Voluntary surveillance systems are subject to under-reporting.Figures may underestimate true numbers.Miscategorisation of probable country of infection by presuming the country with the highest prevalence as the likely country of infection will underestimate the number of infections acquired in the United Kingdom, particularly among people originating from countries with high prevalence.New HIV diagnoses do not represent new HIV infections, as diagnosis can occur at any point between infection and death, which in the natural course of infection is typically 10-12 years.Furthermore, surveillance reports do not distinguish between partners infected in high prevalence countries while visiting and partners infected before migrating from those countries.The number of people becoming infected with HIV through heterosexual intercourse in the United Kingdom is rising steadily.As the number of heterosexuals living with HIV (diagnosed and undiagnosed) in the United Kingdom grows, the likelihood of heterosexual transmission within the country will increase, particularly among ethnic minorities.The continuing collaboration of those who contribute to the voluntary HIV/AIDS reporting system in England, Wales and Northern Ireland is gratefully acknowledged, as is the help, advice, and support of Kevin Fenton (Health Protection Agency (HPA)), Noel Gill (HPA), Phillip Mortimer (HPA), Linda Lazarus (Department of Health), and Daniel Thomas (Communicable Disease Surveillance Centre Wales), and administrative support provided by Fay Peyman (HPA) and Fateha Begum (HPA).Contributors: VLG followed up reports.SD analysed surveillance data and wrote the first draft.VLG, SD, KS, and BGE were involved in the drafting of subsequent versions.BGE is guarantor

Aim The DARTS diabetes register was used to determine incidence rates of diabetes and related complications in 1997.Methods The diabetes register records detailed clinical information for all patients diagnosed with diabetes in Tayside, Scotland. The study population included patients who were alive and registered with a Tayside GP for the duration of 1997 or who died in Tayside during this time. Patients who had diabetes prior to 1997, those who developed diabetes in 1997, and those who developed diabetic complications in 1997, were identified.Results In the Tayside population of 385 774 at the start of 1997, there were 942 and 6632 patients with Type 1 and Type 2 diabetes, with a further 29 and 744 patients diagnosed in 1997. The incidence rates (with 95% confidence intervals) of diabetic complications per 1000 patients with Type 1 and Type 2 diabetes, respectively, were: angina 8.8 (4.5-17.3) and 38.4 (33.4-44.2); myocardial infarction 8.6 (4.4-16.9) and 21.9 (18.4-25.9); cerebrovascular accident 1.1 (0.3-6.0) and 14.2 (11.6-17.5); lower extremity amputation 3.2 (1.2-9.4) and 3.1 (2.1-4.8); peripheral vascular disease 5.5 (2.4-12.8) and 13.6 (11.0-16.8); registered blindness 1.1 (0.3-5.9) and 1.6 (0.9-2.9); end-stage renal failure 6.4 (3.0-13.8) and 5.0 (3.6-7.0). Mortality was 14.6 per 1000 (9.6-25.7) in Type 1 diabetes and 50.0 per 1000 (45.1-55.3) in Type 2 diabetes.Conclusion This study provides baseline figures for rates of diabetic complications for Type 1 and Type 2 diabetes, and confirms the increased burden of macrovascular disease in Type 2 diabetes.

OBJECTIVE:To compare the mortality of people who were diagnosed with type 2 diabetes over 65 years of age with that of nondiabetic individuals.RESEARCH DESIGN AND METHODS:Using a population-based diabetes information system for an observational cohort study in Tayside, Scotland, people who were diagnosed with type 2 diabetes over the age of 65 years between 1993 and 2002 were identified. Nondiabetic comparators, matched for age and sex, were identified from the nondiabetic population. The two cohorts were followed up for mortality and cardiovascular mortality according to death certification records.RESULTS:There were 3,594 people with type 2 diabetes (48% male) and 7,188 matched comparators identified in the study. Over a mean follow-up period of 4.6 +/- 2.9 years for 3,594 people with type 2 diabetes and 7,188 comparators, 909 (25.3%) patients in the diabetic cohort and 1,651 (23.0%) in the nondiabetic cohort died. The adjusted relative risk for mortality in the diabetic cohort compared with the nondiabetic cohort was 1.06 (95% CI 0.94-1.19) for men and 1.29 (1.15-1.45) for women. Cardiovascular deaths accounted for 49.4% of the deaths in people with and 45.2% in those without diabetes (adjusted relative risk 1.01 [0.93-1.10]).CONCLUSIONS:Men diagnosed with type 2 diabetes over the age of 65 years have no excess mortality compared with their nondiabetic counterparts, a finding that was not replicated for women.

