Contributions
Abstract: 57
Type: Oral
Abstract Category: Clinical aspects of MS - MS Variants
Introduction: Neuromyelitis optica (NMO) is an antibody-mediated autoimmune disease of the central nervous system (CNS) in which the primary target of attack is aquaporin 4 (AQP4). Discovery of highly specific AQP4 antibodies has considerably aided diagnosis and has facilitated new diagnostic criteria for a condition which often has a worse prognosis than other demyelinating diseases. In order to ascertain the frequency of this condition in Australia and New Zealand we have conducted a population-based, clinical survey.
Methods: Possible cases of NMO were identified from 2011 to 2013 by a network of 37 adult and paediatric neurologists specialising in demyelinating disease of the CNS. Cases were referred if they had clinical features previously identified as being of high risk for NMO. Cases were defined as having NMO if they met the 2015 Wingerchuk criteria. AQP4 antibodies were identified using immunofluorescence and cell-based assays. A capture-recapture technique was utilised for seropositive cases through the records of the three laboratories in Australia providing routine testing for both countries. Incidence and prevalence rates were calculated with 95% confidence intervals and prevalence analysed by age, gender, latitude and ethnicity.
Results: A total of 177 suspected cases of NMO were referred, 10/177 (6%) were excluded. NMO was confirmed in 79/167 (47%), 72 were seropositive and 7 were seronegative. An additional 66 seropositive cases were identified from laboratory data. The crude annual incidence was 0.32 (95% CI 0.21-0.43) per million. The prevalence estimate was 0.75 (0.71-0.80) per 100,000. The female to male ratio was 6:1. The peak age range for women was 40-49 years and for men was 60-69 years. There was no evidence for a latitudinal gradient with a trend towards a reverse gradient compared to that seen with MS. The prevalence estimate for the Asian population was 3-fold higher than in the remainder of the population (1.61 vs 0.54).
Discussion: The incidence and prevalence of NMO in Australian and New Zealand are at the lower end or below those quoted for other countries with predominantly European populations (incidence 0.7-4.0 per million and prevalence 0.72-4.4 per 100,000). We have demonstrated a higher prevalence of NMO amongst Asians consistent with studies of Asian populations (0.9-1.1 per 100,000). We have confirmed a female predominance in NMO. The present study suggests that there is no latitudinal gradient in NMO.
Disclosure: This research was support by grants from Multiple Sclerosis Research Australia, The Brain Foundation, Griffith University and the Gold Coast Hospital Foundation.
All authors have nothing to disclose in relation to this abstract.
ANZ NMO Collaboration Members:
David Abernethy, Michael H Barnett, Sandeep Bhuta, Stefan Blum, Mike Boggild, Karyn Boundy, Bruce J Brew, Simon A Broadley, Matthew Brown, Walace Brownlee, Wajih Bukhari, Christine Bundell, Helmut Butzkueven, William M Carroll, Celia Chen, Laura Clarke, Alan Coulthard, Russell C Dale, Chandi Das, Keith Dear, David Fulcher, David Gillis, Simon Hawke, Robert Heard, Andrew Henderson, Saman Heshmat, Suzanne Hodgkinson, Sofia Jimenez-Sanchez, Allan G Kermode, Trevor J Kilpatrick, John King, Christopher Kneebone, Andrew Kornberg, Jeanette Lechner-Scott, Christopher Lynch, Richard Macdonnell, Mark Marriott, Deborah F Mason, Pamela McCombe, Cullen O"Gorman, John Parratt, Michael Pender, John D Pollard, Kerri Prain, Stephen Reddell, Cameron Shaw, Roger Silvestrini, Mark Slee, Jennifer Somerfield, Judy Spies, Jim Stankovich, Ian Sutton, Bruce V Taylor, Angela Vincent, Steve Vucic, Michael Walsh, Patrick Waters, Ernest Willoughby, Robert Wilson, Richard Wong, Mark Woodhall, Eppie Yiu.
