NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
ECRI Health Technology Assessment Group. Diagnosis and Treatment of Swallowing Disorders (Dysphagia) in Acute-Care Stroke Patients. Rockville (MD): Agency for Health Care Policy and Research (US); 1999 Jul. (Evidence Reports/Technology Assessments, No. 8.)
This publication is provided for historical reference only and the information may be out of date.
Diagnosis and Treatment of Swallowing Disorders (Dysphagia) in Acute-Care Stroke Patients.
Show detailsThis section provides an in-depth discussion of the number of people in the United States affected by neurogenic dysphagia and resulting complications and death. This subject was touched upon briefly in the Burden of Illness section, and a summary of the figures is shown in Tables 8 and 9. We must stress that these numbers are rough estimates, as they are taken from several different small clinical trials. Often, only one number was available, and therefore used by default, not because it was necessarily an accurate number. A determination of the number of people affected in the United States is done using vital statistics data provided by the U.S. government.
Stroke
The rate of stroke in the United States cannot be definitively determined from the literature, as estimates have ranged widely. For the calculation of burden of illness, therefore, the most reasonable way to proceed is to offer a probable low estimate and high estimate. Brown et al. (1996) at the Mayo Clinic estimated the annual incidence of stroke to be 145 per 100,000. This included both hospitalized and nonhospitalized cases (Brown, Whisnant, Sicks et al., 1996). They made several adjustments to avoid double counting cases and to ensure only new incident cases were counted and prevalent cases were excluded. On the other hand, Modan and Wagener (1992), using the National Hospital Discharge Survey, reported an annual incidence of 290 per 100,000. Their methodology has a strong chance of double counting and including prevalent cases, even though the researchers limited their survey to acute-care facilities and excluded chronic and rehabilitative care. On the other hand, the population surveyed by Brown et al. was a predominantly white population, which has a lower stroke rate than other races, and therefore may not be representative of the entire U.S. population.
As of 1996, there were slightly more than 265 million people in the United States (U.S. Department of Commerce, 1997). Using these rates to model low and high possibilities, we calculated that 384,662 to 768,528 Americans suffer a stroke each year.
Of those 65 and older, the annual incidence rate of stroke has been estimated to be 953 per 100,000 men, and 736 per 100,000 women in a health care plan in Oregon (Barker and Mullooly, 1997); this was the only study to report incidence rates in the elderly group as a whole. In 1996, there were approximately 14 million men over 65, and 20 million women [Centers for Disease Control and Prevention (CDC), 1998]. Thus, the total burden of illness for stroke in the U.S. elderly population is approximately 279,338 individuals. This makes up 36.3 to 72.6 percent of all strokes in the population from the calculations above. Elderly patients normally make up the majority of all stroke incidents; three studies report that the proportion of stroke patients that are elderly range from 59 to 79 percent (Broderick, Phillips, Whisnant et al., 1989; Brown, Whisnant, Sicks et al., 1996; Taub, Wolfe, Richardson et al., 1994). This indicates that either the total stroke incidence rate reported by Modan et al. is too high, or that the rate for the elderly reported by Barker et al. is too low; one factor may be that Barker et al. allowed fewer ICD-9 stroke codes for inclusion than did Modan, but which of these methods is the more accurate is impossible to determine.
Not enough published data are available to calculate the number of nursing home patients affected by an acute stroke event each year.
Dysphagia
CDC indicates that there are almost 44 million people in the United States over the age of 60 [Centers for Disease Control and Prevention (CDC), 1998]. Of those, one study (the only study reporting this statistic) estimated that approximately 14.2 percent suffer from dysphagia (Baum and Bodner, 1983). Thus, the total elderly population affected by dysphagia is approximately 6,228,116.
There were not enough data to calculate the rate of dysphagia in a nursing home population specifically.
Dysphagia in Stroke
The annual incident stroke population, as calculated above, constitutes 385,000 to 769,000 people each year, depending on which study estimate is used. The rate of dysphagia within stroke has been calculated in various ways; for the purposes of this discussion, we will examine the occurrence of dysphagia as measured by videofluoroscopic swallowing study (VFSS) and bedside examination (BSE) separately. In general, more patients are diagnosed dysphagic when a VFSS is used than when a BSE is used.
