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Biomedical subjects

L Smeeth

Publications and source records attributed to L Smeeth.

At least 19 recordsLinked to original sources
PubMed2001

Randomised comparison of three methods of administering a screening questionnaire to elderly people: findings from the MRC trial of the assessment and management of older people in the community.

OBJECTIVE: To compare three different methods of administering a brief screening questionnaire to elderly people: post, interview by lay interviewer, and interview by nurse. DESIGN: Randomised comparison of methods within a cluster randomised trial. SETTING: 106 general practices in the United Kingdom. PARTICIPANTS: 32 990 people aged 75 years or over registered with participating practices. MAIN OUTCOME MEASURES: Response rates, proportion of missing values, prevalence of self reported morbidity, and sensitivity and specificity of self reported measures by method of administration of questionnaire for four domains. RESULTS: The response rate was higher for the postal questionnaire than for the two interview methods combined (83.5% v 74.9%; difference 8.5%, 95% confidence interval 4.4% to 12.7%, P<0.001). The proportion of missing or invalid responses was low overall (mean 2.1%) but was greater for the postal method than for the interview methods combined (4.1% v 0.9%; difference 3.2%, 2.7% to 3.6%, P<0.001). With a few exceptions, levels of self reported morbidity were lower in the interview groups, particularly for interviews by nurses. The sensitivity of the self reported measures was lower in the nurse interview group for three out of four domains, but 95% confidence intervals for the estimates overlapped. Specificity of the self reported measures varied little by method of administration. CONCLUSIONS: Postal questionnaires were associated with higher response rates but also higher proportions of missing values than were interview methods. Lower estimates of self reported morbidity were obtained with the nurse interview method and to a lesser extent with the lay interview method than with postal questionnaires.

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PubMed2001

A case-control study of autism and mumps-measles-rubella vaccination using the general practice research database: design and methodology.

BACKGROUND: An association between mumps-measles-rubella (MMR) vaccination and the onset of symptoms typical of autism has recently been suggested. This has led to considerable concern about the safety of the vaccine. METHODS: A matched case-control study using data derived form the United Kingdom General Practice Research Database. Children with a possible diagnosis of autism will be identified from their electronic health records. All diagnoses will be validated by a detailed review of hospital letters and by using information derived from a parental questionnaire. Ten controls per case will be selected from the database. Conditional logistic regression will be used to assess the association between MMR vaccination and autism. In addition case series analyses will be undertaken to estimate the relative incidence of onset of autism in defined time intervals after vaccination. The study is funded by the United Kingdom Medical Research Council. DISCUSSION: Electronic health databases offer tremendous opportunities for evaluating the adverse effects of vaccines. However there is much scope for bias and confounding. The rigorous validation of all diagnoses and the collection of additional information by parental questionnaire in this study are essential to minimise the possibility of misleading results.

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PubMed2000

Community screening for visual impairment in the elderly.

BACKGROUND: While the aims of multicomponent screening of older people are broad, any benefit arising from the inclusion of a vision component in the assessment will necessarily be dependent on improved vision. OBJECTIVES: The objective of this review is to assess the effects on vision of mass screening of older people for visual impairment. SEARCH STRATEGY: We searched the Cochrane Eye and Vision Group specialised register, the Cochrane Controlled Trials Register - Central, MEDLINE, EMBASE, SciSearch and reference lists of relevant trial reports and review articles. We contacted investigators to identify additional published and unpublished trials. The most recent searches were conducted in April 1998. SELECTION CRITERIA: We included randomised trials of visual or multicomponent screening for vision impairment in people aged 65 or over in a community setting. DATA COLLECTION AND ANALYSIS: Both reviewers independently extracted data and assessed trial quality. MAIN RESULTS: Visual outcome data were available for 3494 people in five trials of multicomponent assessment. Length of follow up ranged from two to four years. All the trials used self-reported measures for visual impairment, both as screening tools and as outcome measures. In four of the trials people reporting visual problems were referred to either the eye services or to a physician. In one trial people reporting visual problems received information about resources in the community designed to assist those with poor vision. The proportions of participants in the intervention and control groups who reported visual problems at the time of outcome assessment were 0.26 and 0.23 respectively (relative risk for visual impairment 1.03, 95% confidence interval 0.92 to 1.15). REVIEWER'S CONCLUSIONS: There is no evidence that community-based screening of asymptomatic older people results in improvements in vision.