Objective To compare risks of cardiovascular outcomes between patients with type 2 diabetes and patients with established coronary heart disease.Design Cross sectional study and cohort study using routinely collected datasets.Setting Tayside, Scotland (population 400 000) during 1988-95.Subjects In the cross sectional study, among patients aged 45-64,1155 with type 2 diabetes were compared with 1347 who had had a myocardial infarction in the preceding 8 years. In the cohort stud), 3477 patients of all ages with newly diagnosed type 2 diabetes were compared with 7414 patients who had just had a myocardial infarction.Main outcome measures Risk ratios for death from all causes, cardiovascular death, and hospital admission for myocardial infarction were calculated by Cox proportional hazards analysis and adjusted for age and sex.Results In the cross sectional study the adjusted risk ratio for death from all causes was 2.27 (95% confidence interval 1.82 to 2.83) for patients who had had myocardial infarction compared with those with diabetes, and the risk ratio for hospital admission for myocardial infarction was 1.33 (1.14 to 1.55). In die cohort study, patients who had just had a myocardial infarction had a higher risk of death from all causes (adjusted risk ratio 1.35 (1.25 to 1.44)), cardiovascular death (2.93 (2.54 to 3.41)), and hospital admission for myocardial infarction (3.10 (2.57 to 3.73)).Conclusions Patients with type 2 diabetes were at lower risk of cardiovascular outcomes than patients with established coronary heart disease.

The Medicines Monitoring Unit (MEMO) is a University‐based organization that uses record‐linkage techniques to construct an observational database for the population of Tayside, Scotland (approximately 400 000 people). This contains healthcare data indexed by a unique identifier, including data on all prescriptions dispensed, which facilitates pharmacoepidemiological (and other) research. It has hitherto been possible to carry out drug safety studies in the entire population, with access to original medical records of patients where necessary, that have satisfied ethical concerns and confidentiality legislation. However, the recent UK Data Protection Act 1998 (which enforces the 1995 European Directive on Data Protection) has important implications for MEMO's research. The Act has necessitated changes to the way in which research studies are carried out, with MEMO's objective being to ensure that research can continue while protecting the rights and privacy of individual patients. This involves anonymization of data, seeking specific ethical approval for research studies and obtaining relevant permissions from ‘Caldicott Guardians’, as described in this article. Copyright © 2001 John Wiley & Sons, Ltd.

Record-linkage refers to the linking together of data relating to the same individual from separate source files. In this paper, we discuss ways in which the technique can enhance observational prescribing research in large populations. We draw upon the work of the Medicines Monitoring Unit (MEMO), University of Dundee, to illustrate its contribution to prescribing research.

AIMS:To evaluate whether diabetes mellitus is a risk factor for the development of primary open angle glaucoma or ocular hypertension (OHT).METHODS:A historical cohort study of an unselected population comprising all residents of the Tayside region of Scotland was performed using record linkage techniques followed by case note review. Ascertainment of prevalent diabetes was achieved using the Diabetes Audit and Research in Tayside Study (DARTS) validated regional diabetes register. Glaucoma and treated OHT were defined by encashment of community prescriptions and the statutory surgical procedure coding database.RESULTS:The study population comprised 6631 diabetic subjects and 166 144 non-diabetic subjects aged >40 years without glaucoma or OHT at study entry. 65 patients with diabetes and 958 without diabetes were identified as new cases of glaucoma or treated OHT during the 24 month study period, yielding a standardised morbidity ratio of 127 (95% CI, 96-158). Case note review demonstrated non-differential misclassification of prevalent glaucoma and OHT as incident disease (diabetic cohort 20%, non-diabetic cohort 24%; p=0.56) primarily as a result of non-compliance in medically treated disease. Removing misclassified cases and adjusting for age yielded an incidence of primary open angle glaucoma in diabetes of 1.1/1000 patient years (95% CI, 0.89-1. 31) compared to 0.7/1000 patient years (95% CI, 0.54-0.86) in the non-diabetic cohort; RR 1.57 (95% CI, 0.99-2.48).CONCLUSIONS:This study failed to confirm an association between diabetes mellitus and primary open angle glaucoma and ocular hypertension. A non-significant increase in diagnosed and treated disease in the diabetic population was observed, but evidence was also found that detection bias contributes to this association.

