What determines geographical variation in rates of acceptance onto renal replacement therapy in England?

OBJECTIVE: To determine the independent effects of need and supply factors on the known geographical variation in acceptance rates onto renal replacement therapy (RRT) in England. METHODS: Data were obtained from all renal units in England on the characteristics of all cases aged 16 years and over, resident in England, who were accepted onto RRT in 1991 and 1992. Of these, 5715 (94.5%) had a valid postcode that could be matched to a census ward. Multilevel modelling using Poisson regression was used. The number of acceptances in each census ward within age bands 16-34, 35-64 and 65+ was the dependent variable. Independent effects modelled were: (1) individual factors (age, sex); (2) census ward need factors--ethnicity (expressed as the percentage of the ward population that was Asian or African-Caribbean), socio-economic deprivation--and supply factors--'access' to the nearest renal unit using crowfly and road travel time and distance, and services available to each ward expressed as number of haemodialysis stations per 100,000 catchment population of the nearest renal unit; (3) district health authority level effects. RESULTS: Age was a major determinant of acceptance, with a 7-fold higher rate in males aged over 64 years compared with younger men. Acceptance rates were lower in females, with a negative age-sex interaction in females aged over 64 years. The percentage of both Asian and African-Caribbean populations per ward was a highly significant positive determinant. Deprivation was also a significant determinant, best represented by a customised index. There was an inverse relation of acceptance with distance, especially road travel time. Other supply side variables had a significant effect though there was no independent district effect. There was some variation in the strength of these relationships by type of area (Greater London, urban and non-urban). CONCLUSIONS: Need and supply factors influence service use as expressed as acceptance onto RRT. Pressure to expand RRT services needs to be aimed at areas with large minority ethnic populations and those living far from existing units.     

Validity of predicting mean arterial blood pressure during exercise

PURPOSE: Mean arterial blood pressure (mean arterial pressure (MAP)) at rest is conventionally estimated as the product of the diastolic pressure plus one-third of the pulse pressure. Since pulse wave forms and the duration of diastole change during exercise, one might question the validity of this prediction equation for the exercise state. Our purpose was to test this by directly measuring blood pressure over a wide range of exercise intensities. METHODS: Pressure was recorded by arterial catheterization in 29 subjects performing progressive exercise and/or constant-load exercise at different intensities. Actual MAP was measured by integrating the area under the pulse curve and compared it with the value which was predicted from systolic and diastolic measures over heart rates ranging from 100 to 200 beats x min(-1). RESULTS: Predicted values were quite close to actual MAP, and the accuracy of the prediction equation changed minimally with increased exercise intensity. CONCLUSION: This method provides a valid estimation of MAP during exercise.     

Attention problems versus conduct problems as 6-year predictors of signs of disturbance in a national sample.

OBJECTIVE: To test whether attention problems predicted different signs of disturbance than conduct problems over 3 and 6 years. METHOD: Gender-specific criteria for deviance on parents' ratings of attention versus conduct problems were tested as predictors of interview-reported signs of disturbance in a national sample first assessed at ages 4 to 16 years. RESULTS: Males and females deviant on both attention and conduct problems showed higher rates of several signs of disturbance than did those deviant on only one type of problem. Subjects deviant only on conduct problems showed higher rates of several signs than did controls, whereas those deviant only on attention problems exceeded controls mainly on special education services. Unaggressive "delinquent" conduct problems predicted dropping out of school, unwed pregnancy, and total signs for both genders during transitions to adulthood. CONCLUSIONS: Attention problems predict receipt of special education but contribute much less than conduct problems to predicting other signs of disturbance. Differential assessment of aggressive versus unaggressive conduct problems can improve prediction, as can gender specificity in setting criteria for deviance and in testing outcomes.     

