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Biomedical subjects

L Whitaker

Publications and source records attributed to L Whitaker.

At least 19 recordsLinked to original sources
PubMed1999

Demograghic and socio-economic determinants of community and hospital services costs for people with HIV/AIDS in London.

We examined the influence of demographic, social and economic background of people with HIV/AIDS in London on total community and hospital services costs. This was a retrospective study of community and hospital service use, needs and costs based on structured questionnaires administered by trained interviewers and costing information obtained from the service purchasers and providers, based on two Genito-urinary Medicine clinics in London: the Jefferiss Wing at St. Mary's Hospital and Patric Clements at the Central Middlesex Hospital, London, England. The subjects were 225 HIV infected patients (105 asymptomatic, 59 symptomatic non-AIDS and 61 AIDS). We found that over and above well established determinants of health care costs for HIV infected people such as disease stage and transmission category, social and economic factors such as employment and support of a living-in partner significantly reduced community services costs. Private health insurance had a similar effect, though only a small proportion of HIV people had such cover. The cost of community services for HIV infected non-European Union nationals, mainly of African origin, was one quarter that for the European Union nationals. Community services costs were highest for heterosexually infected women and lowest for heterosexually infected men after adjusting for other factors. Hospital services costs were significantly higher for HIV infected people lacking educational qualifications and employment. We conclude that access to community care for HIV infected non-EU nationals appears to be very poor as the cost of their community services was one quarter that for the EU nationals after adjusting for the effects of transmission category, disease stage, living with a partner, employment and having a private health insurance. Additional incentives for informal care for HIV infected people could be a cost-effective way to improve their community health service provisions.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Mucosal subepithelial binding sites for the bacterial chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (FMLP).

BACKGROUND: The bacterial chemotactic peptide N-formyl-methionine-leucine-phenylalanine (FMLP) is produced by enteric flora and is one of the factors implicated in contributing to inflammatory bowel disease. Expression of receptors for FMLP on human phagocytes (polymorphs and monocytes) is well established, but there is conflicting evidence regarding the potential expression of FMLP receptors on other cells within the mucosa, particularly the epithelial cells. AIMS: To map FMLP receptors within intestinal mucosa using several different experimental approaches. METHODS AND RESULTS: Radioligand binding assays with 'H-FMLP' revealed no specific binding to primary cultured colonic enterocytes or to the cell line HT29, whereas neutrophils, as expected, exhibited specific binding with a Kd of 19 nM and approximately 2 x 10(4) receptors per cell. FITC labelled FMLP exhibited specific, displaceable binding on flow cytometry to neutrophils and monocytes but not to 10 gastrointestinal epithelial cell lines. Isolated lamina propria lymphocytes and peripheral blood lymphocytes exhibited no binding. To confirm the absence of receptors on epithelia, reverse transcription polymerase chain reaction for mRNA for the classic FMLP receptor was performed. While the presence of message was detected in activated peripheral blood phagocytes, it was not detected in epithelial cell lines. To exclude the possibility of FMLP binding to other receptors such as tachykinin receptors on epithelia, FITC labelled FMLP binding in tissue sections confirmed that the binding is subepithelial--that is, in the lamina propria. CONCLUSION: Receptors for FMLP are subepithelial and map to the lamina propria of the gastrointestinal mucosa.

Animals↗
PubMed1998

Heterosexual HIV transmission and STD prevalence: predictions of a theoretical model.

BACKGROUND: Previous studies suggest that concurrent sexually transmitted infection may enhance HIV transmission. This paper explores some theoretical consequences of this using a mathematical model of transmission of HIV and other STD pathogens. OBJECTIVES: To develop a deterministic mathematical model to describe the heterosexual transmission dynamics of both HIV and a bacterial STD. STUDY DESIGN: We used survey derived estimates of sexual behaviour in a young heterosexual London population in our deterministic mathematical model to estimate the effects on an HIV epidemic of different levels of STD prevalence in such a population. RESULTS: We show that the predictions of the model are plausible and suggest that, even under conditions both of low STD prevalence and of low HIV transmission enhancement, a substantial proportion of HIV transmission events may be attributable to concurrent STD. CONCLUSIONS: It is likely that epidemics of heterosexually transmitted HIV infection in industrialised countries have been limited in size by the relative success of efforts to control STD. None the less, a significant proportion of heterosexual transmission events which do occur may be attributable to concurrent STD. In developing countries, cheap and simple STD care is likely to be a highly cost effective strategy to prevent HIV transmission.

