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OBJECTIVE: The annual prevalence of antiepileptic drug (AED) prescribing reported in the literature differs considerably among European countries due to use of different type of data sources, time periods, population distribution, and methodologic differences. This study aimed to measure prevalence of AED prescribing across seven European routine health care databases in Spain, Denmark, The Netherlands, the United Kingdom, and Germany using a standardized methodology and to investigate sources of variation. METHODS: Analyses on the annual prevalence of AEDs were stratified by sex, age, and AED. Overall prevalences were standardized to the European 2008 reference population. RESULTS: Prevalence of any AED varied from 88 per 10,000 persons (The Netherlands) to 144 per 10,000 in Spain and Denmark in 2001. In all databases, prevalence increased linearly: from 6% in Denmark to 15% in Spain each year since 2001. This increase could be attributed entirely to an increase in "new," recently marketed AEDs while prevalence of AEDs that have been available since the mid-1990s, hardly changed. AED use increased with age for both female and male patients up to the ages of 80 to 89 years old and tended to be somewhat higher in female than in male patients between the ages of 40 and 70. No differences between databases in the number of AEDs used simultaneously by a patient were found. SIGNIFICANCE: We showed that during the study period of 2001-2009, AED prescribing increased in five European Union (EU) countries and that this increase was due entirely to the newer AEDs marketed since the 1990s. Using a standardized methodology, we showed consistent trends across databases and countries over time. Differences in age and sex distribution explained only part of the variation between countries. Therefore, remaining variation in AED use must originate from other differences in national health care systems.

OBJECTIVE: To investigate how smoking status is recorded in UK primary care; to evaluate whether appropriate multiple imputation (MI) of smoking status yields results consistent with health surveys. SETTING: UK primary care and a population survey conducted in the community. PARTICIPANTS: We identified 354 204 patients aged 16 or over in The Health Improvement Network (THIN) primary care database registered with their general practice 2008-2009 and 15 102 individuals aged 16 or over in the Health Survey for England (HSE). OUTCOME MEASURES: Age-standardised and age-specific proportions of smokers, ex-smokers and non-smokers in THIN and the HSE before and after MI. Using information on time since quitting in the HSE, we estimated when ex-smokers are typically recorded as non-smokers in primary care records. RESULTS: In THIN, smoking status was recorded for 84% of patients within 1 year of registration. Of these, 28% were smokers (21% in the HSE). After MI of missing smoking data, the proportion of smokers was 25% (missing at random) and 20% (missing not at random). With increasing age, more were identified as ex-smokers in the HSE than THIN. It appears that those who quit before age 30 were less likely to be recorded as an ex-smoker in primary care than people who quit later. CONCLUSIONS: Smoking status was relatively well recorded in primary care. Misclassification of ex-smokers as non-smokers is likely to occur in those quitting smoking at an early age and/or a long time ago. Those with no smoking status information are more likely to be ex-smokers or non-smokers than smokers.

BACKGROUND: Oesophageal adenocarcinoma (OAC) incidence is rising rapidly and prognosis remains poor. Endoscopic surveillance of Barrett's oesophagus (BO) remains controversial. OBJECTIVE: A nested case-control study was undertaken to evaluate risk factors for progression of BO to OAC, potentially guiding surveillance efforts. METHODS: The Health Improvement Network database includes general practitioner consultations from 5 million UK subjects. BO subjects with 1-year minimum of follow up were followed until development of OAC or end of time on database. Demographic variables (age, gender, smoking, body mass index) and data on medication considered negatively (aspirin/nonsteroidal anti-inflammatory drugs/proton pump inhibitors) or positively associated (lower oesophageal sphincter-relaxing and asthma drugs) with OAC development were studied. Cox regression analysis-derived hazard ratios with 95% confidence intervals estimated the relative risk for OAC progression. RESULTS: A total of 3749 BO subjects were studied: 55 developed OAC during 17,743 patient years of follow up, a progression rate of 0.3% per annum. There was 96.7% of the cohort who took proton-pump inhibitors, with no association observed. Increasing age (1.03, 95% CI 1.01-1.05, p = 0.005), male gender (3.06, 95% CI 1.50-6.24, p = 0.002), and having ever smoked (2.36, 95% CI 1.13-4.93, p = 0.023) were associated with progression to OAC, (although smoking lost association on multivariate analysis). Increasing number of drugs used for asthma (2.91, 95% CI 1.10-7.68, p= 0.0314) was also associated. CONCLUSION: In this nested case-control study of BO, male gender, increasing age, and increasing use of asthma drugs were associated with progression to OAC.

