Biomedical subjects

John Walt

Publications and source records attributed to John Walt.

9 recordsLinked to original sources

PubMed2006

Evaluation of quality of life for patients with glaucoma.

PURPOSE: To understand the impact of glaucoma on ability to function and on quality of life to guide therapeutic choices and strategies for improved adherence to therapeutic regimens and to suggest alterations to environments to help the patient to cope better with the effects of the disease. DESIGN: Review of the published literature on quality-of-life assessments of patients with glaucoma. METHODS: The published literature on quality-of-life impacts of glaucoma was reviewed with a focus on the design and evolution of quality-of-life instruments, correlations of responses with objective measures of disease progression, and insights that were gained from the analyses of results. RESULTS: Information about the impact of glaucoma has been derived from responses to general health-related questionnaires, vision-specific questionnaires, and questionnaires that were designed to be glaucoma specific. Responses to glaucoma-specific instruments tend to correlate best with visual field measurements and other objective measures of disease progression, which suggests that such responses reflect the effects of glaucoma rather than the effects of other health-related issues in this patient population. Recent advances in the design of glaucoma-specific instruments and in analysis of the responses to them have provided some interesting insights. For example, patients who have experienced significant (peripheral) visual field loss attach greater importance to their central vision than do patients with less-advanced disease, but these patients seem to have accepted or adapted to their difficulties with outdoor mobility. CONCLUSION: Continued improvements in the collection and analysis of quality-of-life data should assist health care providers with the effective delivery of therapies to patients with glaucoma.

Glaucoma↗

PubMed2006

Measurement of persistence and adherence to regimens of IOP-lowering glaucoma medications using pharmacy claims data.

PURPOSE: Determine persistence and adherence of glaucoma patients to therapeutic regimens of prostaglandin/prostamide-class IOP-lowering medications. DESIGN: Retrospective, population-based study. METHODS: Glaucoma patients in the IMS Health LifeLink database with a pharmacy claim for latanoprost (n = 1567), travoprost (n = 381), or bimatoprost (n = 476) between September, 2001 and March, 2002 who had no claims for IOP-lowering medication in the previous 180 days, and who were persistent during the first 90 days of therapy. Values reported in the quantity dispensed and days supply fields of the database were used in an algorithm that corrected anomalous data and adjusted days supply to calculate the main outcome measures, persistence, and adherence to therapy. RESULTS: The percentage of patients persistent for the 12-month observation period was 69.4% (1087/1567) for those prescribed latanoprost, 70.6% (269/381) for those prescribed travoprost, and 68.1% (324/467) for those prescribed bimatoprost. Mean adherence for patients prescribed latanoprost was 75.4% of the year, for those prescribed travoprost, 77.1% of the year, and for those prescribed bimatoprost, 78.2% of the year. The mean number of days adherent for bimatoprost-treated patients (291.2 days) was significantly greater than for latanoprost-treated patients (281.0 days), and not remarkably different from travoprost-treated patients (287.0 days). CONCLUSIONS: Overall, patients in this study who were taking IOP-lowering prostaglandin/prostamide medications had a mean adherence rate of 76% on average, suggesting that opportunities remain for improvement of adherence to therapeutic regimens for glaucoma treatment with prostamides and prostaglandins.

Antihypertensive Agents↗

PubMed2006

The cost-effectiveness of bimatoprost, latanoprost and timolol in treatment of primary open angle glaucoma in five European countries.

