Medicine (St Vincent's) - Research Publications
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ItemEarly Mortality in a Multinational Systemic Sclerosis Inception Cohort(WILEY, 2017-05)OBJECTIVE: To determine mortality and causes of death in a multinational inception cohort of subjects with systemic sclerosis (SSc). METHODS: We quantified mortality as standardized mortality ratio (SMR), years of life lost, and percentage mortality in the first decade of disease. The inception cohort comprised subjects recruited within 4 years of disease onset. For comparison, we used a prevalent cohort, which included all subjects irrespective of disease duration at recruitment. We determined a single primary cause of death (SSc related or non-SSc related) using a standardized case report form, and we evaluated predictors of mortality using multivariable Cox regression. RESULTS: In the inception cohort of 1,070 subjects, there were 140 deaths (13%) over a median follow-up of 3.0 years (interquartile range 1.0-5.1 years), with a pooled SMR of 4.06 (95% confidence interval [95% CI] 3.39-4.85), up to 22.4 years of life lost in women and up to 26.0 years of life lost in men, and mortality in the diffuse disease subtype of 24.2% at 8 years. In the prevalent cohort of 3,218 subjects, the pooled SMR was lower at 3.39 (95% CI 3.06-3.71). In the inception cohort, 62.1% of the primary causes of death were SSc related. Malignancy, sepsis, cerebrovascular disease, and ischemic heart disease were the most common non-SSc-related causes of death. Predictors of early mortality included male sex, older age at disease onset, diffuse disease subtype, pulmonary arterial hypertension, and renal crisis. CONCLUSION: Early mortality in SSc is substantial, and prevalent cohorts underestimate mortality in SSc by failing to capture early deaths, particularly in men and those with diffuse disease.
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ItemIncidence, Risk Factors, and Outcomes of Cancer in Systemic Sclerosis(WILEY, 2020-11)OBJECTIVE: To quantify the burden of cancer in systemic sclerosis (SSc). METHODS: Standardized incidence ratios (SIRs) and standardized mortality ratios relative to the general Australian population were derived. Cox proportional hazards regression was used to estimate survival in patients with SSc with cancer compared to patients without. Determinants of cancer were identified using logistic regression. Health care cost was quantified through cross-jurisdictional data linkage. RESULTS: This SSc cohort of 1,727 had a cancer incidence of 1.3% per year and a prevalence of 14.2%, with a SIR of 2.15 (95% confidence interval [95% CI] 1.84-2.49). The most common cancers were breast, melanoma, hematologic, and lung. Anti-RNA polymerase III (RNAP) antibody was associated with an increased risk of cancer (odds ratio [OR] 2.9, P = 0.044), diagnosed within 5 years of SSc disease onset. Calcium channel blockers were associated with a higher risk of overall cancer (OR 1.47, P = 0.016), breast cancer (OR 1.61, P = 0.051), and melanoma (OR 2.01, P = 0.042). Interstitial lung disease (ILD) was associated with lung cancer (OR 2.83, P = 0.031). Incident SSc cancer patients had >2-fold increased mortality compared to patients with SSc without cancer (hazard ratio 2.85 [95% CI 1.51-5.37], P = 0.001). Patients with SSc and cancer utilized more health care than those without cancer, with an excess annual health care cost of $1,496 Australian (P < 0.001). CONCLUSION: SSc carries an increased risk of developing cancer, particularly lung cancer associated with ILD, and breast cancer and melanoma occurring close to SSc disease onset in association with RNAP antibodies. Compared to those patients without cancer, patients with SSc and cancer had higher mortality and an increased health care cost, with an annual excess per patient cost of $1,496 Australian (P < 0.001).