IMPORTANCE The period immediately after bereavement has been reported as a time of increased risk of cardiovascular events. However, this risk has not been well quantified, and few large population studies have examined partner bereavement. OBJECTIVE To compare the rate of cardiovascular events between older individuals whose partner dies with those of a matched control group of individuals whose partner was still alive on the same day. DESIGN, SETTING, AND PARTICIPANTS Matched cohort study using a UK primary care database containing availale data of 401 general practices from February 2005 through September 2012. In all, 30 447 individuals aged 60 to 89 years at study initiation who experienced partner bereavement during follow-up were matched by age, sex, and general practice with the nonbereaved control group (n = 83 588) at the time of bereavement. EXPOSURES Partner bereavement. MAIN OUTCOMES AND MEASURES The primary outcome was occurrence of a fatal or nonfatal myocardial infarction (MI) or stroke within 30 days of bereavement. Secondary outcomes were non-MI acute coronary syndrome and pulmonary embolism. All outcomes were compared between the groups during prespecified periods after bereavement (30, 90, and 365 days). Incidence rate ratios (IRRs) from a conditional Poisson model were adjusted for age, smoking status, deprivation, and history of cardiovascular disease. RESULTS Within 30 days of their partner's death, 50 of the bereaved group (0.16%) experienced an MI or a stroke compared with 67 of the matched nonbereaved controls (0.08%) during the same period (IRR, 2.20 [95% CI, 1.52-3.15]). The increased risk was seen in bereaved men and women and attenuated after 30 days. For individual outcomes, the increased risk was found separately for MI (IRR, 2.14 [95% CI, 1.20-3.81]) and stroke (2.40 [1.22-4.71]). Associations with rarer events were also seen after bereavement, including elevated risk of non-MI acute coronary syndrome (IRR, 2.20 [95% CI, 1.12-4.29]) and pulmonary embolism (2.37 [1.18-4.75]) in the first 90 days. CONCLUSIONS AND RELEVANCE This study provides further evidence that the death of a partner is associated with a range of major cardiovascular events in the immediate weeks and months after bereavement. Understanding psychosocial factors associated with acute cardiovascular events may provide opportunities for prevention and improved clinical care.

BACKGROUND: The incidence of malignancy in patients with chronic pruritus and nondiseased skin is unknown. OBJECTIVE: We sought to assess the hazard ratio (HR) of incident overall malignancy and incident malignancy by subtype in patients with chronic pruritus during the 5 years after diagnosis. METHODS: A population-based cohort study was performed in the Health Improvement Network. In all, 8744 patients with chronic pruritus were matched with 31,580 patients without chronic pruritus based on sex, age, and practice. Primary outcomes were HR of incident malignancy and HR of malignancy subtypes. RESULTS: The fully adjusted HR for incident malignancy in patients with chronic pruritus was 1.14 (95% confidence interval 0.98-1.33). The fully adjusted HR for incident hematologic malignancy and incident bile duct malignancy in patients with chronic pruritus was 2.02 (95% confidence interval 1.48-2.75) and 3.73 (95% confidence interval 1.55-8.97), respectively. The incidence of hematologic malignancy and cholangiocarcinoma in patients with chronic pruritus was 0.0016 and 0.0003 per person-year, respectively. LIMITATIONS: Potential for misclassification and detection biases is a limitation. CONCLUSIONS: Chronic pruritus without concomitant skin changes is a risk factor for having undiagnosed hematologic and bile duct malignancies, but not other malignancies. The overall incidence of these malignancies in patients with chronic pruritus is very low.

