Showing papers by "Gary C. Brown published in 2001"

Utility values associated with blindness in an adult population

Abstract: AIM—To ascertain utility values associated with varying degrees of legal blindness. METHODS—A cross sectional study on three group of patients. There were: (1) 15 patients with complete absence of vision (no light perception) in at least one eye who were asked to assume a scenario of no light perception in the second eye as well, (2) 17 patients with light perception to counting fingers in the better seeing eye, and (3) 33 patients with 20/200-20/400 vision in the better seeing eye. Utility values were measured using the time trade-off and standard gamble methods in each of the three groups. RESULTS—The mean time trade-off utility value for the no light perception group with the theoretical scenario of bilateral absence of light perception was 0.26 (95% CI, 0.19-0.33). The mean utility value for the light perception to counting fingers group was 0.47 (95% CI, 0.33-0.61), and the mean utility value for the 20/200-20/400 group was 0.65 (95% CI, 0.58-0.72). Thus, patients with no light perception in one eye, who were presented with the same scenario in the second eye as well, were willing to trade almost 3 out of every 4 years of remaining life in return for perfect vision in each eye. Those with light perception to counting fingers would trade approximately 1 of 2 remaining years and those with 20/200-20/400 would trade approximately 1 of 3 remaining years. CONCLUSIONS—There is a wide range of utility values associated with legal blindness. The utility value decreases dramatically with perceived total loss of vision (absence of light perception in each eye), compared with counting fingers to light perception vision, indicating that the preservation of even small amounts of vision in patients with legal blindness is critically important to their wellbeing and functioning in life.

The reproducibility of ophthalmic utility values.

Abstract: PURPOSE: Utility values have been used in the ophthalmic literature to measure the quality of life associated with a health state. By convention, a utility value of 1.0 is associated with perfect health, and a value of 0.0 is associated with death. Construct validity of utility values has been demonstrated, particularly in regard to decreasing utility values as the vision decreases in the better seeing eye, but long-term test-retest reliability has not been demonstrated. The purpose of this study was to demonstrate the test-retest reliability of ophthalmic utility values. METHODS: One hundred fifteen patients with ophthalmic diseases and stable visual acuity underwent time trade-off utility analysis with retesting at various intervals ranging from 1 month to 2 years. The results were analyzed using the Wilcoxon signed rank test. The study was designed to have an 50% power, using a two-sided alpha of 5%, to be able to detect a 10% difference between the test and retest groups. RESULTS: The mean time from testing to retesting was 0.87 years, with a median time of 1.0 year and range of 1 month to 2 years. The mean utility value in the test group was 0.766 (SD = .21; 95% CI, 0.730-0.802), while the mean utility value in the retest group was 0.763 (SD = .22; 95% CI, 0.724-0.802). The difference between the means of the test-retest groups was not significant (P = .99). The intraclass correlation between the initial and follow-up utility scores was .5246 (P < .00005). CONCLUSIONS: Ophthalmic utility values appear to have good test-retest reliability over prolonged periods of time. This information is important because it gives researchers increased confidence in the validity of basic tools for ophthalmic cost-effective (cost-utility) analyses.

Reliability of the time trade-off technique of utility assessment in patients with retinal disease.

Abstract: Background: Studies in medical fields other than ophthalmology have given conflicting results regarding the reliability of the time trade-off technique of utility assessment We performed a study to determine the test-retest reliability of the time trade-off technique for assessing utilities in patients with ocular diseases of the retina and to investigate possible factors associated with differences in utility over time Methods: Patients referred to the retina service of a tertiary care hospital in eastern Canada were eligible for the initial interview if they had best corrected vision of 20130 or worse in at least one eye and were deemed competent to answer the required questions Patients were interviewed prospectively between December 1999 and March 2000 during a normal 30-minute period needed for pharmacologic mydriasis to occur Demographic, clinical (including Snellen visual acuity) and time trade-off utility information was collected through chart review and standardized interview Patients who completed the interview successfully were called back 28 days later for follow-up Results: Of the 138 eligible patients 112 (812%) completed the initial interview Of the 112, 96 (857%) completed the second interview Half of the respondents were women, and all but one respondent were white The mean age was 653 years The primary reasons for visual loss included diabetic retinopathy (59 patients [614%]) and age-related macular degeneration (14 patients [146%]) The intraclass correlation coefficient between the initial and follow-up visual utilities was 07634 (95% confidence interval 06655–08355) Interpretation: Our results show excellent reliability of the time trade-off technique of utility assessment in patients with ocular diseases of the retina

The cost-effectiveness of early vitrectomy for the treatment of vitreous hemorrhage in diabetic retinopathy.

Abstract: Diabetic vitrectomy has been found to be efficacious for the treatment of vitreous hemorrhage secondary to diabetic retinopathy. The purpose of this study is to determine the cost-effectiveness of early vitrectomy for the management of vitreous hemorrhage secondary to diabetic retinopathy. The analysis was performed from the perspective of a third-party insurer. A cost-utility Markov model was used to determine the cost per quality-adjusted life year (QALY) gained from early versus deferral of vitrectomy. The model used 2-, 3-, and 4-year results from the Diabetic Retinopathy Vitrectomy Study, patient-based utilities, life expectancy data, and incremental medical costs. Early vitrectomy was the dominant strategy and was associated with a gain of 0.41 QALYs over the 57-year expected life span for a hypothetical patient. The cost per additional QALY gained from early vitrectomy treatment was $1910 (US$ discounted at 3%). When sensitivity analyses were performed by varying efficacy probabilities and utilities across their 95% confidence intervals, early treatment was always the dominant strategy. Additionally, even at the extreme sensitivity values, the cost per QALY of early vitrectomy treatment remained under $10,000. Overall, early vitrectomy for the treatment of vitreous hemorrhage secondary to diabetic retinopathy is highly cost-effective.

