Odds Are…Incidence, Prevalence, and Costs of Commonly Encountered Patient Populations

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By Phil Stevens, MEd, CPO, FAAOP

I grew up in a small town. It was large enough to have its own elementary school but not its own grocery store. Getting to the middle school required a 20-minute drive to a slightly larger town. To find such luxuries as a high school, an airport, or a zoo required a 45-minute drive through a rather barren Indian reservation, broken up only once by the bright lights of an isolated bingo hall just off the freeway. It was a rather tedious drive in the days before DVD players were commonplace in every family automobile, but that was life in my small town.

As with many products of small towns, I have no desire to go back. It's a good thing really; small town life as an O&P practitioner is usually available only to those willing to embrace a significant commute because of the sizable population it takes to sustain an O&P practice. The disabilities that bring individuals to our treatment centers, while more common than many affected families would prefer, are fairly rare. And so we largely find ourselves consigned to more populous communities where there's enough need to sustain a practice.

12% of population graphic

According to the 2012 Annual Compendium of Disability Statistics, there were just under 40 million people living with a disability in the United States in 2011.1 That equates to just over 12 percent of the nation's population. However, the type and extent of such disabilities further determines just how many of that 12 percent in your community need to come see you. This article reviews recent data as it pertains to the incidence and prevalence of those treatment populations most commonly encountered in lower-limb orthotic practice, including stroke, traumatic brain injury (TBI), spinal cord injury (SCI), and multiple sclerosis (MS).2 In addition, this article presents data regarding the cumulative direct and indirect costs associated with these diagnoses and medical events.


Given its high prevalence in orthotic practice, it's hardly surprising to note a comparatively high prevalence of individuals who have suffered strokes in the United States. Of the roughly 800,000 strokes that occur every year, just over 600,000 are first time events, with the additional 185,000 characterized as recurrent episodes.2 Accruing year after year, the overall prevalence of individuals who survive strokes is reported at almost 7 million, or nearly 3 percent of the U.S. population.

As with many of the other populations discussed within this article, there is considerable variation in individual presentation after a stroke. The subset of patients seen in orthotic clinics fails to represent the most and least affected patients of post-stroke. However, data suggests that half of all those who suffer strokes experience hemiparesis or reduced mobility, and roughly one-third are unable to walk without assistance.2

The average cost of a stroke hospitalization is strikingly low, reported at only $9,500. However, healthcare costs accrue, with outpatient rehabilitation and long-term care contributing to an average lifetime cost of $140,000. As such, the provision of an $800-$1,600 AFO represents somewhere between one-half to 1 percent of the average total healthcare costs of a patient following a stroke.

Given its rather high incidence, cumulative prevalence, and frequently debilitating sequelae, the national healthcare costs associated with strokes are substantial. In their review, Vincent et al. estimate an annual cumulative direct cost of $33 billion with another $27 billion in annual indirect costs. Estimates have placed the total national costs associated with strokes as high as $73 billion.

43% graphic

Traumatic Brain Injury

Somewhat surprisingly, the U.S. Centers for Disease Control and Prevention estimates the annual number of TBIs requiring a physician visit at almost 1.8 million, or roughly twice the incidence of stroke.2 And yet, our waiting rooms are visited much more by patients with the latter rather than with the former. This appears to be because mild brain injuries account for 80 percent of the total occurrences, with severe injuries representing only 10 percent. However, for those patients who experience TBIs severe enough to require acute hospitalization, the long-term burden of disability becomes comparable to that observed with stroke, as 43 percent develop long-term disabilities related to their TBIs. The nuanced figure of roughly 180,000 annual severe TBIs suggests a ratio of stroke and TBI presentations much more consistent with clinical experience.

Perhaps because of the younger ages of patients with TBIs relative to those who have suffered strokes, and the longer lifespans experienced post-TBIs, the cumulative prevalence of individuals in the United States with long-term disabilities due to TBIs has been estimated at 3 to 5 million people, approaching that of survivors of strokes. While the total direct costs in the medical management of patients with TBIs are substantially less than for patients post-stroke, estimated at $13 billion, there are substantial indirect costs due to lost work and productivity estimated at almost $65 billion, or twice that estimated for patients who suffer strokes.2 This increase seems to be the product of the younger ages at the time of injury, longer lifespans, and high cumulative prevalence of severe TBIs.

Spinal Cord Injury

Though frequently associated with similar etiologies, Vincent et al. cite annual estimates of SCIs well below severe TBIs, ranging between 12,000 to 20,000 cases per year.2 Motor vehicle accidents account for the etiology in the majority of these cases, affecting males more than females at a four to one ratio. The prevalence of survivors of SCIs is estimated at 270,000.2

Despite the relatively lower numbers of those who suffer SCIs, the total annual healthcare costs associated with this population are quite high. With an estimated prevalence that is only 5-10 percent of those with TBIs, the national population of those with SCIs has higher annual direct costs, ranging from $14-$18 billion.2 This appears to be due to extremely high individual costs, ranging dramatically according to the level and extent of the SCI. Citing 2011 data, Vincent et al. report average first year costs ranging from $335,000 in cases of incomplete SCIs to over $1 million for patients with high cervical tetraplegia.2 Similar ratios in average individual costs persist in the years following the injury, reported at roughly $40,000 and $180,000 respectively.

