Health Improvement Network Primary Care Research Articles

Prescribing of antipsychotics among people with recorded personality disorder in primary care: a retrospective nationwide cohort study using The Health Improvement Network primary care database

ObjectivesTo investigate the extent of antipsychotic prescribing to people with recorded personality disorder (PD) in UK primary care and factors associated with such prescribing.DesignRetrospective cohort study.SettingGeneral practices contributing to The...

P.514 Contribution of polymorphic variants of MAO genes into prolactin levels in patients with schizophrenia under risperidone therapy

A recent United Kingdom (UK) report found that breast and colorectal cancers were more common in people with severe mental illness (SMI) and recommended targeted screening. Epidemiological evidence is however inconsistent.To estimate relative incidence rates for colorectal, breast and lung cancer, and the overall incidence of the commonest other UK cancers, in people with SMI compared with people without SMI.Cohort study in the UK using The Health Improvement Network (THIN) primary care database between 1990 and June 2008. Poisson regression was used to obtain adjusted incidence rate ratios (IRRs) for cancer, comparing two cohorts of people over 18; with and without a diagnosis of SMI.We identified 20,632 people with SMI and 116,152 people without, with median follow up of over 6 years. No significant associations were observed between SMI and cancers of the breast (adjusted IRR 1.17; 95% confidence interval 0.95–1.45), colon (0.70; 0.46–1.05), rectum (1.05; 0.65–1.69) or lung (0.84; 0.65–1.10). The adjusted IRR for an aggregate cancer outcome in SMI was 0.95; 0.85–1.06. Results were similar for schizophrenia and bipolar disorder.In a cohort analysis within a large UK primary care database, the incidence of colo-rectal, breast and lung cancer, and of all common cancers, did not differ significantly in people with SMI, including schizophrenia, compared with people without SMI. Our results do not support enhanced screening procedures for cancer in people with SMI.

Postnatal checks and primary care consultations in the year following childbirth: an observational cohort study of 309 573 women in the UK, 2006–2016

ObjectiveTo describe women’s uptake of postnatal checks and primary care consultations in the year following childbirth.DesignObservational cohort study using electronic health records.SettingUK primary care.ParticipantsWomen aged 16–49 years who had given...

PDB41 HOW MUCH DOES THERAPEUTIC INERTIA IN TYPE 2 DIABETES COST THE UK? A MODELING EVALUATION OF ECONOMIC BURDEN

Several publications have described the challenge of therapeutic inertia, specifically the failure to intensify therapy to address poor glycemic control in a timely manner, in patients with type 2 diabetes in the UK. The aim of this modeling analysis was to quantify the economic burden of poor glycemic control due to therapeutic inertia in the UK. A published model of type 2 diabetes (IQVIA CORE Diabetes Model) was used to predict the cost of diabetes-related complications and lost productivity for a population with type 2 diabetes. Population characteristics were based predominantly on data from The Health Improvement Network primary care database. Complication rates, mortality and costs were estimated for populations at different levels of glycemic control across a range of delayed treatment intensification scenarios and time horizons. All costs were derived from published sources and expressed in 2017 British Pounds Sterling (GBP). Published estimates of patients failing to meet glycemic control targets in the UK were used, along with epidemiological data, to evaluate the population level burden (approximately 1,163,547 patients with type 2 diabetes were considered to have poor glycemic control). Therapeutic inertia leading to 3 years of poor glycemic control (HbA1c 8.2%, 66 mmol/mol) was projected to increase the cost of complications by GBP 122 million and add GBP 930 million to lost productivity costs compared with good glycemic control (HbA1c 7.0%, 53 mmol/mol) over a 3-year time horizon. The corresponding values assuming 5 years of poor control were GBP 275 million (complication costs) and GBP 1,903 million (lost productivity), making an additional burden of GBP 2,178 million in total due to poor glycemic control at a 5-year time horizon. The economic burden associated with poor glycemic control in type 2 diabetes in the UK is substantial even in the short term.

Trends in oral anticoagulant prescribing in individuals with type 2 diabetes mellitus: a population-based study in the UK

ObjectiveTo evaluate oral anticoagulant (OAC) prescribing trends in type 2 diabetes mellitus (T2DM) in the UK from 2001 to 2015.DesignA cross-sectional drug utilisation study.SettingElectronic health records from The Health Improvement...

Social Inequalities in Life Expectancy and Mortality in People With Dementia in the United Kingdom.

