Predicting dysphagia onset in patients with ALS: the ALS dysphagia risk score.

Purpose: For patients diagnosed with ALS, dysphagia can result in aspiration, malnutrition, and mortality. The purpose of this study was to develop a clinical prediction model capable of identifying patients with ALS at imminent risk for developing swallowing complications. Methods: A retrospective cohort study using the Pooled Resource Open-Access ALS Clinical Trials Database (PRO-ACT) was conducted. After dividing the PRO-ACT database into development and validation cohorts with dysphagia defined from the ALS Functional Rating Scale (ALSFRS), a multivariable Cox proportional hazards regression model estimated the probability of dysphagia at 3, 6, and 12-months with subsequent evaluation of model discrimination and calibration. Results: With 2057 participants in the development cohort and 1891 in the validation cohort, the Cox model included 7 clinical variables: spinal-onset; bulbar, fine and gross motor ALSFRS subscale scores; respiratory impairment; functional progression rate; and time from diagnosis. The cumulative incidence of dysphagia was 18% at 3-months, 29% at 6-months, and 45% at 12-months. The mean predicted probability of dysphagia development ranged from 4.5% in the bottommost risk decile to 40% in the topmost decile at 3 months, 10%-72% at 6 months, and 25%-93% at 12 months. In the validation cohort, the model had good discrimination and calibration with an optimism corrected c-statistic of 0.70 and calibration slope of 0.96. Conclusions: The ALS dysphagia risk score can be used to identify patients with ALS at high risk for self-reported dysphagia development who would benefit from a comprehensive swallowing assessment and proactive dysphagia management strategies.

Validating a Markov model of treatment for hepatitis C virus-related hepatocellular carcinoma.

OBJECTIVE: We created and validated a Markov model to simulate the prognosis with treatment for HCV-related hepatocellular carcinoma (HCC) for assessment of cost-effectiveness for alternative treatments of HCC. METHOD: Markov state incorporated into the model consisted of the treatment as a surrogate for HCC stage and underlying liver function. Retrospective data of 793 patients from three university hospitals were used to determine Kaplan-Meier survival curves for each treatment and transition probabilities were derived from them. RESULTS: There was substantial overlap in the 95% CIs of the Markov model predicted and the Kaplan-Meier survival curves for each therapy. The predicted survival curves were also similar with those from the nationwide survey data supporting the external validity of our model. CONCLUSIONS: Our Markov model estimates for prognosis with HCC have both internal and external validity and should be considered applicable for estimating cost-effectiveness related to HCC.

Hormone replacement therapy after breast cancer: a systematic review and quantitative assessment of risk.

PURPOSE: Hormone replacement therapy (HRT) is typically withheld from women with breast cancer because of concern that it might increase the risk of recurrence. The purpose of this study was to quantify the risk of recurrent breast cancer associated with HRT among breast cancer survivors. METHODS: We performed a systematic literature review through May 1999, calculating the relative risk (RR) of breast cancer recurrence in each study by comparing the number of recurrences in the HRT group to those in the control group. In studies that did not contain a control group, we constructed one by estimating the expected number of recurrences based on data from the Early Breast Cancer Trialists' Collaborative Group, adjusting for nodal status and disease-free interval. RRs across all studies were combined using random-effects models. RESULTS: Of the 11 eligible studies, four had control groups and included 214 breast cancer survivors who began HRT after a mean disease-free interval of 52 months. Over a mean follow-up of 30 months, 17 of 214 HRT users experienced recurrence (4.2% per year), compared with 66 of 623 controls (5.4% per year). HRT did not seem to affect breast cancer recurrence risk (RR = 0.64, 95% confidence interval [CI], 0.36 to 1.15). Including all 11 studies in the analyses (669 HRT users), using estimated control groups for the seven uncontrolled trials, the combined RR was 0.82 (95% CI, 0.58 to 1.15). CONCLUSION: Although our analyses suggest that HRT has no significant effect on breast cancer recurrence, these findings were based on observational data subject to a variety of biases.

Analytic choices in economic models of treatments for rheumatoid arthritis: What makes a difference?