The aim of the study was to evaluate the risks of hospitalisation and death due to hypersensitivity reactions associated with the NSAIDs naproxen and ibuprofen, using a record-linkage database for Tayside, Scotland (population 400,000). Cohorts of patients exposed to naproxen (n=54,038) and ibuprofen (n=79,513) were assembled. There were no deaths due to hypersensitivity. There was an increased risk of unvalidated hypersensitivity reactions during periods on-drug versus off-drug in patients exposed to naproxen and ibuprofen. However, after checking medical records, none of the three valid cases of hypersensitivity in the naproxen cohort and neither of the two in the ibuprofen cohort were judged to be due to NSAID exposure. A "worst-case" scenario gave an adjusted rate-ratio of on-drug with naproxen versus on-drug with ibuprofen of 1.63 (0.50, 5.29). The study shows that hypersensitivity reactions associated with NSAID use are rare, and provides no evidence that the risks of hypersensitivity reactions differ between naproxen and ibuprofen.

Aims  To define the number of people in Tayside, Scotland (population 349 303) with Type 2 diabetes who use metformin, the incidence of contraindications to its continued use in these people and the proportion that discontinued metformin treatment following the development of a contraindication.

AIMS:The influence of socio-economic status on the prevalence of Type 1 and Type 2 diabetes mellitus, and on obesity, was explored using routinely collected healthcare data for the population of Tayside, Scotland. METHODS:Among 366,849 Tayside residents, 792 and 5,474 patients with Type 1 and Type 2 diabetes, respectively, were identified from a diabetes register. The Carstairs Score was used as a proxy for socio-economic status. This is a material deprivation measure derived from the UK census, using postcode data for four key variables. Odds ratios for diabetes prevalence, adjusted for age, were determined for each of six deprivation categories (1 - least deprived, 6/7 - most deprived). The mean body mass index (BMI) in each group was also determined, and the effect of deprivation category explored by analysis of covariance, adjusting for age and sex. RESULTS:The prevalence of Type 2 diabetes, but not Type 1 diabetes, varied by deprivation. People in deprivation category 6 and 7 were 1.6-times (95% confidence interval 1.4-1.8) more likely to have Type 2 diabetes than those least deprived. There was no relationship between deprivation and BMI in Type 1 diabetes (P = 0.36), but there was an increase in BMI with increasing deprivation in Type 2 diabetes (P < 0.001; test of linearity P < 0.001). CONCLUSIONS:The study confirms the relationship between deprivation and the prevalence of Type 2 diabetes. There are more obese, diabetic patients in deprived areas. They require more targeted resources and more primary prevention.

OBJECTIVEUtilization and costs of prescription drugs were investigated in diabetic and nondiabetic patients.RESEARCH DESIGN AND METHODSThe study was carried out in Tayside, Scotland, U.K. A validated population-based diabetes register was used to identify patients with type 1 and type 2 diabetes, and a database of all prescriptions dispensed in the community was used to investigate drug utilization in 1995.RESULTSIn a population of 406,526, there were 974 (0.2%) with type 1 diabetes and 6,869 (1.7%) with type 2 diabetes. The mean dispensed prescribing rates for all drugs (excluding antidiabetic medication) were higher across all age-groups for diabetic patients. After adjusting for age, patients with type 1 diabetes were 2.07 times (95% CI 2.03-2.11) more likely and patients with type 2 diabetes were 1.70 times (1.69-1.71) more likely to be dispensed a drug item than people without diabetes. This likelihood was increased in every drug category, even those not directly related to diabetes, and the proportion and cost of drug items dispensed to diabetic patients was therefore higher than expected given the prevalence of diabetes. Upon projecting these results to the U.K. population, it was discovered that nearly 8% of the U.K. drug budget (Pound Sterling 350 million) is accounted for by patients with diabetes (90% of that by patients with type 2 diabetes).CONCLUSIONSThis study highlights the increased usage and cost of prescription drugs in diabetes, with type 2 diabetes constituting a particular burden. It was discovered that 1.4% of drug usage in the entire population can be accounted for by the increased prescribing rate of diabetic patients compared with that of nondiabetic patients.

