Objective. To study the relationship between serum hydroxychloroquine (HCQ) concentrations and flares of systemic lupus erythematosus (SLE) in a longitudinal cohort of patients. Methods. Patients who fulfilled ‡4 American College of Rheumatology classification criteria for SLE and had been treated with HCQ for >6 months were studied. Blood was assayed for HCQ levels by tandem mass spectrometry. Patients were serially assessed for disease activity, using the Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA) version of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and flares (SELENA flares instrument). Comparison of the mean summated SLEDAI scores over time and rates of flares in groups with different HCQ levels was performed by the Kruskal-Wallis test. Results. A total of 276 SLE patients were studied (93% women, mean 6 SD age 41.0 6 13.8 years). The proportion of patients with HCQ levels <10 (total noncompliance), 10-500 (subtherapeutic), and >500 ng/ml (therapeutic) was 11%, 77%, and 12%, respectively. HCQ levels correlated significantly with the prescribed dose but not with body weight or renal function. The prescribed HCQ dose also correlated significantly with baseline SLEDAI scores, indicating that higher doses were used for more active manifestations. After a mean 6 SD observation period of 32.5 6 5.5 months, the mean summated SLEDAI score and the incidence of SLE flares was not statistically different among patients with different baseline HCQ levels. In a subgroup of 73 patients with serologic and clinical remission and having therapeutic HCQ levels, a trend of lower disease activity and fewer incidences of flares was observed. Conclusion. Noncompliance and subtherapeutic serum HCQ levels were seen frequently in these SLE patients, which was partly due to the low prescribed dose. In patients in remission, higher HCQ concentrations were associated with a trend showing fewer flares over time.

Durable remission can be achieved in a quarter of patients with SLE. Patients with remission for ≥5 years have significantly less damage accrual and better QOL. Prolonged remission is an appropriate criterion for outcome assessment in SLE.

Objectives The aim of this study was to study the relationship between immunosuppressive drug treatment and survival in patients with systemic lupus erythematosus (SLE). Methods Patients who fulfilled four or more American College of Rheumatology criteria for SLE were followed longitudinally. Clinical characteristics, use of immunosuppressive agents and mortality were reviewed. Cox regression was used to study the relationship between immunosuppressive treatment and survival, adjusted for age, sex, vascular risk factors, organ damage, the anti-phospholipid antibodies and a propensity score for the indication of individual immunosuppressive agent derived from separate regression models. Results A total of 803 SLE patients were studied (92% women; age of SLE onset 33.2±14 years; follow-up time 10.8±7.7 years). The frequencies of ever use of immunosuppressive agents were: high-dose prednisolone (≥0.6 mg/kg/day for ≥4 weeks) (85%), azathioprine (63%), cyclophosphamide (25%), mycophenolate mofetil (27%), the calcineurin inhibitors (23%) and hydroxychloroquine (69%). Ninety-seven patients (12%) died and 56 (7%) patients were lost to follow-up. The causes of death were infection (44%), cerebrovascular events (12%), cardiovascular events (10%) and malignancy (8.2%). Cox regression revealed that the ever use of high-dose prednisolone, mycophenolate mofetil, calcineurin inhibitors or cyclophosphamide was not significantly associated with improved survival. However, the ever use of hydroxychloroquine (hazard ratio 0.59 (0.37-0.93); P=0.02) and azathioprine (hazard ratio 0.46 (0.28-0.75); P=0.002) was significantly associated with reduced mortality (41% and 54%, respectively) after adjustment for the propensity score and other confounding factors. A similar beneficial effect of hydroxychloroquine and azathioprine on survival was also observed in patients with lupus nephritis. Conclusions In this longitudinal cohort of Chinese SLE patients, the ever use of hydroxychloroquine and azathioprine was significantly associated with a probability of better survival. Treatment with high-dose prednisolone, cyclophosphamide, mycophenolate mofetil or the calcineurin inhibitors was not associated with long-term survival benefit.

Objectives The objective of this paper is to study the time trend and risk factors of avascular bone necrosis (AVN) in patients with systemic lupus erythematosus (SLE). Methods Between 1999 and 2014, patients who fulfilled the ACR criteria for SLE and developed symptomatic AVN were identified from our cohort database and compared with those without AVN, matched for age, sex and SLE duration. The standardized incidence ratios (SIRs) of AVN in different SLE age groups were calculated from data derived from our hospital registry and population census. Risk factors for AVN were studied by logistic regression, adjusted by a propensity score for ever use of high-dose glucocorticoids (GCs). Results Fifty-five SLE patients with AVN and 220 SLE patients without AVN were studied. There were 104 AVN sites involved, with the hips being most commonly affected (82%). The point prevalence of AVN in our SLE cohort was 7.4%. The SIRs of AVN in our SLE patients were 131 (86.6-199; p < 0.001) and 56.0 (34.3-91.4; p < 0.001), respectively, in the periods 1995-2004 and 2005-2014. In both decades, the age-stratified SIR was highest in the youngest age group (<19 years). AVN patients were more likely to be treated with GCs and had received a significantly higher cumulative dose of prednisolone since SLE diagnosis (16.5 vs 10.7 grams; p = 0.001). The SLE damage score (excluding AVN) was also significantly higher in AVN than non-AVN patients (2.5 vs 0.4; p < 0.001). Logistic regression revealed that preceding septic arthritis of the involved joint (odds ratio (OR) 17.7 (1.5-205); p = 0.02), cushingoid body habitus (OR 2.4 (1.1-5.2); p = 0.04), LDL cholesterol level (OR 1.4 (1.0-1.9); p = 0.04), maximum daily dose of prednisolone (OR 6.4 (1.2-33.3); p = 0.03) and cumulative dose of prednisolone received in the first six months of the first lupus flare (OR 1.3 (1.0-1.8); p = 0.046) were independently associated with AVN. Conclusions AVN is prevalent in SLE, particularly in younger patients. The use of GCs remains the strongest independent risk factor. A trend of reduction in the SIR of AVN in our SLE patients is observed over the past two decades.

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