Inequalities in life expectancy and mortality by social deprivation in the general population of the United Kingdom are widening. For people with dementia, data on potential gradients in life expectancy and mortality by social deprivation are sparse. This study aimed to explore potential differentials in life expectancy and mortality in people with dementia according to social deprivation. Using The Health Improvement Network (THIN) primary care database, we included people with a diagnosis of dementia in the United Kingdom in 2000 to 2016 and obtained data on age at death and mortality. Comparisons were made according to social deprivation quintiles adjusting for age at diagnosis. Among 166,268 people with dementia there were no differences in life expectancy and mortality in the most deprived compared with the least deprived. This pattern has been stable during the study period, as no increasing inequalities in life expectancy and mortality according to social deprivation were found. Contrary to the general population, there were limited inequalities in life expectancy and mortality according to social deprivation for people with dementia.

Cigarette smoking as a risk factor for schizophrenia or all non-affective psychoses.

Smoking tobacco is regarded as an epiphenomenon in patients with schizophrenia when it may be causal. We aimed to examine whether smoking status is related to the onset of schizophrenia or the broader diagnosis of non-affective psychosis, including schizophrenia. We used data from The Health Improvement Network primary care database to identify people aged 15-24 between 1 January 2004 and 31 December 2009. We followed them until the earliest of: first diagnosis of schizophrenia (or psychosis), patient left the practice, practice left THIN, patient died or 31 December 2014. In men, incidence rates for schizophrenia per 100 000 person years at risk were higher in smoking initiators (non-smoker who became a smoker during the study) than in non-smokers (adjusted IRR 1.94; 95% CI 1.29-2.91) and higher still in smokers (adjusted IRR 3.32; 95% CI 2.67-4.14). Among women, the incidence rate of schizophrenia was higher in smokers than in non-smokers (adjusted IRR 1.50; 95% CI 1.06-2.12), but no higher in smoking initiators than non-smokers. For non-affective psychosis, the pattern was similar for men but more evident in women where psychosis incidence rates were higher in smoking initiators (adjusted IRR 1.90; 95% CI 1.40-2.56) and in smokers (adjusted IRR 2.13; 95% CI 1.76-2.57) than in non-smokers. We found an important and strong association between smoking and incidence of schizophrenia. Smoking may increase risk through as yet unknown pathways or smoking may share genetic risk with schizophrenia and non-affective psychoses.

Impact of bariatric surgery on cardiovascular outcomes and mortality: a population-based cohort study.

Cohort studies have shown that bariatric surgery may reduce the incidence of and mortality from cardiovascular disease (CVD), but studies using real-world data are limited. This study examined the impact of bariatric surgery on incident CVD, hypertension and atrial fibrillation, and all-cause mortality. A retrospective, matched, controlled cohort study of The Health Improvement Network primary care database (from 1 January 1990 to 31 January 2018) was performed (approximately 6 per cent of the UK population). Adults with a BMI of 30 kg/m2 or above who did not have gastric cancer were included as the exposed group. Each exposed patient, who had undergone bariatric surgery, was matched for age, sex, BMI and presence of type 2 diabetes mellitus (T2DM) with two controls who had not had bariatric surgery. A total of 5170 exposed and 9995 control participants were included; their mean(s.d.) age was 45·3(10·5)years and 21·5 per cent (3265 of 15 165 participants) had T2DM. Median follow-up was 3·9 (i.q.r. 1·8- 6·4)years. Mean(s.d.) percentage weight loss was 20·0(13·2) and 0·8(9·5) per cent in exposed and control groups respectively. Overall, bariatric surgery was not associated with a significantly lower CVD risk (adjusted hazard ratio (HR) 0·80; 95 per cent c.i. 0·62 to 1·02; P=0·074). Only in the gastric bypass group was a significant impact on CVD observed (HR 0·53, 0·34 to 0·81; P=0·003). Bariatric surgery was associated with significant reduction in all-cause mortality (adjusted HR 0·70, 0·55 to 0·89; P=0·004), hypertension (adjusted HR 0·41, 0·34 to 0·50; P < 0·001) and heart failure (adjusted HR 0·57, 0·34 to 0·96; P=0·033). Outcomes were similar in patients with and those without T2DM (exposed versus controls), except for incident atrial fibrillation, which was reduced in the T2DM group. Bariatric surgery is associated with a reduced risk of hypertension, heart failure and mortality, compared with routine care. Gastric bypass was associated with reduced risk of CVD compared to routine care.