OBJECTIVES: To compare the analytic judgments, data, and assumptions of different models used in the economic evaluation of infliximab, one of a new class of drugs for rheumatoid arthritis (RA). METHODS: A detailed assessment was made of 4 models, 1 submitted (in a reimbursement dossier) by the manufacturer, 1 produced by an independent academic group, and 2 recently published in the literature. Factors considered included the key data inputs, assumptions about the sequencing of treatments for RA, the methods used to calculate health utilities, and the estimation of cost offsets. RESULTS: Two of the 4 models, although embodying different methodological approaches, gave fairly similar results (approximately 25,000 pounds- 35,000 pounds cost per additional quality-adjusted life year [QALY] gained). The other 2 models, both by an independent academic group, gave much higher estimates, ranging from 50,000 pounds to 60,000 pounds to more than 100,000 pounds per additional QALY. The differences appeared to depend mainly on differences in model structure, the assumptions about the positioning of infliximab in the treatment sequence, and the relationship between Health Assessment Questionnaire (HAQ) states and QALYs. CONCLUSIONS: Economic models of treatments for RA incorporate different key data inputs and analytic judgments. However, convergence was observed in some of the estimates produced by the models, particularly when adjustments were made for some of the differences in input parameters. Nevertheless, differences in the choice of model structure and in key assumptions also had a major impact on results. Therefore, more discussion is needed to reach a consensus on some of these methodological issues.

Who should be screened for HIV infection? A cost-effectiveness analysis.

BACKGROUND: The advent of effective prophylactic treatments for asymptomatic persons infected with human immunodeficiency virus has led to interest in widespread screening programs. However, the costs of screening programs and therapy are high, and the prevalence of infection above which screening becomes an appropriate use of scarce health care dollars remains undetermined. METHODS: To examine the cost-effectiveness of screening in populations with differing prevalences of infection, we developed a Markov model to compare costs and life expectancy for two strategies: (1) screening and prophylactic treatment for infected persons who have or who develop low CD4+ (T4) cell counts, and (2) no screening. Based on studies in the literature, we estimated the prevalence of HIV infection, the rate of T4-cell loss, the rates of developing the acquired immunodeficiency syndrome and Pneumocystis pneumonia stratified by T4 cell counts, the life expectancy with the acquired immunodeficiency syndrome, the efficacy of prophylactic therapies, and costs. RESULTS: In populations with a prevalence of infection more than 5%, which includes known risk groups, screening costs less than $11,000 per life-year gained. In populations with a prevalence as low as 0.15%, screening costs only $29,000 per life-year gained. Even when the efficacy of zidovudine is assumed to be limited to 3 years, screening still costs less than $40,000 per life-year gained in populations with a prevalence of 0.5% or greater. However, in populations with a very low prevalence of infection (two to 10/100,000), such as members of the general population without reported risk factors, screening costs rise to between $290,000 and $1,277,400 per life-year gained. CONCLUSIONS: When considering only direct medical benefits, screening for asymptomatic human immunodeficiency virus infection in the general population, without regard to reported risk factors or seroprevalence data, would be expensive. In populations with a prevalence of infection of 0.5% or greater, however, the cost-effectiveness of screening falls within the range of currently accepted medical practices. These results suggest that screening be offered routinely to all persons in defined populations, such as persons receiving care at hospitals or clinics, or residing in geographic areas, where the seroprevalence is 0.5% or more, and underscore the need to conduct seroprevalence studies to identify such populations.

Individualizing therapy to prevent long-term consequences of estrogen deficiency in postmenopausal women.

BACKGROUND: Alendronate sodium and raloxifene hydrochloride were recently approved for the prevention of postmenopausal osteoporosis, but data on their clinical efficacy are limited. We compared these drugs with hormone replacement therapy (HRT) to help women and physicians guide postmenopausal treatment decisions. OBJECTIVE: To help physicians understand how they can best help women choose the most beneficial therapy after menopause based on their individual risk profile. METHODS: We developed a decision analytic Markov model to compare the effects of alendronate therapy, raloxifene therapy, and HRT on risks of hip fracture, coronary heart disease (CHD), breast cancer, and life expectancy. Regression models linked individual risk factors to future disease risks and were modified by drug effects on bone density, lipid levels, and associated breast cancer effects. RESULTS: Hormone replacement therapy, alendronate therapy, and raloxifene therapy have similar predicted efficacies in preventing hip fractures (estimated relative risk, 0.57, 0.54, and 0.58, respectively). Hormone replacement therapy should be more than 10 times more effective than raloxifene therapy in preventing CHD, but raloxifene therapy may not induce breast cancer. Women at low risk for hip fracture, CHD, and breast cancer do not benefit significantly from any treatment. Among women at average risk, HRT was preferred unless raloxifene therapy could reduce the risk of breast cancer by at least 66%, compared with a 47% increase for HRT. Women at high risk for CHD benefit most from HRT; women at high risk for breast cancer but low risk for CHD benefit most from raloxifene therapy, but only if it lowers the risk of breast cancer. CONCLUSION: Because of significant differences in the impact of these drugs, treatment choice depends on an individual woman's risk for hip fracture, CHD, and breast cancer.