OBJECTIVES: A number of studies have demonstrated a trophic effect of gastrin on pancreatic cancer cells in vitro. Pernicious anemia (PA) is a clinical condition characterized by chronic hypergastrinemia. The aim of this study was to determine if PA is a risk factor for pancreatic cancer. METHODS: This study is a retrospective cohort study using The Health Improvement Network database, which contains comprehensive health information on 7.5 million patients in the United Kingdom from 1993 to 2009. All patients with PA in the study cohort were identified and composed of the exposed group. Each exposed patient was matched on practice site, sex, and age with up to 4 unexposed patients without PA. The outcome was incident pancreatic cancer. The hazard ratio and 95% confidence intervals were estimated using multivariable Cox regression analysis. RESULTS: We identified 15,324 patients with PA and 55,094 unexposed patients. Mean follow-up time was similar between groups (exposed 4.31 [SD, 3.38] years, unexposed 4.63 [SD, 3.44] years). The multivariable adjusted hazard ratio for pancreatic cancer associated with PA was 1.16 (95% confidence interval, 0.77-1.76; P = 0.47). CONCLUSIONS: There is no significant association between PA and the risk of pancreatic cancer.

BACKGROUND: Children are frequently prescribed medication 'off-label', meaning there has not been sufficient testing of the medication to determine its safety or effectiveness. The main reason this safety knowledge is lacking is due to ethical restrictions that prevent children from being included in the majority of clinical trials. OBJECTIVE: The objective of this paper is to investigate whether an ensemble of simple study designs can be implemented to signal acutely occurring side effects effectively within the paediatric population by using historical longitudinal data. The majority of pharmacovigilance techniques are unsupervised, but this research presents a supervised framework. METHODS: Multiple measures of association are calculated for each drug and medical event pair and these are used as features that are fed into a classifier to determine the likelihood of the drug and medical event pair corresponding to an adverse drug reaction. The classifier is trained using known adverse drug reactions or known non-adverse drug reaction relationships. RESULTS: The novel ensemble framework obtained a false positive rate of 0.149, a sensitivity of 0.547 and a specificity of 0.851 when implemented on a reference set of drug and medical event pairs. The novel framework consistently outperformed each individual simple study design. CONCLUSION: This research shows that it is possible to exploit the mechanism of causality and presents a framework for signalling adverse drug reactions effectively.

RATIONALE: Autism spectrum disorders (ASDs) affect 1 % of children, having significant impact on health and social outcomes. Psychotropic medication use by individuals with ASD in the USA increased over time, and polypharmacy occurred in >50 % of those prescribed. In the UK, no psychotropic drugs are approved in ASDs, and little is known about patterns of pharmacological treatment in the ASD population and associated co-morbidities. METHODS: We used The Health Improvement Network, a nationally representative primary care database, to assess the prevalence of ASD diagnoses, psychotropic drug prescribing and neuropsychiatric co-morbidities of 0-24 year olds between 1992 and 2008. RESULTS: ASD prevalence increased 65-fold from 0.01 % (1992) to 0.50 % (2008). Psychotropic drugs were prescribed to 29 % (1,619/5,651) of the ASD cohort; the most prescribed drugs were sleep medication (9.7 % of prescribed patients), psychostimulants (7.9 %) and antipsychotics (7.3 %). More patients were given psychostimulants and sleep medications over time from 1.5-6.3 % and 2.2-5.9 % respectively. Thirty-seven per cent of the cohort had ≥ 1 record of a neuropsychiatric co-morbidity, the most common being developmental difficulties and learning disabilities (12.6 %), behavioural, conduct and personality disorders (11.1 %) and attention deficit hyperactivity disorder (7.5 %). CONCLUSIONS: British physicians are more conservative in prescribing practice than American colleagues. However, use of psychostimulants and antipsychotics is much higher in those with ASD than in the general population. Polypharmacy was seen in 34 % of prescribed patients in 2008. Additional studies examining use, efficacy, and long-term safety of antipsychotics and psychostimulants in autistic individuals are warranted.

