Changes in Cost and Outcome Among US Patients With Stroke Hospitalized in 1990 to 1991 and Those Hospitalized in 2000 to 2001
Background and Purpose— The purpose of this study was to evaluate the impact of new treatments by examining the changes between 1990 to 1991 and 2000 to 2001 in in-hospital mortality rates and hospital charges in adult patients with stroke.
Methods— From the Nationwide Inpatient Survey, the largest all-payer inpatient care database in the United States, patients with stroke admitted in 1990 to 1991 or 2000 to 2001 were studied. We analyzed hospital charges (adjusted for inflation based on the Consumer Price Index of the Bureau of Labor Statistics) and patient outcomes by type of institution: rural, urban nonteaching, and urban teaching in 1990 to 1991 and in 2000 to 2001.
Results— In 1990 to 1991, there were 1 736 352 admissions for cerebrovascular diseases, and in 2000 to 2001, there were 1 958 018 admissions. The number of admissions in urban teaching hospitals increased by 13%, 19%, and 25%, for ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, respectively. The overall in-hospital mortality rate relatively declined by 36% for ischemic stroke, by 6% for intracerebral hemorrhages, and by 10% for subarachnoid hemorrhage. The mean hospital charges increased from $10 500 to $16 200 for patients with ischemic stroke, from $18 300 to $28 800 for patients with intracerebral hemorrhage, and from $37 400 to $65 900 for patients with subarachnoid hemorrhage. Mortality rates among patients admitted after ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage were all lower in urban teaching hospitals than in rural and urban nonteaching hospitals and the mean charges per admission were all higher.
Conclusions— There has been an increase in the inflation-adjusted hospital charges for all patients with stroke and a reduction in mortality rates for all stroke subtypes probably related to an increase in the proportion of patients with stroke admitted to urban teaching hospitals.
- hospital charges
- intracerebral hemorrhage
- nationwide inpatient sample
- subarachnoid hemorrhage
New therapeutic strategies such as thrombolytic and endovascular treatment and improvement in stroke unit care are expected to improve the overall outcome of patients with stroke.1–3 We performed this study to estimate changes in outcomes and hospital charges for patients with stroke between 1990 to 1991 and 2000 to 2001 in the United States.
Materials and Methods
We used the data from the Nationwide Inpatient Sample that is the largest all-payer inpatient care database in the United States.4 International Classification of Disease, 9th Revision, Clinical Modification primary diagnosis codes were used to identify the patients admitted with stroke and stroke subtypes and secondary codes to identify those with stroke-associated complications and related procedures (Table 1). We looked at l990 to 1991 when none of the new stroke treatment modalities were available and at 2000 to 2001 when several new modalities were available. The numbers of hospitals included were 844, 828, 960, and 959 for the years 1990, 1991, 2000, and 2001, respectively.
The variables analyzed included patients’ age, sex, race/ethnicity, length of stay, discharge status, medical complications, procedures performed, and total hospitalization charges. These charges represent the amount that hospitals billed for services, but not how much hospital services actually cost or the specific amounts received in payment. The charges therefore include hospital overhead costs, charity care, and bad debt, among other costs. The total charges do not include physicians’ professional fees. Inflation effect on hospital charges were adjusted using the Bureau of Labor Statistic’s Consumer Price Index (www.bls.gov/cpi/). We also estimated the incremental cost per additional survival by dividing the total Consumer Price Index-adjusted cost per patient increase by proportion of additional survivors for each of the stroke subtypes.
We also evaluated the association among various patient outcomes and the hospitals in which they were treated (rural, urban nonteaching, and urban teaching hospitals) as defined previously (www.hcup-us.ahrq.gov). To account for differences in the relative prevalence of various stroke subtypes during time or hospital type comparisons, we used the previously described method5 for adjustment. We used the χ2 test for categorical data and analysis of variance for continuous data to detect any significant differences in variables among 3 types of facilities and between 1990 to 1991 and 2000 to 2001 and applied the Bonferroni adjustment when making multiple comparisons. To determine the effect of changes in proportion of admission to urban teaching hospitals, we performed multivariate regression analyses using the study periods (1990 to 1991 and 2000 to 2001) as independent variables and inflation and subtype-adjusted hospital charges or subtype-adjusted mortality as the dependent variable with and without adjustment for admission to urban teaching hospitals.
We estimated that there were 1 736 352 admissions for cerebrovascular diseases in US hospitals in 1990 to 1991 and 1 958 018 in 2000 to 2001, a 12.8% increase (Table 2). The proportion of patients with cerebrovascular diseases admitted to urban teaching hospitals also increased significantly over the 10-year period, by 13% for those who had an ischemic stroke, 19% for those who had intracerebral hemorrhage (ICH), and 25% for those who had a subarachnoid hemorrhage (SAH; Table 3). The mean length of hospital stay was significantly lower in 2000 to 2001 than in 1990 to 1991 for all patients with stroke combined, patients with ischemic stroke, patients with ICH, and those with SAH (Table 2). The rate of carotid endarterectomy among patients with ischemic stroke increased from 12.8% in 1990 to 1991 to 21.7% in 2000 to 2001 for patients with ischemic stroke (P<0.001).
