Medicine (St Vincent's) - Research Publications
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ItemA systematic review of the epidemiology, disease characteristics and management of systemic sclerosis in Australian adults(WILEY, 2017-11)OBJECTIVE: Australia has one of the highest prevalence rates of systemic sclerosis (SSc) worldwide. In order to highlight management deficiencies and key areas for further research, it is essential to understand its local epidemiological patterns, natural history, prognosis and mortality trends over time. METHODS: To identify Australian SSc-specific information through a systematic review focusing on areas of epidemiology, disease characteristics, treatment, functional ability, disease burden and health-related quality of life (HRQoL). RESULTS: MEDLINE, EMBASE and the Cochrane Library were searched on 14 September, 2016. All original full text articles on SSc in Australia were included. Of the 54 articles included in this review, the majority of studies recruited from South Australia, Victoria and New South Wales. The prevalence of SSc in Australia is increasing and is similar among the general population and the Aboriginal population. Despite improvements in care over the last three decades, morbidity and mortality remain high, with an overall standardized mortality ratio of 3.4 and a 10-year survival of 84% in a newly diagnosed patient. Cardiorespiratory manifestations are the leading cause of SSc-related death. Malignancy is the leading cause of non-SSc-related death. The role of autoantibodies in predicting disease subtype, visceral involvement and their use as a prognostic marker is becoming increasingly recognized. CONCLUSION: Information on SSc in Australia, particularly unmet healthcare needs, HRQoL and economic burden, is limited. As a heterogenous condition, SSc requires a multi-disciplinary approach to care. Research aimed at quantifying HRQoL and burden of disease in Australia is essential for advocacy and resource allocation.
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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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ItemLong-term efficacy and tolerability of mycophenolate mofetil therapy in diffuse scleroderma skin disease(WILEY, 2017-04)OBJECTIVES: To assess the long-term efficacy and tolerability of mycophenolate mofetil (MMF) in patients with diffuse cutaneous systemic sclerosis (dcSSc). METHODS: Patients enrolled in the Australian Scleroderma Cohort study with dcSSc and baseline modified Rodnan skin score (mRSS) ≥ 12 who were treated for a minimum of 12 months with MMF for the primary indication of skin disease were included and their prospectively collected data retrieved. Change in mRSS, the proportion with a clinically significant improvement (reduction in mRSS ≥ 5 from baseline) and adverse effects due to therapy were determined. RESULTS: Seventy-four participants treated with MMF were identified and of these, 42 met inclusion criteria. The mean age was 53 ± 12 years, with mean disease duration at MMF commencement of 4.8 ± 4.3 years. Twenty-one participants (50%) commenced MMF within 2 years of disease onset and the mean duration of therapy was 2.7 ± 1.7 years. The mean mRSS at baseline was 25.9 ± 9.2 with a reduction of 3.7 ± 7.1 (P = 0.07) after 1 year of therapy, 7.6 ± 8.3 after 2 years (P = 0.01) and 10.5 ± 10.3 after 5 years (P < 0.01). Response to treatment was not affected by disease duration at MMF commencement or baseline skin score. Eighteen participants (43%) demonstrated clinically significant improvement after 1 year, increasing to 92% after 4 years. Two participants (5%) ceased MMF due to adverse effects. CONCLUSION: MMF was associated with a modest improvement in mRSS and was well tolerated in the treatment of dcSSc. Given the natural history of dcSSc where skin involvement can spontaneously improve, randomized, placebo-controlled studies are required to confirm whether improvement can be attributed to MMF therapy.
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ItemCost savings with a novel algorithm for early detection of systemic sclerosis-related pulmonary arterial hypertension: alternative scenario analyses(WILEY, 2019-06)Pulmonary arterial hypertension is an important cause of death and disability in patients with systemic sclerosis (SSc). Yearly screening of all SSc patients with transthoracic echocardiography (TTE) is recommended in international guidelines and currently utilised by the Australian Scleroderma Interest Group (ASIGSTANDARD ). Owing to the limitations of TTE, the ASIG developed a new screening algorithm (ASIGPROPOSED ) utilising a serum biomarker, NT-proBNP, in place of TTE, which has been shown to be equally accurate as the current algorithm. The aim of this study was to compare the cost of these two algorithms using different scenarios. The new algorithm resulted in significant yearly cost savings of between AU$42 913.35 and AU$84 570 in screening and diagnosis of an Australian cohort which, if extrapolated to the Australian population, would result in a yearly cost saving of between AU$367 066 and AU$725 564. There was no scenario in which the proposed algorithm did not result in a cost saving.