Three studies examined the rate of dysphagia in hospitalized stroke patients shortly after the event (within 5 days) using VFSS (see Evidence Table 3) (Daniels, Brailey, Priestly et al., 1998; Daniels, McAdam, Brailey et al., 1997; Kidd, Lawson, Nesbitt et al., 1993). Given that none of these studies shows any particular superiority over any other, we will use the median occurrence rate of dysphagia reported by these studies, 74.6 percent (Daniels, McAdam, Brailey et al., 1997). Using this figure and the incident stroke statistics reported above, it appears that approximately 287,000 to 573,000 individuals are diagnosed with dysphagia by VFSS after a stroke each year.
Several studies have also examined the rate of dysphagia in hospitalized stroke patients as measured by BSE, water swallow test, or structured observation. Again, these studies report widely varying rates but do not appear to have study or patient characteristics that account for the differences. The median rate reported by those studies examining hospitalized patients within 5 days after stroke was 41.7 percent (Kidd, Lawson, Nesbitt et al., 1993). This calculates to an overall burden of illness of 160,000 to 320,000 individuals per year.
For elderly stroke patients specifically, the occurrence of dysphagia appears to be higher than the population as a whole, when measured by BSE. More than 279,000 people over age 65 suffer from stroke each year [Barker and Mullooly, 1997; Centers for Disease Control and Prevention (CDC), 1998]. One study examined specifically the rate of occurrence of dysphagia immediately after the stroke event in patients age 70 and older; using BSE, the rate was 35.5 percent (Barer, 1989). This calculates to a burden of illness of about 99,165 elderly stroke patients with dysphagia each year.
Malnutrition in Stroke
The results from a single, European study suggest that within 1 week of an acute stroke, 26.4 percent of patients are malnourished (Davalos, Ricart, Gonzalez-Huix et al., 1996). This calculates to 101,551 to 202,891 possible cases of malnutrition occurring within 1 week after an acute stroke.
The same European study as discussed above reported that 48.4 percent of all stroke patients with dysphagia became malnourished within 1 week of the event (Davalos, Ricart, Gonzalez-Huix et al., 1996). If we assume that 160 to 320 stroke patients have dysphagia, then the burden of illness resulting from malnutrition in dysphagia is 77,636 to 155,110 individuals.
Aspiration in Stroke
Aspiration, in particular, is a condition that can lead to serious morbidity, especially in stroke patients. As stated above, stroke affects 385,000 to 769,000 people each year. Several studies have examined the occurrence of aspiration shortly after the stroke incident. Of studies reporting this rate in acute hospital strokes within 5 days after the event as measured by VFSS or modified barium swallow (MBS), the median reported rate is 33.5 percent (an average from two median studies reporting 32.2 percent and 34.7 percent) (Daniels, McAdam, Brailey et al., 1997; Kidd, Lawson, Nesbitt et al., 1993). This calculates to an annual burden of illness of 128,862 to 257,457 stroke patients with documented aspiration on VFSS.
Pneumonia
The annual incidence rate of pneumonia most recently calculated by CDC from 1994 estimated 1,600 cases per 100,000 people per year (Adams and Marano, 1995). Calculated with the total population for 1996 (U.S. Department of Commerce, 1997), approximately 4,244,544 people each year contract pneumonia.
The rate of pneumonia increases as age increases (Houston, Silverstein, and Suman, 1995); elderly people are particularly susceptible to this illness. The elderly over 65 number almost 34 million [Centers for Disease Control and Prevention (CDC), 1998]. The rate of pneumonia among this subset of the population is estimated at 3,032 per 100,000 per year (Houston, Silverstein, and Suman, 1995). Thus, the total number of elderly people affected is approximately 1,026,662 each year. This is just over 24 percent of all pneumonia cases.
Pneumonia After Stroke
An acute stroke incident occurs in 385,000 to 769,000 people each year, as calculated above. The rate of pneumonia after stroke (as shown in Evidence Table 13) is best represented for the entire population by Young et al. (1990), who examined hospitalized patients with no age limits (Young and Durant-Jones, 1990). The hospital diagnosis rate of pneumonia after stroke reported by these researchers was 13 percent. Thus, the total number of individuals afflicted with pneumonia during an acute-care hospital stay after stroke is approximately 50,006 to 99,909 each year.
