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Biomedical subjects

David Covert

Publications and source records attributed to David Covert.

10 recordsLinked to original sources
PubMed2006

Patient-reported behavior and problems in using glaucoma medications.

OBJECTIVE: The objectives of the current study were to describe the different types of problems patients receiving adjunctive therapy reported having when taking their glaucoma medications and to examine the relationship between patient-reported problems in taking their glaucoma medications and patient adherence. DESIGN: Cross-sectional survey. PARTICIPANTS: A survey was distributed to glaucoma patients in 4 geographically distinct ophthalmology practices. We excluded patients using only 1 glaucoma medication. The survey was completed by 324 patients. METHODS: For each patient, average percent adherence to his or her glaucoma medication regimen was calculated. Logistic regression was used to examine how patient characteristics and problems in using glaucoma medications were related to reported adherence. MAIN OUTCOME MEASURE: Whether patients were less than 100% adherent in the previous week. RESULTS: We found that 60% of patients reported 1 or more problems with taking their glaucoma medications. Fourteen percent of patients reported being less than 100% adherent to their glaucoma regimen medications during the previous week. Patients who had difficulty remembering to take their glaucoma medications and those who reported that they had other problems or concerns with their glaucoma medications were significantly less likely to be 100% adherent. CONCLUSIONS: Patient adherence to a glaucoma medication regimen could be improved among patients receiving adjunctive therapy. Ophthalmologists and their clinical colleagues should make sure to discuss the problems and concerns that patients may have in taking their glaucoma medications in an effort to improve adherence.

Adult↗
PubMed2006

Validation of the Daily Living Tasks Dependent on Vision (DLTV) questionnaire in a U.S. population with age-related macular degeneration.

PURPOSE: The Daily Living Tasks Dependent on Vision questionnaire (DLTV) has been used to assess functional impairment among patients with age-related macular degeneration (AMD). This study evaluated the psychometric properties of the DLTV using patient-reported rates of use of services and devices in an outpatient population. METHODS: The DLTV was included in a survey mailed to members of an AMD advocacy organization. Included in the survey were questions about demographic and clinical characteristics as well as questions about use of low vision aids and care-giving. Respondents provided informed consent. Data were analyzed in SAS. RESULTS: Four respondents of 803 did not complete the DLTV; missing data were uncommon. Most (56%) respondents were male; the mean age was 73 years. Internal consistency reliability of the DLTV was 0.9699. Construct validity was demonstrated with moderate to high correlations between the DLTV and use of services and devices. The DLTV demonstrated discriminant validity and could distinguish between respondents with different levels of impairment, i.e., those who reported regular care-giving compared to those without regular care-giving. CONCLUSIONS: In this outpatient population, the DLTV demonstrated reliability and validity. This analysis complements existing research and supports the use of the DLTV in AMD patients.

Activities of Daily Living↗
PubMed2006

Adjunctive glaucoma therapy use associated with travoprost, bimatoprost, and latanoprost.

PURPOSE: This study contrasts the utilization of adjunctive medication associated with travoprost, bimatoprost, or latanoprost, as primary glaucoma therapies. METHODS: Patients in the Medco Health database who initiated prostaglandin analog therapy on travoprost, bimatoprost or latanoprost between January 1, 2002 and July 31, 2002 were selected if they had no prostaglandin analog use in the prior 6 months. Patients were also required to have 12 months of prostaglandin therapy subsequent to the initial prescription. Data were available through July 31, 2003. The t-test and chi-square were used where appropriate to calculate p-values and assess significant differences. RESULTS: A total of 13 171 benefit-eligible subjects were identified of which 8381 (64%), 2637 (20%), and 2153 (16%) patients were treated with latanoprost, bimatoprost, and travoprost, respectively. There were no significant differences in mean age or gender between the three study groups with the exception that latanoprost patients were statistically older than travoprost patients (69.0 vs. 68.0). This was not considered a clinically meaningful difference. Overall, patients using travoprost or bimatoprost had a significantly lower rate of adjunctive medication use compared to patients starting on latanoprost monotherapy (22.5%, 23.2%, and 30.2 %, respectively). Therefore, for every 14 patients treated with latanoprost instead of travoprost or bimatoprost, one additional patient would be expected to need adjunctive therapy with another agent. The difference between travoprost and bimatoprost patients was not significant. CONCLUSIONS: The use of adjunctive medications to control intraocular pressure was significantly higher for latanoprost patients compared to travoprost and bimatoprost patients. This finding should be interpreted in the context that this study was based only on prescription claims data. It is important to simplify ophthalmic medical regimen as it is more cost effective, better for the patient, and minimizes the washout effect from administering two eye medications within 5 min. Decreasing the complexity of the patients' drug regimen may lead to increased adherence to prescribed therapy and a decreased risk of the incidence of blindness.

