Differences in intermediate outcomes for Asian and non-Asian adult hemodialysis patients in the United States

BACKGROUND: There is a paucity of information regarding the clinical experience of Asian hemodialysis patients. This paper describes intermediate outcomes for adult Asian hemodialysis patients compared to Caucasians and African Americans. METHODS: Dialysis facility staff abstracted clinical information on a national random sample of adult hemodialysis patients from October through December 2000. Associations of race with intermediate outcomes were tested by bivariate analyses and multivariable logistic regression modeling. RESULTS: A total of 429 patients were identified as Asian, 4403 as Caucasians, and 3103 as African Americans. Asian and Caucasian patients were older than African Americans [mean 63.2 (+/-15.6), 63.9 (+/-15.2), and 57.7 (+/-14.7) years, P < 0.001], and had fewer years on dialysis [mean 3.5 (+/-3.8), 3.1 (+/-3.8), and 4.1 (+/-4.1) years, P < 0.001]. Ninety three percent of Asians, 87% of Caucasians, and 84% of African Americans had a mean Kt/V > or =1.2 (P < 0.001). In addition, 36% of Asians, 32% of Caucasians, and 26% of African Americans had an arteriovenous (AV) fistula as their vascular access (P < 0.001). Hemoglobin profiles were only slightly different among the three racial groups. More Asians and African Americans had a mean serum albumin > or =4.0/3.7 g/dL compared to Caucasians (33% and 31% compared to 27%, respectively, P < 0.001). In the final multivariable logistic regression model, Asians were twice as likely to have a mean Kt/V > or =1.2 compared to Caucasians (the referent group) [odds ratio (OR) (95% CI) 2.10 (1.33, 3.32), P < 0.01]. They experienced similar intermediate outcomes for vascular access, anemia management, and serum albumin compared to the majority racial group. CONCLUSION: These findings indicate that adult hemodialysis Asian patients experience similar or better intermediate outcomes compared to the majority racial group. Further study is needed to determine if these results are associated with improved survival and less morbidity in this minority group.     

The role of tumor size in the radiosurgical management of patients with ambiguous brain metastases

OBJECTIVE: To identify a size cutoff below which it is safe to observe obscure brain lesions suspected of being metastases so that treatment of nonmetastases can be avoided. METHODS: Medical records from patients who underwent linear accelerator-based radiosurgery from August 1991 to October 2001 were reviewed. Inclusion criteria were defined as brain metastasis tumor volume less than 5 cm(3) (diameter, thick similar 2.1 cm) treated with a dose of 20 Gy or more. One hundred thirty-five patients had 153 evaluable brain metastases with follow-up imaging that met inclusion criteria. Median age was 54 years (range, 18-79 yr). Lesion primaries were non-small-cell lung (n = 39), melanoma (n = 44), renal (n = 37), breast (n = 18), colon (n = 3), sarcoma (n = 5), other (n = 5), and unknown primary (n = 2). Median tumor volume was 0.67 cm(3) (range, 0.06-4.58 cm(3)). The minimum peripheral dose was 20 Gy (n = 132) or 21 to 24 Gy (n = 21). At the time of analysis, the median follow-up for all patients was 10 months (range, 0.2-99 mo). RESULTS: The 1- and 2-year actuarial local control rates for all of the lesions were 69 and 46%, respectively. For lesions of 1 cm (0.5 cm(3)) or less, the corresponding local control rates were 86 and 78%, respectively, which was significantly higher than the corresponding rates of 56 and 24%, respectively, for lesions larger than 1 cm (0.5 cm(3)) (P = 0.0016). CONCLUSION: A convincing brain metastasis measuring less than 1 cm should be pursued aggressively. If the suspected brain metastasis is ambiguous, observation is proposed up to a diameter of 1 cm. This is the first study in the literature to identify a 1-cm cutoff for radiosurgical control of small brain metastases, and validation by additional studies is required.     