Cost-effectiveness of treatments for chronic hepatitis C.

With increasing concern by consumers, employers, health-care payers, and policy makers, interest has grown in determining the economic efficiency of drugs. Consequently, numerous pharmacoeconomic studies have sought to estimate the marginal cost-effectiveness of initial interferon treatment for chronic hepatitis C. The effects of treating patients with histologically mild chronic hepatitis C for 6 months with interferon was compared with no interferon treatment using a computer simulation model. Data were obtained from five prospective trials, natural history studies from the literature, and actual cost data for hepatitis C patients. After applying the currently recommended annual discount rate (3%), the computer model projects a $400 reduction in lifetime cost of care and a 1.5-year increase in life expectancy associated with interferon treatment. Economic savings derived from preventing future cases of cirrhosis and hepatocellular carcinoma more than offset the initial treatment cost. By preventing future liver complications in responders, interferon treatment should prolong life expectancy and reduce costs. When compared with other well-accepted medical interventions, interferon treatment should be considered "cost-effective." Economic rationales should not restrict the availability of interferon for patients with hepatitis C.

Cost effectiveness of ribavirin/interferon alfa-2b after interferon relapse in chronic hepatitis C.

PURPOSE: Many patients with chronic hepatitis C who are treated with interferon suffer a relapse after an initial response. About half of these patients have a sustained virological response to retreatment with the combination of ribavirin and interferon alfa-2b. The aim of this study was to estimate the cost effectiveness of retreatment with combination therapy versus interferon alone for patients who have previously relapsed after interferon. SUBJECTS AND METHODS: Data from a randomized trial among 345 relapsed patients that compared combination therapy with interferon alone were used to project lifelong clinical and economic outcomes. Natural history and economic estimates (discounted at 3% per year) were based upon published literature, expert panel estimates, and cost and reimbursement data. RESULTS: Compared with retreatment with interferon alone, combination therapy should prolong life expectancy by about 2 discounted quality-adjusted life years (3 life years, undiscounted) while increasing costs modestly. The results were robust, maintaining an advantage to combination therapy in sensitivity analysis for all subgroups and with reasonable variations in all model parameters. CONCLUSION: For patients with chronic hepatitis C who relapse after an initial response to interferon alone, retreatment with the combination of ribavirin and interferon alfa-2b should prolong life and be cost effective.

Treatment of early Lyme disease.

PURPOSE: To compare the safety and efficacy of azithromycin, amoxicillin/probenecid, and doxycycline for the treatment of early Lyme disease, to identify risk factors for treatment failure, and to describe the serologic response in treated patients. PATIENTS AND METHODS: Fifty-five patients with erythema migrans and two patients with flu-like symptoms alone and fourfold changes in antibody titers to Borrelia burgdorferi were randomized to receive (1) oral azithromycin, 500 mg on the first day followed by 250 mg once a day for 4 days; (2) oral amoxicillin 500 mg and probenecid 500 mg, three times a day for each for 10 days; or (3) doxcycline, 100 mg twice a day for 10 days. If symptoms were still present at 10 days, treatment was extended with amoxicillin/probenecid or doxycycline for 10 more days. Evaluations were done at study entry and 10, 30, and 180 days later. RESULTS: Three of the patients who initially had symptoms suggestive of spread of the spirochete to the nervous system, one from each antibiotic treatment group, subsequently developed neurologic abnormalities, but symptoms in the other 54 patients resolved within 3 to 30 days after study entry. Six of the 19 patients (32%) (95% confidence interval, 13% to 57%) given amoxicillin/probenecid developed a drug eruption, whereas none of the patients given azithromycin or doxycycline had this complication. The presence of dysesthesias at study entry was the only risk factor significantly associated with treatment failure (p less than 0.001). By convalescence, 72% of the patients were seropositive, and 56% still had detectable IgM responses to the spirochete 6 months later. CONCLUSIONS: The three antibiotic regimens tested in this study were generally effective for the treatment of early Lyme disease, but the regimens differ in the frequency of side effects and in ease of administration.

