Synergistic effect of cumulative corticosteroid dose and immunosuppressants on avascular necrosis in patients with systemic lupus erythematosus

Objectives

Avascular necrosis (AVN) is one of the most common causes of organ damage in patients with systemic lupus erythematosus (SLE) and often causes serious physical disability. The aims of this study were to investigate clinical risk factors associated with symptomatic AVN and to analyze their synergistic effects in a large SLE cohort in Korea.

Methods

Patients with SLE were enrolled and followed from 1998 to 2014 in the Hanyang BAE Lupus cohort, and damage was measured annually according to the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). AVN was confirmed by imaging study if patients had symptoms. To determine risk factors for AVN, clinical, laboratory and therapeutic variables were analyzed by logistic regression. Relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (S) were calculated to measure interactions between significant variables.

Results

Among 1219 SLE patients, symptomatic AVN was the most common type of musculoskeletal damage (10.8%, n = 132). SLE patients with AVN showed an earlier onset age, demonstrated AVN more commonly in conjunction with certain other clinical manifestations such as renal and neuropsychiatric disorders, and received significantly higher total cumulative corticosteroid dose and immunosuppressive agents than did patients without AVN. However, in multivariable analysis, only two variables including use of a cumulative corticosteroid dose greater than 20 g (odds ratio (OR) 3.62, p = 0.015) and use of immunosuppressants including cyclophosphamide or mycophenolate mofetil (OR 4.51, p < 0.001) remained as significant risk factors for AVN. Patients with cumulative corticosteroid dose > 20 g and immunosuppressant use had a 15.44-fold increased risk for AVN, compared with patients without these risk factors ( p < 0.001). RERI, AP and S, which define the strength of interactions between two risk factors, were 9.01 (95% confidence interval (CI) 1.30–16.73), 0.58 (95% CI 0.36–0.81) and 2.66 (95% CI 1.42–4.99), respectively, supporting the presence of synergistic interactions in the development of symptomatic AVN in our Korean lupus cohort.

Conclusions

An individual risk assessment for AVN development should be made prior to and during treatment for SLE, especially in patients with high-dose corticosteroid and immunosuppressant use regardless of clinical manifestations and disease activity.

Precuneus hypoperfusion plays an important role in memory impairment of patients with systemic lupus erythematosus

The present study was designed to identify regional cerebral blood flow (rCBF) abnormalities in systemic lupus erythematosus (SLE) patients with memory impairments. Nineteen SLE patients (mean age 36.1 ± 8.6 years, range 17-47) with subjective memory complaints underwent brain single-photon emission computed tomography (SPECT). The Korean Wechsler Adult Intelligence Scale (K-WAIS) and the Rey-Kim Memory Test (RKMT) were used objectively to evaluate cognitive functions in these patients. On the basis of the Intelligence Quotient-Memory Quotient (IQ-MQ) difference score, patients were classified into two groups: those with below one standard deviation (SD) from the mean for normal subjects of comparable age and education (memory impairment, n = 6) and those with without memory impairment (non-memory impairment, n = 13). Their brain SPECT images were analyzed by statistical parametric mapping (SPM) for group comparisons. The group of SLE patients with memory impairment showed significant hypoperfusion in the right precuneus compared with those with non-memory impairment (p < 0.001). Hypoperfusion of the precuneus may play a significant role in the memory function of SLE patients. SPM analysis of brain SPECT images could be a useful and objective tool for identifying abnormal rCBF in SLE patients with memory impairment.

Genetic associations of LYN with systemic lupus erythematosus

We targeted LYN, a src-tyosine kinase involved in B-cell activation, in case-control association studies using populations of European-American, African-American and Korean subjects. Our combined European-derived population, consisting of 2463 independent cases and 3131 unrelated controls, shows significant association with rs6983130 in a female-only analysis with 2254 cases and 2228 controls (P=1.1 x 10(-4), odds ratio (OR)=0.81 (95% confidence interval: 0.73-0.90)). This single nucleotide polymorphism (SNP) is located in the 5' untranslated region within the first intron near the transcription initiation site of LYN. In addition, SNPs upstream of the first exon also show weak and sporadic association in subsets of the total European-American population. Multivariate logistic regression analysis implicates rs6983130 as a protective factor for systemic lupus erythematosus (SLE) susceptibility when anti-dsDNA, anti-chromatin, anti-52 kDa Ro or anti-Sm autoantibody status were used as covariates. Subset analysis of the European-American female cases by American College of Rheumatology classification criteria shows a reduction in the risk of hematological disorder with rs6983130 compared with cases without hematological disorders (P=1.5 x 10(-3), OR=0.75 (95% CI: 0.62-0.89)). None of the 90 SNPs tested show significant association with SLE in the African American or Korean populations. These results support an association of LYN with European-derived individuals with SLE, especially within autoantibody or clinical subsets.

Health-related quality of life among Koreans with chronic respiratory disease

OBJECTIVE

To evaluate the health-related quality of life (HRQoL) and to identify physiological and psychosocial variables predicting the HRQoL among Korean people with chronic respiratory disease (CRD).

DESIGN

A cross-sectional correlation study was done with a convenience sample of 112 participants (aged 62.9 +/- 12.9 years, forced expiratory volume in 1 second [FEV(1)%] predicted = 52.3 +/- 20.2) from the out-patient respiratory clinic of a large university hospital in Korea. HRQoL was measured using the chronic respiratory disease questionnaire (CRDQ). To identify the influencing factors, physiological (lung function, dyspnoea, symptom experience and exercise performance) and psychological (mood states and self-efficacy) variables were examined using path analysis.

RESULTS

Participants had a moderate level of HRQoL, with the lowest scores in CRDQ-fatigue (3.3 +/- 1.3) and the highest in CRDQ-mastery (5.2 +/- 1.0). Anxiety and a depressive mood state (-0.38) exerted the highest influence on HRQoL, followed by self-efficacy (0.36), dyspnoea (-0.27), exercise performance (0.22) and respiratory symptoms (-0.17).

CONCLUSION

Our findings emphasise the importance of a multidimensional therapeutic approach to improve HRQoL. Comprehensive interventions, including enhanced exercise performance, self-efficacy and symptom management, should be considered to improve HRQoL in Koreans with CRD.

Measurement of spectral, directional reflectivities of solids at high temperatures between 9 and µm

A new apparatus to measure spectral,<directional reflectivities of solids for temperatures up to 1100 °C is developed. Reflectivities of two ceramic materials, silicon nitride (Si(3)N(4)) and silicon carbide α-SiC, are measured at wavelengths between 9 and 11 µm (the operating range of tunable CO(2) lasers) for various temperatures, angles of incidence, and for two types of polarization, the electric vector perpendicular and parallel to the plane of incidence. Reflectivities are measured by comparing the power of the beam reflected from the sample (heated in the furnace) with that of the incident beam. This experimental setup is limited to relatively specular surfaces (with a collection half-angle of 15°). The measurements show that the reflectivity of α-SiC at room temperature rises sharply near ~10.2 µm because of the presence of a 12.6-µm reflection band (restrahlen band), and the occurrence of this phenomenon gradually shifts to longer wavelengths as the temperature is raised to 1000 °C. At 10.6 µm, where most CO(3) lasers operate, the reflectivity of SiC diminishes rapidly as the temperature is raised. Si(3)N(4) has two restrahlen bands on both sides of 9.9 µm at room temperature that gradually shift to longer wavelengths with temperature. However, the decrease in reflectivity of Si(3)N(4) with temperature at 10.6 µm is very small.