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ItemLupus Low Disease Activity State and Reduced Direct Health Care Costs in Patients With Systemic Lupus Erythematosus(WILEY, 2020-09)OBJECTIVE: Treat-to-target end points for systemic lupus erythematosus (SLE) have been assessed for their impact on damage accrual and flare, but whether they have an impact on the high health care utilization and costs in SLE has not been studied. The purpose of this study was to examine our hypothesis that the recently described lupus low disease activity state (LLDAS) would be associated with reduced health care cost. METHODS: Data from a single tertiary hospital longitudinal SLE cohort were assessed. Baseline demographics, disease activity (Systemic Lupus Erythematosus Disease Activity Index 2000 [SLEDAI-2K], physician global assessment [PhGA], and flare index), and medication use were evaluated, and direct health care utilization and cost data were obtained from hospital information systems. LLDAS was defined as previously published: briefly, SLEDAI-2K ≤4 with no new activity, PhGA ≤1, prednisolone ≤7.5 mg/day, and optimal standard immunosuppressive agents. Analysis was performed using multivariable linear regression. RESULTS: Two hundred SLE patients, contributing 357.8 person-years of observation, were included. A history of lupus nephritis was present in 42% of patients, and damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index >0) was present at study commencement in 57.3% of patients. The mean ± SD annual direct medical cost per patient was US$7,413 ± 13,133/year. In multivariable analysis, increased cost was associated with the presence of baseline organ damage (41.7% increase; P = 0.009) and corticosteroid use (>7.5-15 mg/day: 55.7% increase; P = 0.02; and >15 mg/day: 202% increase; P < 0.001). In contrast, spending ≥50% of the observation period in LLDAS was associated with a 25.9% reduction in annual direct medical cost (P = 0.04). CONCLUSION: Greater time spent in LLDAS was associated with significantly reduced direct hospital health care costs among patients with SLE.
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ItemDevelopment and validation of the Scleroderma Clinical Trials Consortium Damage Index (SCTC-DI): a novel instrument to quantify organ damage in systemic sclerosis(BMJ PUBLISHING GROUP, 2019-06)OBJECTIVE: We sought to develop the first Damage Index (DI) in systemic sclerosis (SSc). METHODS: The conceptual definition of 'damage' in SSc was determined through consensus by a working group of the Scleroderma Clinical Trials Consortium (SCTC). Systematic literature review and consultation with patient partners and non-rheumatologist experts produced a list of potential items for inclusion in the DI. These steps were used to reduce the items: (1) Expert members of the SCTC (n=331) were invited to rate the appropriateness of each item for inclusion, using a web-based survey. Items with >60% consensus were retained; (2) Using a prospectively acquired Australian cohort data set of 1568 patients, the univariable relationships between the remaining items and the endpoints of mortality and morbidity (Physical Component Summary score of the Short Form 36) were analysed, and items with p<0.10 were retained; (3) using multivariable regression analysis, coefficients were used to determine a weighted score for each item. The DI was externally validated in a Canadian cohort. RESULTS: Ninety-three (28.1%) complete survey responses were analysed; 58 of 83 items were retained. The univariable relationships with death and/or morbidity endpoints were statistically significant for 22 items, with one additional item forced into the multivariable model by experts due to clinical importance, to create a 23-item weighted SCTC DI (SCTC-DI). The SCTC-DI was predictive of morbidity and mortality in the external cohort. CONCLUSIONS: Through the combined use of consensus and data-driven methods, a 23-item SCTC-DI was developed and retrospectively validated.
