confidence intervals (95 % CI) 0.31-0.88, Pcorr. = 0.05] but not in the CPH cohort, although the OR suggested a trend in the same direction, and when combining the two patient cohorts, ORs were 0.57, 95 % CI 0.37-0.88. None of the other investigated polymorphisms showed any association with SLE. Regarding phenotypes, we found a statistically significant association between rs1990760 and malar rash in the CPH cohort, with ORs suggesting a protective effect (OR 0.28, 95 % CI 0.13-0.62 for heterozygotes and OR 0.11, 95 % CI 0.03-0.41 for homozygotes, Pcorr. = 0.0001). There were no significant associations between rs1990760 and presence of anti-dsDNA, anti-U1RNP, or anti-Smith antibodies. Our study supports previous findings of an association between the rs1990760 polymorphism of IFIH1 and SLE and indicates that this SNP may also be associated with malar rash in SLE patients although this finding needs confirmation.

Single nucleotide polymorphisms in genes encoding toll-like receptors 7, 8 and 9 in Danish patients with systemic lupus erythematosus

Several studies indicate a role for toll-like receptors (TLRs) in the pathogenesis of systemic lupus erythematosus (SLE). We aimed to investigate the risk of SLE and typical clinical and serological manifestations of SLE potentially conferred by selected single nucleotide polymorphisms (SNPs) of genes encoding TLR7, TLR8, and TLR9. Using a multiplexed bead-based assay, we analyzed eight SNPs in a cohort of 142 Danish SLE patients and a gender-matched control cohort comprising 443 individuals. Our results showed an association between the rs3853839 polymorphism of TLR7 and SLE (G vs. C, P = 0.008, OR 1.60, 95 % CI 1.12-2.27 in females; P = 0.02, OR 4.50, 95 % CI 1.18-16.7 in males) confirming recent findings in other populations. Additionally, an association between the rs3764879 polymorphism of TLR8 and SLE (G vs. C, P < 0.05, OR 1.36, 95 % CI 0.99-1.86 in females; P = 0.06, OR 4.00, 95 % CI 0.90-17.3 in males) was found. None of the other investigated SNPs were associated with SLE but several SNPs were associated with clinical and serological manifestations. In summary, a previously shown association between the rs3853839 SNP of TLR7 and SLE in Asian patients was also found in Danish patients. Together with the association of several other SNPs of TLR8 and TLR9 with various clinical and serological manifestations of SLE these findings corroborate the pathogenic significance of TLRs in SLE.

Can the Glycemic Index (GI) be used as a tool in the prevention and management of Type 2 diabetes?

The large increase in type 2 diabetes (T2DM), the considerable lifetime risk of diabetes and the loss of lifetime call for concerted action to prevent T2DM and its complications. Since diabetes is characterized by abnormal glucose metabolism, the question arises of whether a high intake of carbohydrates that are rapidly absorbed as glucose may increase the risk and worsen the course of T2DM. To quantify the impact of carbohydrates on blood glucose the glycemic index (GI) and the glycemic load (GL) have been applied. The GI of a food is a method of ranking carbohydrate rich foods according to their glycemic responses. GI is defined as the incremental area under the blood glucose curve of 50g carbohydrate of a test food expressed as a percentage of the area of the response to an equivalent amount of a reference food (glucose or white bread). In relation to GI/GL and prevention of T2DM there is insufficient information from observational studies to determine whether a positive association exists or not. Only randomized controlled clinical intervention studies will be able to provide the final answer. From meta-analyses of randomised controlled clinical trials comparing low and high GI diets in the treatment of diabetes it has been found that low GI diets improve the glycemic control. Labeling of foods with GI would be helpful for persons with diabetes, but the usefulness for healthy subjects remains to be clarified. At present it seems premature to introduce GI labeling for the entire population.