Hussein Hollands

Converting visual acuity to utilities

BACKGROUNDnUtility theory can be used to quantify dysfunction associated with various diseases and thus can represent a hard measure of quality of life. By determining utility values, one can compare the quality of life of patients with ocular disease to that of patients with non-ophthalmic problems. We performed a study to determine whether utility values from patients with ocular disease are associated with clinical variables, including visual acuity in the better-seeing eye, and to develop a mathematical method for converting visual acuity to utility value, if there is an association between the two.nnnMETHODSnCross-sectional study. A total of 239 patients from a tertiary care retinal practice with various ocular conditions, including macular degeneration, cataract, glaucoma and diabetic retinopathy, were interviewed under standardized conditions to determine their utility values by the time trade-off technique. Visual acuity, duration of visual loss and number of concomitant conditions were also determined. Multiple linear regression was performed to determine which variables were associated with utility values.nnnRESULTSnThe mean acuity in the better-seeing eye was 0.479 (near 20/40 vision). The mean utility value was 0.72. Accordingly, the average patient in our series was willing to trade 2.8 of every 10 remaining years of life to obtain perfect vision in both eyes. Utility value was significantly associated with visual acuity in the better-seeing eye (F = 69.1, p < 0.001). Other variables were not significantly associated with utility value. The association with duration of visual loss approached statistical significance (p = 0.075). Utility values (U) for patients with ocular disease can be derived from the following formula: U = (0.374)(visual acuity in better-seeing eye) + 0.514.nnnINTERPRETATIONnUtility values from patients with ocular disease were strongly associated with visual acuity and could be estimated mathematically.

The Quality of Life of Patients With Hypertension

The authors evaluated the self‐reported quality of life in patients with systemic arterial hypertension and assessed whether clinicians and normotensive respondents from the general public appreciate the impact that hypertension has on health‐related quality of life. A quality‐of‐life questionnaire was completed by 385 individuals: persons with hypertension (n=188), normotensive persons (n=148), and clinicians (n=49). A utility score, which represents ones self‐perceived health‐related quality of life, was generated for each group by using standardized time tradeoff questionnaires. Quality of life with hypertension was judged to be significantly higher according to affected individuals (mean utility score, 0.980), compared with normotensive persons (mean utility score, 0.948) and clinicians (mean utility score, 0.942), who were asked to assume that they had hypertension (p<0.0005). Clinicians and normotensive individuals tend to overemphasize the impact that hypertension has on quality of life, as compared to affected patients. The relatively low impact that hypertensive individuals indicate high blood pressure has on their quality of life May contribute to their lack of compliance with treatment regimens

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 (81.2%) completed the initial interview. Of the 112, 96 (85.7%) completed the second interview. Half of the respondents were women, and all but one respondent were white. The mean age was 65.3 years. The primary reasons for visual loss included diabetic retinopathy (59 patients [61.4%]) and age-related macular degeneration (14 patients [14.6%]). The intraclass correlation coefficient between the initial and follow-up visual utilities was 0.7634 (95% confidence interval 0.6655–0.8355). 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 grid laser photocoagulation for the treatment of diabetic macular edema: results of a patient-based cost-utility analysis.

Grid laser therapy has been demonstrated to be of benefit for the treatment of diabetic macular edema. The purpose of the present study was to determine the cost-effectiveness of grid laser therapy for the treatment of diabetic macular edema. The analysis was performed from the perspective of a third-party insurer. Decision analyses and cost-effectiveness analyses were performed by incorporating the data from the Early Treatment Diabetic Retinopathy Study, expected longevity data, and patient-based utilities. Various sensitivity analyses were performed to determine the robustness of the models. Laser treatment conferred an overall improvement in quality-of-life adjusted years of approximately 3 months over the duration of disease for a hypothetical patient. The unadjusted cost per quality-of-life adjusted year (QALY) was US

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

3,101. Net present value analysis demonstrated that the cost per QALY could increase to

Quality of life and systemic comorbidities in patients with ophthalmic disease

3,655, assuming a 5% discount rate. Overall, grid laser photocoagulation for diabetic macular edema is a very cost-effective treatment based on the results of this cost-utility analysis.

Comparison of photodynamic therapy and transpupillary thermotherapy for subfoveal choroidal neovascularization due to age-related macular degeneration

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

Update on utilities and cost-utility analyses.

1910 (US

Regression of Subretinal Lymphoma After Diagnostic Vitrectomy

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

The reproducibility of ophthalmic utility values.

10,000. Overall, early vitrectomy for the treatment of vitreous hemorrhage secondary to diabetic retinopathy is highly cost-effective.