Cost-effectiveness of PET in the diagnosis of Alzheimer disease

PURPOSE: To evaluate the cost-effectiveness of positron emission tomography (PET) in the diagnosis of Alzheimer disease (AD) in community-dwelling patients with mild or moderate dementia who present to specialized AD centers. MATERIALS AND METHODS: A decision-analytic model was used to compare costs and quality-adjusted life years (QALYs) associated with strategies involving single photon emission computed tomography (SPECT), dynamic susceptibility-weighted contrast material-enhanced magnetic resonance (MR) imaging, and PET as functional imaging adjuncts to the standard clinical work-up. Sensitivity analyses were performed to examine changes in test characteristics, health-related quality-of-life survey instruments, therapeutic effectiveness, and treatment rules. RESULTS: The use of PET to confirm the results of the standard clinical work-up cost more but yielded fewer benefits than a strategy in which dynamic susceptibility-weighted contrast-enhanced MR imaging was substituted for the typically performed structural computed tomography. This relationship remained stable in scenarios in which standard diagnostic work-up accuracy, drug treatment effectiveness, and version of the Health Utilities Index were altered. Dynamic susceptibility-weighted contrast-enhanced MR imaging cost US dollars 598800 per QALY gained (range, US dollars 74400 to US dollars 1.9 million per QALY), compared with the cost of the standard diagnostic work-up. Treating all patients with dementia was the dominant imaging strategy, except when side effects in patients with non-AD-related dementia were modeled. In all scenarios, SPECT yielded fewer benefits than other strategies at a higher cost. CONCLUSION: PET may have high diagnostic accuracy, but adding it to the standard diagnostic regimen at AD clinics would yield limited, if any, benefits at very high costs.     

Cost-effectiveness of hepatic metastasectomy in patients with metastatic colorectal carcinoma: a state-transition Monte Carlo decision analysis

OBJECTIVE: To evaluate the cost-effectiveness of hepatic resection ("metastasectomy") in patients with metachronous liver metastases from colorectal carcinoma (CRC), and to investigate the impact of operative and follow-up strategies on outcomes, cost, and cost-effectiveness. SUMMARY BACKGROUND DATA: There is substantial evidence that resection of CRC liver metastases can result in long-term survival in some patients. However, several unresolved issues are difficult to address using currently available clinical data. These include the appropriate threshold for resection, whether to perform repeat resection, and the relative cost-effectiveness of the procedure(s). METHODS: The authors developed a state-transition Monte Carlo decision model to evaluate the (societal) cost-effectiveness of hepatic metastasectomy in patients with metachronous CRC liver metastases. The model tracks the presence, number, size, location, growth, detection, and removal of up to 15 individual metastases in each patient. Survival, quality of life, and cost are predicted on the basis of disease extent. Imaging and surgery affect outcomes via detection and removal of individual metastases. Several patient management strategies were developed and compared with respect to cost, effectiveness, and incremental cost-effectiveness ($/quality-adjusted life year [QALY]). A reference strategy in which metastasectomy is not offered and imaging is not performed for the purpose of assessing resectability or operative planning ("no-surgery" strategy) was included for comparison. Extensive sensitivity analysis was performed to evaluate the impact of alternative model assumptions on results. RESULTS: A strategy permitting resection of up to six metastases and one repeat resection, with CT follow-up every 6 months, resulted in a gain of 2.63 QALYs relative to the no-test/no-treat strategy, at an incremental cost of 18,100 US dollars/QALY. When additional surgical strategies were considered, the incremental cost-effectiveness ratio (ICER; relative to the next least effective strategy) of the six metastases, one repeat, 6-month strategy was 31,700 US dollars/QALY. Across a range of model assumptions, more aggressive treatment strategies (i.e., resection of more metastases, resection of recurrent metastases) were superior to less aggressive strategies and had ICERs below 35,000 US dollars/QALY. Findings were insensitive to changes in most model parameters but somewhat sensitive to changes in surgery and treatment costs. CONCLUSIONS: Hepatic metastasectomy is a cost-effective option for selected patients with metachronous CRC metastases limited to the liver. When considering metastasectomy, more aggressive approaches are generally preferred to less aggressive approaches. Overall, surgeons should be encouraged to consider resection for all patients whose metastases can technically be removed.     

Structure and function evaluation (SAFE): II. Comparison of optic disk and visual field characteristics