However, the indirect costs associated with SCIs are much less than those associated with TBIs or strokes, estimated at only $2.5-$4 billion. This number appears to reflect the comparatively lower incidence and prevalence rate associated with SCIs, but may be further influenced by this population's subsequent employability. Vincent et al. report that the majority of these individuals are employed following their injuries. Understandably, the employment rate one year after the injury is low, reported at only 12 percent. However, two decades post injury, employment rates are cited at 35 percent.2

Multiple Sclerosis

MS is unique among these presentations as it is not marked by a clear, catastrophic event, but is rather a diagnosis of exclusion in which symptoms often manifest themselves well before the formal diagnosis is made. It is a disease that is highly variable in its presentation, with both mild and severe forms that may progress very slowly or very quickly. On average, however, difficulties with walking are experienced eight years after the onset of the disease; cane use is required 15 years post onset; and wheelchair use is required 30 years post onset. As such, the diagnosis does not lend itself well to formal reports of annual incidence. Rather, the presentation has been described in terms of rate over time. For example, Vincent et al. cite a rate of 2 cases of MS per 100,000 person years in men and 3.6 cases per 100,000 person years in women.2 National prevalence rates are more reasonably estimated and have been suggested at 400,000 individuals affected by the disease.

In contrast to employment trends in those with SCIs where there is an immediate drop-off following the accident and then a progressive return to employment, the employment rate in patients with MS sees a progressive decline as the disease takes its toll. Once patients begin to experience functional limitations, Vincent et al. report a 3 percent drop per year in the employment rate within the MS community.

This is an important consideration in the United States, where healthcare coverage is often tied to employment. Average annual healthcare costs of roughly $20,000-$40,000 have been reported. For those with health insurance, approximate out-of-pocket costs average $2,000 per year, with a quarter of the population paying more than this figure.2 Himmelstein et al. describe a particularly concerning survey of 2,314 individuals who had filed for bankruptcy in 2007.3 Out-of-pocket expenditures for neurological diseases like MS represented the highest medical bills seen in the survey at an average of $34,000 per person. These expenses exceeded those observed in the more frequently encountered presentations of stroke, diabetes, and heart disease.3


The national averages regarding annual incidence and cumulative prevalence for stroke, TBI, SCI, and MS are shown in Table 1. Also included are the estimated national costs, both direct and indirect, associated with each diagnosis. Examination of these figures paints a reasonable clinical picture for each diagnosis. Stroke, as the most commonly occurring pathology, has very high direct costs, presumably due to the extensive acute inpatient hospital stays, outpatient rehabilitation, and long-term care. TBI, when severe enough to warrant an inpatient admission and cause post-injury disability, has a much lower incidence rate but a fairly high cumulative prevalence rate, presumably due to the younger ages at which it occurs. Direct costs for TBIs are reduced, presumably because many patients are younger and live in their homes with family members rather than requiring long-term care. However, higher indirect costs suggest greater losses to productivity and employment, due again to younger ages at the time of injury. SCI, while much less common than TBI or stroke, creates a substantial national direct cost burden. However, the indirect costs are more measured, reflecting a lower prevalence and greater employability. MS, as the only progressive disorder under discussion, has a prevalence rate greater than SCI but far less than stroke or TBI. Unlike the dramatic immediate costs associated with the preceding diagnoses, its costs are cumulative and progressive. Ultimately, it is a very expensive diagnosis, reflecting both considerable healthcare costs and indirect costs associated with the progressive decline in employment in these individuals.

Table 1

Table 1: National estimates of incidence, prevalence, direct costs, and indirect costs associated with each presentation. TBI=traumatic brain injury, SCI=spinal cord injury, MS=multiple sclerosis, NR=not reported. Data derived from Vincent et al.

However, the reported incidence and prevalence rates also underscore the relative scarcity of these diagnoses on a national scale. Consider stroke as the most prevalent of the discussed diagnoses. According to the American Heart Associations' "Heart Disease and Stroke Statistics-2015 Update," on average, every 40 seconds someone in the United States has a stroke.4 Yet the population of stroke survivors fails to account for 3 percent of the national census, a relatively small percentage of the overall U.S. population.

This data, then, has an impact on the likely distribution of the patients in need of our O&P services. Ultimately, as a profession, we'll simply need to adapt to larger cities or find a more pleasant way to commute. Fortunately for the communities we live in, the populations encountered in lower-limb orthotic practice are fairly small on a national scale.

Phil Stevens, MEd, CPO, FAAOP, is in clinical practice with Hanger Clinic, Salt Lake City. He can be reached at .


  1. Houtenville, A. J. and T Ruiz. 2012. 2012 Annual Compendium of Disability Statistics. University of New Hampshire.
  2. Vincent, Y. M., L. Chan, and K. J. Carruthers. 2014. The incidence, prevalence, costs and impact of disability of common conditions requiring rehabilitation in the US: Stroke, spinal cord injury, traumatic brain injury, multiple sclerosis, osteoarthritis, rheumatoid arthritis, limb loss and back pain. Archives of Physical Medicine and Rehabilitation 95 (5):986-95.
  3. Himmelstein, D. U., D. Thorne, E. Warren, and S. Woolhandler. 2009. Medical bankruptcy in the United States, 2007 results of a national study. The American Journal of Medicine 122 (8):741-6.
  4. Mozaffarian, D. et al. on behalf of the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. 2015. Executive Summary: Heart Disease and Stroke Statistics-2015 Update: A report from the American Heart Association. Circulation 131:434-41.