A utility analysis correlation with visual acuity: methodologies and vision in the better and poorer eyes

Abstract: Objective: To ascertain the correlation between visual acuity levels and ophthalmic utility values obtained using time tradeoff and standard gamble utility analysis methodologies. Methods: Three hundred twenty-five consecutive patients with visual loss to 20/40 or less in at least one eye with predominantly vitreoretinal pathology were evaluated in a cross-sectional fashion using a standardized testing methodology to obtain ophthalmic time tradeoff and standard gamble utility values. Spearman correlation coefficients were employed to correlate the utility values with visual acuity in better seeing and poorer seeing eyes. Results: The Spearman correlation coefficient for time tradeoff utility values and vision in the better seeing eye was 0.455 (p < 0.001), while that for time tradeoff utility values and visual acuity in the poorer seeing eye was 0.268 (p < 0.001). The coefficient for standard gamble utility values and the better seeing eye was 0.371 (p < 0.001), while that for standard gamble utility values and vision in the poorer seeing eye was 0.250 (p < 0.001). Conclusions: There is a greater correlation between ophthalmic utility values and vision in the better seeing eye, as versus vision in the poorer seeing eye. Time tradeoff ophthalmic utility values demonstrate a greater correlation with vision in the better seeing eye than do standard gamble utility values.

Improvement in quality of life from photodynamic therapy: a Canadian perspective.

Abstract: Background: The Treatment of Age-Related Macular Degeneration with Photodynamic Therapy (TAP) Study showed that at I year, photodynamic therapy significantly reduced the chances of severe visual loss (15 letters or greater) compared with placebo treatment in patients with "predominantly classic" subfoveal choroidal neovascularization (CNV). We performed a study to determine the expected gain in quality of life associated with photodynamic therapy for the treatment of subfoveal CNV in a Canadian cohort of patients with age-related macular degeneration. Methods: We created a decision analysis model to determine the incremental gain in quality-adjusted life years (QALYs) associated with photodynamic therapy over placebo over a 2-year period. The analysis was conducted using efficacy data derived from the TAP Study and patient-based utilities collected by means of the time tradeoff technique. We conducted one-way and two-way sensitivity analyses to determine the robustness of our model. A Monte Carlo simulation was used to determine whether the observed gain in QALYs with photodynamic therapy was significant. Results: Photodynamic therapy was associated with a relative increase in QALYs of 11.3% compared with placebo. In one-way and two-way sensitivity analyses, the relative increase in quality of life associated with photodynamic therapy ranged from 4.2% to 25.7%. The Monte Carlo simulation showed that the gain in QALYs conferred from photodynamic therapy was statistically significant ( p Interpretation: Photodynamic therapy improves the quality of life of Canadians with predominantly classic subfoveal CNV secondary to agerelated macular degeneration.

Physician manpower and health care expenditures in the United States: a thirty-year perspective.

Abstract: Data gathered on the number of physicians and health care costs in the United States over a 30-year period from 1970 through 1999 were correlated and analyzed using bivariate linear regression. The rise in the number of practicing physicians theoretically predicts 96 percent of the variability in rise of total U.S. health expenditures, 96 percent of the variability in rise of physician service expenditures, 98 percent of the variability in rise of hospital service expenditures, and 86 percent of the variability in rise of prescription pharmaceutical expenditures. If the rate of growth in the number of physicians continues unchanged in the current fee-for-service climate, the model herein predicts that the growth in health care costs will likely continue to rise substantially faster than the rate of growth of the U.S. population and the rate of inflation. The addition of nonphysician providers with the same clinical privileges will likely exacerbate the situation of rapidly escalating medical costs. It is also possible that the excess number of physicians and other health care providers with the same clinical privileges as physicians may decrease the overall quality of health care. Reducing the rise in the number of physicians and nonphysician practitioners may help to decrease overall health care expenditures and improve overall quality of health care in the United States.

Patient-initiated second medical opinions: their necessity and economic cost.

Abstract: PURPOSE To assess the value of patient-initiated second medical opinions (SMO). METHODS The authors prospectively collected demographic data from 100 consecutive patients. The authors recorded major changes in the patients' care, such as inappropriate surgery recommended, inadequate treatment performed, and appropriate treatment not recommended. The authors also recorded costs incurred or saved by the patients and the third-party payers. RESULTS In nearly 15 of the cases, the authors had major disagreements with the initial diagnosis or management. Surgery had been recommended in 28 cases. They advised against it in nine. In 72 cases, no surgery had been recommended. They advised and performed it in five. The management of five other patients was not in accordance with that recommended by large clinical trials or was inadequately done. Including the consultation fees, surgery performed or advised against, retinal angiography, and ultrasonography, the 100 SMO cost third-party payers $12,426. If the authors subtract the cost of noncontroversial surgery they recommended and if the patients had paid the consultation fee and had brought along their fluorescein angiograms, third-party payers would have saved $4,079. CONCLUSION The savings SMO generated by eliminating unnecessary surgery resulted in improved patient care at minimal cost to third-party payers.