Abstract: 57
Type: Oral
Abstract Category: Clinical aspects of MS - MS Variants
Introduction: Neuromyelitis optica (NMO) is an antibody-mediated autoimmune disease of the central nervous system (CNS) in which the primary target of attack is aquaporin 4 (AQP4). Discovery of highly specific AQP4 antibodies has considerably aided diagnosis and has facilitated new diagnostic criteria for a condition which often has a worse prognosis than other demyelinating diseases. In order to ascertain the frequency of this condition in Australia and New Zealand we have conducted a population-based, clinical survey.
Methods: Possible cases of NMO were identified from 2011 to 2013 by a network of 37 adult and paediatric neurologists specialising in demyelinating disease of the CNS. Cases were referred if they had clinical features previously identified as being of high risk for NMO. Cases were defined as having NMO if they met the 2015 Wingerchuk criteria. AQP4 antibodies were identified using immunofluorescence and cell-based assays. A capture-recapture technique was utilised for seropositive cases through the records of the three laboratories in Australia providing routine testing for both countries. Incidence and prevalence rates were calculated with 95% confidence intervals and prevalence analysed by age, gender, latitude and ethnicity.
Results: A total of 177 suspected cases of NMO were referred, 10/177 (6%) were excluded. NMO was confirmed in 79/167 (47%), 72 were seropositive and 7 were seronegative. An additional 66 seropositive cases were identified from laboratory data. The crude annual incidence was 0.32 (95% CI 0.21-0.43) per million. The prevalence estimate was 0.75 (0.71-0.80) per 100,000. The female to male ratio was 6:1. The peak age range for women was 40-49 years and for men was 60-69 years. There was no evidence for a latitudinal gradient with a trend towards a reverse gradient compared to that seen with MS. The prevalence estimate for the Asian population was 3-fold higher than in the remainder of the population (1.61 vs 0.54).
Discussion: The incidence and prevalence of NMO in Australian and New Zealand are at the lower end or below those quoted for other countries with predominantly European populations (incidence 0.7-4.0 per million and prevalence 0.72-4.4 per 100,000). We have demonstrated a higher prevalence of NMO amongst Asians consistent with studies of Asian populations (0.9-1.1 per 100,000). We have confirmed a female predominance in NMO. The present study suggests that there is no latitudinal gradient in NMO.
Disclosure: This research was support by grants from Multiple Sclerosis Research Australia, The Brain Foundation, Griffith University and the Gold Coast Hospital Foundation.
All authors have nothing to disclose in relation to this abstract.
ANZ NMO Collaboration Members:
David Abernethy, Michael H Barnett, Sandeep Bhuta, Stefan Blum, Mike Boggild, Karyn Boundy, Bruce J Brew, Simon A Broadley, Matthew Brown, Walace Brownlee, Wajih Bukhari, Christine Bundell, Helmut Butzkueven, William M Carroll, Celia Chen, Laura Clarke, Alan Coulthard, Russell C Dale, Chandi Das, Keith Dear, David Fulcher, David Gillis, Simon Hawke, Robert Heard, Andrew Henderson, Saman Heshmat, Suzanne Hodgkinson, Sofia Jimenez-Sanchez, Allan G Kermode, Trevor J Kilpatrick, John King, Christopher Kneebone, Andrew Kornberg, Jeanette Lechner-Scott, Christopher Lynch, Richard Macdonnell, Mark Marriott, Deborah F Mason, Pamela McCombe, Cullen O"Gorman, John Parratt, Michael Pender, John D Pollard, Kerri Prain, Stephen Reddell, Cameron Shaw, Roger Silvestrini, Mark Slee, Jennifer Somerfield, Judy Spies, Jim Stankovich, Ian Sutton, Bruce V Taylor, Angela Vincent, Steve Vucic, Michael Walsh, Patrick Waters, Ernest Willoughby, Robert Wilson, Richard Wong, Mark Woodhall, Eppie Yiu.