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PubMed2000

Photodynamic therapy for neovascular age-related macular degeneration.

BACKGROUND: In neovascular age-related macular degeneration, new vessels grow under the retina, distorting vision and leading to scarring. This is further exacerbated if the blood vessels leak. Photodynamic therapy, originally used in cancer treatment, has been investigated as a way to treat the neovascular membranes without affecting the retina. OBJECTIVES: The aim of this review is to examine the evidence for the safety and effectiveness of photodynamic therapy in the treatment of neovascular age-related macular degeneration. SEARCH STRATEGY: We searched for trials in the Cochrane Eyes and Vision Group trials register (available in the Cochrane Controlled Trials Register), the Cochrane Controlled Trials Register, Medline and Embase. We used the Science Citation Index to search for reports that cited identified relevant study reports. We contacted experts in the field for further trials information, and we searched the reference lists of identified relevant studies for further trial reports. Searches were conducted in December 1999. SELECTION CRITERIA: We included randomised trials of photodynamic therapy in people with choroidal neovascularisation due to age-related macular degeneration. DATA COLLECTION AND ANALYSIS: Two reviewers extracted the data independently. Meta analysis was not performed. MAIN RESULTS: One published trial was identified. Outcome data were available at 12 months after the first treatment. Patients received an average of 3.7 treatments. The relative risk of losing three or more lines of visual acuity at 12 months comparing the intervention with the control group was 0.72 (95% confidence interval 0.61 to 0.86). The relative risk of losing six or more lines of visual acuity at 12 months comparing the intervention with the control group was 0.62 (95% confidence interval 0.44 to 0.87). Subgroup analyses suggest that the benefits may be confined to people with no occult choroidal neovascularisation. REVIEWER'S CONCLUSIONS: Photodynamic therapy in people with classic choroidal neovascularisation due to age-related macular degeneration is effective in preventing visual loss. This evidence is drawn from a subgroup analysis of 143 participants in one trial. Outcomes and potential adverse effects of this treatment should be monitored closely. There is no evidence that photodynamic therapy is beneficial for people with evidence of occult choroidal neovascularisation. These people should be offered treatment in the context of a randomised trial.

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PubMed1998

Effectiveness of screening older people for impaired vision in community setting: systematic review of evidence from randomised controlled trials.

OBJECTIVE: To assess whether population screening for impaired vision among older people in the community leads to improvements in vision. DESIGN: Systematic review of randomised controlled trials of population screening in the community that included any assessment of vision or visual function with at least 6 months' follow up. SUBJECTS: Adults aged 65 or over. MAIN OUTCOME MEASURE: Proportions with visual impairment in intervention and control groups with any method of assessing visual impairment. RESULTS: There were no trials that primarily assessed visual screening. Outcome data on vision were available for 3494 people in five trials of multiphasic assessment. All the trials used self reported measures for vision impairment, both as screening tools and as outcome measures. The inclusion of a visual screening component in the assessment did not result in improvements in self reported visual problems (pooled odds ratio 1.04:95% confidence interval 0.89 to 1.22). A small reduction (11%) in the number of older people with self reported visual problems cannot be excluded. CONCLUSIONS: Screening of asymptomatic older people in the community is not justified on present evidence. Visual impairment in this age group can usually be reduced with treatment. It is unclear why no benefit was seen. Further work is needed to clarify what interventions are appropriate for older people with unreported impairment of vision.

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PubMed1998

Assessing the likely effectiveness of screening older people for impaired vision in primary care.

Screening for visual impairment is frequently included in multiphasic screening assessments for older people, although evidence for the effectiveness of screening from randomized trials is lacking. This paper uses previously developed criteria for assessing the likely effectiveness of community screening programmes to review the non-trial evidence around visual screening. Unreported or undiagnosed visual impairment is common among older people and is associated with considerable morbidity. Testing for visual acuity is easy and quick, but may not accurately reflect the level of functional disability caused by the visual problem in everyday living. Effective therapeutic interventions exist for most symptomatic patients, but the effects of treating unreported visual impairment detected by screening have not been evaluated. Existing barriers to effective treatment for older people with symptomatic visual problems include financial costs to the patient, and an inability of ophthalmic services to meet demand. These same factors may be barriers to the uptake of treatment following screening. Further work is needed to assess the needs of older people with unreported visual problems, and to clarify barriers to effective screening.

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