Objectives To investigate patterns of self monitoring of blood glucose concentration in diabetic patients who use insulin and to determine whether frequency of self monitoring is related to glycaemic control.Setting Diabetes database, Tayside, Scotland.Subjects Patients resident in Tayside in 1993-5 who were using insulin and were registered on the database and diagnosed with insulin dependent (type 1) or non-insulin dependent (type 2) diabetes before 1993.Main outcome measures Number of glucose monitoring reagent strips dispensed (reagent strip uptake) derived from records of prescriptions. First recorded haemoglobin A(1c), concentration in the study period, and reagent strips dispensed in the previous 6 months.Results Among 807 patients with type 1 diabetes, 128 (16%) did not redeem any prescriptions for glucose monitoring reagent strips in the 3 year study period. Only 161 (20%) redeemed prescriptions for enough reagent strips to test glucose daily. The corresponding figures for the 790 patients with type 2 diabetes who used insulin were 162 (21%; no strips) and 131 (17%; daily tests). Reagent strip uptake was influenced both by age and by deprivation category. There was a direct relation between uptake and glycaemic control for 258 patients (with recorded haemoglobin A(1c) concentrations) with type 1 diabetes. In a linear regression model the decrease in haemoglobin A(1c) concentration for every extra 180 reagent strips dispensed was 0.7%. For the 290 patients with type 2 diabetes who used insulin there was no such relation.Conclusions Self monitoring of blood glucose concentration is associated with improved glycaemic control in patients with type 1 diabetes. Regular self monitoring in patients with type 1 and type 2 diabetes is uncommon.

We share the concerns of Hershel Jick and colleagues1MacDonald TM McDevitt DG The Tayside Medicines Monitoring Unit (MEMO).in: Strom BL Pharmacoepidemiology, second edition. John Wiley & Sons Ltd, Chichester1994: 245-255Google Scholar that observational research on adverse and beneficial drug effects could be discredited if it is not done properly, despite being a useful tool. However, we would like to clarify further some of the points made on the basis of our work at the Tayside Medicines Monitoring Unit.2McMahon AD Evans JMM McGilchrist MM McDevitt DG MacDonald TM Drug exposure risk windows and unexposed comparator groups for cohort studies in pharmacoepidemiology.Pharmacoepidemiol Drug Safety. 1988; 7: 275-280Crossref Scopus (32) Google Scholar The most appropriate drug-exposure model can usually be determined objectively by the data, without recourse to a subjective value judgment of appropriateness.2McMahon AD Evans JMM McGilchrist MM McDevitt DG MacDonald TM Drug exposure risk windows and unexposed comparator groups for cohort studies in pharmacoepidemiology.Pharmacoepidemiol Drug Safety. 1988; 7: 275-280Crossref Scopus (32) Google Scholar, 3Evans JMM MacDonald TM Misclassification and selection bias in case-control studies using an automated database.Pharmacoepidemiol Drug Safety. 1997; 6: 313-318Crossref PubMed Scopus (29) Google Scholar Such objective methods are important because the exposure measure that they give might not be similar to that chosen intuitively. The validation of cases should be carried out with caution, and preferably only when it is possible to validate each case. We have found that the existence or availability of case records varies between patients, which could theoretically be associated with exposure status.4Barbone F McMahon AD Davey PG et al.Association of road-traffic accidents with benzodiazepine use.Lancet. 1998; 352: 1331-1336Summary Full Text Full Text PDF PubMed Scopus (526) Google Scholar If cases are excluded from a study because it is not possible to validate them, there is the potential for selection bias with unpredictable results. Without case validation, there is potential for misclassification, but if this is non-differential it will tend to bias a result towards the null hypothesis, and is therefore predictable. We would also like to recommend the use of the case-crossover design in drug epidemiology. This design is suitable for transient risks, and the main advantage is the way in which confounding is neatly dealt with.4Barbone F McMahon AD Davey PG et al.Association of road-traffic accidents with benzodiazepine use.Lancet. 1998; 352: 1331-1336Summary Full Text Full Text PDF PubMed Scopus (526) Google Scholar With respect to the accurate definition of exposure measures by computerised medical information, we believe the ability to identify prescriptions that have actually been dispensed to patients in the pharmacy (rather than prescribed by the doctor) is an advantage since many prescriptions are never redeemed by patients. Otherwise, exposure misclassification due to primary non-compliance can be introduced, in that patients who do not redeem their prescriptions are erroneously classified as exposed. Mercury in hair—but from where?Authors' reply Full-Text PDF