Biomedical subjects

H Hollands

Publications and source records attributed to H Hollands.

13 recordsLinked to original sources

PubMed2003

Ocular photodynamic therapy with verteporfin for choroidal neovascularization secondary to ocular histoplasmosis syndrome.

PURPOSE: To evaluate the use of ocular photodynamic therapy (OPT) with verteporfin in patients with choroidal neovascularization (CNV) from ocular histoplasmosis syndrome (OHS) and to compare these results with those for a natural history group. METHODS: A retrospective chart review was performed to identify cases of CNV secondary to OHS treated with OPT. Complete data were available for 38 of 41 eligible eyes. Data regarding the following variables were abstracted from the patient charts: demographic characteristics, previous surgery, angiographic features, number and timing of treatments with OPT, follow-up time, and visual acuity. The visual acuity results of eyes receiving photodynamic therapy were compared with those for a natural history cohort. RESULTS: On average, OHS patients who received treatment developed 0.88 line of visual improvement. Visual acuity improved or stayed the same in 69% (22 of 32) of eyes, improved by > or = 2 lines in 44% (14 of 32), and improved by > or = 4 lines in 22% (7 of 32). Patients who received OPT were 2.07 times more likely to have improved or constant vision than were those in the natural history group as described in one retrospective series (odds ratio = 2.07; 95% confidence interval, 0.78-5.56; P = 0.162). Thirty-eight percent (12 of 32) of eyes had undergone submacular surgery for CNV before any OPT. CONCLUSIONS: Ocular photodynamic therapy with verteporfin may be beneficial in patients with CNV secondary to OHS, even in the setting of previous submacular surgery.

Adolescent↗

PubMed2003

Quality of life with macular degeneration: perceptions of patients, clinicians, and community members.

BACKGROUND/AIMS: Age related macular degeneration (ARMD) is a common ophthalmological disorder that can significantly impair a patient's ability to function independently and potentially have a dramatic impact on health related quality of life. The aim of this study is to evaluate the quality of life of patients with ARMD, through the use of utility evaluation, and assess whether clinicians and healthy volunteers appreciate the impact of ARMD on health related quality of life. METHODS: A standardised questionnaire using the time-tradeoff method of utility analysis was created to assess health related quality of life. This questionnaire was distributed to 115 patients with ARMD. A similar questionnaire was distributed to 142 healthy volunteers and 62 clinicians who were asked to assume that they had ARMD. Comparisons were made among the responses from the members of the three groups. RESULTS: There was a significant difference in the utility scores among respondents with mild, moderate, and severe ARMD when compared to members of the general public and clinicians who were asked to assume they had each severity of ARMD. For mild ARMD the mean utility scores were 0.932, 0.960, and 0.832, for the general public, clinicians, and patients respectively (F = 21.7; p <0.001). No significant difference was found between the community members and clinicians (p <0.166); however, the patient group differed significantly from the general public (p<0.001) and clinician (p <0.001) groups. The utility scores for moderate ARMD for the general public, clinicians, and patients were 0.918, 0.877, and 0.732, respectively. (F = 34.6, p <0.001). There was no significant difference between the general public and clinicians (p <0.143); however, the patient group differed significantly compared with the general public (p <0.001) and clinician (p <0.001) groups. The utility scores for people with severe ARMD in the general public, clinician, and patient groups were 0.857, 0.821, and 0.566, respectively (F = 45.5; p <0.001). No significant difference was shown between the community members and clinicians (p <0.386); however, a significant difference was seen when comparing the patient group with the community member and clinician (p<0.001) groups. CONCLUSION: Clinicians and community members may greatly underestimate the impact of mild, moderate, and severe ARMD on health related quality of life.

Adolescent↗

PubMed2003

Utilities associated with diabetic retinopathy: results from a Canadian sample.

BACKGROUND/AIMS: To report patient based utilities, using the time trade-off technique, associated with visual loss secondary to diabetic retinopathy in a sample of Canadian patients. In addition, to compare these utility values with a sample collected in a similar manner in a tertiary care practice in the United States. METHODS: A cross sectional study of eligible patients with diabetic retinopathy presenting to a tertiary facility was performed. Demographic and clinical variables (including Snellen visual acuity), and utilities were collected both through chart review and standardised interviews with diabetic patients. RESULTS: 221 patients with diabetic retinopathy were eligible for this study and completed the interview. The mean age was 63.5 (SD 12.5) years, and 48.4% were female. Over 35% of the sample had visual acuity in the affected eye of 6/60 or worse. The mean utility for the sample was 0.79 (SD 0.23). The mean utility from this sample did not differ significantly from that obtained from a series of patients with diabetic retinopathy who were referred to a tertiary facility in the United States (mean 0.77, SD 0.21, p=0.313). Our cross border comparison had a power of 95% to detect a difference in utility of 0.1 between the two groups. CONCLUSION: On average, Canadian patients with diabetic retinopathy were willing to trade off over 20% of their remaining lifespan in order to eliminate their ocular disease. The mean utility obtained from our sample of Canadian patients with diabetic retinopathy was not statistically different from that obtained from a similar sample of American patients.

