CEO’s Perspective July 13, 2016
Epidemiology and Market Opportunity Around the World – July 13, 2016
We at InVivo are driven by our mission to redefine the life of the spinal cord injury (SCI) patient. Although we have been focused to date on SCI patients in the United States, we realize that the tremendous burden of SCI does not end at our borders. We recognize that traumatic spinal cord injury is a global problem and today’s announcement to expand clinical operations into Canada is a significant step toward addressing that problem. Our goal is to be the worldwide leader in SCI and to one day treat patients around the world with a portfolio of products that have a significant impact on their lives.
Following is a brief overview of various reported incidence and prevalence rates as clarification of the impact of spinal cord injury around the world and the global problem we are working to address.
Defining Incidence and Prevalence
In the case of traumatic spinal cord injury, incidence refers to the number of new cases of spinal cord injuries that have occurred due to traumatic events — such as motor vehicle accidents and falls — over a year. Prevalence, on the other hand, refers to the proportion or number of a group of individuals having a clinical condition at a given point in time. For traumatic spinal cord injury, the prevalent population is all of the people currently living in a wheelchair or experiencing deficits as a result of a spinal cord injury. Both numbers are often expressed as rates in terms of cases or individuals per million inhabitants per year. Multiplying the incidence and prevalence rates by the population of a country or region will yield a rough estimation for how many people in that country or region are newly injured in a given year and how many people are living with a spinal cord injury, respectively.
Limitations of Estimating SCI Rates
Epidemiology is the study of the causes, incidence/prevalence, distribution, and control of conditions. Although estimating incidence and prevalence may seem like it should be a simple counting task, the field of epidemiology is actually quite complicated. In large countries, there are rarely all-inclusive registries of patients with a given condition across the entire country. Instead, studies usually focus on a smaller region (like a city, state, or province) and often use imperfect identification methodology. For example, many epidemiology studies for spinal cord injury rely on the use of diagnosis codes (in the U.S. ICD-9/10-CM codes), but these codes can be used incorrectly, and it can be challenging to discern a true acute, traumatic SCI hospitalization from a follow-up or rehabilitation hospitalization.
Epidemiology in the United States and Canada
A recent review by Furlan et al [1] summarizes studies that have evaluated the incidence of acute traumatic SCI around the world. The Furlan article cites 14 different studies in the United States that evaluated different geographies (eg, Utah, San Diego, New York State) and utilized different identification methodologies (eg, registries, surveys, diagnosis codes). Most of the studies evaluated incidence rates in the 1980s or 1990s. Recent (since 1980) incidence rate estimates ranged from 23.9/million/year (Colorado) to 83/million/year (Alaska). The median incidence rate from the 14 studies was about 40/million/year, and this figure has been widely used in the spinal cord injury field.
Multiplying this rate by the U.S. population yields an incidence estimate of about 12,000-13,000 new injuries per year.
The National Spinal Cord Injury Statistical Center (NSCISC) traditionally has used the incidence rate estimate of 40/million/year, but in its most recent Facts and Figures publication, NSCISC started using an incidence rate of 54/million/year [2]. This incidence rate comes from a recent study conducted by Jain et al [3] in 2012, and yields an annual incidence of approximately 17,000 new cases per year. This is notably higher than the previous estimate. For now, we at InVivo will continue to use the 40/million/year number in our market size estimates, but we are constantly evaluating the literature for updates and additional information. We may adopt the higher estimate in the future.
In Canada, the incidence rates are about the same as in the US. In a widely-cited recent study, Noonan et al [4] estimated the discharge incidence of traumatic SCI to be 41/million/year. Since the Canadian population is almost an order of magnitude smaller than the United States, this incidence rate translates to just under 1,500 new cases per year in the country.
As there are no available treatments to effectively change the course of this condition, the vast majority of the incident population moves into the prevalent population. DeVivo et al [5] estimates the prevalent population to be 906 per million persons in the United States and Noonan et al [4] estimates 1,288 per million persons in Canada. This translates to roughly 290,000 and 44,000 prevalent cases in the United States and Canada, respectively.
Epidemiology in Europe and Japan
Incidence and prevalence estimates across Europe vary significantly. According to Furlan et al [1], incidence rates were reported as low as 8/million/year in Spain and as high as 131/million/year in Bulgaria. For studies performed in European Union (EU) member countries, the median incidence rate was 19.4/million/year. Using this incidence rate, the incidence of SCI in EU countries is estimated to be about 10,000 per year. Prevalence rates ranged from 227 to 419 per million persons in Sweden and Norway, respectively. Although reported incidence and prevalence rates in Europe are lower than those in the United States and Canada, there is still a large market opportunity in Europe. We look forward to announcing our first INSPIRE site in Europe in the coming months as a first step on the path to European commercialization.
Japan represents another significant market for our products. The median reported incidence rates from Furlan et al [1] is 39.4/million/year, which yields an annual incidence of about 5,000 new SCIs per year. Although we do not have any immediate plans for initiating clinical studies in Japan, we have already engaged in preliminary discussions with potential Japanese partners.
SCI: A Worldwide Problem
My hope in describing these epidemiology rates is twofold: first, to demonstrate that spinal cord injury is a global problem that affects populations across the world; second, to demonstrate that SCI epidemiological data are imperfect and that incidence and prevalence estimates can vary widely from source to source and study to study. Many of the cited authors stressed the need for a more formal and rigorous spinal cord injury recording and reporting system. Until countries formalize a system to effectively capture spinal cord injury data, it will be impossible to know exactly how many individuals suffer from acute and chronic SCI.
At InVivo, our mission stands without prejudice to country of origin, and while our clinical strategy to date has been U.S.-centric, over the next several years we plan to execute on a clinical, regulatory, commercialization, and business development strategy that will allow us to address SCI patients across the globe.
Mark Perrin, CEO and Chairman
June 13, 2016
References
Furlan, Julio , et al. “Global incidence and prevalence of traumatic spinal cord injury.” The Canadian Journal of Neurological Sciences 40.04 (2013): 456-464.
National Spinal Cord Injury Statistical Center, Facts and Figures at a Birmingham, AL: University of Alabama at Birmingham, 2016.
Jain, Nitin , et al. “Traumatic spinal cord injury in the United States, 1993-2012.” JAMA 313.22 (2015): 2236-2243.
Noonan, Vanessa , et al. “Incidence and prevalence of spinal cord injury in Canada: a national perspective.” Neuroepidemiology 38.4 (2012): 219-226.
DeVivo, Michael , et al. “Prevalence of spinal cord injury: a reestimation employing life table techniques.” Archives of neurology 37.11 (1980): 707-708.