Ethnic Differences in the Prevalence of Type 2 Diabetes Diagnoses in the UK: Cross-Sectional Analysis of the Health Improvement Network Primary Care Database.

Aims/HypothesisType 2 diabetes mellitus is associated with high levels of disease burden, including increased mortality risk and significant long-term morbidity. The prevalence of diabetes differs substantially among ethnic groups. We examined the prevalence of type 2 diabetes diagnoses in the UK primary care setting.MethodsWe analysed data from 404,318 individuals in The Health Improvement Network database, aged 0–99 years and permanently registered with general practices in London. The association between ethnicity and the prevalence of type 2 diabetes diagnoses in 2013 was estimated using a logistic regression model, adjusting for effect of age group, sex, and social deprivation. A multiple imputation approach utilising population-level information about ethnicity from the UK census was used for imputing missing data.ResultsCompared with those of White ethnicity (5.04%, 95% CI 4.95 to 5.13), the crude percentage prevalence of type 2 diabetes was higher in the Asian (7.69%, 95% CI 7.46 to 7.92) and Black (5.58%, 95% CI 5.35 to 5.81) ethnic groups, while lower in the Mixed/Other group (3.42%, 95% CI 3.19 to 3.66). After adjusting for differences in age group, sex, and social deprivation, all minority ethnic groups were more likely to have a diagnosis of type 2 diabetes compared with the White group (OR Asian versus White 2.36, 95% CI 2.26 to 2.47; OR Black versus White 1.65, 95% CI 1.56 to 1.73; OR Mixed/Other versus White 1.17, 95% CI 1.08 to 1.27).ConclusionThe prevalence of type 2 diabetes was higher in the Asian and Black ethnic groups, compared with the White group. Accurate estimates of ethnic prevalence of type 2 diabetes based on large datasets are important for facilitating appropriate allocation of public health resources, and for allowing population-level research to be undertaken examining disease trajectories among minority ethnic groups, that might help reduce inequalities.

Evaluating the burden of poor glycemic control associated with therapeutic inertia in patients with type 2 diabetes in the UK

Background and aims: Effective glycemic control is the cornerstone of successful type 2 diabetes management. However, many patients fail to reach glycemic control targets, and therapeutic inertia (failure to intensify therapy to address poor glycemic control in a timely manner) has been widely reported. The aim of the present study was to evaluate the economic burden associated with diabetes-related complications due to poor glycemic control for patients with type 2 diabetes in the UK. Methods: A validated long-term model of type 2 diabetes (IQVIA CORE Diabetes Model) was used to project cost outcomes for a UK population with type 2 diabetes, based on data from The Health Improvement Network primary care database, at different levels of glycemic control. Costs associated with diabetes-related complications were accounted in 2017 Pounds Sterling (GBP). Complication costs were estimated for populations achieving different glycated hemoglobin (HbA1c) targets, in a number of delayed treatment intensification scenarios, and across a range of time horizons. Results: For patients with an HbA1c level of 8.2% (66 mmol/mol), 7 years in poor control could increase mean costs associated with diabetes-related complications by over GBP 690 per patient and lead to costs of over GBP 1,500 in lost workplace productivity compared with achieving good glycemic control (HbA1c 7.0%, 53 mmol/mol) over a 10-year time horizon. Based on published estimates of the proportion of type 2 diabetes patients failing to meet glycemic targets in the UK, this corresponds to an additional economic burden of ∼GBP 2,600 million (complication costs plus lost productivity costs). Conclusions: The economic burden of poor glycemic control in type 2 diabetes in the UK is substantial. Efforts to avoid therapeutic inertia could substantially reduce diabetes-related complication costs even in the short-term.

No increased risk of nephrotoxicity associated with 5‐aminosalicylic acid in IBD: a population‐based cohort and nested case‐control study