Living-donor versus cadaveric liver transplantation for non-resectable small hepatocellular carcinoma and compensated cirrhosis: a decision analysis.

BACKGROUND: Cadaveric liver transplantation is effective for nonresectable early hepatocellular carcinoma. However, the scarcity of cadaveric organs has prompted some centers to use living donors, which guarantees transplantation, but entails a risk to the donor. In the absence of controlled trials, decision analysis can be used to help explicate the tradeoffs involved when considering living donor versus cadaveric liver transplantation for nonresectable early hepatocellular carcinoma. METHODS: Using a Markov model, a hypothetical cohort of patients with Child's A cirrhosis and a single 3.5-cm tumor received one of three strategies: 1) no transplant; 2) intent to perform cadaveric liver transplantation; or 3) living donor liver transplantation. Data were obtained from natural history and retrospective studies. All probabilities in the model were varied simultaneously using a Monte Carlo simulation. RESULTS: Living-donor liver transplantation was the best strategy, improving life expectancy by 4.5 years compared with cadaveric liver transplantation. This strategy remained dominant even when varying severity of cirrhosis, age, tumor doubling time, tumor growth pattern, blood type, regional transplant volume, initial tumor size, and rate of progression of cirrhosis. CONCLUSIONS: Living-donor liver transplantation should confer a substantial survival advantage for patients with compensated cirrhosis and non-resectable early stage hepatocellular carcinoma.

Ablative radioactive iodine therapy for apparently localized thyroid carcinoma. A decision analytic perspective.

Adjuvant therapy with ablative radioiodine after surgical resection of apparently localized thyroid carcinoma remains controversial because of the favorable prognosis of thyroid carcinoma and the risk of leukemia from the radioiodine. No controlled trials have been performed to examine this issue. We constructed a decision analytic model to examine whether patients with apparently localized thyroid carcinoma should receive radioiodine. Our analysis suggests that radioiodine modestly improves life expectancy by 2 to 15 months, depending on the patient's age and sex. This model predicts that the benefit of a reduction in the likelihood of recurrence outweighs the risk of leukemia from radioiodine.

A cost-effectiveness analysis of peginterferon alfa-2b plus ribavirin for the treatment of naive patients with chronic hepatitis C.

AIM: To estimate the cost-effectiveness of therapy and analyse the effect of therapy compliance in naive patients with chronic hepatitis C. METHODS: A decision analysis using the Markov model was performed for four different therapeutic strategies using peginterferon alfa-2b plus ribavirin or interferon alfa-2b plus ribavirin. Clinical data were obtained from available published reports and from the Spanish health system perspective. RESULTS: The incremental cost-effectiveness ratio of peginterferon alfa-2b plus ribavirin at a fixed dose, compared with interferon alfa-2b plus ribavirin, was 8478 euros per life year saved and 3737 euros per quality-adjusted life year gained. Good therapeutic compliance and weight-adjusted doses of ribavirin decreased the incremental cost-effectiveness ratio to 1636 euros per life year saved and 721 euros per quality-adjusted life year gained. In compliant genotype 1 patients, the incremental cost-effectiveness ratio decreased to 916 euros per life year saved and 404 euros per quality-adjusted life year gained, with an increase from 64 to 69 years in the threshold age at which therapy was cost-effective. The sensitivity analysis demonstrated that changes in the values of the most relevant parameters do not modify the study outcomes. CONCLUSION: From the clinical and pharmaco-economics perspective, the use of decision therapeutic analysis models suggests that the most effective therapy for chronic hepatitis C is peginterferon alfa-2b plus ribavirin adjusted to patient body weight and with good compliance, particularly in genotyped patients.

Effect of failed extubation on the outcome of mechanical ventilation.