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ItemSignificance of anti-neutrophil cytoplasmic antibodies in systemic sclerosis(BMC, 2019-02-14)BACKGROUND: Up to 12% of patients with systemic sclerosis (SSc) have anti-neutrophil cytoplasmic antibodies (ANCA). However, the majority of these patients do not manifest ANCA-associated vasculitis (AAV) and the significance of ANCA in these patients is unclear. The aim of this study is to determine the prevalence of ANCA in a well-characterised SSc cohort and to examine the association between ANCA and SSc clinical characteristics, other autoantibodies, treatments and mortality. METHODS: Clinical data were obtained from 5 centres in the Australian Scleroderma Cohort Study (ASCS). ANCA positive was defined as the presence of any one or combination of cytoplasmic ANCA (c-ANCA), perinuclear ANCA (p-ANCA), atypical ANCA, anti-myeloperoxidase (anti-MPO) or anti-proteinase-3 (anti-PR3). Associations of demographic and clinical features with ANCA were investigated by logistic or linear regression. Survival analysis was performed using Kaplan-Meyer curves and Cox regression models. RESULTS: Of 1303 patients, 116 (8.9%) were ANCA positive. Anti-PR3 was more common than anti-MPO (13.8% and 11.2% of ANCA-positive patients, respectively). Only 3 ANCA-positive patients had AAV. Anti-Scl-70 was more common in ANCA positive vs ANCA negative (25% vs 12.8%, p < 0.001), anti-MPO positive vs anti-MPO negative (38.5% vs 13.6%, p = 0.006) and anti-PR3 positive vs anti-PR3 negative patients (44.4% vs 13.4%, p < 0.001). A higher prevalence of interstitial lung disease (ILD) was found in the ANCA positive (44.8% vs 21.8%, p < 0.001) and the anti-PR3 positive groups (50.0% vs 23.4%, p = 0.009). In multivariable analysis, ANCA-positive status remained associated with ILD after adjusting for anti-Scl-70 antibodies. Pulmonary embolism (PE) was more common in ANCA-positive patients (8.6% vs 3.0%, p = 0.002) and anti-PR3-positive patients (16.7% vs 3.3%, p = 0.022). ANCA-positive status remained associated with PE in a multivariable analysis adjusting for anti-phospholipid antibodies. Kaplan-Meier analysis revealed increased mortality in ANCA-positive patients (p = 0.006). In Cox regression analysis, ANCA was associated with increased mortality, after adjusting for age and sex. CONCLUSIONS: ANCA is associated with increased prevalence of ILD and PE in SSc. ANCA should be tested in SSc, as it identifies individuals with worse prognosis who require close monitoring for adverse outcomes.
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ItemSurvival and quality of life in incident systemic sclerosis-related pulmonary arterial hypertension(BMC, 2017-06-02)BACKGROUND: Pulmonary arterial hypertension (PAH) is a leading cause of mortality in systemic sclerosis (SSc). We sought to determine survival, predictors of mortality, and health-related quality of life (HRQoL) related to PAH in a large SSc cohort with PAH. METHODS: We studied consecutive SSc patients with newly diagnosed (incident) World Health Organization (WHO) Group 1 PAH enrolled in a prospective cohort between 2009 and 2015. Survival methods were used to determine age and sex-adjusted standardised mortality ratio (SMR) and years of life lost (YLL), and to identify predictors of mortality. HRQoL was measured using the Short form 36 (SF-36) instrument. RESULTS: Among 132 SSc-PAH patients (112 female (85%); mean age 62 ± 11 years), 60 (45.5%) died, with a median (±IQR) survival time from PAH diagnosis of 4.0 (2.2-6.2) years. Median (±IQR) follow up from study enrolment was 3.8 (1.6-5.8) years. The SMR for patients with SSc-PAH was 5.8 (95% CI 4.3-7.8), with YLL of 15.2 years (95% CI 12.3-18.1). Combination PAH therapy had a survival advantage (p < 0.001) compared with monotherapy, as did anticoagulation compared with no anticoagulation (p < 0.003). Furthermore, combination PAH therapy together with anticoagulation had a survival benefit compared with monotherapy with or without anticoagulation and combination therapy without anticoagulation (hazard ratio 0.28, 95% CI 0.1-0.7). Older age at PAH diagnosis (p = 0.03), mild co-existent interstitial lung disease (ILD) (p = 0.01), worse WHO functional class (p = 0.03) and higher mean pulmonary arterial pressure at PAH diagnosis (p = 0.001), and digital ulcers (p = 0.01) were independent predictors of mortality. CONCLUSIONS: Despite the significant benefits conferred by advanced PAH therapies suggested in this study, the median survival in SSc PAH remains short at only 4 years.
