An additional dimension to health inequalities: disease severity and socioeconomic position.

OBJECTIVE: To investigate the association between the severity of hip pain and disability, and a number of measures of socioeconomic position, using a range of individual and ecological socioeconomic indicators. DESIGN: Interviewer administered and self completed questionnaires on symptoms of pain and disability, general health and socioeconomic indicators, completed by people reporting hip pain in a cross sectional, postal, screening questionnaire. SETTING: 40 general practices from inner city, suburban and rural areas of south west England. PARTICIPANTS: 954 study participants who had reported hip pain in a postal questionnaire survey of 26,046 people aged 35 and over, selected using an age/sex stratified random probability sample. DATA: Individual indicators of socioeconomic position: social class based on occupation, maximum educational attainment, car ownership, gross household income, manual or non-manual occupation and living alone. Area level measures of socioeconomic position: Townsend scores for material deprivation at enumeration district level; urban or rural location based on the postcode of residence. Severity of hip disease, measured by the pain, disability and independence components of the New Zealand score for major joint replacement. Self reported comorbidity validated using general practice case notes and summary measures of general health. MAIN RESULTS: Increasing disease severity was strongly associated with increasing age and a variety of measures of general health, including comorbidity. The data provide considerable evidence for the systematic association of increased severity of hip disease with decreasing socioeconomic position. Measures of socioeconomic position that were systematically associated with increasing disease severity, standardised for age and sex, included educational attainment (relative index of inequality 1.95 (95% confidence intervals 1.29 to 2.62) and income (relative index of inequality 4.03 (95% confidence intervals 3.43 to 4.64). Those with access to a car (mean disease severity 15.5) had statistically significant lower severity of hip disease than those without (mean 17.5, p < 0.01). Similar results were found for access to higher or further education and living with others. For a given level of income, people with greater comorbidity had more severe hip pain and disability. The gradient in disease severity between rich and poor was steepest among those with the most comorbidity. CONCLUSIONS: People with lower socioeconomic position experience a greater severity of hip disease. The poorest sector of the population seem to be in double jeopardy: they not only experience a greater burden of chronic morbidity but also a greater severity of hip disease. This study has implications for health care provision, if the National Health Service is to live up to its principle of equal treatment for equal medical need.

Deprivation and cause specific morbidity: evidence from the Somerset and Avon survey of health.

OBJECTIVE: To investigate the association between cause specific morbidity and deprivation in order to inform the debates on inequalities in health and health services resource allocation. DESIGN: Cross sectional postal questionnaire survey ascertaining self reported health status, with validation of a 20% sample through general practitioner and hospital records. SETTING: Inner city, urban, and rural areas of Avon and Somerset. SUBJECTS: Stratified random sample of 28,080 people aged 35 and over from 40 general practices. MAIN OUTCOME MEASURES: Age and sex standardised prevalence of various diseases; Townsend deprivation scores were assigned by linking postcodes to enumeration districts. Relative indices of inequality were calculated to estimate the magnitude of the association between socioeconomic position and morbidity. RESULTS: The response rate was 85.3%. The prevalence of most of the conditions rose with increasing material deprivation. The relative index of inequalilty, for both sexes combined, was greater than 1 for all conditions except diabetes. The conditions most strongly associated with deprivation were diabetic eye disease (relative index of inequality 3.21; 95% confidence interval 1.84 to 5.59), emphysema (2.72; 1.67 to 4.43) and bronchitis (2.27; 1.92 to 2.68). The relative index of inequality was significantly higher in women for asthma (P < 0.05) and in men for depression (P < 0.01). The mean reporting of prevalent conditions was 1.07 for the most deprived fifth of respondents and 0.77 in the most affluent fifth (P < 0.001). CONCLUSIONS: Material deprivation is strongly linked with many common diseases. NHS resource allocation should be modified to reflect such morbidity differentials.

Achieving equal probability of selection under various random sampling strategies.

The underlying objective of epidemiological investigations is to extrapolate results from a sample to the relevant population. The simplest way of achieving this is to adopt a sampling strategy in which each individual in the population has the same chance of being selected--that is, to employ an 'equal probability of selection method' (epsem). The easiest ways of achieving this are to use simple random sampling or stratified random sampling with a constant sampling fraction. These strategies are often impracticable, however, particularly in large investigations covering a wide geographical area where resource implications dictate a more complex approach such as multi-stage or cluster sampling. Following detailed definitions and appropriate illustrations of these terms, the main purpose of this paper is to provide a working guide of how to achieve epsem using these various random sampling techniques. In brief, for multi-stage sampling with the rare feature of equal-sized first stage units, epsem is achieved by applying the above simple or stratified approaches to the first stage units. Even in the more realistic scenario of unequal first stage units, the same options apply provided that a fixed proportion of second stage units are to be selected (cluster sampling is in fact just one example of this, with 100% sampling of second stage units). If on the other hand a fixed number of second stage units are to be selected then for epsem the first stage units should be selected with each one having a probability proportionate to its size.

Vision-related quality of life impairment in an elderly UK population: associations with age, sex, social class and material deprivation.

