Scientific
publications

INTRODUCTION: Uric acid is the most abundant molecule with antioxidant properties found in human blood serum. We examined the relationship between serum uric acid and the incidence of respiratory disease including any effect modification by smoking status. METHODS: A cohort with serum uric acid measured between 1 January 2000 and 31 December 2012 was extracted from The Health Improvement Network primary care research database. New diagnoses of COPD and lung cancer were ascertained based on diagnostic codes entered into the medical records. RESULTS: During 1 002 496 person years (PYs) of follow-up, there were 3901 COPD diagnoses and 1015 cases of lung cancer. After multivariable adjustment, strong interactions with smoking status were detected (p<0.001) for both outcomes with significant negative relationships between serum uric acid and respiratory disease for current smokers but no strong relationships for never-smokers or ex-smokers. The relationships were strongest for lung cancer in heavy smokers (≥20 cigarettes per day) with predicted incidence rates 97 per 10 000 PYs (95% CI 68 to 126) in the lowest serum uric acid quintile (100-250 µmol/L) compared with a predicted 28 per 10 000 PYs (95% CI 14 to 41) in the highest quintile (438-700 µmol/L). CONCLUSIONS: Low levels of serum uric acid are associated with higher rates of COPD and lung cancer in current smokers after accounting for conventional risk factors.

INTRODUCTION: Stroke is a major health problem and transient ischaemic attack (TIA) is an important risk factor for stroke. Primary prevention of stroke and TIA will have the greatest impact on reducing the burden of these conditions. Evidence-based guidelines for stroke/TIA prevention identify individuals eligible for preventative interventions in primary care. This study will investigate: (1) the proportion of strokes/TIAs with prior missed opportunities for prevention in primary care; (2) the influence of patient characteristics on missed prevention opportunities and (3) how the proportion of missed prevention opportunities has changed over time. METHODS AND ANALYSIS: A retrospective case review will identify first-ever stroke and patients with TIA between 2000 and 2013 using anonymised electronic medical records extracted from the health improvement network (THIN) database. Four categories of missed opportunities for stroke/TIA prevention will be sought: untreated high blood pressure in patients eligible for treatment (either blood pressure ≥160/100 or ≥140/90 mm Hg in patients at high cardiovascular disease (CVD) risk); patients with atrial fibrillation with high stroke risk and no anticoagulant therapy; no lipid modifying drug therapy prescribed in patients at high CVD risk or with familial hypercholesterolaemia. The proportion of patients with each missed opportunity and multiple missed opportunities will be calculated. Mixed effect logistic regression will model the relationship between demographic and patient characteristics and missed opportunities for care; practice will be included as a random effect. ETHICS AND DISSEMINATION: THIN data collection was approved by the NHS South East Multi-centre Research Ethics Committee (MREC) in 2003. This study was approved by the independent scientific review committee in May 2013. Dissemination of findings has the potential to change practice, improve the quality of care provided to patients and ultimately reduce the incidence of strokes and TIAs. Findings will be published in a peer-reviewed journal and disseminated at national and international conferences.

BACKGROUND: We investigated the association between hemorrhagic stroke and migraine using data from The Health Improvement Network database. FINDINGS: We ascertained 1,797 incident cases of intracerebral hemorrhage (ICH) and 1,340 of subarachnoid hemorrhage (SAH). Density-based sampling was used to select 10,000 controls free from hemorrhagic stroke. Using unconditional logistic regression models, we calculated the risk of hemorrhagic stroke associated with migraine, adjusting for age, sex, calendar year, alcohol, body mass index, hypertension, previous cerebrovascular disease, oral contraceptive use, and health services utilization.The risk (odds ratio [OR]) of ICH among migraineurs was 1.2 (95% confidence interval [CI] 0.9-1.5), and of SAH was (1.2, 95% CI 0.9-1.5). The association with ICH was stronger for migraine diagnosed ≥20 years prior to ICH (OR 1.6, 95% CI 1.0-2.4), but not with SAH (OR 1.1, 95% CI 0.6-2.1). In analyses stratified by migraine type and gender, the OR of ICH in women with migraine with aura was 1.7 (95% CI 0.9-3.4) and the corresponding OR of SAH in women was 1.2 (95% CI 0.6-2.3). CONCLUSION: No clear increased risk of ICH or SAH was observed in migraineurs.

OBJECTIVE: To estimate risks of major congenital anomaly (MCA) among children of mothers prescribed antidepressants during early pregnancy or diagnosed with depression but without antidepressant prescriptions. DESIGN: Population-based cohort study. SETTING: Linked UK maternal-child primary care records. POPULATION: A total of 349,127 singletons liveborn between 1990 and 2009. METHODS: Odds ratios adjusted for maternal sociodemographics and comorbidities (aORs) were calculated for MCAs, comparing women with first-trimester selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs) and women with diagnosed but unmedicated depression, or women without diagnosed depression. MAIN OUTCOME MEASURES: Fourteen system-specific MCA groups classified according to the European Surveillance of Congenital Anomalies and five specific heart anomaly groups. RESULTS: Absolute risks of MCA were 2.7% (95% confidence interval, 95% CI, 2.6-2.8%) in children of mothers without diagnosed depression, 2.8% (95% CI 2.5-3.2%) in children of mothers with unmedicated depression, and 2.7% (95% CI 2.2-3.2%) and 3.1% (95% CI 2.2-4.1%) in children of mothers with SSRIs or TCAs, respectively. Compared with women without depression, MCA overall was not associated with unmedicated depression (aOR 1.07, 95% CI 0.96-1.18), SSRIs (aOR 1.01, 95% CI 0.88-1.17), or TCAs (aOR 1.09, 95% CI 0.87-1.38). Paroxetine was associated with increased heart anomalies (absolute risk 1.4% in the exposed group compared with 0.8% in women without depression; aOR 1.78, 95% CI 1.09-2.88), which decreased marginally when compared with women with diagnosed but unmedicated depression (aOR 1.67, 95% CI 1.00-2.80). CONCLUSIONS: Overall MCA risk did not increase with maternal depression or with antidepressant prescriptions. Paroxetine was associated with increases of heart anomalies, although this could represent a chance finding from a large number of comparisons undertaken.