Aged↗
PubMed2006

Screening for glaucoma in Canada: a systematic review of the literature.

BACKGROUND: To provide a recommendation on screening for glaucoma in Canada based on a review of recent evidence available in the literature. METHODS: A systematic literature review was performed to identify publications from MEDLINE, EMBASE, HealthSTAR, and Cochrane databases from 1990 to 2005. Relevant articles were categorized as economic studies, epidemiologic and intervention studies, or policy papers. Web sites and publications from provincial, state, national, and international health authorities were reviewed for policy recommendations and guidelines. RESULTS: We identified 39 articles (34 epidemiology and intervention, and 5 economic studies) for the review. From the economic studies, 2 were simple cost analyses and 3 were full economic evaluations (cost-effectiveness). Gaps were observed from these economic studies, where incremental cost-effectiveness analyses of modelled screening programmes were not observed. A large number of alternatives (i.e., screening techniques) and diverse outcome measures were found in the 34 epidemiology and intervention studies. This shows that evidence on the effectiveness of glaucoma screening programmes is available to be used in future modelled analyses. Neutral recommendation made by the Canadian Task Force on Periodic Health Examination regarding glaucoma screening in Canada could be related to the lack of reliable data and models used in past cost-effectiveness analyses. INTERPRETATION: A need exists to reevaluate the cost-effectiveness of a screening programme for glaucoma in Canada with updated efficacy and cost data. Health and monetary benefits could be improved compared with current practice and decision-makers would have the best available data when reevaluating the policy on screening for glaucoma.

Canada↗
PubMed2005

Does adjunctive glaucoma therapy affect adherence to the initial primary therapy?

OBJECTIVE: To examine the effect of adding complexity to a glaucoma medical treatment regimen--specifically, what would occur to the refill rate (and, by inference, to adherence) when a second medication was added to a currently used once-daily drug. DESIGN: Open-label retrospective review of patient records. PARTICIPANTS: Patients of a large national health care provider who had received a prescription for latanoprost between July 1, 2001 and June 30, 2002. There were 1784 patients who had a second medication added and 3146 patients who remained on monotherapy. METHODS: For each patient, the mean number of days between refills was calculated for both the period before and that subsequent to the addition of the second medication, and an interperiod difference in refill interval between the 2 periods was calculated. Probability comparisons were performed using paired t tests (continuous) and Wilcoxon signed rank tests (categorical). RESULTS: The mean age of the population using second-line therapy was 68.3+/-14.5 years (range, 4-97), and 56% were female. In this population of 1784 patients who used 2 different ocular-hypotensive medications, mean refill intervals for latanoprost were 40.6+/-21.8 days before the addition of a second drug and 47.4+/-24.4 days after the addition of a second drug, with a mean increase of 6.7+/-25.6 days. For 22.9% (409/1784) of patients, the interval was increased by >2 weeks (P<0.0001). The mean refill interval was longer than that for the 3146 patients who continued on latanoprost monotherapy, which was 41+/-24 days. CONCLUSIONS: This statistically and clinically significant increase in refill intervals may affect intraocular pressure control. We suggest that, when adding a second drug, physicians need to consider the possible impact on the patient's adherence to the first drug.

Adolescent↗
PubMed2005

Association between corneal thickness, mean intraocular pressure, disease stability and severity, and cost of treatment in glaucoma: a Canadian analysis.

PURPOSE: We determined the association between the mean corneal thickness (CT) and visual field mean defect (VF) severity as well as with mean intraocular pressure (IOP), disease stability, and cost of glaucoma therapy in a Canadian setting. METHODS: Data were collected from charts of patients diagnosed with primary open-angle glaucoma (POAG). CT measures, VF scores, IOP measurements, physicians' impressions, and resources used (physician visits, diagnostic tests, procedures, and medications) were recorded over a minimum of 2.5 years. CT was compared across the three VF severity levels [mild (0 to < 5 dB), moderate (5 to < 12 dB), and severe (>/= 12 dB)] using a Kruskall-Wallis test. Initial VF was regressed on Age, CT, IOP, and Optic Disc Ratio. Stability and Cost were regressed on IOP. RESULTS: Of the 411 charts, 132 included CT measures. Patients included 50 with mild, 43 with moderate, and 39 with severe disease. The mean CTs of the overall, mild, moderate, and severe groups were 545.9 mum, 554.7 mum, 549.8 mum, and 523.3 mum, respectively. There were statistically significant differences (p < 0.05) between the CT pp of the mild and severe groups as well as between the moderate and severe groups. Regression analyses suggested that CT may be a predictor of disease severity, but not of cost. It was also found that IOP may be a predictor of disease progression. CONCLUSIONS: Patients with severe VFs tend to be those who have thinner corneas. Further research is warranted, as a result of the limited sample size, to clarify the definitive association among corneal thickness, disease progression, and the cost of therapy.