BACKGROUND: Guidance in England and Wales recommends that nicotine replacement therapies (NRTs), varenicline or bupropion should be offered for smoking cessation support. Research on general practitioner (GP) NRT prescribing patterns for smoking cessation is lacking in the published literature. METHODS: UK primary care electronic health records were retrospectively analysed to identify the most common GP initiated NRT prescribing patterns, characterise people who receive NRT and determine whether NRTs given in a first quit attempt are different from subsequent attempts. RESULTS: The study population comprised 38,954 individuals in UK primary care data with a first ever NRT patch smoking cessation attempt for the period January 2008-December 2011. The majority (64.3%) received NRT patch monotherapy at first smoking cessation attempt, and the most common NRT was 21 mg/24 hours patch monotherapy (15.2%). Of the 35.7% first smoking cessation attempts which were NRT combination therapy, the most common combination was patch + inhalator (56.2%). The proportion of people who started a smoking cessation attempt with combination therapy increased from 25.7% in 2008 to 44.8% in 2011. The majority of the population had one recorded smoking cessation attempt but a significant minority (20.2% N = 7,868) started a second smoking cessation attempt. Second and third attempts, while predominantly patch monotherapy, also demonstrated an increasing use of NRT combinations over the study period (2ndepisode: 20.6%-38.2%; 3rdepisode: 20.0%-36.8%). However, a minority received only non-patch NRT during second and third NRT episodes. Taking into account the 39,068 people prescribed NRT patch during the study period with a history of NRT at baseline (excluded from the analysis), the total proportion of people prescribed NRT patch between 2008-2011 who had more than one NRT episode was 48.4% (46,936/96,986) and of 128,115 NRT users, only 14.7% (N = 18,838) were prescribed bupropion or varenicline prior to NRT use. CONCLUSIONS: The study findings represent new data describing GP NRT prescription patterns in the UK. Given the predominance of NRT patch monotherapy observed, health policy makers and service commissioners should ensure that GPs provide equality of access to all recommended smoking cessation pharmacotherapies.

Little is known about the incidence of rotator cuff pathology or its demographic associations in the general population. We undertook a large epidemiological study of rotator cuff pathology in the United Kingdom using The Health Improvement Network (THIN) database. The incidence of rotator cuff pathology was 87 per 100,000 person-years. It was more common in women than in men (90 cases per 100,000 person-years in women and 83 per 100,000 person-years in men; p < 0.001). The highest incidence of 198 per 100,000 person-years was found in those aged between 55 and 59 years. The regional distribution of incidence demonstrated an even spread across 13 UK health authorities except Wales, where the incidence was significantly higher (122 per 100,000 person-years; p < 0.001). The lowest socioeconomic group had the highest incidence (98 per 100,000 person-years). The incidence has risen fourfold since 1987 and as of 2006 shows no signs of plateauing. This study represents the largest general population study of rotator cuff pathology reported to date. The results obtained provide an enhanced appreciation of the epidemiology of rotator cuff pathology and may help to direct future upper limb orthopaedic services.

