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Biomedical subjects

J Hollowell

Publications and source records attributed to J Hollowell.

11 recordsLinked to original sources
PubMed2003

Validity and interpretation of mortality, health service and survey data on COPD and asthma in England.

The comparability of asthma and chronic obstructive pulmonary disease (COPD) epidemiology in different English routine data sources was examined to explore their use and validity in investigating environmental influences on respiratory health. National data were obtained for mortality, emergency hospital admissions, general practitioner contacts and symptoms in the early 1990s. Age/sex patterns, seasonal variations and regional and urban/rural age/sex standardised event ratios were examined. Spearman rank correlations were used to describe consistency of regional rankings across data sets. Asthma showed inconsistent disease patterns in different data sources and weak correlations for regional rankings but COPD was notably consistent. Unmeasured confounders may partly explain the findings, but individual level adjustment for social class and smoking (possible for symptoms) only partially attenuated the higher COPD rates in northern and urban areas and did not affect findings for asthma. When epidemiological patterns are consistent across data sources as with chronic obstructive pulmonary disease in England, healthcare use is likely to reflect the underlying prevalence and severity of disease and can be used to study environmental influences. When patterns vary, as with asthma, the validity of the data in relation to its intended use must be carefully considered.

Adolescent↗
PubMed2000

Revision of the International Classification of Impairments, Disabilities, and Handicaps: developmental issues.

Variability in approaches to define and classify disability has constituted persistent problems in documenting the epidemiology of disability and providing appropriate services. The major institutions of health care, mental health, and welfare often have separate systems of classification and terminology related to defining eligibility for programs and funding for services. In 1980, the International Classification of Impairments, Disabilities and Handicaps-ICIDH was published by the World Health Organization as a companion document of the International Classification of Disease to document the consequences of illness or injury. Current problems concerning the classification of childhood disability in health, education, and related services have resulted in growing interest in the revision of the ICIDH as a classification tool. The strengths and limitations of the ICIDH are examined in general, as well as with specific reference to its ability to document the nature and epidemiology of childhood disability. This paper (1) describes the ICIDH taxonomy and representative contributions; (2) reviews issues and concerns contributing to its revision; (3) summarizes changes in the revised ICIDH2 draft document, and (4) identifies issues of particular relevance to children and public health applications.

Activities of Daily Living↗
PubMed2000

Use of iodine for water disinfection: iodine toxicity and maximum recommended dose.

Iodine is an effective, simple, and cost-efficient means of water disinfection for people who vacation, travel, or work in areas where municipal water treatment is not reliable. However, there is considerable controversy about the maximum safe iodine dose and duration of use when iodine is ingested in excess of the recommended daily dietary amount. The major health effect of concern with excess iodine ingestion is thyroid disorders, primarily hypothyroidism with or without iodine-induced goiter. A review of the human trials on the safety of iodine ingestion indicates that neither the maximum recommended dietary dose (2 mg/day) nor the maximum recommended duration of use (3 weeks) has a firm basis. Rather than a clear threshold response level or a linear and temporal dose-response relationship between iodine intake and thyroid function, there appears to be marked individual sensitivity, often resulting from unmasking of underlying thyroid disease. The use of iodine for water disinfection requires a risk-benefit decision based on iodine's benefit as a disinfectant and the changes it induces in thyroid physiology. By using appropriate disinfection techniques and monitoring thyroid function, most people can use iodine for water treatment over a prolonged period of time.

Humans↗
PubMed1999

Use of the General Practice Research Database (GPRD) for respiratory epidemiology: a comparison with the 4th Morbidity Survey in General Practice (MSGP4).

BACKGROUND: The General Practice Research Database (GPRD) covers over 6% of the population of England and Wales and holds data on diagnoses and prescribing from 1987 onwards. Most previous studies using the GPRD have concentrated on drug use and safety. A study was undertaken to assess the validity of using the GPRD for epidemiological research into respiratory diseases. METHODS: Age-specific and sex-specific rates derived from the GPRD for 11 respiratory conditions were compared with patient consultation rates from the 4th Morbidity Survey in General Practice (MSGP4). Within the GPRD comparisons were made between patient diagnosis rates, patient prescription rates, and patient "prescription plus relevant diagnosis" rates for selected treatments. RESULTS: There was good agreement between consultation rates in the MSGP4 and diagnosis or "prescription plus diagnosis" from the GPRD in terms of pattern and magnitude, except for "acute bronchitis or bronchiolitis" where the best comparison was the combination category of "chest infection" and/or "acute bronchitis or bronchiolitis". Within the GPRD, patient prescription rates for inhalers, tuberculosis or hayfever therapy showed little similarity with diagnosis only rates but a similarity was seen with the combination of "prescription plus diagnosis" which may be a better reflection of morbidity than diagnosis alone. CONCLUSIONS: The GPRD appears to be valid for primary care epidemiological studies by comparison with MSGP4 and offers advantages in terms of large size, a longer time period covered, and ability to link prescriptions with diagnoses. However, careful interpretation is needed because not all consultations are recorded and the coding system used contains terms which do not directly map to ICD codes.

