| 1. |
- Baptista, Antonio M. G., et al.
(författare)
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Causes of Vision Impairment in Portugal : A hospital based study
- 2015
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Ingår i: Investigative Ophthalmology and Visual Science. - 0146-0404 .- 1552-5783. ; 56:7
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Causes of vision impairment (VI) are influenced by factors such as race or socio-economic circumstances. Because of this collecting national information is important for planning reduction of vision loss. The aim of this study was to determine causes of vision impairment in a population visiting ophthalmology departments in public hospitals in Portugal.Methods This study was designed according with the guidelines of the Vancouver Economic Burden of Vision Loss Group (IOVS, 2010, V51/4/1801). Recommendations are to collect hospital data during 1 year to determine causes of VI. We selected four public hospitals that are expected to have over 120-140K appointments per year. Files are analysed weekly to detect patients with vision impairment. Inclusion criteria are: visual acuity with the current refractive correction equal or less than 0.5 (20/40) in the better-seeing eye and/or a visual field of less than 20 degrees. Patients were selected by trained hospital staff (medics and orthoptists) and inserted in a database. Diagnoses were classified according the ICD9. Data collected included fundamental demographic information, main diagnosis, secondary diagnosis and comorbidities.Results We have now 2462 patients selected that correspond to 4 to 33 weeks of data collection. The number of weeks is variable because we did not start all hospitals simultaneously. From the current number of cases detected, 58% are female, 1.9% are under 20, 8.2% are between 20 and 50 and 89.9% are 50 years or older. The leading causes of vision impairment among these patients are diabetic retinopathy (DR), cataract (C), glaucoma (GC) and age-related macular degeneration (AMD). Using the North American definition of VI the proportions are 26.8% for DR, 25.5% for C, 10.4% for GC and 8.2% for AMD. The remaining causes of VI have percentages below 5% and in total they correspond to approximately 29% of the cases detected.Conclusions Our results show that the most common causes of vision impairment are eye diseases related with systemic conditions and aging of the population. Vision impairment was relatively low under the age of 20 and the causes were mostly inherited diseases. Numbers reported now will be more accurate at the end of the study but they already highlight the importance of targeting conditions such as diabetes.
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| 2. |
- Carneiro de Freitas, Rui, et al.
(författare)
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Prevalence of Visual Impairment in Portugal : study design and initial results
- 2015
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Ingår i: Investigative Ophthalmology and Visual Science. - 0146-0404 .- 1552-5783. ; 56:7
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Information about the prevalence of visual impairment is fundamental to define policies that deal with vision loss. The aim of this study is to determine the prevalence of visual impairment (VI) in the population looking for eye care in public hospitals in Portugal.Methods We designed an observation, cross-sectional prospective study (Prevalence and Costs of Visual Impairment in Portugal: PC-VIP study) to investigate the prevalence of VI in patients attending outpatient appointments in four public hospitals in Portugal. Hospital selected provide from general eye care (3-6 ophthalmologists) to high-specialized eye care (40+ ophthalmologists) that in total have between 120-140K hospital appointments per year. Files of patients are analysed weekly to detect patients with VI. Inclusion criteria were: visual acuity equal or worse than 0.5 (USA definition 20/40) in the better eye and/or a visual field of less than 20deg. Cases are selected by trained hospital staff and inserted in a database. Data collected included demographic information, acuity from both eyes, qualitative information about visual field (good, reduced, requires investigation), main diagnosis, secondary diagnosis and comorbidities. Diagnoses were classified according with ICD9.Results We have now detected 2462 cases of VI that correspond to 4 to 33 weeks of data collection. The number of weeks is variable because collection did not start simultaneously in all sites. From the number of cases detected, 58% were female, 1.9% were under 20y, 8.2% were between 20y and 50y and 89.9% were ≥50y. The mean prevalence of visual impairment was 13.6% (SD=5.6) using the USA definition and it was 7.0%(SD=4.1) using the WHO definition (acuity equal or worse than 0.3 or ~20/63). With a methodology that controls for demographics the lowest and highest estimates were calculated. Considering the USA definition, the prevalence in the general population would be in the range 0.4 -0.4% (age<40y) and 0.8-2.4% (age>=40y). Considering WHO definition, it would be 0.2-0.5% (age<40y) and 0.4-1.0% (age>=40y).Conclusions A hospital-based study can provide effective estimates of the prevalence of visual impairment in a population. Estimates for the country are in agreement with the expected results that can be deducted from neighbour countries and self-reported visual impairment in census 2001.
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| 3. |
- Lima Ramos, Pedro, et al.