Dysphagia that leads to pneumonia after stroke
Dysphagia is an important symptom of stroke if it leads to decreased quality of life (QOL), serious morbidity, or mortality. As reported above, approximately 160,000 to 320,000 individuals suffer from dysphagia as a result of stroke each year, as measured by BSE; 287,000 to 573,000 as measured by VFSS. One study reported the rate of pneumonia after dysphagia was diagnosed with a water swallow test in hospitalized acute stroke patients at a facility with no directed dysphagia treatment program (Nilsson, Ekberg, Olsson et al., 1998). (No studies were available that reported dysphagia and pneumonia after VFSS or MBS in a hospital with no directed dysphagia treatment program.) The reported rate was 14.3 percent. Because dysphagia was diagnosed in this study using a noninstrumental method, we must apply the pneumonia rate to the dysphagic-stroke rate calculated by BSE (16,000 to 320,000); this therefore makes it impossible to correlate aspiration-related morbidity with dysphagia-related morbidity because they are diagnosed by two very different methods.
The calculated burden of illness is therefore 22,938 to 45,828 individuals who would contract pneumonia while in the hospital after acute dysphagic stroke each year if no dysphagia treatment program exists. (Contrarily, in a hospital where a dysphagia program does exist, rates of pneumonia after swallow therapy in acute care have ranged from 0 to 5.0 percent (Nilsson, Ekberg, Olsson et al., 1998; Odderson, Keaton, and McKenna, 1995), which would result in a burden of illness of 0 to 16,024 individuals with pneumonia each year.
As calculated above, more than 99,000 elderly stroke patients are diagnosed with dysphagia on BSE. No pneumonia statistics specific to the elderly were available on stroke patients with dysphagia (except from two studies that specifically examined nursing homes). If we assume the elderly have a similar pneumonia rate to the dysphagic stroke population as a whole, then 14,181 cases of pneumonia co-occur with dysphagic stroke in the elderly each year.
Aspiration that leads to pneumonia after stroke
Aspiration is diagnosed in 129,000 to 257,000 stroke patients each year using VFSS. Aspiration places patients at particular risk of contracting aspiration pneumonia. The only study that examined stroke patients in an acute-care hospital reported that 21.6 percent of all aspirating stroke patients contracted aspiration pneumonia if given no specific dysphagia treatment (Schmidt, Holas, Halvorson et al., 1994). Thus, approximately 27,834 to 55,611 stroke patients with aspiration will contract pneumonia each year.
Nondysphagic stroke to pneumonia
It is important to point out that stroke patients with dysphagia are not the only stroke patients to contract pneumonia. Those without dysphagia, while their chances are smaller, do place a burden of illness on society resulting from pneumonia and pneumonia deaths as well. It would also be interesting to compare the burden of illness that these patients create compared with stroke patients with dysphagia.
By subtracting dysphagic stroke from total stroke (discussed above), we calculate that 224,000 to 448,000 stroke patients each year appear not to be dysphagic. We can assume that these patients do not receive any directed swallow therapy, no matter whether the hospital incorporates such a therapy into the treatment paradigm or not. Reynolds, Gilbert, Good et al. (1990) reported that 19.8 percent of nonstroke patients with dysphagia (as measured by BSE) came down with pneumonia in an acute hospital setting (Young and Durant-Jones, 1990). Therefore, approximately 44,403 to 88,714 nonstroke patients with dysphagia will contract pneumonia each year.
Proportion of post-stroke pneumonia co-occurring with dysphagia
We have calculated that pneumonia occurs in approximately 50,000 to 100,000 individuals after an acute stroke incident. Dysphagic stroke leads to pneumonia in approximately 23,000 to 46,000 individuals. Thus, the proportion of pneumonia in stroke that co-occurs with BSE-diagnosed dysphagia is estimated at 45.9 percent when using a combination of medical literature and government population statistics. However, BSE-diagnosed dysphagia does not include many cases of aspiration, and therefore this estimate is likely under-representing the burden of illness for this population.