BACKGROUND: Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant genetic disorder of aberrant blood vessel development characterised by arteriovenous malformations. HHT is associated with significant morbidity due to complications including epistaxis, gastrointestinal bleeding and stroke. We explored the hypothesis that a diagnosis of HHT is associated with sex, socioeconomic status and geographical location. METHODS: We used The Health Improvement Network, a longitudinal, computerised general practice database covering 5% of the UK population to calculate prevalence estimates for HHT stratified by age, sex, socioeconomic status and geographical location. RESULTS: The 2010 UK point prevalence for HHT was 1.06/10 000 person years (95% CI 0.95 to 1.17) or 1 in 9400 individuals. The diagnosed prevalence of HHT was significantly higher in women compared with men (adjusted prevalence rate ratio (PRR) 1.53, 95% CI 1.24 to 1.88) and in those from the most affluent socioeconomic group compared with the least (adjusted PRR 1.74, 95% CI 1.14 to 2.64). The PRR varied between different regions of the UK, being highest in the South West and lowest in the West Midlands (adjusted PRR for former compared with latter 1.86, 95% CI 1.61 to 2.15). CONCLUSIONS: HHT prevalence is more common in the UK population than previously demonstrated, though this updated figure is still likely to be an underestimate. HHT appears to be significantly under-diagnosed in men, which is likely to reflect their lower rates of consultation with primary care services. There is under-diagnosis in patients from lower socioeconomic groups and a marked variation in the prevalence of diagnosis between different geographical regions across the UK that requires further investigation.

OBJECTIVES To develop and validate algorithms to identify new users of long-acting reversible contraceptives (LARCs) in a primary care database, The Health Improvement Network (THIN). METHODS Women in THIN aged 12 to 49 years in 2005 were studied. THIN was searched using Read and MULTILEX codes to identify new users of copper intrauterine devices (Cu-IUDs), the levonorgestrel-releasing intrauterine system (LNG-IUS) and progestogen-only implants. Validation was undertaken for a randomly selected sample of 398 LARC users, in which their primary care physicians were asked to complete a questionnaire detailing LARC use. RESULTS Questionnaires were received for 379 patients (95%), confirming 316 (83%) as new LARC users. Confirmation rates for Cu-IUDs, the LNG-IUS and progestogen-only implants were 64%, 94% and 89%, respectively. The use of Read codes alone had the lowest confirmation rate, particularly for Cu-IUD users. Confirmation rates increased by using MULTILEX codes when available, or by examination of computerised medical records. CONCLUSIONS Computer algorithms were used to identify new LARC users. While THIN is a useful resource for studying LARC uptake, steps to gather additional information are necessary to ensure the validity of LARC classification.

BACKGROUND: United Kingdom (UK) national guidelines recommend that all pregnant women who smoke should be advised to quit at every available opportunity, and brief cessation advice is an efficient and cost-effective means to increase quit rates. The Quality and Outcomes Framework (QOF) implemented in 2004 requires general practitioners to document their delivery of smoking cessation advice in patient records. However, no specific targets have been set in QOF for the recording of this advice in pregnant women. We used a large electronic primary care database from the UK to quantify the pregnancies in which women who smoked were recorded to have been given smoking cessation advice, and the associated maternal characteristics. METHODS: Using The Health Improvement Network database we calculated annual proportions of pregnant smokers between 2000 and 2009 with cessation advice documented in their medical records during pregnancy. Logistic regression was used to assess variation in the recording of cessation advice with maternal characteristics. RESULTS: Among 45,296 pregnancies in women who smoked, recorded cessation advice increased from 7% in 2000 to 37% in 2004 when the QOF was introduced and reduced slightly to 30% in 2009. Pregnant smokers from the youngest age group (15-19) were 21% more likely to have a record of cessation advice compared to pregnant smokers aged 25-29 (OR 1.21, 95% CI 1.10-1.35) and pregnant smokers from the most deprived group were 38% more likely to have a record for cessation advice compared to pregnant smokers from the least deprived group (OR 1.38, 95% CI 1.14-1.68). Pregnant smokers with asthma were twice as likely to have documentation of cessation advice in their primary care records compared to pregnant smokers without asthma (OR 1.97, 95% CI 1.80-2.16). Presence of comorbidities such as diabetes, hypertension and mental illness also increased the likelihood of having smoking cessation advice recorded. No marked variations were observed in the recording of cessation advice with body mass index. CONCLUSION: Recorded delivery of smoking cessation advice for pregnant smokers in primary care has increased with some fluctuation over the years, especially after the implementation of the QOF, and varies with maternal characteristics.