(författare)
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A review of capture-recapture methods and its possibilities in ophthalmology and vision sciences
- 2020
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Ingår i: Ophthalmic Epidemiology. - : Taylor & Francis. - 0928-6586 .- 1744-5086. ; 27:4, s. 310-324
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Forskningsöversikt (refereegranskat)abstract
- Epidemiological information is expected to be used to develop key aspects of eye care such as to control and minimise the impact of diseases, to allocate resources, to monitor public health actions, to determine the best treatment options and to forecast the consequence of diseases in populations. Epidemiological studies are expected to provide information about the prevalence and/or incidence of eye diseases or conditions. To determine prevalence is necessary to perform a cross-sectional screening of the population at risk to ascertain the number of cases.The aim of this review is to describe and evaluate capture-recapture methods (or models) to ascertaining the number of individuals with a disease (e.g. diabetic retinopathy) or condition (e.g. vision impairment) in the population.The review covers the fundamental aspects of capture-recapture methods that would enable non-experts in epidemiology to use it in ophthalmic studies. The review provides information about theoretical aspects of the method with examples of studies in ophthalmology in which it has been used. We also provide a problem/solution approach for limitations arising from the lists obtained from registers or other reliable sources.We concluded that capture-recapture models can be considered reliable to estimate the total number of cases with eye conditions using incomplete information from registers. Accordingly, the method may be used to maintain updated epidemiological information about eye conditions helping to tackle the lack of surveillance information in many regions of the globe.
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| 4. |
- Lima Ramos, Pedro, et al.
(författare)
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Cross-sectional study investigating the prevalence and causes of vision impairment in Northwest Portugal using capture–recapture: [SV] Tvärsnittsstudie som undersöker prevalensen och orsakerna till synnedsättning i nordvästra Portugal med hjälp av infångning-återfångst[PT] Estudo transversal que investiga a prevalência e as causas da deficiência visual no Noroeste de Portugal utilizando captura-recaptura
- 2022
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of this study was to estimate the prevalence and causes of vision impairment (VI) in Portugal.Setting Information about people with VI was obtained from primary care centres, blind association (ACAPO) and from hospitals (the PCVIP study) in the Northwest of Portugal during a period spanning years 2014–2015. Causes of VI were obtained from hospitals.Participants Administrative and medical records of people with visual acuity in the better seeing eye of 0.5 decimal (0.30logMAR) or worse and/or visual field less than 20° were investigated. Capture–recapture with log-linear models was applied to estimate the number of individuals missing from lists of cases obtained from available sources.Primary and secondary outcome measures Log-linear models were used to estimate the crude prevalence and the category specific prevalence of VI.Results Crude prevalence of VI was 1.97% (95% CI 1.56% to 2.54%), and standardised prevalence was 1% (95% CI 0.78% to 1.27%). The age-specific prevalence was 3.27% (95% CI 2.36% to 4.90%), older than 64 years, 0.64% (95% CI 0.49% to 0.88%), aged 25–64 years, and 0.07% (95% CI 0.045% to 0.13%), aged less than 25 years. The female-to-male ratio was 1.3, that is, higher prevalence among females. The five leading causes of VI were diabetic retinopathy, cataract, age-related macular degeneration, glaucoma and disorders of the globe.Conclusions The prevalence of VI in Portugal was within the expected range and in line with other European countries. A significant number of cases of VI might be due to preventable cases and, therefore, a reduction of the prevalence of VI in Portugal seems possible. Women and old people were more likely to have VI and, therefore, these groups require extra attention. Future studies are necessary to characterise temporal changes in prevalence of VI in Portugal.No data are available. Raw data can be requested from the first author.
