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Biomedical subjects

Liam Smeeth

Publications and source records attributed to Liam Smeeth.

At least 37 records · Page 2Linked to original sources
PubMed2004

Rate of first recorded diagnosis of autism and other pervasive developmental disorders in United Kingdom general practice, 1988 to 2001.

BACKGROUND: There has been concern that the incidence of autism and other pervasive developmental disorders (PDDs) is increasing. Previous studies have been smaller, restricted to autism (excluding other pervasive developmental disorders such as Asperger's syndrome), included boys only, or have not been based on a national sample. We investigated time trends in the rates of diagnosis of pervasive developmental disorders. METHODS: We analysed the rates of first diagnosis of pervasive developmental disorders among people registered with a practice contributing to the United Kingdom General Practice Research Database during the period 1988 to 2001. We included 1410 cases from over 14 million person-years of observation. The main outcome measures were rates of diagnosis of pervasive developmental disorders by year of diagnosis, year of birth, gender and geographical region. RESULTS: The rate increased progressively from 0.40/10,000 person-years (95% CI 0.30 to 0.54) in 1991 to 2.98/10,000 (95% CI 2.56 to 3.47) in 2001. A similar change occurred in the age standardised incidence ratios, from 35 (95% CI: 26-47) in 1991 to 365 (95% CI: 314-425) in 2001. The temporal increase was not limited to children born during specific years nor to children diagnosed in a specific time period. The rate of diagnosis of PDDs other than autism rose from zero for the period 1988-1992 to 1.06/10,000 person-years in 2001. The rate of diagnosis of autism also increased but to a lesser extent. There was marked geographical variation in rates, with standardised incidence ratios varying from 66 for Wales to 141 for the South East of England. CONCLUSIONS: Better ascertainment of diagnosis is likely to have contributed to the observed temporal increase in rates of diagnosis of PDD, but we cannot exclude a real increase.

Asperger Syndrome↗
PubMed2004

Validity of the Clock-Drawing Test as a screening tool for cognitive impairment in the elderly.

The authors studied the validity of the Clock-Drawing Test (CDT) in comparison with the Mini-Mental State Examination (MMSE) and the association between the CDT and mortality in a large general population sample of persons aged 75 years or more. Data were obtained from the MRC Trial of the Assessment and Management of Older People in the Community. Baseline assessments were conducted between 1995 and 1999 in the United Kingdom. A total of 13,557 subjects with both CDT and MMSE scores were included in the analysis. The median follow-up period was 4.7 years. The sensitivity and specificity of the CDT for detecting moderate-to-severe cognitive impairment (MMSE score <or= 17) were 77% and 87%, respectively, for nurse administration and 40% and 91%, respectively, for postal administration. Sensitivity was higher among females and increased with age. In Cox proportional hazards regression, a worse CDT score was associated with increased risk of all-cause mortality and mortality from cerebrovascular and respiratory diseases, even after adjustment for potential confounders. The authors conclude that the CDT may have value as a brief face-to-face screening tool for moderate/severe cognitive impairment in an older community population but is relatively poor at detecting milder cognitive impairment.

Age Distribution↗
PubMed2004

Validation of the diagnosis of autism in general practitioner records.

BACKGROUND: We report on the validity of the computerized diagnoses of autism in a large case-control study investigating the possible association between autism and the measles, mumps and rubella vaccine in the UK using the General Practitioner Research Database (GPRD). We examined anonymized copies of all relevant available clinical reports, including general practitioners' (GP) notes, consultant, speech therapy and educational psychologists reports, on 318 subjects born between 1973 and 1997 with a diagnosis of autism or a related disorder recorded in their electronic general practice record. METHODS: Data were abstracted to a case validation form allowing for the identification of developmental symptoms relevant to the diagnosis of pervasive developmental disorders (PDDs). Information on other background clinical and familial features was also abstracted. A subset of 50 notes was coded independently by 2 raters to derive reliability estimates for key clinical characteristics. RESULTS: For 294 subjects (92.5%) the diagnosis of PDD was confirmed after review of the records. Of these, 180 subjects (61.2%) fulfilled criteria for autistic disorder. The mean age at first recording of a PDD diagnosis in the GPRD database was 6.3 years (SD = 4.6). Consistent with previous estimates, the proportion of subjects experiencing regression in the course of their development was 19%. Inter-rater reliability for the presence of a PDD diagnosis was good (kappa =.73), and agreement on clinical features such as regression, age of parental recognition of first symptoms, language delay and presence of epilepsy was also good (kappas ranging from.56 to 1.0). CONCLUSIONS: This study provides evidence that the positive predictive value of a diagnosis of autism recorded in the GPRD is high.