PURPOSE: To describe the prevalence of vision-related quality of life (VR-QOL) impairment in an elderly UK population sample. METHOD: The survey, using the VCM1 questionnaire, was based on an age- and sex-stratified random population sample of 2783 individuals aged 55 years or over. RESULTS: One thousand eight hundred and forty-six (69.7%) of 2647 eligible subjects responded. One thousand six hundred and eighty-three individuals completed all 10 VCM1 items. Overall the prevalence of a VCM1 score >2.0 ('more than a little' concern about vision) was 4.6% (95% CI = 3.7% to 5.7%), leading to an estimate of more than 550,000 individuals in England with substantial VR-QOL impairment. The prevalence increased with age from 2.1% in the 55-64 year age group to 17.9% in the group aged 85 years and older. The prevalence also increased as social class became lower, from 0 in social class I to 10.2% in social class V, and increased with increasing material deprivation, from 1.2% in the most affluent quintile to 6.8% in the most deprived quintile. Multivariable logistic regression analysis showed that age (p = 0.0001), decreasing social class (p = 0.03) and increasing material deprivation (p = 0.008) were independently associated with VR-QOL impairment (VCM1 score >2.0), whilst gender and means of questionnaire administration were not associated with VR-QOL impairment at the 5% level. CONCLUSIONS: The findings suggest a substantial national prevalence of VR-QOL impairment, and are consistent with earlier studies linking ocular disease with social deprivation. Consideration should be given to directing resources more carefully towards groups at higher risk of VR-QOL impairment, in particular the very elderly and socially deprived.

Population requirement for primary knee replacement surgery: a cross-sectional study.

OBJECTIVES: To determine the population requirement for total knee replacement (TKR) in England. METHODS: Population-based study using an age/sex-stratified random sample of 28 080 individuals aged 35 yr and over. Incident disease was estimated from prevalence by statistical modelling. The New Zealand priority criteria for major joint replacement were used for case selection. RESULTS: Patients with knee disease were less likely than those with equally severe hip disease to have been referred to a specialist, to have consulted an orthopaedic surgeon or to be on a waiting list for joint replacement. The estimated annual requirement of TKRs in England, based on New Zealand Scores alone, was 55,800 (95% CI 40 700-70,900), contrasting sharply with an annual provision of 29,300 actually observed. However, in contrast to previously reported hip replacement data, when patient willingness to undergo surgery was considered, this estimate decreased considerably. CONCLUSIONS: There appears to be an underprovision of TKR in England. This may be due in part to differences in perception of disease severity and likely response to surgery between patients and general practitioners on one hand, and rheumatologists and orthopaedic surgeons on the other.

Socio-economic inequalities in diabetes complications, control, attitudes and health service use: a cross-sectional study.

AIMS: To investigate socio-economic inequalities in diabetes complications, and to examine factors that may explain these differences. METHODS: Cross-sectional questionnaire survey of 770 individuals with diabetes among 40 general practices in Avon and Somerset. General practice, optometrist and eye hospital records over time (median 7 years) were analysed. Slope indices of inequality, odds ratios and incidence rate ratios were calculated to estimate the magnitude of inequality between the most and least educated, and the highest and lowest earning patients, adjusted for age, sex and type of diabetes, and clustering of outcomes within practices. RESULTS: The least educated patients were more likely than the most educated patients to have diabetic retinopathy [adjusted odds ratio (OR) 4.3; 95% confidence interval 0.8, 23.7] and heart disease (adjusted OR 3.6; 1.1, 11.8), had higher HbA1c levels (adjusted slope index of inequality 0.9; 0.3, 1.5), felt that diabetes more adversely affected their social and personal lives (adjusted slope index of inequality 0.8; 0.5, 1.1 Diabetes Care Profile units), were more likely to be recorded as non-compliant by their health professionals, and had lower rates of hospital attendance (adjusted rate ratio 0.43; 0.26, 0.71). However, they did not see themselves as less compliant, and had higher general practice attendance rates (adjusted rate ratio 1.5; 1.1, 2.2). CONCLUSIONS: Less educated and lower earning individuals with diabetes bear a larger burden of morbidity but use hospital care less. Health service resource allocation should reflect the distribution of chronic illness.

Population requirement for primary hip-replacement surgery: a cross-sectional study.

BACKGROUND: There has been a long-standing failure in many countries to satisfy the demand for several elective surgical treatments, including total hip replacement. We set out to estimate the population requirement for primary total hip replacement in England. METHODS: We undertook a cross-sectional study of a stratified random sample of 28,080 individuals aged 35 and over from 40 general practices in inner-city, urban, and rural areas of Avon and Somerset, UK. Prevalent disease was identified through a two-stage process: a self-report screening questionnaire (22,978 of 26,046 responded) and subsequent clinical examination. Incident disease was estimated from the point prevalence by statistical modelling. The requirement for total hip replacement surgery was estimated on the basis of pain and loss of functional ability, with adjustment for evidence of comorbidity and patients' treatment preferences. FINDINGS: 3169 people reported hip pain on the screening questionnaire. 2018 were invited for clinical examination, and 1405 attended. The prevalence of self-reported hip pain was 107 per 1000 (95% CI 101-113) for men and 173 per 1000 (166-180) for women. The prevalence of hip disease severe enough to require surgery was 15.2 (12.7-17.8) per 1000 aged 35-85 years. The corresponding annual incidence of hip disease requiring surgery was estimated as 2.23 (1.56-2.90), which suggests an overall requirement in England of 46,600 operations per year for patients who expressed a preference for, and were suitable for, surgery; the recent actual provision in England was about 43,500. INTERPRETATION: This research suggests that the satisfaction of demand for total hip replacement, given agreed criteria for surgery, is a realistic objective.