The morbidity of prolonged wound drainage after kidney transplantation

PURPOSE: The consequences of prolonged wound drainage, defined as extravasation of more than 50 ml. fluid daily for more than 1 week through a drain or wound after renal transplantation, have not been well described in the literature. We examine the association of prolonged wound drainage with other clinical events, and its impact on hospitalization, and patient and graft survival. MATERIALS AND METHODS: We prospectively documented prolonged wound drainage in 392 recipients of cadaver and live renal transplants from July 1993 to December 1997. Potential risk factors, associated outcomes within the first 6 months and effect on length of hospital stay due to prolonged wound drainage were determined. RESULTS: Prolonged wound drainage was significantly associated with pre-transplantation weight, weight gain by post-transplantation day 3, delayed graft function and continuous ambulatory peritoneal dialysis on univariate analysis but only with delayed graft function (odds ratio 2.8, 95% confidence intervals 1.4 to 5.6) on multivariate analysis. Post-transplantation lymphoceles (5.2, 9 to 14), wound infection (27, 5.7 to 130) and wound dehiscence (5.8, 1.7 to 20) were associated with prolonged wound drainage. Patients with prolonged wound drainage stayed 8.7 additional days during the first hospitalization and overall 11.3 additional days during the first 6 months after transplantation independent of other co-morbid events, such as delayed graft function, rejection or cytomegalovirus disease. CONCLUSIONS: Prolonged wound drainage is an important post-renal transplantation event that impacts patient outcomes and hospital resource use. Efforts to prevent this complication should be considered.     

Investigation of under-ascertainment in epidemiological studies based in general practice

BACKGROUND: One of the aims of the Study of Infectious Intestinal Disease (IID) in England is to estimate the incidence of IID presenting to general practice. This sub-study aims to estimate and correct the degree of under-ascertainment in the national study. METHODS: Cases of presumed IID which presented to general practice in the national study had been ascertained by their GP. In 26 general practices, cases with computerized diagnoses suggestive of IID were identified retrospectively. Cases which fulfilled the case definition of IID and should have been ascertained to the coordinating centre but were not, represented the under-ascertainment. Logistic regression modelling was used to identify independent factors which influenced under-ascertainment. RESULTS: The records of 2021 patients were examined, 1514 were eligible and should have been ascertained but only 974 (64%) were. There was variation in ascertainment between the practices (30% to 93%). Patient-related factors independently associated with ascertainment were: i) vomiting only as opposed to diarrhoea with and without vomiting (OR 0.37) and ii) consultation in the surgery as opposed to at home (OR 2.18). Practice-related factors independently associated with ascertainment were: i) participation in the enumeration study component (OR 1.78), ii) a larger number of partners (OR 0.3 for 7-8 partners); iii) rural location (OR 2.27) and iv) previous research experience (OR 1.92). Predicted ascertainment percentages were calculated according to practice characteristics. CONCLUSION: Under-ascertainment of IID was substantial (36%) and non-random and had to be corrected. Practice characteristics influencing variation in ascertainment were identified and a multivariate model developed to identify adjustment factors which could be applied to individual practices. Researchers need to be aware of factors which influence ascertainment in acute epidemiological studies based in general practice.     

Removal of silicone oil with vision improvement after rhegmatogenous retinal detachment following CMV retinitis in patients with AIDS

PURPOSE: To report that silicone oil may be safely removed from immuno-recovered patients with acquired immunodeficiency syndrome (AIDS) after instillation for cytomegalovirus (CMV)-related rhegmatogenous retinal detachment. METHOD: We report two patients with CMV-related retinal detachment who had previously been treated with vitrectomy and silicone oil. RESULTS: Six months after removal of silicone oil, the retina remained attached in both patients. Without specific anti-CMV therapy, there was no relapse of CMV retinitis while patients were undergoing highly active antiretroviral therapy. Best-corrected visual acuity improved in both patients. CONCLUSION: It appears to be possible to remove silicone oil safely from patients with AIDS who show immune recovery, thus avoiding side effects of long-standing silicone oil and increasing quality of life. After silicone oil removal, visual acuity was improved.     

Measles in the 1980s

We detail aspects of measles immunization programmes in several countries. Live measles vaccine has been available in Australia for 16 years, yet, in 1981, there were outbreaks of measles in the State of New South Wales (population 5 200 000) which led to 2200 admissions to hospital and five deaths. In response to complaints of "vaccine failure", a survey determined that 22.5% of children with measles seen by general practitioners and 10.3% of those admitted to hospitals had been previously immunized. There was no evidence of waning immunity, and noparticular batch of vaccine was implicated. The vaccine failures are attributed in part to failure of seroconversion in some recipients when immunized at 12 months of age as a result of interference by transplacentally acquired antibodies. As more of the susceptible population is vaccinated, there will be fewer cases of measles, but among these cases will be an increasing proportion of cases occurring in previously vaccinated individuals. The equation to calculate this expected proportion of "vaccine failures" is given. We support the measures to increase immunization compliance.