Age of Onset↗
PubMed2004

Topical treatments for seasonal allergic conjunctivitis: systematic review and meta-analysis of efficacy and effectiveness.

BACKGROUND: Evidence for the effectiveness of topical treatments, in providing symptomatic relief from ocular allergy, remains uncertain. AIMS: To assess the effectiveness and relative efficacy of topical treatments for the management of seasonal allergic conjunctivitis. DESIGN OF STUDY: A systematic review and meta-analysis. SETTING: A literature search of the Cochrane Library, Medline, and EMBASE bibliographic databases. METHOD: Double-masked randomised controlled trials were identified, that compared the use of topical mast cell stabilisers (sodium cromoglycate, nedocromil, lodoxamide) with placebo, topical antihistamines with placebo, and topical mast cell stabilisers with topical antihistamines. RESULTS: A meta-analysis of six trials showed that patients using sodium cromoglycate were 17 times (95% confidence interval [CI] = 4 to 78) more likely to perceive benefit compared with those using a placebo, although this estimate may be partially influenced by publication bias. Five trials indicated that those patients using nedocromil were 1.8 times (95% CI = 1.3 to 2.6) more likely to perceive their allergy to be moderately or totally controlled than those using a placebo. Four trials showed that those using antihistamines were 1.3 times (95% CI = 0.8 to 2.2) more likely to perceive a 'good' treatment effect than those using mast cell stabilisers, although this beneficial effect was not statistically significant. Limited evidence suggests that antihistamines might have a faster therapeutic effect compared to mast cell stabilisers. CONCLUSION: Overall, these findings confirm the benefit of topical mast cell stabilisers and antihistamines over placebo for the treatment of allergic conjunctivitis. There is, however, insufficient evidence to recommend the use of one type of medication over another. Treatment preferences should therefore be based on convenience of use (with reduced frequency of instillation for some preparations), patient preference, and costs, especially as important side effects were not reported with any medication.

Administration, Topical↗
PubMed2003

Screening older people for impaired vision in primary care: cluster randomised trial.

OBJECTIVE: To determine the effectiveness of screening for visual impairment in people aged 75 or over as part of a multidimensional screening programme. DESIGN: Cluster randomised trial. SETTING: General practices in the United Kingdom participating in the MRC trial of assessment and management of older people in the community. PARTICIPANTS: 4340 people aged 75 years or over randomly sampled from 20 general practices, excluding people resident in hospitals or nursing homes. INTERVENTION: Visual acuity testing and referral to eye services for people with visual impairment. Universal screening (assessment and visual acuity testing) was compared with targeted screening, in which only participants with a range of health related problems were offered an assessment that included acuity screening. MAIN OUTCOME MEASURES: Proportion of people with visual acuity less than 6/18 in either eye; mean composite score of 25 item version of the National Eye Institute visual function questionnaire. RESULTS: Three to five years after screening, the relative risk of having visual acuity < 6/18 in either eye, comparing universal with targeted screening, was 1.07 (95% confidence interval 0.84 to 1.36; P = 0.58). The mean composite score of the visual function questionnaire was 85.6 in the targeted screening group and 86.0 in the universal group (difference 0.4, 95% confidence interval -1.7 to 2.5, P = 0.69). CONCLUSIONS: Including a vision screening component by a practice nurse in a pragmatic trial of multidimensional screening for older people did not lead to improved visual outcomes.