OBJECTIVE: To examine medical outcomes associated with reintubation for extubation failure after discontinuation of mechanical ventilation. DESIGN: Prospective cohort study of consecutive intubated medical ICU patients who underwent a trial of extubation at a tertiary-care teaching hospital. The failed extubation group consisted of all patients reintubated within 72 h or within 7 days (if continuous ICU care had been required) of extubation. All others were considered to be successfully extubated. Study end points included hospital death vs survival, the number of days spent in the ICU and in the hospital after the onset of mechanical ventilation, the likelihood of requiring > or = 7 or > or = 14 days of ICU care after extubation, and the need for transfer to either a long-term care or rehabilitation facility among the survivors. RESULTS: Of 289 intubated patients, 247 (85%) were successfully extubated, and 42 (15%) required reintubation for failed extubation (time to reintubation 1.5+/-0.2 days). Reintubation for extubation failure resulted in 12 additional days of mechanical ventilation. When compared with successfully extubated patients, reintubated patients were more likely to die in the hospital (43% vs 12%; p<0.0001), spend more time in the ICU (21.2+/-2.8 days vs 4.5+/-0.6 days; p<0.001) and in the hospital (30.5+/-3.3 days vs 16.3+/-1.2 days; p<0.001) after extubation, and require transfer to a long-term care or rehabilitation facility (38% vs 21%; p<0.05). Using multiple logistic regression, extubation failure was an independent predictor for death and the need for transfer to a long-term care facility. Compared with those successfully extubated, patients who failed extubation were seven times (p<0.0001) more likely to die, 31 times (p<0.0001) more likely to spend > or = 14 days in the ICU after extubation, and six times (p<0.001) more likely to need transfer to a long-term care or rehabilitation facility if they survived. CONCLUSION: After adjusting for severity of illness and comorbid conditions, extubation failure had a significant independent association with increased risk for death, prolonged ICU stay, and transfer to a long-term care or rehabilitation facility. Extubation failure may serve as an additional independent marker of severity of illness. Alternatively, poor outcomes may be etiologically related to extubation failure. If the latter proves to be the case, identifying patients at risk for poor outcomes from extubation failure and instituting alternative care practices may reduce mortality, duration of ICU stay, and need for transfer to a long-term care facility.

Cost-effectiveness of anti-tumor necrosis factor agents.

Rheumatoid arthritis can lead to substantial morbidity, disability and mortality. The development of anti-tumor necrosis factor antibodies from the bench to the bedside over the past 15 years has ushered in the new era of biologic therapies for rheumatic diseases. Etanercept, infliximab and adalimumab have all been approved for the treatment of rheumatoid arthritis on the basis of improved clinical outcomes. Because these treatments, however, are expensive and not uniformly effective, concerns have arisen regarding their cost-effectiveness. This paper reviews the disease burden of rheumatoid arthritis, costs of drug therapy, costs of rheumatoid arthritis and the economics and cost-effectiveness of anti-tumor necrosis factor antibody agents.

A pragmatic and cost-effective strategy of a combination therapy of interferon alpha-2b and ribavirin for the treatment of chronic hepatitis C.

BACKGROUND: Combination of interferon (IFN) alpha and ribavirin is considered the standard treatment for patients with chronic hepatitis C. While combination therapy is more effective than IFN alone, the optimal management of combination treatment remains uncertain. OBJECTIVE: To assess a pragmatic and cost-effective strategy for the therapy of treatment-naive patients with chronic hepatitis C. DESIGN: Markov model on original data of two randomized trials. METHODS: A validated computer simulation model was applied to non-cirrhotic hepatitis C virus (HCV)-infected patients. Patient characteristics and efficacy of treatment were extracted from two randomized trials reporting on 1,445 non-cirrhotic patients. Different strategies were compared separately for genotype 1 and genotype non-1 (mostly genotype 2/3) infections: (1) no treatment; (2) IFN for 48 weeks (if at 12 weeks HCV RNA undetectable); (3) IFN and ribavirin for 24 weeks; (4) IFN and ribavirin for 48 weeks; (5) IFN and ribavirin for 48 weeks (if at 24 weeks HCV RNA undetectable). All strategies were tested for different combinations of known response factors. RESULTS: In genotype non-1 infection, 24 weeks of combination therapy dominates all other strategies. In genotype 1 infection, 48 weeks of combination therapy for week-24 responders only prolongs life expectancy at a favourable cost-effectiveness ratio (CE) of 7,135 euros per quality-adjusted life year (QALY). Taking response factors other than genotype into account does not add to the effectiveness or cost effectiveness. CONCLUSION: Treating non-cirrhotic patients with chronic hepatitis C according to genotype only is most cost effective independent of the number of other known response factors.