If instead we add together our estimates of dysphagic-pneumonia and nondysphagic-pneumonia, the total rate of pneumonia in stroke is estimated at 67,000 to 134,000, three times the rate as calculated using stroke-to-pneumonia statistics. When we calculate the burden of illness using the dysphagia plus nondysphagia calculations, the proportion of pneumonia cases co-occurring with dysphagia shrinks to 34.1 percent. It is impossible to determine which of these estimates is correct.
Proportion of post-stroke pneumonia co-occurring with aspiration
Approximately 28,000 to 56,000 aspirating stroke patients contract pneumonia each year. Thus, the proportion of pneumonia in stroke that co-occurs with diagnosed aspiration is 55.7 percent.
Pneumonia Mortality
Pneumonia resulting in pneumonia-specific death
Pneumonia was the reported cause of death for 81,972 people in 1996 [Centers for Disease Control and Prevention (CDC), 1998]. This includes all etiologies (not just stroke or patients with dysphagia). (We assume, for the purposes of this discussion, that once an elderly person contracts pneumonia, his/her probability of dying is the same no matter the etiology of the pneumonia.) The number of elderly people who reportedly died of pneumonia or influenza in 1995 (the most recent year reported) was 74,297 (Department of Health & Human Services, 1997 ). These figures suggest that the large majority (90.6 percent) of pneumonia deaths occur in the elderly. While the death rate for pneumonia for all age groups is 1,900 per 100,000 cases (1.9 percent), we calculated that the death rate for the elderly is 7,200 per 100,000 (74,297 out of 1,026,662) (7.2 percent), 10,300 per 100,000 of those hospitalized (71,000 out of 690,000) (10.3 percent) (using Mayo Clinic and government data) [Centers for Disease Control and Prevention (CDC), 1998a; Centers for Disease Control and Prevention (CDC), 1998b; Department of Health & Human Services, 1997 ; Houston, Silverstein, and Suman, 1995]. This is somewhat lower than the rates reported in the medical literature (Evidence Table 20), where 14 to 40 percent of pneumonia patients died from this illness (a rate of 19.8 percent was used below for burden of illness calculations). It is possible that government-collected data do not count all cases because the cause of death listed on death certificates is not always accurate.
Dysphagia leading to pneumonia death
Above, we calculated that 23,000 to 46,000 stroke patients with dysphagia contract pneumonia each year. If 19.8 percent of these patients die of pneumonia, that is a burden of illness of 4,542 to 9,074 deaths per year possibly attributable to dysphagia in stroke victims. (However, these statistics do not imply causation; any attribution is purely speculative.)
Aspiration leading to pneumonia death
We have calculated that 28,000 to 56,000 aspirating stroke patients will contract pneumonia. If we assume a 19.8 percent mortality rate for pneumonia, this suggests that 5,511 to 11,011 pneumonia deaths each year will result after aspirating stroke. These numbers appear to be conundrums when compared with the dysphagia figures above, because there are more aspirators dying than dysphagics dying, and aspiration is a subset of dysphagia. However, these numbers are not comparable because the dysphagia numbers are calculated from BSE diagnosis, while the aspiration numbers are calculated from VFSS diagnosis rates.
Nondysphagic stroke leading to pneumonia death
As calculated above, about 44,000 to 89,000 nonstroke patients with dysphagia will contract pneumonia each year. Again assuming a pneumonia-specific mortality rate of 19.8 percent, the burden of illness is 8,792 to 17,565 individuals with non-dysphagic stroke dying of pneumonia each year. This is a substantially lower burden of illness than that resulting after dysphagic or aspirating strokes.
Summary
There are many discrepancies in the information presented above because the statistics have come from many different sources, and the reliability of the information from the medical literature is questionable because of varying followup times, different diagnostic methods, small patient populations, and methodologies that were not described adequately.
Other Neurologic Disorders
Table 11 in the Burden of Illness section shows a summary of the burden of illness (i.e., the number of people affected) caused by dysphagia resulting from Parkinson's disease, motor neuron disease (MND), amyotrophic lateral sclerosis (ALS), and progressive supranuclear palsy (PSP). Table 13 in that same section give details on the calculations described below. Not enough data are available to determine the burden of illness resulting from pneumonia or death in these patients. All rates discussed are annual incidence rates, in order to calculate an annual burden of disease.
Table
Table 13. Total Number of Patients with Dysphagia in Other Neurologic Diseases.