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ItemLongitudinal association of type 1 interferon-induced chemokines with disease activity in systemic lupus erythematosus(NATURE PORTFOLIO, 2018-02-19)Type I interferon (IFN) pathways are significant in SLE pathogenesis. Less is known about the utility of measuring markers of IFN activity in patients, or whether patient subsets with different profiles exist. We explored the longitudinal associations of IFN-induced chemokines with disease activity in a cohort of SLE patients. We calculated a validated composite score (IFN-CK) of three type I IFN-inducible chemokines (CCL2/CXCL10/CCL19) measured in 109 SLE patients (median 7 occasions over 3.2 years). Longitudinal associations of IFN-CK score with disease activity (SLEDAI-2K) and other variables were assessed using general estimating equation (GEE) methods. IFN-CK was detectable in all patients. SLEDAI-2K was significantly associated with IFN-CK, damage score and prednisolone dose. SLEDAI-2K remained significantly associated with IFN-CK over time after adjustment of covariates. Patients with high time-adjusted mean IFN-CK had lower complement and higher time-adjusted disease activity. Concordance between IFN-CK and SLEDAI-2K varied widely among patients, with some individuals having none, others weak, and a subset very high concordance. In summary in our cohort of SLE patients, serum IFN-CK varied over time with disease activity, but with wide variation in concordance. Differing relationships between IFN pathway activation and disease activity may be valuable in assigning patients to emerging IFN-pathway targeting treatments.
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ItemAssociation of the lupus low disease activity state (LLDAS) with health-related quality of life in a multinational prospective study(BIOMED CENTRAL LTD, 2017-03-20)BACKGROUND: Systemic lupus erythematosus (SLE) is associated with significant impairment of health-related quality of life (HR-QoL). Recently, meeting a definition of a lupus low disease activity state (LLDAS), analogous to low disease activity in rheumatoid arthritis, was preliminarily validated as associated with protection from damage accrual. The LLDAS definition has not been previously evaluated for association with patient-reported outcomes. The objective of this study was to determine whether LLDAS is associated with better HR-QoL, and examine predictors of HR-QoL, in a large multiethnic, multinational cohort of patients with SLE. METHODS: HR-QoL was measured using the Medical Outcomes Study 36-item short form health survey (SF-36v2) in a prospective study of 1422 patients. Disease status was measured using the SLE disease activity index (SLEDAI-2 K), physician global assessment (PGA) and LLDAS. RESULTS: Significant differences in SF-36 domain scores were found between patients stratified by ethnic group, education level and damage score, and with the presence of active musculoskeletal or cutaneous manifestations. In multiple linear regression analysis, Asian ethnicity (p < 0.001), a higher level of education (p < 0.001), younger age (p < 0.001) and shorter disease duration (p < 0.01) remained significantly associated with better physical component scores (PCS). Musculoskeletal disease activity (p < 0.001) was negatively associated with PCS, and cutaneous activity (p = 0.04) was negatively associated with mental component scores (MCS). Patients in LLDAS had better PCS (p < 0.001) and MCS (p < 0.001) scores and significantly better scores in multiple individual SF-36 domain scores. Disease damage was associated with worse PCS (p < 0.001), but not MCS scores. CONCLUSIONS: Ethnicity, education, disease damage and specific organ involvement impacts HR-QoL in SLE. Attainment of LLDAS is associated with better HR-QoL.