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ItemN-terminal pro-brain natriuretic peptide in a novel screening algorithm for pulmonary arterial hypertension in systemic sclerosis: a case-control study(BMC, 2012)INTRODUCTION: Pulmonary arterial hypertension is a major cause of mortality in systemic sclerosis. N-terminal pro-brain natriuretic peptide (NT-proBNP) has emerged as a candidate biomarker that may enable the early detection of systemic sclerosis-related pulmonary arterial hypertension (SSc-PAH). The objective of our study was to incorporate NT-proBNP into a screening algorithm for SSc-PAH that could potentially replace transthoracic echocardiography (TTE) as a more convenient and less costly "first tier" test. METHODS: NT-proBNP levels were measured in patients from four clinical groups: a group with right heart catheter (RHC)-diagnosed SSc-PAH before commencement of therapy for PAH; a group at high risk of SSc-PAH based on TTE; a group with interstitial lung disease; and systemic sclerosis (SSc) controls with no cardiopulmonary complications. NT-proBNP levels were compared by using ANOVA and correlated with other clinical variables by using simple and multiple linear regression. ROC curve analyses were performed to determine the optimal cut point for NT-proBNP and other clinical variables in prediction of PAH. RESULTS: NT-proBNP was highest in the PAH group compared with other groups (P < 0.0001), and higher in the risk group compared with controls (P < 0.0001). NT-proBNP was positively correlated with systolic pulmonary artery pressure (PAP) on TTE (P < 0.0001), and mean PAP (P = 0.013), pulmonary vascular resistance (P = 0.005), and mean right atrial pressure (P = 0.006) on RHC. A composite model wherein patients screened positive if NT-proBNP was ≥ 209.8 pg/ml, and/or DLCOcorr was < 70.3% with FVC/DLCOcorr ≥ 1.82, had a sensitivity of 100% and specificity of 77.8% for SSc-PAH. CONCLUSION: We have proposed a screening algorithm for SSc-PAH, incorporating NT-proBNP level and PFTs. This model has high sensitivity and specificity for SSc-PAH and, if positive, should lead to TTE and confirmatory testing for PAH. This screening algorithm must be validated prospectively.
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ItemDigital ulcers in systemic sclerosis: their epidemiology, clinical characteristics, and associated clinical and economic burden(BMC, 2019-12-23)BACKGROUND: To determine the frequency and clinical characteristics of systemic sclerosis-related digital ulcers, and associated direct health care costs, quality of life, and survival. METHODS: Digital ulcers (DUs) were defined as an area with a visually discernible depth and a loss of continuity of epithelial coverage. DU severity was calculated based on the physician reported highest number of new DUs at clinical review (mild = 1-5 DUs, moderate 6-10 DUs, severe > 10 DUs). Healthcare use was captured through data linkage, wherein SSc clinical data captured prospectively in a dedicated clinical database were linked with health services databases to capture hospital admissions, emergency department (ED) presentations and ambulatory care (MBS) utilization and cost for the period 2008-2015. Healthcare cost determinants were estimated using logistic regression. RESULTS: Among 1085 SSc patients, 48.6% experienced a DU over a mean follow-up of 5.2 ± 2.5 years. Those who developed DUs were more likely to have diffuse disease subtype (34.9% vs 18.2%, p < 0.001), anti-Scl-70 antibody (18.9% vs 9.3%, p < 0.001), and a younger age at SSc onset (43.6 ± 13.9 vs 48.8 ± 14.0 years, p < 0.001) in addition to reduced health-related quality of life (HRQoL) measured by the SF-36 but without a significant impact on survival. SSc patients with a history of a DU utilized significantly more healthcare resources per annum than those without a DU, including hospitalizations, ED presentation, and ambulatory care services. Total healthcare services, excluding medications, were associated with an annual excess cost per DU patient of AUD$12,474 (8574-25,677), p < 0.001, driven by hospital admission and ED presentation costs. CONCLUSION: DUs place a large burden on the patient and healthcare system through reduced HRQoL and increased healthcare resource utilization and associated cost.