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| 5. |
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| 6. |
- Lima Ramos, Pedro
(författare)
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Studying prevalence using capture-recapture methods : visual impairment in Portugal
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Visual impairment (VI) due to eye diseases remains a significant healthproblem worldwide and, also, in Europe. There are an estimated 15 million peoplesuffering from moderate or severe visual impairment in Western Europe. VI has asignificant impact on the quality of life by reducing functional status and interferingwith the ability of the subject to maintain independence in a safe manner. Prevalenceof VI needs to be estimated regularly so that the progress of the vision health of apopulation can be evaluated and monitored. In addition, it is important to ascertainthe causes behind VI so that health programs can be designed to lower itsprevalence. There is currently a lack of epidemiological information about theprevalence and causes of VI in Portugal. Therefore, the aim of this thesis was todetermine the prevalence of VI in a large region Portugal using data from lists ofcases of VI.Capture-recapture models have been applied in several disciplines, asbiomedical sciences, epidemiology or ecology, to estimate the size of populations. Inparticular, they have been used to estimate the prevalence of several diseases orconditions. Developing these inferential models is of great importance to avoid thehigh costs and unreasonable time spending of cross-sectional studies. However,applying capture-recapture models is challenging, as they are very sensitive to listdependence and possible capture rates heterogeneity among subgroups of thepopulation. In particular, applying these models to human population samples isadditionally challenging, as in most epidemiologic studies only a small number oflists are available. There are two main differences between human and wildlifepopulations. First, human population lists generally have not a well-defined timeorder. Second, in wildlife studies there are often more trapping samples than inhuman population studies. In most epidemiologic surveys, only two to four lists areavailable. This can be problematic and is an additional difficulty when applyingcapture-recapture models in the context of human populations.The main objective of this work was to estimate the prevalence of VI usingcapture-recapture models. We estimated a crude prevalence of1.97%,95%CI=[1.56,2.54] to the Northwest of Portugal in the time period between2014 and 2015, specifically at the regions of Minho and Douro Litoral. Almost 2 ofevery 100 inhabitants of the Portuguese Northwest suffer from visual impairment.This prevalence value is in line with the values in some countries, particularly withSpain. Diabetic Retinopathy was the main cause (31%), followed by Cataract (15%),Age-related Macular Degeneration (14%) and Glaucoma (10%). This thesis provides asignificant contribution to the understanding of the CR methodology in human populations and for the knowledge of the epidemiological information about VI inPortugal.
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| 7. |
- Lima Ramos, Pedro, et al.
(författare)
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Predicting participation of people with impaired vision in epidemiological studies
- 2018
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Ingår i: BMC Ophthalmology. - : BioMed Central (BMC). - 1471-2415. ; 18, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Background: The characteristics of the target group and the design of an epidemiologic study, in particular the recruiting methods, can influence participation. People with vision impairment have unique characteristics because those invited are often elderly and totally or partially dependent on help to complete daily activities such as travelling to study sites. Therefore, participation of people with impaired vision in studies is less predictable than predicting participation for the general population. Methods: Participants were recruited in the context of a study of prevalence and costs of visual impairment in Portugal (PCVIP-study). Participants were recruited from 4 Portuguese public hospitals. Inclusion criteria were: acuity in the better eye from 0.5 decimal (0.30logMAR) or worse and/or visual field of less than 20 degrees. Recruitment involved sending invitation letters and follow-up phone calls. A multiple logistic regression model was used to assess determinants of participation. The J48 classifier, chi-square and Fisher's exact tests were applied to investigate the possible differences between subjects in our sample. Results: Individual cases were divided into 3 groups: immediate, late and non-participants. A participation rate of 20% was obtained (15% immediate, 5% late). Factors positively associated with participation included years of education, annual hospital attendance, and intermediate visual acuity. Females and greater distance to the hospital were inversely associated with participation. Conclusion: In our study, a letter followed by a phone call was efficient to recruit a significant number of participants from a larger group of people with impaired vision. However, the improvement in participation observed after the phone call might not be cost-effective. People with low levels of education and women were more difficult to recruit. These findings need to be considered to avoid studies whose results are biased by gender or socioeconomic inequalities of their participants. Young subjects and those at intermediate stages of vision impairment, or equivalent conditions, may need more persuasion than other profiles.
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| 8. |
- Marques, Ana Patrícia, et al.
(författare)
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Diffusion of anti-VEGF injections in the Portuguese National Health System
- 2015
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 5:11, s. 11-
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesTo analyse the temporal and geographical diffusion of antivascular endothelial growth factor (anti-VEGF) interventions, and its determinants in a National Health System (NHS).SettingNHS Portuguese hospitals.ParticipantsAll inpatient and day cases related to eye diseases at all Portuguese public hospitals for the period 2002–2012 were selected on the basis of four International Classification of Diseases 9th revision, Clinical Modification (ICD-9-CM) codes for procedures: 1474, 1475, 1479 and 149.Primary and secondary outcome measuresWe measured anti-VEGF treatment rates by year and county. The determinants of the geographical diffusion were investigated using generalised linear modelling.ResultsWe analysed all hospital discharges from all NHS hospitals in Portugal (98 408 hospital discharges corresponding to 57 984 patients). National rates of hospitals episodes for the codes for procedures used were low before anti-VEGF approval in 2007 (less than 12% of hospital discharges). Between 2007 and 2012, the rates of hospital episodes related to the introduction of anti-VEGF injections increased by 27% per year. Patients from areas without ophthalmology departments received fewer treatments than those from areas with ophthalmology departments. The availability of an ophthalmology department in the county increased the rates of hospital episodes by 243%, and a 100-persons greater density per km2 raised the rates by 11%.ConclusionsOur study shows a large but unequal diffusion of anti-VEGF treatments despite the universal coverage and very low copayments. The technological innovation in ophthalmology may thus produce unexpected inequalities related to financial constraints unless the implementation of innovative techniques is planned and regulated
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| 9. |
- Marques, Ana Patricia, et al.