Fitting nutrition into the medical model: the role of decision analytic cost-effectiveness techniques.

Physicians are accustomed to making decisions based on information regarding the prevalence of disease, symptoms, physical signs, laboratory test results, and the risks and benefits of alternative treatments. If nutritional assessment and therapeutics are to become more common components of medical practice, significant barriers in each of these areas must be overcome. Even rudimentary dietary assessment is often missing from physician education. Dietary assessment tools that are readily available and that have demonstrated usefulness are largely unknown. In addition, many nutritional interventions have not been formally investigated in randomized, controlled trials, and thus their cost-effectiveness remains unknown. We present one approach to these issues by discussing the construction of a decision model examining strategies for vitamin D and calcium screening. The application of medical decision making techniques to problems in clinical nutrition illustrates how findings from research studies may be used to determine the risks, benefits and costs of alternative population based health related nutrition policies which can then be applied by physicians in their daily interactions with patients.

Meta-analysis of failure-time data with adjustment for covariates.

The objective of this study was to present and illustrate a technique for combining failure-time data from various sources, adjusting for differences in case-mix among studies. Based on the proportional-hazards model and the actuarial life-table approach, the method used assumes that the variation across studies is in part due to heterogeneity of the case-mix and adjusts for the case-mix before pooling results. As an example, the technique is applied to life-table data from six selected papers reporting patency of affected arteries following femoropopliteal angioplasty. Published 4- and 5-year patency results ranged from 25% to 58%, with a pooled five-year cumulative patency rate (without adjustment for case-mix) of 45% (+/- 2%). The populations in these studies, however, differed markedly in the prevalence of factors with prognostic value: type of lesion and distal runoff vessels. After adjustment for these differences in case-mix, the pooled five-year patency rates ranged from 60% (+/- 2%) for patients with stenotic lesions and good runoff to 24% (+/- 9%) for those with occlusion and poor runoff. The authors conclude that pooling studies without considering the effect of case-mix yields an average result with inappropriately narrow confidence intervals that does not reflect the variability across subgroups. The presented technique provides a method for combining failure-time data, adjusting for case-mix.

A peripartum neurologic event: shooting from the hip.

We have shown that a simplified model, generated quickly in response to an emergency consultation, may provide useful insights in certain situations. A more developed model was useful in verifying these insights. Because the more complex model considered a longer time horizon than the simple model, it allows us to consider questions regarding long-term benefits of aneurysm repair. When modeling any problem, the most important reason for performing decision analysis is to gain insight from analyzing the clinical setting and from constructing the model. The quantitative results are usually of only minor importance. However, our most important insights are sometimes gained by looking beyond the quantitative level to understand the interactions of various effects within the model. In this case, it was those insights that were of the greatest benefit to the patient in arriving at a decision to have cerebral arteriography.

Patency results of percutaneous and surgical revascularization for femoropopliteal arterial disease.

To estimate the patency results of percutaneous transluminal angioplasty and bypass surgery in the treatment of femoropopliteal arterial disease, a Medlars search of the English-language medical literature was performed. Inclusion required that studies 1) report original data, 2) report patency with a life table or Kaplan-Meier analysis with the number at risk or standard errors, 3) define patency as hemodynamic improvement, 4) report the distribution of covariates, and 5) not duplicate other published material. Using a method based on the proportional-hazards model and the actuarial life-table approach, the results were adjusted for differences in case-mix of the study populations and patency was predicted for subgroups at various levels of risk for failure. The unadjusted pooled life tables yielded five-year patencies of 45% (+/- 2%) for angioplasty, 73% (+/- 2%) for bypass surgery using a vein graft, and 49% (+/- 3%) for bypass surgery using a polytetrafluoroethylene graft. Adjusted five-year primary patencies after angioplasty varied from 12% to 68%, the best results being for patients with claudication and stenotic lesions. Adjusted five-year primary patencies after surgery varied from 33% to 80%, the best results being for saphenous vein bypass performed for claudication. The authors conclude that pooling life-table data without adjustment for covariates can be misleading. Indication, lesion type, vein graft availability, and site of the distal graft anastomosis need to be considered in predicting patency results of revascularization for femoropopliteal arterial disease.