OBJECTIVE: The objective of this cost-effectiveness analysis is to evaluate cost-effectiveness ratios of the intraocular pressure (IOP)-lowering agents bimatoprost, latanoprost and timolol in five major European countries: France, Germany, Italy, Spain and the UK. METHODS: The cost-effectiveness analysis is based on achievement of IOP targets between 13 and 18 mm Hg. Thus, the cost-effectiveness ratios express the costs of having one patient successfully achieving IOP target. The perspective of the analysis is that of the health care sector payer, including costs of medicine and costs of ophthalmologist visits. The time frame is first year of glaucoma treatment. Four treatment strategies are analysed: Timolol as first line with add-on latanoprost or bimatoprost if IOP targets are not met, and latanoprost and bimatoprost as first line with add-on timolol. RESULTS: In the UK, Spain, Italy and Germany the timolol first with add-on of bimatoprost is the least expensive treatment. This strategy dominates both strategies involving latanoprost (as add-on to timolol or as first line) in these four countries. The incremental cost-effectiveness ratio of bimatoprost first-line therapy versus timolol with add-on bimatoprost varies from each country and target (from 305 pounds sterlings to 43,720 euros per patient). In France the timolol first line and latanoprost add-on is not dominated and is the cheapest alternative. The incremental cost-effectiveness ratio of timolol with add-on bimatoprost versus add-on latanoprost lies between 71 euros and 355 euros per patient depending on target (18 and 13 mm Hg, respectively). CONCLUSION: First-line treatment of latanoprost is dominated in all countries. In four out of five countries the timolol first-line therapy with add-on latanoprost is also dominated. Based on this pharmacoeconomic analysis, the most cost-effective strategy seems to be timolol first line with add-on bimatoprost if target is not met after 3 months.

Amides↗

PubMed2006

Estimated comparative costs of achieving a 20% reduction in intraocular pressure with bimatoprost or latanoprost in patients with glaucoma or ocular hypertension.

BACKGROUND: Although the probability of treatment success should be the primary factor guiding the choice of an intraocular pressure (IOP)-lowering medication, treatment cost is also important to physicians, patients and third-party payers. The objective of the present study was to compare the cost effectiveness of bimatoprost with that of latanoprost in the treatment of glaucoma and ocular hypertension. METHODS: Estimated yearly costs and cost per treatment success for bimatoprost ophthalmic solution 0.03% once daily (Lumigan), Allergan, Inc., Irvine, CA, USA) were compared with those for latanoprost ophthalmic solution 0.005% once daily (Xalatan), Pfizer, Inc., New York, NY, USA). The pharmacoeconomic model was based on medical resource costs and the percentage of patients achieving > or =20% decrease in IOP from baseline at 8:00 am, 12:00 pm and 4:00 pm after 6 months of treatment (clinical success rate). Calculations were also made using the average success rate throughout the day and the average success rate minus the percentage of patients who withdrew from treatment as a result of adverse events. RESULTS: After 6 months of treatment, the clinical success rates were significantly higher with bimatoprost than with latanoprost (p < or = 0.003). The average expected yearly cost per patient was similar for bimatoprost (US1151 dollars) and latanoprost (US1193 dollars). The cost per treatment success, however, averaged US568 dollars less with bimatoprost (US1501 dollars/success) than with latanoprost (US2069 dollars/success). This was true even when the percentage of patients who withdrew from treatment as a result of adverse events was subtracted from the clinical success rate. CONCLUSION: The greater efficacy of bimatoprost resulted in a lower cost per treatment success than was seen with latanoprost. This remained true even when responder rates were adjusted by subtracting the percentage of patients who withdrew from treatment as a result of adverse events.

Algorithms↗

PubMed2006

Cost considerations in the medical management of glaucoma in the US: estimated yearly costs and cost effectiveness of bimatoprost compared with other medications.