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ItemIFNL3 genotype is associated with pulmonary fibrosis in patients with systemic sclerosis(NATURE PORTFOLIO, 2019-10-16)Fibrosis across different organs and tissues is likely to share common pathophysiological mechanisms and pathways. Recently, a polymorphism (rs12979860) near the interferon lambda gene (IFNL3) was shown to be associated with fibrosis in liver across multiple disease etiologies. We determined whether this variant is a risk factor for pulmonary fibrosis (PF) and worsening cutaneous fibrosis in systemic sclerosis (SSc). Caucasian patients with SSc (n = 733) were genotyped to test for association with the presence of PF and worsening of skin fibrosis. Serum IFN-λ3 levels from 200 SSc cases were evaluated. An association of the IFNL3 polymorphism with PF was demonstrated (OR: 1.66 (95% CI: 1.142-2.416, p = 0.008). The IFNL3 variant was not a risk factor for worsening of skin fibrosis. Functionally, IFN-λ3 serum levels were higher among subjects with PF compared to those unaffected (P < 0.0001). In conclusion, IFNL3 serum levels and the genetic variant known to be associated with liver fibrosis are similarly linked to PF, but not to worsening of skin fibrosis in SSc. These data highlight both common fibrosis pathways operating between organs, as well as differential effects within the same disease.
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ItemThe economic burden of systemic sclerosis related pulmonary arterial hypertension in Australia(BMC, 2019-11-27)BACKGROUND: To quantify the financial cost of pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc). METHODS: Healthcare use was captured through data linkage, wherein clinical data for SSc patients enrolled in the Australian Scleroderma Cohort Study were linked with hospital, emergency department (ED) and ambulatory care databases (MBS) for the period 2008-2015. PAH was diagnosed on right heart catheter according to international criteria. Determinants of healthcare cost were estimated using logistic regression. RESULTS: Total median (25th-75th) healthcare cost per patient (including hospital, ED and MBS cost but excluding medication cost) for our cohort during 2008-2015 was AUD$37,685 (18,144-78,811) with an annual per patient healthcare cost of AUD$7506 (5273-10,654). Total healthcare cost was higher for SSc-PAH patients compared with those without PAH with a total cost per patient of AUD$70,034 (37,222-110,814) vs AUD$34,325 (16,093 - 69,957), p < 0.001 respectively with an annual excess healthcare cost per PAH patient of AUD$2463 (1973-1885), p < 0.001. The cost of SSc-PAH occurs early post PAH diagnosis with 89.4% utilizing a healthcare service within the first 12 months post PAH diagnosis with an associated cost per patient of AUD$4125 (0-15,666). PAH severity was the main significant determinant of increased healthcare cost (OR 2.5, p = 0.03) in our PAH cohort. CONCLUSIONS: Despite SSc-PAH being a low prevalence disease, it is associated with significant healthcare resource utilization and associated economic burden, predominantly driven by the severity of PAH.
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ItemGWAS for systemic sclerosis identifies multiple risk loci and highlights fibrotic and vasculopathy pathways(NATURE PUBLISHING GROUP, 2019-10-31)Systemic sclerosis (SSc) is an autoimmune disease that shows one of the highest mortality rates among rheumatic diseases. We perform a large genome-wide association study (GWAS), and meta-analysis with previous GWASs, in 26,679 individuals and identify 27 independent genome-wide associated signals, including 13 new risk loci. The novel associations nearly double the number of genome-wide hits reported for SSc thus far. We define 95% credible sets of less than 5 likely causal variants in 12 loci. Additionally, we identify specific SSc subtype-associated signals. Functional analysis of high-priority variants shows the potential function of SSc signals, with the identification of 43 robust target genes through HiChIP. Our results point towards molecular pathways potentially involved in vasculopathy and fibrosis, two main hallmarks in SSc, and highlight the spectrum of critical cell types for the disease. This work supports a better understanding of the genetic basis of SSc and provides directions for future functional experiments.
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ItemCost savings with a novel algorithm for early detection of systemic sclerosis-related pulmonary arterial hypertension.(Wiley, 2019)Pulmonary Arterial Hypertension (PAH) is an important cause of death and disability in Scleroderma (SSc) patients. Yearly screening of all SSc patients with transthoracic echocardiography (TTE) is recommended in international guidelines and currently utilised by the Australian Scleroderma Interest Group (ASIGSTANDARD). Due to the limitations of TTE, the Australian Scleroderma Interest Group (ASIG) developed a new screening algorithm (ASIGPROPOSED) utilizing a serum biomarker, NT-proBNP, in place of TTE, which has been shown to be equally accurate as the current algorithm. The aim of this study was to compare the cost of these two algorithms. The new algorithm resulted in significant yearly cost savings of between AUD$42,913.35 and AUD$84,570 in screening and diagnosis of the ASCS cohort which, if extrapolated to the Australian population, would result in a yearly cost saving of between AUD$367,066 and AUD$725,564. There was no scenario in which the proposed algorithm did not result in a cost saving.