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 oVers 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.

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.

Objective To examine socioeconomic differences in general practice consultation rates among patients aged 65 years and over. Design Secondary analysis of data from the fourth national survey of morbidity in general practice. Setting 60 general practices in England and Wales. Subjects 71 984 people aged 65 years and over. Main outcome measures Annual contact rates and home visiting rates with general practitioners and practice nurses. Results Social class differences in contact rates were greatest in 65-74 year olds, with rates 23% higher in patients from social class V than in class I (4.82 v 3.93 per person). In 75-84 year olds there was no clear association between social class and contact rates, and in people aged >85 years contact rates were highest in patients from class I. Home visiting rates were twice as high in patients from class V as in patients from class I (1.38 v 0.66 per person). Contact rates were 17% higher in people living in communal establishments and 8% higher in those living alone than in those living with others but not in a communal establishment. 66% of contacts with patients in communal establishments and 26% of those with patients living alone were in patients' homes compared with 18% with those living in standard accommodation. These differences persisted after adjustment in a generalised linear model. Conclusions Elderly people show socioeconomic differences in consultation rates. The extra workload generated by elderly people living alone and in communal establishments suggests additional payments to general practitioners are needed.

No abstract