INTRODUCTION: The aim of this study was to evaluate the cost effectiveness of glaucoma treatment with bimatoprost compared with other intraocular pressure (IOP)-lowering medications in adult patients with chronic glaucoma or ocular hypertension (IOP of between 22 mm Hg and 34 mm Hg), from a US healthcare payers' perspective. METHODS: Estimated yearly costs and cost per treatment success for 0.03% bimatoprost once daily (Lumigan) were compared with 0.5% timolol twice daily (generic), 0.005% latanoprost once daily (Xalatan) and the fixed combination of 0.5% timolol and 2.0% dorzolamide twice daily (Cosopt). The model was based on year 2003 medical resource costs (physician visits and drug acquisition costs) and treatment success rates from published clinical trials. The clinical measure utilised was the percentage of patients achieving target IOPs. RESULTS: A higher percentage of patients achieved target IOPs with bimatoprost than with each of the other medications. At most target pressures, the cost per treatment success for patients starting treatment on bimatoprost was less than that for patients started on other drugs. This was true despite that, when looking at costs alone, the estimated yearly costs for bimatoprost (averaged over both patient success and patient failures) were similar to or greater than those for the other drugs. The greatest differences in cost per treatment success were seen at target pressures < or =15 mm Hg. For example, at a target pressure of 13 mm Hg, the cost per treatment success based on the model was 9238-10,229 US dollars for bimatoprost, 23,218 US dollars for timolol, 21,943 US dollars for latanoprost and 16,034 US dollars for timolol/dorzolamide. The incremental cost of achieving additional clinical success for bimatoprost ranged from 800 US dollars to 1,700 US dollars versus generic timolol, and from 300 US dollars to 3,100 US dollars versus timolol/dorzolamide. Bimatoprost was more effective and less costly than latanoprost. CONCLUSION: In our simplified model of cost per treatment success based on responder rates at varying IOPs, the greater efficacy of bimatoprost resulted in a cost per treatment success that was generally lower for bimatoprost than for timolol, latanoprost or timolol/dorzolamide. This was most pronounced at target pressures <15 mm Hg.

Adrenergic beta-Antagonists↗

PubMed2005

The reliability, validity, and preliminary responsiveness of the Eye Allergy Patient Impact Questionnaire (EAPIQ).

BACKGROUND: The Eye Allergy Patient Impact Questionnaire (EAPIQ) was developed based on a pilot study conducted in the US and focus groups with eye allergy sufferers in Europe. The purpose of this study was to present the results of the psychometric validation of the EAPIQ. METHODS: One hundred forty six patients from two allergy clinics completed the EAPIQ twice over a two-week period during the fall and winter allergy seasons, along with concurrent measures of health status, work productivity, and utility. Construct validity, reliability (internal consistency and test-retest), concurrent, known-group, and clinical validities, and responsiveness of the EAPIQ were assessed. Known-group validity was assessed by comparing EAPIQ scale scores between patients grouped according to their self-rating of ocular allergy severity (no symptoms, very mild, mild, moderate, severe, very severe). Clinical validity was assessed by assessing differences in EAPIQ scores between groups of patients rated by their clinician as non-symptomatic, mild, moderate, and severe. RESULTS AND DISCUSSION: Results from the validation study suggested the deletion of 14 of 43 items (including embedded questions) that required patients to complete the percentage of time they were troubled by something (daily activity limitations/emotional troubles). These items yielded a significant amount of missing or inconsistent data (50%). The resulting factor analysis suggested four domains: symptoms, daily life impact, psychosocial impact, and treatment satisfaction. When included as separate scales, the symptom-bother and symptom-frequency scales were highly correlated (> 0.9). As a consequence, and due to superior discriminative validity, the symptom bother and frequency items were summed. All items met the tests for item convergent validity (item-scale correlation = 0.4). The success rate for item discriminant validity testing was 97% (item-scale correlation greater with own scale than with any other). The criterion for internal consistency reliability (alpha coefficient > or = 0.70) was met for all EAPIQ scales (range 0.89-0.93), as was the criterion for test-retest reliability (intraclass correlation [ICC] > or = 0.70). Largely moderate correlations between the scales of the EAPIQ and the mini Rhinoconjunctivitis Quality of Life Questionnaire (miniRQLQ) and low correlations with the Health Utilities Index 2/3 (HUI2/3) were indicative of satisfactory concurrent validity. The EAPIQ symptoms, Daily Life Impact, and Psychosocial Impact scales were able to distinguish between patients differing in eye allergy symptom severity, as rated by patients and clinicians, providing evidence of satisfactory known-group and clinical validities, respectively. Preliminary analyses indicated the EAPIQ Symptoms, Daily Life Impact, and Psychosocial Impact scales to be responsive to changes in eye allergies. CONCLUSION: Following item reduction, construct validity, reliability, concurrent validity, known-group validity, and preliminary responsiveness were satisfactory for the EAPIQ in this population of ocular allergy patients.