BACKGROUND: The aim of this study was to assess sex differences in major congenital anomaly (CA) diagnoses within a national population sample; to examine the influence of sociodemographic and maternal factors on these risks; and to conduct a meta-analysis using estimates from other population-based studies. METHODS: We conducted a population-based study in a United Kingdom research database of prospectively collected primary care data (The Health Improvement Network) including children born 1990 to 2009 (n = 794,169) and identified major CA diagnoses using EUROCAT (European Surveillance of Congenital Anomalies) classification. Prevalence ratios (PR) were used to estimate the risk of CA in males compared with females for any CA, system-specific subgroups and specific CA diagnoses. In a subpopulation of children whose medical records were linked to their mothers', we assessed the effect of adjusting for sociodemographic and maternal factors on sex odds ratios. PRs were pooled with measures from previously published studies. RESULTS: The prevalence of any CA was 307/10,000 in males (95% CI, 302-313) and 243/10,000 in females (95% CI, 238-248). Overall the risk of any CA was 26% greater in males (PR (male: female) 1.26, 95% CI, 1.23-1.30) however there was considerable variation across specific diagnoses. The magnitude and direction of risk did not change for any specific CA upon adjustment for sociodemographic and maternal factors. Our PRs were highly consistent with those from previous studies. CONCLUSION: The overall risk of CA is greater in males than females, although this masked substantial variation by specific diagnoses. Sociodemographic and maternal factors do not appear to affect these risks.

PURPOSE: To develop a method to identify incident diabetes mellitus (DM) using an electronic medical records (EMR) database and test this classification by comparing incident and prevalent DM with common outcomes related to DM duration. METHODS: Incidence rates (IRs) of DM (defined as a first diagnosis or prescription) were measured in 3-month intervals through 36 months after registration in The Health Improvement Network, a primary care database, from 1994 to 2012. We used Joinpoint regression to identify the point where a statistically significant change in the trend of IRs occurred. Further analyses used this point to distinguish those likely to have incident (n = 50 315) versus prevalent (n = 28 337) DM. Incident and prevalent cohorts were compared using Cox regression for all-cause mortality, cardiovascular disease (CVD), diabetic retinopathy, diabetic nephropathy, and diabetic neuropathy. Analyses were adjusted for age, sex, smoking, obesity, hyperlipidemia, hypertension, and calendar year. RESULTS: Trends in DM IRs plateaued 9 months after registration (p = 0.04). All cause-mortality was increased (hazard ratio (HR) 1.62, 95% CI 1.53-1.70) among patients diagnosed with DM prior to 9 months following registration (prevalent DM) compared to those diagnosed after 9 months (incident DM). Similarly, the risk of DM-related complications was higher in prevalent versus incident DM patients [CVD, HR 2.24 (2.08-2.40); diabetic retinopathy, HR 1.31 (1.24-1.38); diabetic nephropathy, HR 2.30 (1.95-2.72); diabetic neuropathy, HR 1.28 (1.16-1.41)]. CONCLUSION: Joinpoint regression can be used to identify patients with newly diagnosed diabetes within EMR data. Failure to exclude patients with prevalent DM can lead to exaggerated associations of DM-related outcomes.

OBJECTIVE: The objective of this study was to evaluate the incidence of diabetes among patients with PsA and RA in the general population. METHODS: We conducted a cohort study using an electronic medical records database representative of the UK general population (1986-2010). We estimated hazard ratios (HRs) for incident diabetes in PsA, psoriasis and RA cohorts compared with age- and sex-matched comparison cohorts without the corresponding conditions, adjusting for BMI, smoking, alcohol use, co-morbidities and glucocorticoids at baseline. RESULTS: Cohorts included 4196 persons with PsA, 59 281 with psoriasis and 11 158 with RA, with mean follow-up times of 5.9, 5.8 and 5.5 years, respectively. Incidence rates for diabetes were 7.3, 6.4 and 6.3 cases per 1000 person-years among individuals with PsA, psoriasis and RA, respectively. Age- and sex-matched HRs for diabetes were 1.72 (95% CI 1.46, 2.02) in PsA, 1.39 (95% CI 1.32, 1.45) in psoriasis and 1.12 (95% CI 1.01, 1.25) in RA. After adjustment for BMI, smoking and alcohol, the HRs were attenuated substantially (1.43, 1.24 and 1.00, respectively). With further adjustment for baseline glucocorticoid use and co-morbidities, the HRs were 1.33 (1.09, 1.61) in PsA, 1.21 (1.15, 1.27) in psoriasis and 0.94 (0.84, 1.06) in RA. CONCLUSION: This general population study suggests an increased incidence of diabetes in PsA and RA, which is substantially explained by obesity and lifestyle factors. These findings support the importance of managing such factors in PsA and RA patients.