Adult↗
PubMed1998

Mortality in people taking selegiline: observational study.

OBJECTIVE: To evaluate mortality among patients with Parkinson's disease receiving different treatment. DESIGN: Cohort study based on computerised medical records. SETTING: UK General Practice Research Database. SUBJECTS: 12 621 patients aged between 35 and 90 years who had received a prescription for an antiparkinsonian drug, whether or not a diagnosis of Parkinson's disease had been recorded. Patients prescribed an antipsychotic drug before or at the same time as their first antiparkinsonian drug or before age 35 were excluded to avoid including drug-induced Parkinsonism. MAIN OUTCOME MEASURE: Death from any cause. RESULTS: 1720 deaths occurred during 14 000 person-years of observation. There was a non-significant 11% (95% confidence interval 0% to 23%) increase in the risk of death associated with taking selegiline either alone or in combination with levodopa. The death rate was higher among younger patients (aged under 80 years) and those with a recorded diagnosis of Parkinson's disease taking selegiline alone. CONCLUSIONS: The results are compatible with a small excess mortality in people taking selegiline and suggest a larger excess in patients under 80 years of age and those with a confirmed diagnosis of Parkinson's disease taking selegiline without levodopa.

Adult↗
PubMed1998

The General Practice Research Database. Scientific and Ethical Advisory Group.

We describe a powerful new information resource for pharmacovigilance, pharmaco-economic studies, clinical epidemiology and health service research, which involves automated linkage of demographic, diagnostic and prescription information on some 3.4 million patients enrolled in over 500 separate general practices. Information is subject to regular validation checks. Access to this resource is available for bona fide research workers, subject to appropriate safeguards for patient anonymity and for scientific and ethical standards of the proposed studies. This database has depended upon the participating general practitioners and has already resulted in a substantial output of studies in peer-reviewed literature. It has great potential for further work of major relevance to public health, and its increasing use is to be actively encouraged.

Adolescent↗
PubMed1997

The General Practice Research Database: quality of morbidity data.

In 1994, ONS took over the running of the General Practice Research Database-formerly the VAMP Research Database. As the database had not been widely used for general health monitoring purposes, ONS undertook a study to evaluate the representativeness, quality and validity of the data. This article compares GPRD patient consulting rates for four conditions (chicken pox, hay fever, asthma and diabetes) with equivalent data from the 4th National Morbidity Survey in General Practice; and compares GPRD patient treatment rates for asthma with epidemiological survey data. The results suggest that the GPRD is a potentially useful source of national morbidity data.

Adolescent↗
PubMed1994

Comparison of asthmatic patients admitted to hospital from health districts experiencing high and low asthma mortality rates.

Geographical variation in asthma mortality rates within the United Kingdom could be a reflection of variability in effectiveness of medical care services, or epidemiological variation. In order to ascertain whether differing hospital admission processes could contribute to this variation, asthmatic patients admitted from two districts, experiencing above and below average mortality rates were compared. The present study was part of a cohort study of 1,200 consecutive acute adult admissions in 1987/88. In the main study, social data and information on referral were collected by interview for all patients. The admitting doctors' perception of the patient's severity was assessed on the basis of the severity of symptoms, and likelihood of morbidity or mortality if the patient was not admitted. Further information on asthmatic patients (treatment and physiological measurements) was retrieved from the notes. Sixty-six asthmatic patients resident in Wandsworth (a district with high asthma mortality rates) were admitted to St George's Hospital or St James' Hospital (WW) and 31 patients resident in East Surrey (ES) (a district with low asthma mortality rates) were admitted to the East Surrey Hospital (ESH). Notes were obtained on 55 (83%) and 27 (87%) of patients in the two districts, respectively. WW received significantly more patients by self-referral: 68% of patients called an ambulance or came directly to casualty compared with 30% in ES (chi-squared = 13.7, d.f. = 2, P = < 0.001). There was a tendency for more admissions to ESH to be taking oral steroids (chi-squared = 3.2, d.f. = 1, P = 0.07). Patients admitted in WW tended to have more severe disease: 39 (85%) of patients admitted to WW had peak expiratory flow less than 200 1/minute on admission compared to 14 (58%) in ES (chi-squared = 6, d.f. = 1, P = 0.01). In WW the mean first recorded peak expiratory flow on admission was 154 1/minute compared to 172 1/minute in ES; their mean peak flow on discharge was 318 1/minute compared with 377 1/minute in ES. Twenty-one (38%) of admissions in WW were considered to be very urgent by the admitting hospital doctor compared to four (15%) in ESH (chi-squared = 4.67, d.f. = 1, P = 0.03). This opportunistic study found that, in an area experiencing high mortality rates, more patients with severe disease were admitted to hospital compared to a low mortality area. This does not appear to be due to differing hospital practices but rather to increased levels of morbidity in the community. As patients with more severe asthma are at a greater risk of dying, these finding reinforce the need to standardize asthma treatment in the community.

Acute Disease↗