PURPOSE: To evaluate the relationship between glaucomatous structural damage to the optic nerve and development of visual field loss with standard automated perimetry (SAP) and short wavelength automated perimetry (SWAP). DESIGN: Cohort study. METHODS: Patients with elevated intraocular pressure and normal SAP visual fields were enrolled in this prospective study. Stereo optic disk photographs, SAP, and SWAP visual fields were obtained annually over a period of 4 or more years. Trained readers evaluated baseline and follow-up optic disk photographs for evidence of glaucomatous damage. Standard automated perimetry and SWAP examinations were evaluated according to previously validated criteria for development of confirmed visual field changes. RESULTS: Two-hundred ninety-five subjects (479 eyes) were enrolled. Following masked assessment of stereo photographs by an optic disk reading center, 272 of the 479 eyes were judged to have glaucomatous optic neuropathy at the time of study entry. Depending on the criteria employed, approximately 10% to 17.5% of all eyes developed confirmed visual field loss for SAP (conversions). Of the conversions, 75% to 80% had baseline glaucomatous optic disk damage, whereas normal and glaucomatous optic disks were equally divided (50%) among the nonconversion eyes. This difference was statistically significant (P <.003). Depending on the criteria employed, 4% to 12% of the eyes had confirmed SWAP deficits at baseline, and 4% to 8% developed confirmed SWAP defects at a follow-up examination. There was a greater percentage of eyes with a glaucomatous optic neuropathy in the group with SWAP deficits (75%-100%) than for those eyes in which SWAP remained normal (45%-60%). Some of these differences were statistically significant (P <.05). CONCLUSIONS: A strong relationship exists between glaucomatous optic disk damage at study entry and the subsequent development of a confirmed glaucomatous SAP visual field defect. A higher percentage of glaucomatous optic disks were also found in patients with SWAP deficits at baseline and in those who later developed SWAP deficits. These findings support the premise that a glaucomatous optic disk is predictive of the subsequent development of glaucomatous visual field loss.     

Reliability of the electronic early treatment diabetic retinopathy study testing protocol in children 7 to <13 years old

PURPOSE: To assess the test-retest reliability of the electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) visual acuity algorithm using the computerized Electronic Visual Acuity (EVA) tester in children 7 to <13 years old. DESIGN: Test-retest reliability study. METHODS: This multicenter study involved 245 subjects at four clinical sites. As the main outcome measure, visual acuity was measured twice using the E-ETDRS testing protocol on the EVA system, which uses a programmed handheld device to communicate with a personal computer and a 17-inch monitor at a 3-m test distance. RESULTS: Test-retest reliability was high (r =.94 for right eyes and 0.96 for left eyes) and for both right and left eyes, 89% of retest scores were within 0.1 logarithm of the minimal angle of resolution (logMAR) (five letters) of the initial test score and 99% of retests were within 0.2 logMAR (10 letters). Reliability was high across the age range of 7 to <13 years. Based on 95% confidence level estimates, a change in visual acuity of 0.2 logMAR (10 letters) from a previous acuity measure is unlikely to result from measurement variability. CONCLUSIONS: The E-ETDRS protocol using the EVA has high test-retest reliability in children 7 to <13 years of age. Potential advantages include better standardization across multiple sites, the ability to directly capture data electronically with an automatic acuity score calculation, the reduction of potential bias by limiting the tester's role, and the requirement of only a single testing distance for measurements from 20/800 to 20/12. This computerized testing method should be considered when visual acuity is used as an outcome measure in eye research involving children 7 to <13 years old.     

Corneal thickness as a risk factor for visual field loss in patients with preperimetric glaucomatous optic neuropathy

PURPOSE: To determine whether central corneal thickness (CCT) is a risk factor for visual field loss development among patients diagnosed with preperimetric glaucomatous optic neuropathy (GON). DESIGN: Observational cohort study. METHODS: The study included 98 eyes of 98 patients with GON, with a mean follow-up time of 4.3 +/- 2.7 years. Diagnosis of GON was based on masked assessment of optic disk stereophotographs. All patients had normal standard automated perimetry visual fields at baseline. Criteria for visual field abnormality were derived from a prior study. Several clinical factors (CCT, intraocular pressure, vertical cup-to-disk ratio, refraction, age, gender, family history of glaucoma, high blood pressure, cardiovascular disease, and migraine) were investigated to ascertain whether there is an association with development of repeatable visual field loss. Cox proportional hazards models were used to obtain hazard ratios (HR) and identify factors that predicted which individuals developed glaucomatous visual field loss during the follow-up period. RESULTS: Thirty-four patients (35%) developed repeatable visual field abnormality during follow-up. In multivariate analysis, risk factors that predicted the development of visual field loss were a thinner CCT (adjusted HR = 1.62/40 microm thinner; P =.023; 95% confidence interval [CI]: 1.07-2.45), higher baseline intraocular pressure (adjusted HR = 1.07/mm Hg; P =.022; 95% CI: 1.01-1.14), and larger baseline vertical cup-to-disk ratio (adjusted HR = 1.63/0.1 larger; P =.009; 95% CI: 1.13-2.35). The mean +/- standard deviation CCT of GON patients who developed visual field loss was 543 +/- 36 microm compared with 565 +/- 35 microm of those who did not develop visual field abnormalities (P =.005, Student t test). CONCLUSIONS: Central corneal thickness is a risk factor for development of visual field loss among patients diagnosed with preperimetric GON. It is important to consider CCT when establishing target intraocular pressure of patients with GON.