Adolescent↗
PubMed1997

Infections in craniofacial surgery: a combined report of 567 procedures from two centers.

This retrospective review of infectious complications was undertaken at two craniofacial centers (Dallas and Philadelphia). Fourteen infections were identified over a 6.5-year period in 567 intracranial procedures primarily for craniosynostosis. There were no infections in infants under 13 months of age and no cases of meningitis. The overall infection rate was 2.5 percent, and 85 percent of infections occurred in secondary reoperative cases. Tracheostomies were not identified as a risk factor for infection. No difference was found in infection rates between patients with shaved and unshaved scalps. Candida and Pseudomonas were the two most common organisms identified, and 28 percent of our infections involved yeast. The average time to diagnose infection was 11.5 days (excluding three patients who averaged 5 months). Thirteen of the fourteen infections were treated surgically with placement of a subgaleal irrigation/drainage system. Initial bony debridement was kept to a minimum. Based on our findings, recommendations are made to further lower infection rates, particularly those caused by opportunistic organisms.

Antibiotic Prophylaxis↗
PubMed1997

An association between non-gonococcal urethritis and bacterial vaginosis and the implications for patients and their sexual partners.

OBJECTIVES: The aetiology of non-gonococcal urethritis (NGU) in a considerable proportion of men remains unaccounted for. We wished to investigate the possible aetiological role of bacterial vaginosis (BV), the commonest cause of abnormal discharge in women, in this condition. METHODS: We carried out two studies. In the first, case-control, study, we recruited men with and without NGU and examined their female partners for evidence of BV. The second, cohort design, study which ran concurrently with the first study involved recruiting women with and without BV and examining their male partners for evidence of NGU. The diagnoses of both NGU and BV were made microscopically to include symptomatic and asymptomatic individuals in both disease categories. RESULTS: In the case-control study 51 couples were recruited. Of these 39 men had NGU and 12 (31%) of their female contacts had BV. In contrast, of 12 men without NGU, only one (8%) of the female partners had BV (odds ratio 4.89, 95% CI: 0.51-42.27). When only Chlamydia trachomatis negative patients were considered, the odds ratio for an association between BV and NGU was increased to 6.77, 95% CI: 0.73-62.68). Thirty eight couples were recruited to the cohort design study. Of 17 women with BV, 12 (71%) of their male partners had NGU. In contrast, of 21 women without BV, seven (33%) of their male partners had NGU (p = 0.049, odds ratio 4.8). When only C trachomatis negative patients were considered, the significance of the association was increased (p = 0.037; odds ratio 5.42). CONCLUSIONS: An association exists between NGU and BV, and vice versa. If BV arises de novo the findings could help to explain the development of urethritis in stable sexual relationships.

Adult↗
PubMed1996

Community service needs of people with HIV infection in London.

The objectives of this study were to describe the expressed needs for community services of HIV-infected individuals by disease stage, gender and transmission category and the barriers which prevent the receipt of such services. Structured interviewer-administered questionnaires concerning a 6-month retrospective period were used to obtain information on need for community services and problems which prevented the receipt of services. The study sample included 70 homosexual men with asymptomatic HIV disease, 42 homosexual men with symptomatic non-AIDS, 53 homosexual men with AIDS, 23 heterosexual men, 29 heterosexual women, 9 male and 9 female injecting drug users. The main outcome measures were the extent to which needs for community services were met and person/service combinations for which problems or barriers prevented the receipt of community services. On average, subjects expressed a need for 10 categories of community services over the 6-month period: homosexuals expressed a mean of 10, heterosexuals 10, injecting drug users 11, subjects with asymptomatic HIV infection 9, subjects with symptomatic non-AIDS 11, subjects with AIDS 13, men 9 and women 14. A total of 58% of community service needs were always met, 6% were rarely not met, 16% were sometimes not met, 6% were often not met and 14% were not met at all. The extent to which subjects felt that their needs were met was similar for the different study groups, but the needs of women were met somewhat less frequently than those of men. Similarly, people with AIDS felt that their needs were met slightly less often. Reported levels of unmet need were high for a wide range of services. The most common reason subjects gave for not having received a community service for which they expressed a need was ignorance of where or how to obtain the service. This was mentioned in one-third of all such cases. Anxieties over the competence with which a service would be rendered was mentioned in 13% of cases and long waiting times in 11%. The frequencies of unmet need for many community services were high and often seemed to arise either from a lack of awareness on the part of subjects on how and where services could be obtained or from doubts about the relevance of services offered. Both of these barriers should be surmountable through the provision of better information to patients, extending user involvement in service development and the better co-ordination of service delivery through care management approaches.

