Hasnat Ahmad1, Ingrid van der Mei1, Bruce V Taylor1, Robyn M Lucas2, Anne-Louise Ponsonby3, Jeannette Lechner-Scott4, Keith Dear5, Patricia Valery6, Philip M Clarke7, Steve Simpson8, Andrew J Palmer1. 1. Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia. 2. National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia/Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Perth, WA, Australia. 3. National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia/Murdoch Children's Research Institute, The University of Melbourne, Melbourne, VIC, Australia. 4. Hunter Medical Research Institute and The University of Newcastle, Callaghan, NSW, Australia. 5. Duke Kunshan University, Kunshan, China. 6. QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia. 7. Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia. 8. Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia/Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia.
Abstract
BACKGROUND: Transition probabilities are the engine within many health economics decision models. However, the probabilities of progression of disability due to multiple sclerosis (MS) have not previously been estimated in Australia. OBJECTIVES: To estimate annual probabilities of changing disability levels in Australians with relapsing-remitting MS (RRMS). METHODS: Combining data from Ausimmune/Ausimmune Longitudinal (2003-2011) and Tasmanian MS Longitudinal (2002-2005) studies (n = 330), annual transition probabilities were obtained between no/mild (Expanded Disability Status Scale (EDSS) levels 0-3.5), moderate (EDSS 4-6.0) and severe (EDSS 6.5-9.5) disability. RESULTS: From no/mild disability, 6.4% (95% confidence interval (CI): 4.7-8.4) and 0.1% (0.0-0.2) progressed to moderate and severe disability annually, respectively. From moderate disability, 6.9% (1.0-11.4) improved (to no/mild state) and 2.6% (1.1-4.5) worsened. From severe disability, 0.0% improved to moderate and no/mild disability. Male sex, age at onset, longer disease duration, not using immunotherapies greater than 3 months and a history of relapse were related to higher probabilities of worsening. CONCLUSION: We have estimated probabilities of changing disability levels in Australians with RRMS. Probabilities differed between various subgroups, but due to small sample sizes, results should be interpreted with caution. Our findings will be helpful in predicting long-term disease outcomes and in health economic evaluations of MS.
BACKGROUND: Transition probabilities are the engine within many health economics decision models. However, the probabilities of progression of disability due to multiple sclerosis (MS) have not previously been estimated in Australia. OBJECTIVES: To estimate annual probabilities of changing disability levels in Australians with relapsing-remitting MS (RRMS). METHODS: Combining data from Ausimmune/Ausimmune Longitudinal (2003-2011) and Tasmanian MS Longitudinal (2002-2005) studies (n = 330), annual transition probabilities were obtained between no/mild (Expanded Disability Status Scale (EDSS) levels 0-3.5), moderate (EDSS 4-6.0) and severe (EDSS 6.5-9.5) disability. RESULTS: From no/mild disability, 6.4% (95% confidence interval (CI): 4.7-8.4) and 0.1% (0.0-0.2) progressed to moderate and severe disability annually, respectively. From moderate disability, 6.9% (1.0-11.4) improved (to no/mild state) and 2.6% (1.1-4.5) worsened. From severe disability, 0.0% improved to moderate and no/mild disability. Male sex, age at onset, longer disease duration, not using immunotherapies greater than 3 months and a history of relapse were related to higher probabilities of worsening. CONCLUSION: We have estimated probabilities of changing disability levels in Australians with RRMS. Probabilities differed between various subgroups, but due to small sample sizes, results should be interpreted with caution. Our findings will be helpful in predicting long-term disease outcomes and in health economic evaluations of MS.