Adult↗

PubMed2005

The impact of diabetic retinopathy on health-related quality of life.

PURPOSE OF REVIEW: To review recent evidence evaluating the effect of diabetic retinopathy and diabetic macular edema on health-related quality of life. RECENT FINDINGS: A search of PubMed was conducted according to a strategy that combined the text words 'diabetic retinopathy' and 'quality of life' (n = 91; November 11, 2004) and 'diabetic macular edema' and 'quality of life' (n = 6; November 22, 2004). The Methods sections of all abstracts were reviewed for valid generic or disease-specific instruments used to evaluate health-related quality of life. In addition, abstracts were reviewed to ensure that the study sample was made up predominantly of diabetic individuals. Recent data suggest that persons with diabetic retinopathy are willing to trade off significant time to eliminate their ocular condition (mean time tradeoff score = 0.77-0.8) and that laser photocoagulation can improve health-related quality of life (significant improvement noted in 8 of 11 domains in the National Eye Institute Visual Function Questionnaire). In addition, recent research has noted that health-related quality of life can become affected in persons with diabetic retinopathy prior to visual loss, primarily because of anxiety about the future and emotional reaction to diagnosis and treatment. SUMMARY: From a search of the literature, several recent articles could be identified that demonstrated both a qualitative and a quantitative reduction in health-related quality of life in persons with diabetic retinopathy. With many novel treatments being explored for the management of diabetic retinopathy and diabetic macular edema, measuring health-related quality of life will likely play an important role both in the decision to offer treatment and in monitoring relevant health gains that may be derived from intervention.

Diabetic Retinopathy↗

PubMed2005

Analytic review of bimatoprost, latanoprost and travoprost in primary open angle glaucoma.

OBJECTIVE: The objective of this review was to evaluate different measures of efficacy of the intraocular pressure (IOP) lowering lipid class agents bimatoprost, latanoprost and travoprost in the treatment of primary open angle glaucoma. Study arms of timolol in trials including the above mentioned lipid class drugs were also included. METHODS: MEDLINE and EMBASE were searched for randomized clinical trials including one or more of the lipid class drugs bimatoprost, latanoprost and travoprost. The study results were pooled, and the simple, weighted IOP-lowering efficacy was compared among the lipid class drugs and timolol, where data were available. Efficacy parameters were reviewed, including mean reduction of IOP and percentage of patients achieving different levels of IOP. RESULTS: 161 articles were identified of which 42 were included in the analysis. A total of 9295 patients participated in the included trials. Based on all studies, timolol on average had a weighted mean IOP reduction of 22.2%, while latanoprost, travoprost and bimatoprost had a weighted mean IOP reduction of 26.7%, 28.7% and 30.3%, respectively. Analysis of target achievement to various IOP levels shows that bimatoprost seems more efficacious than latanoprost. The direct comparisons (head-to-head studies) also show that bimatoprost is the most efficacious treatment, however it is not conclusive whether latanoprost or travoprost is better in reducing IOP. CONCLUSIONS: This review shows that bimatoprost seems to be the most efficacious treatment in lowering IOP. Head-to-head studies confirm this.

Adrenergic beta-Antagonists↗

PubMed2002

Best practice treatment algorithm for primary open-angle glaucoma: implications for U.S. ophthalmology practice.

The objective of this study was to develop a "best-practice" treatment algorithm for the management of primary open-angle glaucoma in patients receiving initial medical therapy, to serve as a consideration for future ophthalmology practice. For comparison, a baseline, "common-practice" treatment algorithm was also created that reflects current ophthalmology practice patterns. Survey instruments were developed based on a comprehensive review of relevant literature, along with input from a general ophthalmologist. A panel of eight ophthalmologists subspecialized in glaucoma management was surveyed. Consensus was achieved using a modified Delphi technique. A comparison of common- and best-practice treatment algorithms suggests that in contrast with expert opinion, nonselective beta blockers are currently used more often, and alpha-2 agonists less often, as first-line therapy for the treatment of primary open-angle glaucoma.

Adrenergic alpha-Agonists↗