This study evaluated the risk of cardiovascular events associated with the use of proton pump inhibitors (PPIs) in new users of acetylsalicylic acid (ASA) for the secondary prevention of cardiovascular events. Two cohorts of patients aged 50-84 years were identified from UK primary care databases: individuals with a first prescription for ASA (75-300 mg/day) for secondary prevention of cardiovascular events (n = 39,513; CVD cohort) or with a record of hospitalisation for an acute coronary event (n = 42,542; ACS cohort) in 2000-2007. Cases of non-fatal myocardial infarction (MI) and coronary death were identified: 1,222 in the CVD cohort and 604 among new users of ASA in the ACS cohort. A nested case-control analysis estimated the relative risk (RR) of non-fatal MI or coronary death associated with use vs non-use of PPI therapy. Current continuous use of PPI therapy was not associated with a significant increase in RR overall: in the CVD cohort (RR = 1.14 [95% confidence interval = 0.91-1.43]); in the ACS cohort (0.88 [0.66-1.18]); or among current continuous users of ASA as antiplatelet monotherapy (CVD cohort: 1.15 [0.80-1.66]; ACS cohort: 0.73 [0.43-1.23]; pooled analysis of both cohorts: 0.96 [0.62-1.48]). In conclusion, among first-time users of ASA for the secondary prevention of cardiovascular events, PPI use was not shown to be associated with an increased risk of non-fatal MI or coronary death.

OBJECTIVE: To determine prescription contraceptive use in the UK. DESIGN: Observational study using a primary care database. SETTING: The Health Improvement Network (THIN). POPULATION: Women in THIN aged 12-49 years in 2008, registered with their primary care doctor for at least 5 years, and with a prescription history of at least 1 year were included. METHODS: THIN was searched using the Read and MULTILEX codes for the following methods: combined oral contraceptives (COCs), progestogen-only pills (POPs), copper intrauterine devices (Cu-IUDs), the levonorgestrel-releasing intrauterine system (LNG-IUS), progestogen-only implants, progestogen-only injections, and contraceptive patches. MAIN OUTCOME MEASURES: Prevalence, switching, and duration of prescriptions. RESULTS: A cohort of 194 054 women was identified. The prevalence of contraceptive use was: COCs, 16.2% (95% confidence interval, 95% CI 16.1-16.3%); POPs, 5.6% (95% CI 5.5-5.6%); Cu-IUD, 4.5% (95% CI 4.4-4.5%); LNG-IUS, 4.2% (95% CI 4.1-4.2%); progestogen-only implants, 1.5% (95% CI 1.5-1.6%); progestogen-only injections, 2.4% (95% CI 2.3-2.4%); and contraceptive patches, 0.1% (95% CI 0.1-0.2%). Within 1 year, 9.8% of new COC users switched to alternative COCs, and 9.0% changed to a different method. Among new COC users who did not switch method, 34.8% did not continue use beyond 3 months, and were no longer using a prescription contraceptive. CONCLUSIONS: Among users of oral contraceptives who did not switch method, over one-third did not continue use beyond 3 months. This supports current UK guidelines recommending a follow-up consultation with a healthcare professional 3 months after the first prescription of COCs.