Aged↗
PubMed2003

Exposure to tricyclic and selective serotonin reuptake inhibitor antidepressants and the risk of hip fracture.

The use of tricyclic antidepressants is associated with an increased risk of hip fracture. Despite a better side effect profile, this adverse effect has also been reported for selective serotonin reuptake inhibitors. To determine whether these findings result from bias arising from the case-control method, the authors have performed a case-control analysis and a self-controlled case-series analysis using 1987-1999 diagnosis data for 16,341 cases of hip fracture and 29,889 controls drawn from the United Kingdom General Practice Research Database. Both analyses showed an association between hip fracture and antidepressant treatment, and this was most marked during the first 15 days of treatment. The estimates from the case-control study were larger than those from the case-series analysis: The odds ratios for fracture within the first 15 days of a prescription for tricyclic antidepressants and serotonin reuptake inhibitors were 4.76 (95% confidence interval (CI): 3.06, 7.41) and 6.30 (95% CI: 2.65, 14.97), whereas the equivalent incidence ratios were 2.30 (95% CI: 1.82, 2.90) and 1.96 (95% CI: 1.35, 2.83). Tricyclic antidepressants and serotonin reuptake inhibitors are both associated with an independent increase in hip fracture incidence during the first weeks of treatment. The estimates from the case-series analyses were smaller than those from the case-control analyses, suggesting that the case-control method is subject to bias.

Aged↗
PubMed2003

Factors associated with depression in a representative sample of 14 217 people aged 75 and over in the United Kingdom: results from the MRC trial of assessment and management of older people in the community.

BACKGROUND: Several social, demographic and physical factors have been shown to be associated with depression in later life, but results have been inconsistent. We aimed to assess factors associated with depression in old age, using data from the MRC trial of assessment and management of older people in the community. METHOD: Analysis of cross-sectional data. Depression was measured with a threshold of <6/6+ on the GDS-15. Independent associations with social, demographic, physical and social network variables were assessed by logistic regression. RESULTS: In a fully adjusted analysis, odds ratios (OR) for depression were greater in older people, (adjusted OR for those aged 80-84 years = 1.1, 85-90 years = 1.5 and 90+ years = 1.8), those in rented (OR:1.3) or sheltered/residential accommodation (OR:1.5), and those widowed, divorced or separated (OR:1.2). Life events, (OR:1.4), smoking (OR:1.6), having two or more physical illnesses (OR:1.6) or no confiding relationship (OR:3.4) were also significantly associated with depression. Higher alcohol consumption was not predictive. Female sex and living alone were associated with depression in a crude analysis, but not after full adjustment for confounding. CONCLUSIONS: The importance of these results lies in the large size and representative nature of the sample. In contrast to some previous reports, increasing age was associated with increasing risk of depression, but sex, living alone and alcohol were not associated. Social isolation was more important than living alone per se. Other associations largely concurred with previous work.

Aged↗
PubMed2003

There is no evidence of an inverse relationship between TH2-mediated atopy and TH1-mediated autoimmune disorders: Lack of support for the hygiene hypothesis.

BACKGROUND: The findings of an inverse relationship between T(H)1- and T(H)2-mediated disorders would provide strong empiric support to the hygiene hypothesis. OBJECTIVE: We sought to investigate the relationship between T(H)2-mediated atopic allergy and T(H)1-mediated autoimmune conditions in a nationally representative population. METHODS: We used logistic regression to analyze adult data from the Third National Health and Nutrition Examination Survey. Data on allergic and autoimmune disease history were available for 20,050 subjects, and data on atopy were available for a subsample of 7304 subjects. Atopy was defined by one or more positive skin prick test responses (wheal of > or =3 mm) to 10 common aeroallergens. Allergic disease was defined by patient reports of physician-diagnosed asthma, hay fever, or both. T(H)1-mediated autoimmune disease was defined by patient reports of physician-diagnosed type 1 diabetes mellitus, thyroid disorders, and/or rheumatoid arthritis. RESULTS: Adjusted for age and sex and taking into account the complex survey design, there was no relationship between atopy and a history of autoimmune disorders (adjusted odds ratio, 1.01; 95% CI, 0.61-1.67; P =.97). In contrast, physician diagnosis of allergic disorders was associated with a significant increased risk of physician-diagnosed autoimmune disorders (adjusted odds ratio, 1.67; 95% CI, 1.35-2.07; P <.001). CONCLUSION: We found no evidence of an inverse relationship between atopy and patient reports of physician-diagnosed common autoimmune disorders in the adult American population. Contrary to our initial hypothesis, reports of physician-diagnosed common allergic disorders are positively associated with reports of physician-diagnosed autoimmune disorders, with this possibly being caused by ascertainment bias. These findings suggest that the T(H)1/T(H)2 paradigm might be an oversimplification.