Parkinson's Disease
Only one study looked at the incidence rate of Parkinson's disease for the entire population (all ages and both sexes): Mayeux et al. (1995) reported an incidence rate of 13 per 100,000 per year (Mayeux, Marder, Cote et al., 1995) from a Mayo Clinic study. As there are more than 265 million people in the United States (Department of Commerce, 1997), the number of people affected by Parkinson's disease each year is 34,487.
The diagnosed occurrence of dysphagia in Parkinson's disease has been reported by several studies, using both videofluoroscopy and noninstrumental methods. Of two studies using videofluoroscopy that withheld L-dopa on the day of testing (which can affect dysphagia), the mean rate, 69.1 percent, was calculated (Bushmann, Dobmeyer, Leeker et al., 1989; Fuh, Lee, Wang et al., 1997). This indicates that of the 34,487 individuals affected by Parkinson's disease each year, 31,394 of them demonstrate dysphagia on videofluoroscopy. Data are not available to determine burden of illness resulting from malnutrition, pneumonia, or death.
Motor Neuron Disease
The annual incidence rate of MND, reported by Lilienfeld, Sprafka, Pham et al., (1991), was 6 per 100,000 in 1984, the most recent statistics available. In a population of more than 265 million, this means that 15,917 individuals are affected by MND each year.
There was only one potentially reliable number on the rate of dysphagia in MND, provided by Leighton, Burton, Lund et al. (1994), who reported that 51.2 percent of MND patients demonstrated swallowing graded as moderate or poor on videofluoroscopy. The total annual burden of illness is therefore 8,150 individuals affected by dysphagia in MND.
Amyotrophic Lateral Sclerosis
The most common form of MND is ALS. The annual incidence of ALS has been reported at 1.8 per 100,000 (Annegers, Appel, Lee et al., 1991). Thus, the total number of people affected by ALS in the United States each year is 4,775.
Only one study examined the rate of dysphagia in ALS. Leighton, Burton, Lund et al. (1994) reported a rate of 29 percent of poor or moderate swallowing as demonstrated on VFSS. Thus, 1,385 people are affected by dysphagia resulting from ALS.
Progressive Supranuclear Palsy
The annual incidence rate of PSP has been reported at 1.10 per 100,000 (Bower, Maraganore, McDonnell et al., 1997) (the prevalence has not been reported). Thus, approximately 2,918 people are affected by PSP each year.
Only one study reported the rate of dysphagia in PSP; Litvan, Sastry and Sonies (1997) reported that 55.6 percent of PSP patients complained of swallowing problems. This calculates to 1,622 people each year experiencing swallow problems as a result of PSP.
Huntington's Disease
The annual rate of new cases of Huntington's disease is 0.2 per 100,000 (Kokmen, Ozekmekci, Beard et al., 1994). The burden of illness is therefore approximately 531 each year in the U.S. population. The diagnosed occurrence of dysphagia was reported by a single study, at 100 percent of all Huntington's disease patients (Kagel and Leopold, 1992). Thus, the total number of new dysphagic Huntington's disease patients each year is 531.
Summary
Approximately 51,435 people this year will be affected by dysphagia resulting from these neurologic disorders. The large majority of these cases are the result of Parkinson's disease (more than 34,000). Combined with stroke, approximately 340,000 to 625,000 people will be affected by dysphagia resulting from a variety of neurologic disorders this year. Many of these patients may subsequently be affected by aspiration or pneumonia as the result of a disordered swallow although, presently, lack of data in the published literature makes the calculation of these rates impossible. If, however, we were to assume that the rates of aspiration and pneumonia were the same for all neurologic patients as for stroke, then we would estimate that approximately 14.3 percent of these patients with dysphagia would contract pneumonia (48,390 to 89,340 cases of pneumonia each year). If pneumonia death occurs at a rate of 19.8 percent, then approximately 9,581 to 17,689 patients will possibly die as a result of their untreated dysphagia.
- Appendix B. Burden of Illness of Dysphagia and Its Complications in Neurologic D...Appendix B. Burden of Illness of Dysphagia and Its Complications in Neurologic Diseases - Diagnosis and Treatment of Swallowing Disorders (Dysphagia) in Acute-Care Stroke Patients
Your browsing activity is empty.
Activity recording is turned off.
See more...