PURPOSE: Cardiac glycosides affect several pathways central for tumor formation. We sought to evaluate the association between digoxin use and colorectal cancer (CRC) risk. METHODS: We conducted a nested case-control study using The Health Improvement Network (THIN), a medical record database representative of the broader UK population. Study cases were defined as those with a diagnostic code for CRC. Each case was matched to up to four eligible controls on age, sex, practice site, and duration of follow-up before index date using incidence density sampling. Exposure of interest was digoxin therapy before index date. The odds ratios (ORs) and 95% confidence intervals (CIs) for CRC associated with digoxin use were estimated using conditional logistic regression analysis, adjusted for BMI, alcoholism, smoking history, diabetes mellitus, heart disease, chronic NSAIDs use and previous screening colonoscopies. RESULTS: The case-control analysis included 20 990 CRC patients and 82 054 controls whose mean follow-up time before index date was 6.5 years (SD 4.0). The adjusted OR for CRC among current digoxin users was increased compared with non-users with an adjusted ORs of 1.41 (95%CI 1.25-1.59, p < 0.0001), 1.45 (95%CI 1.22-1.72, p < 0.0001) and 1.41 (95%CI 1.00-1.99, p = 0.049) for first prescriptions 1-5 years, 5-10 years and more than 10 years before index date respectively. Similar results were observed when cumulative duration and number of digoxin prescriptions were analyzed. The risk was not elevated for past digoxin users. CONCLUSIONS: Current digoxin use is associated with increased CRC risk.

OBJECTIVES: Pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancers (BTC) are often diagnosed late and at an advanced stage. Population-based screening programmes do not exist and diagnosis is primarily dependent on symptom recognition. Recently symptom-based cancer decision support tools (CDSTs) have been introduced into primary care practices throughout the UK to support general practitioners (GPs) in identifying patients with suspected PDAC. However, future refinement of these tools to improve their diagnostic accuracy is likely to be necessary. SETTING: The Health Improvement Network (THIN) is a primary care database, which includes more than 11 million electronic patient records, from 562 GP practices in the UK. PARTICIPANTS: All patients with a diagnosis of PDAC or BTC between 2000 and 2010 were included in the study along with six matched controls; 2773 patients with PDAC, 848 patients with BTC and 15,395 controls. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary aim of this study was to determine the early symptom profiles of PDAC and BTC. Secondary aims included comparing early symptom trends between BTC and PDAC, defining symptom onset in PDAC and evaluating trends in routine blood tests nearest to the time of diagnosis. RESULTS: In the year prior to diagnosis, patients with PDAC visited their GP on a median of 18 (IQR 11-27) occasions. PDAC was associated with 11 alarm symptoms and BTC with 8. Back pain (OR 1.33 (95% CI 1.18 to 1.49) p<0.001), lethargy (1.42 (95% CI 1.25 to 1.62) p<0.001) and new onset diabetes (OR 2.46 (95% CI 2.16 to 2.80)) were identified as unique features of PDAC. CONCLUSIONS: PDAC and BTC are associated with numerous early alarm symptoms. CDSTs are therefore likely to be useful in identifying these tumours at an early stage. Inclusion of unique symptoms, symptoms with an early onset and routinely performed blood tests is likely to further improve the sensitivity of these tools.

BACKGROUND: Varenicline is probably the most effective smoking cessation pharmacotherapy, but is less widely used than nicotine replacement therapy. We therefore set out to identify the characteristics of numerically important groups of patients who typically do, or do not, receive varenicline in the UK. METHODS: We used association rule mining to analyse data on prescribing of smoking cessation pharmacotherapy in relation to age, sex, comorbidity and other variables from 477,620 people aged 16 years and over, registered as patients throughout 2011 with one of 559 UK general practices in The Health Improvement Network (THIN) database, and recorded to be current smokers. RESULTS: 46,685 participants (9.8% of all current smokers) were prescribed any smoking cessation treatment during 2011, and 19,316 of these (4% of current smokers, 41% of those who received any therapy) were prescribed varenicline. Prescription of varenicline was most common among heavy smokers aged 31-60, and in those with a diagnosis of COPD. Varenicline was rarely used among smokers who were otherwise in good health, or were aged over 60, were lighter smokers, or had psychotic disorders or dementia. CONCLUSIONS: Varenicline is being underused in healthy smokers, or in older smokers, and in those with psychotic disorders or dementia. Since varenicline is probably the most effective available single cessation therapy, this study identifies under-treatment of substantial public health significance.