Aged↗
PubMed2004

Association between mean intraocular pressure, disease stability and cost of treating glaucoma in Canada.

PURPOSE: A retrospective analysis determined the association between intraocular pressure (IOP) control levels (mean and last IOP) and disease stability, and the association between IOP and yearly treatment cost in primary open angle glaucoma (POAG). METHODS: Data were collected from POAG patients, referred to a tertiary glaucoma clinic. All IOP measurements, visual field mean deviation (VF) scores, physicians' impressions, and resources used (physician visits, procedures, and medications) were recorded and costed using standard resource unit cost lists from the Ministry of Health's perspective. Patients were categorized by the average VF score of their first three visits [mild (< 5 dB), moderate (> or = 5 dB to < 12 dB) and severe (> or = 12 dB)]. Pearson's r quantified the association between IOP control levels and stability, where stability was defined by the physician's subjective impression of the patient's disease. Spearman's rho was determined to quantify association between mean IOP and yearly treatment cost within VF categories. RESULTS: Four hundred and eleven charts were reviewed of which 265 were acceptable for analysis. A negative relationship was determined between the probability of reaching stability and mean IOP in all three VF severity groups. Pearson's r was -0.68 (p < 0.001), -0.72 (p < 0.001), and -0.52 (p < 0.001) for the mild, moderate, and severe groups, respectively. A similar correlation was determined between the last measured IOP and stability. Pearson's r was -0.49 (p < 0.001), -0.80 (p < 0.001), and -0.65 (p < 0.001) for the mild, moderate and severe groups, respectively. A positive relationship was reported between mean yearly costs and IOP. Spearman's rho between mean yearly costs and mean IOP was 0.11 (p = 0.28), 0.23 (p < 0.05), and 0.26 (p < 0.05) for each respective VF level. DISCUSSION AND CONCLUSION: Lower IOP control levels are associated with higher probabilities of stability. In addition, lower IOP control levels are associated with lower costs of managing POAG in patients either with moderate VF loss or with severe VF loss. Economic burden increased with increasing disease severity.

Canada↗
PubMed2003

Cost of glaucoma in Canada: analyses based on visual field and physician's assessment.

PURPOSE: A longitudinal, retrospective study investigated the cost of primary open angle glaucoma (POAG). METHODS: Patient files from two tertiary care glaucoma practices were reviewed. Patients diagnosed with POAG and >/=2.5 years of follow-up data were included. Data collected included visual field mean deviation, physician's assessment, and resource utilization (physician visits, procedures, and medications). Costs, reported in 2001 Canadian dollars, were compared between groups, based on initial visual field mean deviation, including mild (<5 dB), moderate (5 to <12 dB), and severe (>/=12 dB), and based on physician's assessment, including controlled, uncontrolled, or patients initially uncontrolled for 12 months who become controlled. RESULTS: Of 411 patient charts extracted, 265 were included; 35 were excluded for ocular comorbidities and 111 patients with insufficient follow-up. Mean (standard deviation) yearly costs overall (N = 265) and for mild (n = 90), moderate (n = 91), and severe (n = 84) groups were $508 ($278), $408 ($266), $512 ($288), and $609 ($243), respectively. Differences between mean yearly costs were statistically significant for all three groups (P < 0.05). Costs for controlled (n = 110), uncontrolled (n = 76), and uncontrolled then controlled group (n = 79) were $423 ($243), $594 ($314), and $542 ($256), respectively. The controlled group cost was significantly lower than both of the other groups (P < 0.05). DISCUSSION AND CONCLUSIONS: The cost of treating POAG increases with visual field mean deviation severity and uncontrolled disease. Many patients diagnosed with glaucoma had already progressed to later stages in the disease process. Early disease detection may provide a substantial cost savings to the health care system.

Canada↗
PubMedDate not supplied

Impact of visual impairment on use of caregiving by individuals with age-related macular degeneration.

BACKGROUND: To assess the patient-reported use of caregiving among individuals with age-related macular degeneration (AMD) and evaluate the impact of visual impairment level on this use. METHODS: A survey including the AMD Health and Impact Questionnaire and the Daily Living Tasks Dependent on Vision Questionnaire (DLTV) was mailed to members of the Macular Degeneration Partnership. The study was approved by an institutional review board, and respondents provided consent before participating. Responses were analyzed by estimated visual acuity determined by scores from the DLTV. Deidentified data were analyzed using SAS Version 8.2 (SAS Institute, Cary, NC). RESULTS: Of 803 respondents, 56% were male, and the mean age was 73 years. Use of paid and unpaid help significantly increased as visual acuity decreased. Using a national average for caregiver time, annual costs for caregiving ranged from 225 to 47,086 US dollar depending on visual acuity. CONCLUSION: There are substantial differences in caregiver support with increased AMD severity. Delaying progression of AMD could result in considerable cost savings.

Aged↗