Adult↗
PubMed1996

The economic costs of caring for people with HIV infection and AIDS in England and Wales.

The objectives of this study were firstly to estimate total lifetime care costs for an individual with HIV/AIDS, and secondly to estimate the total costs of caring people with HIV infection and AIDS in England and Wales between 1992 and 1997 inclusive. Questionnaires and monthly diaries were used to collate data on healthcare utilisation from patients with HIV infection over a 6-month period. These data were then used to estimate the annual total direct costs of care (stratified by disease stage), total lifetime costs of care, and present and future total national care costs for England and Wales. Costing data were obtained from providers of services throughout Greater London. In total, 235 patients with HIV infection were recruited from 2 clinics in Greater London. All costs were calculated in 1992-93 pounds sterling (pound; 1 pound = $US1.58, December 1995). Annual care costs were estimated at 4515 pounds ($US7134) for a person with asymptomatic HIV disease, 8836 pounds ($US13,961) for a person with symptomatic non-AIDS and 15 268 pounds ($US24,123) for a person with AIDS. Lifetime care costs were estimated at 84,522 pounds ($US133,545) per patient. The total costs of care for England and Wales were forecast to increase from 116,627,400 pounds ($US184,271,300) in 1992 to 162,638,100 pounds ($US256,968,200) in 1997. In conclusion, our study further emphasises the continued shift in hospital services from the inpatient sector to the outpatient sector. The importance of community care and informal care, in terms of the associated direct economic costs, is also highlighted. This emphasises the need for close collaboration between different agencies and strategic coordination of services. Finally, the study forecasts an increase in care costs in England and Wales during the 1990s.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Provision of sex education and early sexual experience: the relation examined.

OBJECTIVES: To explore the relation between receipt of sex education and experience of first intercourse. SUBJECTS AND DESIGN: The national survey of sexual attitudes and lifestyles is based on a sample of 18,876 respondents aged 16-59, randomly selected from the Post Office's small-user postcode address file. Data were collected between May 1990 and November 1991 by personal interviews combining a self administered questionnaire with a face to face interview. MAIN OUTCOME MEASURES: Age at first intercourse, use of contraception at first intercourse, actual and preferred source of sex education (including school based lessons). RESULTS: Median age at first intercourse fell by four years for women and three years for men over the past four decades, to 17 for both men and women aged 16-19 at the time of interview. Of those respondents for whom school was the main source of information about sexual matters, men were less likely, and women no more likely, to have had intercourse before the age of 16 than were those citing other main sources, such as friends and the media. Both men and women were more likely to have used some method of contraception. In multivariate analysis, these effects remained after controlling for the effect of current age, educational attainment, and religious affiliation. CONCLUSIONS: These data provide no evidence to support the concern that provision of school sex education might hasten the onset of sexual experience. These findings have important implications for the provision of sexual health education and highlight the need to carry out prospective and randomised studies of the impact of sex education.

Adolescent↗
PubMed1995

HIV positive patients first presenting with an AIDS defining illness: characteristics and survival.

OBJECTIVES: To study the presentation and survival of patients who present with their first diagnosis of being HIV positive at the same time as their AIDS defining illness. DESIGN: Retrospective study of patients presenting with AIDS between 1991 and 1993. SETTING: Department of genitourinary medicine, St Mary's Hospital, London. MAIN OUTCOME MEASURES: AIDS defining illness at presentation and survival after diagnosis of AIDS. RESULTS: Between January 1991 and December 1993, 97 out of 436 patients (22%) presented with their first AIDS defining illness coincident with their first positive result of an HIV test (group B). The remaining 339 patients (78%) had tested positive for HIV-1 infection within the previous eight years and had consequently been followed up in clinics before developing their first AIDS defining illness (group A). The two groups of patients did not differ in age and sex distribution, risk factors for HIV-1 infection, nationality, country of origin, or haematological variables determined at the time of the AIDS defining illness. However, the defining illnesses differed between the two groups. Illnesses associated with severe immunodeficiency (the wasting syndrome, cryptosporidiosis, and cytomegalovirus infection) were seen almost exclusively in group A whereas extrapulmonary tuberculosis and Pneumocystis carinii pneumonia were more common in group B. The survival of patients in group B after the onset of AIDS was significantly longer than that of patients in group A as determined by Kaplan-Meier log rank analysis (P = 0.0026). CONCLUSIONS: Subjects who are HIV positive and present late are a challenge to the control of the spread of HIV infection because they progress from asymptomatic HIV infection to AIDS without receiving health care. The finding that presentation with an AIDS defining illness coincident with a positive result in an HIV test did not have a detrimental effect on survival gives insights into the effects of medical intervention on disease progression after a diagnosis of AIDS.