Adolescent↗

PubMed2002

Validity of the time trade-off and standard gamble methods of utility assessment in retinal patients.

AIM: To assess the validity of the time trade-off (TTO) and standard reference gamble (SRG) techniques of utility assessment in patients with retinal disease. A cross section of eligible patients was studied and validity was determined through their relation with two logical constructs, visual acuity and scores from the Visual Function 14 (VF-14) index. METHODS: The study consisted of eligible patients presenting to a tertiary retinal facility who completed an interview. All patients had best corrected vision of 20/40 or worse in at least one eye. TTO and SRG utilities, as well as a VF-14 questionnaire, were administered through a standardised interview. Demographic and clinical (including Snellen visual acuity) information was also collected. RESULTS: 323 patients met these study criteria. Significant predictors of TTO utilities in the multivariate analysis were vision in the better seeing eye (p<0.01) and VF-14 scores (p<0.01). Significant predictors of standard gamble utilities were also vision in the better seeing eye (p<0.01) and VF-14 scores (p<0.05). CONCLUSION: Both the standard gamble and TTO methods demonstrate strong validity when evaluated against visual acuity in the better seeing eye and the VF-14 score.

Adolescent↗

PubMed2001

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

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 20/30 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.

Adult↗

PubMed2001

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

BACKGROUND: The Treatment of Age-Related Macular Degeneration with Photodynamic Therapy (TAP) Study showed that at 1 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 trade-off 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 < 0.001). INTERPRETATION: Photodynamic therapy improves the quality of life of Canadians with predominantly classic subfoveal CNV secondary to age-related macular degeneration.

Canada↗

PubMed2001

The cost-effectiveness of photodynamic therapy for fellow eyes with subfoveal choroidal neovascularization secondary to age-related macular degeneration.

PURPOSE: Photodynamic therapy (PDT) has recently been demonstrated to be beneficial for the treatment of subfoveal choroidal neovascularization secondary to age-related macular degeneration (AMD). Herein, we determine the cost-effectiveness of PDT for the treatment of subfoveal choroidal neovascularization (CNV) in patients with disciform degeneration in one eye and whose second and better-seeing eye develops visual loss secondary to predominantly classic subfoveal CNV. The analysis was performed from the perspective of a for-profit third-party insurer. DESIGN: Cost-utility Markov models were created to determine the cost-effectiveness of PDT under two different scenarios, by using efficacy data derived from the Treatment of Age-Related Macular Degeneration with Photodynamic Therapy (TAP) Study and patient-based utilities. METHODS: Decision analyses were performed by incorporating data from the TAP Study, expected longevity data, and patient-based utilities. Cost-effective models were then created by incorporating incremental medical costs. Various sensitivity analyses were carried out to determine the robustness of our models. A Monte Carlo simulation was also used to determine whether there was a significant difference in quality-of-life adjusted years (QALYs) gained between PDT therapy and the placebo. RESULTS: For the hypothetical patient whose second and better-seeing eye becomes affected and who has 20/40 vision at baseline in this affected eye (base case 1), PDT was associated with a 10.7% relative increase in their quality-of-life (treatment conferred an additional undiscounted 0.1342 QALYs over a 2-year period). For the hypothetical patient whose second and better-seeing eye becomes affected and who has 20/200 vision at baseline in this affected eye (base case 2), PDT was associated with a 7.8% relative increase in their quality-of-life (treatment conferred an additional undiscounted 0.0669 QALYs over a 2-year period). Sensitivity analysis showed our models were robust and that PDT was usually the dominant treatment choice. Our cost-effective model demonstrated that the cost for a QALY was $86,721 (US dollars discounted at 3%) for base case 1, assuming 5.5 treatments; and $173,984 (USD discounted at 3%) for base case 2. CONCLUSIONS: PDT will cost a third-party insurer $86,721 for an AMD patient with 20/40 vision in the better-seeing eye to obtain one QALY and $173,984 for an AMD patient with 20/200 vision in the better-seeing eye to obtain one QALY. PDT can be considered to be a treatment that is of only minimal cost-effectiveness for AMD patients who have subfoveal CNV in their second and better-seeing eyes and who have good presenting visual acuity at baseline. It is a cost-ineffective treatment for AMD patients who have poor visual acuities in their affected better-seeing eyes.

Aged↗

PubMed2001

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

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.

Adult↗

PubMed2001

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

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.

Allied Health Personnel↗

PubMed2001

The reproducibility of ophthalmic utility values.

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.

Adult↗

PubMed2000

Converting visual acuity to utilities.

BACKGROUND: Utility 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. METHODS: Cross-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. RESULTS: The 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. INTERPRETATION: Utility values from patients with ocular disease were strongly associated with visual acuity and could be estimated mathematically.

Aged↗

PubMed2000

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

Adult↗

PubMedDate not supplied

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 one's 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.

Adaptation, Psychological↗