(författare)
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Emergence of intravitreal injections in a National Health System : 2002-2012
- 2014
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Ingår i: Investigative Ophthalmology and Visual Science. - 0146-0404 .- 1552-5783. ; 55:13
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Intravitreal injections of antivascular endothelial growth factor (anti-VEGF) are an innovative procedure with well-proven benefits to preserve vision in certain eye conditions. The aim of this study was to examine the diffusion of this treatment in the Portuguese National Health System.Methods We used a database of all in-patient and day cases stays from all Portuguese public hospitals during period 2002-2012. We selected cases based on four procedures, ICD-9-CM codes: 1414, 1475, 1479, 149. Given that these procedures are not specific for intravitreal injections it is likely that our results captured cases that are not anti-VEGF injections. Because we were only interested in the diffusion of new anti-VEGF treatments we included years 2002-2005 as baseline because during that period drugs anti-VEGF were not licenced. We calculated absolute values, yearly rates of episodes and rates of patients treated per 100,000 habitants.Results Our final sample included 98,408 episodes, 52% performed in men. The total number of episodes increased from 1,815 in 2002 to 25,106 in 2012 (mean annual increase of 32%). These values corresponded to an increase in ratios per 100,000 from 17.4 to 238.77. The highest increase was observed between 2007 and 2009 with an increase of 337%. The number of treated patients was six times higher in 2012 with 11,937 treated compared with 1,561 in 2002 (mean annual increase of 24%). The highest increase was also observed between 2006 and 2009. In 2012, 86.2% of the procedures were performed as day cases, representing an increase of 78.3% as compared to 2002. The percentage of patients older than 60 years increased from 60% in 2002 to 80% in 2012. Five diagnoses (See Figure: wet AMD, diabetic macular oedema, oedema of the retina, retinal neovascularization and non-specific AMD) were associated with 73% of these procedures in 2012, in contrast with only 16% in 2002.Conclusions The number of procedures grew exponentially since anti-VGEF treatments were approved. The aging of the population and the expected growth in conditions such as diabetes and AMD are likely to increase the demand for these procedures in years to come. These factors are likely to impose tremendous challenges to health services. That will happen not only due to the price of the procedures but also for number of physicians and other staff needed in Ophthalmology departments. View
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| 10. |
- Marques, Ana Patricia, et al.
(författare)
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Estimating the cost of visual impairment : initial results
- 2015
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Ingår i: Investigative Ophthalmology and Visual Science. - 0146-0404 .- 1552-5783. ; 56:7
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Vision loss can have a substantial human and economic impact on individuals and society that include disability, loss of productivity and reduction in quality of life. The purpose of this study was to estimate economic burden of visual impairment in Portugal.Methods: A prevalence-based cost of illness approach was adopted to estimate costs of vision impairment. We estimated direct medical costs and indirect economic costs. Direct medical hospital costs were determined using a bottom up approach. For those meeting the inclusion criteria (visual acuity of 20/40 or 0.5decimal or worse in the better eye and/or visual field of less than 20deg) we estimated direct costs by collecting information from administrative records that included: physician’s office visits, emergency and outpatient visits. We developed a survey based in parts of the annotated cost questionnaire-HERU Discussion Paper N.03/01 (UK Working Party on Patient Costs) and the Service Receipt Inventory-European Version. Using the questionnaire that we developed, in face-to-face interviews, we collect direct medical expenditures supported by patients that included: costs with medical prescriptions, low vision aids and devices. With the same questionnaire we collected information for indirect costs calculations. Indirect costs were calculated by estimating the value of productivity losses including employment participation, absenteeism and caregiver costs.Results: Results presented here correspond to 442 patients that met the inclusion criteria. The four main causes of visual impairment in this sample were Diabetic Retinopathy, Cataract, Glaucoma and Age-related macular degeneration. Direct medical hospital costs were accountable for 12% of total costs calculated. Patient expenditures represented 25% of expenses with visual impairment and indirect costs corresponded to 63% of the total. From this data we estimated that the average annual direct cost per patient with VI was 958 euro and average annual indirect cost was 1655 euro.Conclusions: With the instruments and methodology that was adopted we were able quantify direct medical hospital costs as well as indirect costs of visual impairment. Results of this study show that more than half of the costs with VI are indirect. This highlights that particular attention should be given to costs that arise for individuals with vision loss.
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