AIDS Serodiagnosis↗
PubMed1995

The use of air or CO2 as insufflation agents for double contrast barium enema (DCBE): is there a qualitative difference?

One hundred consecutive out-patients referred for double contrast barium enema (DCBE) were randomized in a double-blind prospective study to receive either air or CO2 as an insufflation agent. Each examination was performed by the same radiologist and radiographer. The two groups were equally matched for age and sex. Each completed examination was independently assessed by three radiologists for a variety of parameters. The results show that the patients receiving air as an insufflation agent had better overall colonic distension than the group receiving CO2 and that this was statistically significant (P = 0.0004). There was no significant difference in the mean time taken to perform the examination in the two groups nor was there any significant difference in mucosal coating or preparation. In conclusion, our results suggest that poor colonic distension is a potential problem when CO2 is used for DCBE and that this cannot be solely attributed to the time taken to perform the examination. Poor distension could lead to diagnostic errors and this may outweigh the advantages in patient acceptability when using CO2 as an insufflation agent.

Adult↗
PubMed1995

Estimating the sexual mixing patterns in the general population from those in people acquiring gonorrhoea infection: theoretical foundation and empirical findings.

STUDY OBJECTIVES: To describe mathematically the relationship between patterns of sexual mixing in the general population and those of people with gonorrhoea infection, and hence to estimate the sexual mixing matrix for the general population. DESIGN: Integration of data describing sexual behaviour in the general population, with data describing sexual behaviour and mixing among individuals infected with gonorrhoea. Use of these data in a simple mathematical model of the transmission dynamics of gonorrhoea infection. SETTING: The general population of London and a genitourinary medicine (GUM) clinic in west London. PARTICIPANT: These comprised 1520 men and women living in London who were randomly selected for the national survey of sexual attitudes and lifestyles and 2414 heterosexual men and women who presented to the GUM clinic with gonorrhoea. MAIN RESULTS: The relationship between sexual mixing among people with gonorrhoea and sexual mixing in the general population is derived mathematically. An empirical estimate of the sexual mixing matrix for the general population is presented. The results provide tentative evidence that individuals with high rates of acquisition of sexual partners preferentially select other individuals with high rates as partners (assortative mixing). CONCLUSIONS: Reliable estimates of sexual mixing have been shown to be important for understanding the evolution of the epidemics of HIV infection and other sexually transmitted diseases. The possibility of estimating patterns of sexual mixing in the general population from information routinely collected in gonorrhoea contact tracing programmes is demonstrated. Furthermore, the approach we describe could, in principle, be used to estimate the same patterns of mixing, using contact tracing data for other sexually transmitted diseases, thus providing a way of validating our results.

Adolescent↗
PubMed1995

Cost and utilisation of community services for people with HIV infection in London.

This study aimed to describe the use and costs of community services for HIV-infected people by disease stage, sex and transmission category (homosexual, heterosexual, injecting drug use) by use of a prospective cohort study in which people were followed up for six months. There were two major components; gathering quantitative information on service utilisation from people with HIV infection using two interviewer-administered questionnaires and six self-completed monthly diaries; and estimating the costs of the services provided. People were recruited from two London clinics: the Jefferiss Wing Genito-urinary Medicine (GUM) clinic at St. Mary's Hospital, Paddington, and the Patrick Clements GUM clinic at the Central Middlesex Hospital, Harlesden. Costing data was obtained from providers of community services throughout Greater London. The main outcome measures were contacts per person-year, and costs per person-year, for all community services stratified by service sector. The people studied each made, on average, 139 community service contacts per year at a cost of 2,806 pounds; there was little difference in average utilisation between the three transmission categories. There were differences in both the utilisation of services and costs within the formal and informal sectors for subjects from different disease stages. Although the average number of contacts per person-year were similar for women and men, the total cost of community services was higher for women than for men, reflecting the differences in types of services used. The results indicated a high proportion of total care costs for people with HIV and AIDS is incurred through community-based social care.(ABSTRACT TRUNCATED AT 250 WORDS)

Community Health Services↗
PubMed1994

Using STD occurrence to monitor AIDS prevention.