Adolescent↗
PubMed2003

Performance of a single screening question for depression in a representative sample of 13 670 people aged 75 and over in the UK: results from the MRC trial of assessment and management of older people in the community.

BACKGROUND: A concise, accurate screening question for depression would be an important contribution to the Single Assessment Process for Older People. OBJECTIVE: To examine the performance of a previously validated screening question for depression, in a large community sample. METHODS: Both the single screening question, and the Geriatric Depression Scale (GDS-15) were completed by 13 670 people aged 75 and over in the community. Responses to the question were compared with a "standard" of scoring above different thresholds on the Geriatric Depression Scale (GDS-15). RESULTS: For more severe GDS-15 depression, the best performance of the question was a sensitivity of only 52% and a specificity of 93%. CONCLUSION: Even at its best, the question therefore misses almost half the cases. This highlights the problems of such simple approaches to routine screening.

Aged↗
PubMed2002

Inhaled corticosteroids and hip fracture: a population-based case-control study.

There is accumulating evidence that the use of inhaled corticosteroids is associated with a dose-related reduction in bone mineral density. Whether this translates to an increase in fracture is unclear. We have used the General Practice Research Database to perform a case-control analysis, including 16,341 cases of hip fracture (mean age of 79 years, 79% female, median period prescribing data 2.7 years) and 29,889 control subjects, individually matched by age, sex, and general practice. Data for all prescriptions for corticosteroids and for potential confounders, including other drug use and comorbid illnesses, were extracted, and the impact of inhaled corticosteroid exposure was analyzed using conditional logistic regression. The risk of hip fracture was associated with exposure to inhaled corticosteroids with an odds ratio of 1.26 (95% confidence interval, 1.17 to 1.36). This odds ratio was reduced after adjusting the model for annual courses of oral corticosteroids, the only confounder of note (OR 1.19; 95% CI, 1.10 to 1.28). There was a dose-response relationship between inhaled corticosteroid use and hip fracture even after adjusting for the annual number of courses of oral corticosteroids (p trend = 0.007). In older subjects, the recent use of inhaled corticosteroids is associated with a dose-related increase in hip fracture.

Accidental Falls↗
PubMed2002

Evaluation of adverse effects of vaccines: the case-control approach.

When the hypothesis of a link between vaccination and a possible adverse outcome arises, further investigation is required to confirm or refute the suspicion. Given the rarity of most serious adverse effects, a case-control approach will often be chosen. This paper discusses aspects of the design, analysis and interpretation of case-control studies to evaluate vaccine adverse effects. Potential biases (and how to minimise such biases) in the selection of cases and assessment of vaccine exposure and the potential for confounding are discussed. Finally the increasing use of electronic databases in the evaluation of vaccine adverse effects is considered.

Case-Control Studies↗
PubMed2002

Reduced hearing, ownership, and use of hearing aids in elderly people in the UK--the MRC Trial of the Assessment and Management of Older People in the Community: a cross-sectional survey.