The in-hospital mortality rate fell among patients with ischemic stroke, ICH, and SAH between 1990 to 1991 and 2000 to 2001 (Table 2) with a relative reduction of 36%, 6%, and 10%, respectively. There was also a significant reduction in mortality rates for all 3 categories of patients with stroke at urban teaching hospitals, but not in urban nonteaching and rural hospitals (Table 3). The mean hospital charges for cerebrovascular diseases increased from $13 800 (Consumer Price Index-adjusted) in 1990 to 1991 to $17 100 in 2000 to 2001 (see Table 2) and for all stroke subtypes. The incremental cost per survivor was $204 964, $634 745, and $978 054 for ischemic stroke, ICH, and SAH, respectively. There was a significant increase in hospital charges for all types of institutions over a 10-year interval (Table 3). However, the highest charges in 2000 to 2001 were observed for urban teaching hospitals.
Admission to urban teaching hospitals as a variable reduced the magnitude of inflation- and subtype-adjusted hospital charges (beta coefficient of 3223 reduced to 2550) and subtype-adjusted mortality in the multivariate model (Wald χ2 of 745 reduced to 690) supporting a direct effect.
We found that the increase in mean hospital charges for all subtypes of stroke admissions from 1990 to 1991 and 2000 to 2001 was greater than explained by inflation despite a reduction of patients’ average length of stay and in-hospital mortality rates. The proportion of patients treated with new treatments was too low to significantly affect overall hospital charges and outcome data for patients with stroke. Another potential explanation is that a higher proportion of patients with stroke were admitted to urban teaching hospitals in 2000 to 2001 than in 1990 to 1991. Urban teaching hospitals are more likely to provide a vascular neurologist and stroke units. Previous studies have shown that specialized care by a neurologist or organized inpatient (stroke unit) care reduces rates of pneumonia, hospital stay, and rates of death and disability at discharge and long-term institutional care among patients with stroke.6–8 Early use of antiplatelets, carotid imaging, and carotid endarterectomies may improve the outcomes of patients with stroke in urban teaching hospitals.9 Although we had no data in our study regarding use of antiplatelet agents, we did observe that the rate of carotid endarterectomies was greater in 2000 to 2001 than in 1990 to 1991. However, patients with severe stroke and higher resource needs are transferred to such units and providing specialized services requires more qualified and experienced personnel. This may have contributed to our findings of increased hospital charges but improved outcomes. We also cannot exclude that these finding are part of a global increase in healthcare spending disproportionate to overall economic change reflected by the Gross Domestic Product in since 1998.10
The increasing stroke hospitalization rate suggests that the incidence of stroke in the United States may be increasing, although hospitalization is not an accurate surrogate for incidence.11 A lower threshold for admission and more frequent diagnosis attributable to more frequent neuroimaging may also account for increased rates in 2000 to 2001. Admission of milder strokes may have reduced the case fatality rate by inflating the denominator. No definite comments can be made in the absence of knowledge regarding admission severity between the 2 study periods, although the unchanged rates of mechanical ventilation and medical complications do not support this assumption. We also observed a relative increase in the number of patients with ICH or SAH over a 10-year period. With the availability of more effective ischemic stroke preventive strategies, a disproportionate increase in ICH and SAH admissions can be expected. Such an ongoing trend will result in a nonlinear increase in charges and mortality for a corresponding increase in stroke incidence. The proportion of patients discharged to other facilities increased in 2000 to 2001 probably attributable to early discharge with continuity of acute care at other short-term facilities.
The Nationwide Inpatient Sample had total charge information that correlates strongly with the cost but maybe an under- or overestimate depending on the contribution of overhead costs and professional fees. A review of studies12 evaluating cost-effectiveness suggested that mean total cost per patient in a stroke unit is comparable to care provided in another hospital ward, and early supported discharge services provided care at modestly lower total costs than usual care for patients with stroke with mild or moderate disability. A study13 demonstrated that despite a higher cost of hospitalization in patients treated in stroke units, the total costs over the first year did not differ significantly from those treated with conventional care in general medical wards. Another study14 compared healthcare, social services, and informal care costs for 447 patients with acute stroke randomly assigned to stroke unit, stroke team, or domiciliary stroke care. Improved health outcomes were observed among patients treated at stroke units, but at higher cost with a prominent contribution from cost related to long-term and informal care.
Our analysis provides an overview into changes in in-hospital mortality rates, hospitalization charges, and admission patterns in the United States over the last 10 years.
The views and opinions in this article may not necessarily reflect the views of Centers for Disease Control and Prevention, Atlanta, Ga.
- Received July 11, 2006.
- Revision received August 23, 2006.
- Accepted September 11, 2006.
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