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ItemRisk factors for development of pulmonary arterial hypertension in Australian systemic sclerosis patients: results from a large multicenter cohort study(BMC, 2016-09-27)BACKGROUND: Pulmonary arterial hypertension (PAH) is the leading cause of mortality in patients with systemic sclerosis (SSc). We sought to determine the incidence, prevalence and risk factors for PAH development in a large Australian SSc cohort. METHODS: PAH was diagnosed on right heart catheterisation (mPAP >25 and PAWP <15 mmHg at rest). Patients with PH secondary to interstitial lung disease (ILD; defined as abnormal HRCT scan and FVC < 60 %) were excluded. Summary statistics, chi-square tests, univariate and multivariable logistic regression along with post-estimation diagnostics were used to determine the associations of different combinations of risk factors with PAH. RESULTS: Among 1579 SSc patients, 8.4 % (132 patients) were diagnosed with PAH over a mean (±SD) follow-up of 3.2 (±2.5) years. The incidence of PAH in this cohort was 0.7 % per annum. Of these, 68.9 % had limited disease subtype (lcSSc). In multivariable regression analysis, the presence of anti-centromere antibody (ACA) (OR 1.6, 95 % CI 1.1-2.5, p = 0.03), oesphageal stricture (OR 2.0, 95 % CI 1.2-3.3, p = 0.006), calcinosis (OR 1.9, 95 % CI 1.2-2.9, p = 0.003), sicca symptoms (OR 1.6, 95 % CI 1.1-2.5, p = 0.03), mild ILD (OR 2.3, 95 % CI 1.5-3.7, p < 0.001) and digital ulcers (OR 1.6, 95 % CI 1.0-2.4, p = 0.03) were predictive of PAH. This model had an area under the curve of 0.7 and concordance of 91.8 %. When analysed by disease subtype, the presence of calcinosis (OR 2.2, 95 % CI 1.4-3.7, p = 0.01), sicca symptoms (OR 2.6, 95 % CI 1.5-4.6, p = 0.001), mild ILD (OR 2.3, 95 % CI 1.4-3.8, p = 0.001) and digital ulcers (OR 1.9, 95 % CI 1.2-3.7, p = 0.01) were predictive of PAH in lcSSc; and oesophageal stricture (OR 4.4, 95 % CI 1.9-10.5, p = 0.001), mild ILD (OR 2.8, 95 % CI 1.2-6.8, p = 0.02) and ACA (OR 5.2, 95 % CI 1.8-14.8, p = 0.002) were predictive of PAH in dcSSc. CONCLUSIONS: The incidence and prevalence of PAH in this cohort are 0.7 % per annum and 8.4 %, respectively. The clinical-serologic risk factors for PAH differ based on disease subtype. In both subtypes, mild ILD is associated with PAH, suggesting the possibility of common pathogenic mechanisms underlying both of these disease manifestations. This model identifies a subset of patients at an appreciably higher risk of developing PAH, who should be screened and would in future, benefit from preventative therapies.
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ItemFrequency and predictors of the lupus low disease activity state in a multi-national and multi-ethnic cohort(BIOMED CENTRAL LTD, 2016-11-09)BACKGROUND: Systemic lupus erythematosus (SLE) is a chronic heterogeneous disease with considerable burden from disease activity and damage. A novel clinical treatment target in the form of the lupus low disease activity state (LLDAS) has been recently reported, with retrospective validation showing that time spent in LLDAS translates to reduced damage accrual. The objectives of this study were to describe the frequency and identify the predictors of attaining LLDAS in a large multinational cohort of patients with SLE. METHODS: Data were collected at the recruitment visit in patients with SLE enrolled in a longitudinal study in nine countries. Data were analysed cross-sectionally against the recently published definition of LLDAS, and the frequency and characteristics associated with presence of LLDAS were determined. Stepwise multivariable logistic regression was used to determine predictors of LLDAS. RESULTS: Of the 1846 patients assessed, criteria for LLDAS were met by 44 %. Patients with shorter disease duration were less likely to be in LLDAS (OR 0.31, 95 % CI 0.19-0.49, p < 0.001). Likewise, patients with a history of discoid rash (OR 0.66, 95 % CI 0.49-0.89, p = 0.006), renal disease (OR 0.60, 95 % CI 0.48-0.75, p < 0.001), elevated double stranded DNA (OR 0.65, 95 % CI 0.53-0.81, p < 0.001) or hypocomplementaemia (OR 0.52, 95 % CI 0.40-0.67, p < 0.001) were less likely to be in LLDAS. When countries were compared, higher national social wealth (OR 1.57, 95 % CI 1.25-1.98, p < 0.001) as measured by the gross domestic product per capita was positively associated with LLDAS, but ethnicity was not. CONCLUSION: The lupus low disease activity state is observed in less than half of patients with SLE at a single point in time. Disease duration and phenotype, and national social wealth, are predictive of LLDAS.