BACKGROUND: Reduced hearing in elderly people is important because it is disabling and potentially treatable. We aimed to assess the prevalence of reduced hearing in elderly people and levels of ownership of hearing aids and use. METHODS: We have done a cross-sectional survey of people aged at least 75 years in 106 family practices in the UK. We obtained self-reported data on hearing difficulties for 32,656 people and gave 14,877 a whispered voice test (response rate 78%). FINDINGS: 2537 (8%) of 32,656 participants reported a lot of difficulty hearing and 13,630 (42%) a little or a lot of difficulty. 3795 (26%) of 14877 participants who completed the whispered voice test (95% CI 23-29) failed the test, the proportion rising sharply with age. Following wax removal, 343 passed a retest, leaving 3452 (23%, 20-26) who failed the test, even after wax removal if present. 998 (46%) of 2180 people wearing a hearing aid at the time of testing failed the whispered voice test. More than half the people who failed the test did not own a hearing aid. 2200 (60%) of 3846 people who owned a hearing aid said they used it regularly. Level of use was strongly related to perceived benefit. INTERPRETATION: Reduced hearing is common and provision of hearing aids inadequate in elderly people. Many people who own a hearing aid do not use it regularly, and even when wearing their aid many still have socially disabling levels of hearing loss. A major source of morbidity in elderly people could be alleviated by improvements in detection and management of reduced hearing.

Aged↗
PubMed2002

Geriatric Depression Scale Scores in a representative sample of 14 545 people aged 75 and over in the United Kingdom: results from the MRC Trial of Assessment and Management of Older People in the Community.

BACKGROUND: The 15-item Geriatric Depression Scale (GDS-15) is recommended for screening older people, but there are no large epidemiological studies using this instrument in the UK. We describe the age and sex distribution of GDS-15 scores in the largest ever UK sample of people aged 75 and over. METHOD: We used cross-sectional data from the MRC Trial of the Assessment and Management of Older People in the Community. The GDS-15 was offered to a representative sample of UK people aged 75 and over. Proportions of people attaining thresholds on the GDS-15 were calculated by age group and sex. Crude Odds ratios (ORs) for the effect of age and sex were calculated and the sex/age adjusted ORs estimated using logistic regression for surveys, at three GDS-15 thresholds. RESULTS: Of 21 241 (71.2%; 95% Confidence intervals (CI): 67.9-74.3) eligible people, 15 126 received the assessment including the GDS-15. Of these, 14 545 (96.2%; 94.7-97.2) completed > or =13 GDS-15 answers and were included in the study. Scores showed a marked right skew, with a median of 2 (interquartile range: 1-3; range: 0-14). 34.6% (95% CI: 32.1-37.3) people scored > or =3, 8.0% (6.9-9.2) scored > or =6 and 3.1% (2.5-3.7) scored > or =8. Women were significantly more likely to score above all three thresholds than men, as were older participants. CONCLUSIONS: Depression may be common in later life. The data provide a national picture of the numbers of older people who will score positively for depression in health screens which include the GDS-15, as recommended by the Royal College of General Practitioners.

Age Distribution↗
PubMed2002

Intraclass correlation coefficients for cluster randomized trials in primary care: data from the MRC Trial of the Assessment and Management of Older People in the Community.

The cluster randomized trial, in which groups rather than individuals are allocated to different interventions, is an increasingly popular design. In cluster trials observations on individuals within the same cluster may be correlated, and this lack of independence must be taken into account when designing a new trial. We present intraclass correlation coefficients derived from the Medical Research Council Trial of the Assessment and Management of Older People in the Community. This is a UK-based randomized trial comparing different methods of multidimensional screening for people aged 75 years and over. One hundred six general practices and over 30,000 individuals are taking part. Estimates of the intraclass correlation coefficients were obtained using one-way analysis of variance. This is by far the broadest collection of intraclass correlation coefficients for older people at the level of the primary care clinic published to date. The intraclass correlation coefficients presented will be useful in calculating sample sizes for cluster randomized trials and surveys at the primary care clinic level. In conjunction with other papers presenting collections of intraclass correlation coefficients, this paper should help to improve the quality of cluster randomized trials and hence help lead to more reliable estimates of the effectiveness of health care interventions.

Activities of Daily Living↗