Monitoring the effects of AIDS prevention programmes is increasingly important but methodologically difficult. The use of surveillance derived measures of the occurrence of sexually transmitted diseases as indicators of high risk sexual behaviour, or of HIV incidence, has been widely recognized as a possible approach. This paper first examines the theoretical and empirical basis for this strategy, and highlights, using examples, some of the pitfalls in the interpretation of trends in sexually transmitted disease occurrence. Problems arising in the interpretation of the types of STD surveillance data currently available in countries in Western Europe are discussed. Ways in which STD surveillance systems might be developed so as to enhance their value in monitoring AIDS prevention are proposed. The paper goes on to identify areas of clinical and epidemiological research which might improve our ability to interpret such enhanced STD surveillance data.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Changing use of hospital services and costs at a London AIDS referral centre, 1983-1989.

OBJECTIVE: To describe the use of hospital-based services and associated costs over time for HIV-infected individuals by disease stage and year of treatment. METHODS: Data on service use were abstracted from inpatient and outpatient case-notes of 459 HIV-infected patients (121 asymptomatic and 338 AIDS patients) treated at St Mary's Hospital, London between 1983 and 1989. Cost estimates were derived from a survey of the 37 departments involved with HIV-related care. The number and type of admissions and outpatient visits, referral and discharge venues, number and type of tests and procedures performed, drugs prescribed and associated costs for the study period were the outcome measures used. RESULTS: Most patients were homosexual men. At the time of first HIV-related visit, 80.7% lived in London. Most day cases and planned admissions were organized through the outpatient clinic; 31% of emergency admissions were initiated by patients themselves. For people with AIDS the number of day case admissions increased while planned admissions decreased. There was a marked reduction in the duration of inpatient stays, especially for AIDS patients. Costs associated with inpatient care decreased concomitantly. The number of outpatient visits for patients with symptomatic disease increased, resulting in increased outpatient expenditure. Asymptomatic patients had fewer inpatient tests, while outpatient tests did not change over time; costs followed similar patterns. Mean inpatient and outpatient drug-days prescribed did not change nor did average inpatient drug-costs although outpatient drug-costs increased. Inpatient tests performed on symptomatic non-AIDS patients decreased, while mean outpatient tests increased; average costs followed similar patterns. Inpatient drug-days prescribed and costs remained the same, while outpatient drug-days and average drug-costs increased during the study period. For AIDS patients, the number of inpatient tests performed and their average costs decreased but outpatient tests performed increased, though their average costs remained the same. Mean inpatient drug-days prescribed and average drug-costs decreased, while number of outpatient drug-days prescribed and average drug-costs increased markedly over time. For each disease category, expenditure on admissions and related tests decreased over time, while expenditure on outpatient visits and drug-costs increased. CONCLUSIONS: The shift from an inpatient- to an outpatient-based service has resulted in fewer patients being investigated and treated in hospital and more as outpatients. This has resulted in a reduction of inpatient-related costs, while outpatient-related costs have increased. The overall contribution of drug-costs to the total cost has increased greatly over time. With the anticipated advent of new antiviral compounds, the importance of ascertaining their effectiveness as well as their efficacy will become crucial.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Changing presentation and survival, service utilization and costs for AIDS patients: insights from a London referral centre.

OBJECTIVE: To describe the use of services and associated costs for HIV-infected patients by stage of infection in the context of changing patterns of presentation and survival. METHODS: A retrospective analysis of inpatient and outpatient case-notes of 335 AIDS patients and a survey of HIV-related care provided by 37 departments at St Mary's Hospital, London. Survival from time of diagnosis of AIDS, time from diagnosis of HIV infection to AIDS, and use and costs of services per patient-year were outcome measures. RESULTS: During the study period 1 January 1982 to 30 September 1989, 152 AIDS patients were diagnosed before 1987 (group 1) and 183 since 1987 (group 2), most of whom were homosexual men. The median interval of first HIV-related visit to diagnosis of AIDS increased from 0 (group 1) to 264 days (group 2; P < 0.0001). Median survival from AIDS diagnosis increased from 14.6 (group 1) to 21.0 months (group 2; P < 0.02). Group 2 patients used fewer inpatient services than group 1 patients irrespective of disease stage. Symptomatic patients in group 2 used more outpatient services than group 1 patients. Total HIV-related expenditure was lower for patients without AIDS in group 2 than in group 1, while expenditure for AIDS patients remained similar. CONCLUSION: Earlier patient presentation, a shift from inpatient- to outpatient-based clinical care and increased survival from time of AIDS diagnosis has occurred. Increased drug expenditure was offset by reduced inpatient expenditure. Total expenditure per patient-year was stable; increased survival and introduction of new drugs will increase future lifetime use of resources.

Acquired Immunodeficiency Syndrome↗