There is conflicting evidence about nephrotoxicity risk associated with 5-aminosalicylates for treatment of IBD. To determine population-based temporal trends for 5-aminosalicylates and estimated risk of nephrotoxicity associated with 5-aminosalicylate use for ulcerative colitis (UC) and Crohn's disease (CD). Retrospective cohort and nested case-control study, using the Health Improvement Network primary care database linked to hospital discharge coding for patients in England, 1996-2017. Nephrotoxicity risk analysis was a first recorded renal impairment diagnosis adjusted for key variables and was assessed between 2008 and 2017. A total of 35601 patients with prevalent UC or CD were included. The proportion of patients prescribed 5-aminosalicylates fell from 83% in 1996-1999 to 71% in 2012-2015 for UC patients and 64% to 45% for CD patients. Thirty per cent of patients had prolonged 5-aminosalicylate use. Between 2008 and 2017, the incident rate of nephrotoxicity was similar and stable for UC (12.6/1000 person-years) and CD (10.9/1000 person-years) patients. Multivariate analysis showed no evidence for association between current prescription of 5-aminosalicylate and nephrotoxicity in UC or CD patients, comparing≤30days prescription prior to index vs 31-≤180days. However, active disease, disease duration, concomitant cardiovascular disease or diabetes and nephrotoxic drug use were independently associated with development of nephrotoxicity in UC and CD. Despite the paucity of evidence for their benefit, 5-aminosalicylates were prescribed to approximately half of CD patients (30% prolonged therapy). Nephrotoxicity was rare in this patient cohort, and was not associated with 5-aminosalicylate use, but rather with disease status, comorbidity and use of nephrotoxic drugs.

Trends in the incidence of testing for vitamin D deficiency in primary care in the UK: a retrospective analysis of The Health Improvement Network (THIN), 2005–2015

ObjectiveTo investigate trends in the incidence of testing for vitamin D deficiency and the prevalence of patients with circulating concentrations of 25-hydroxyvitamin D (25(OH)D) indicative of deficiency (<30 nmol/L) between...

Elevated Vitamin B12 Levels and Cancer Risk in UK Primary Care: A THIN Database Cohort Study.

Elevated vitamin B12 levels (B12) are associated with increased short-term cancer risk. However, the implications for early cancer detection in primary care have not been assessed. Individuals with plasma B12 measurements were sampled from The Health Improvement Network primary care database, UK. Persons with low B12 levels were excluded together with persons with cancer or B12 treatment before date of B12 measurement. Incident cancer was the outcome of interest and was identified through Read codes. Individuals were disaggregated according to plasma B12 levels (unit: pmol/L): 150-600 (reference range values), 601-800, 801-1,000, and >1,000. Among the 757,185 persons who met the inclusion criteria, we identified 33,367 incident cancers during 2,874,059 years of follow-up. We found a higher 1-year cancer risk among the 25,783 (3.4%) persons with elevated B12 levels compared with those with normal B12 levels. After multivariable adjustment for lifestyle factors and social deprivation, persons with B12 >1,000 pmol/L had a 1-year incidence rate ratio of 4.72 (95% confidence interval: 3.99-5.58). The association showed a nonlinear dose-response pattern, and it remained robust in stratified analyses, including when reducing the risk of confounding by indication in subanalyses. The risks were particularly elevated for liver cancer, pancreas cancer, and myeloid malignancies among persons with elevated B12 levels. Elevated plasma B12 levels were associated with a higher 1-year cancer risk than normal B12 levels among persons seen in UK primary care, suggesting that some cancers may affect B12 metabolism. Elevated B12 may mark occult cancer.

Imported malaria in the UK, 2005 to 2016: Estimates from primary care electronic health records.

ObjectiveTo investigate trends in the incidence of imported malaria in the UK between 2005 and 2016.DesignAnalysis of longitudinal electronic health records (EHRs) in The Health Improvement Network (THIN) primary care database.SettingUK primary careParticipantsIn total, we examined 12,349,003 individuals aged 0 to 99 years.Outcome measureThe rate of malaria recordings in THIN was calculated per year between 2005 and 2016. Rate ratios exploring differences by age, sex, location of general practice, socioeconomic status and ethnicity were estimated using multivariable Poisson regression.ResultsA total of 1,474 individuals with a first diagnosis of malaria were identified in THIN between 2005 and 2016. The incidence of recorded malaria followed a decreasing trend dropping from a rate of 3.33 in 2005 to 1.36 cases per 100,000 person years at risk in 2016. Multivariable Poisson regression showed that adults of working age (20 to 69 years), men, those registered with a general practice in London, higher social deprivation and non-white ethnicity were associated with higher rates of malaria recordings.ConclusionThere has been a decrease in the number of malaria recordings in UK primary care over the past decade. This decrease exceeds the rate of decline reported in national surveillance data; however there are similar associations with age, sex and deprivation. Improved geographic information on the distribution of cases and the potential for automation of case identification suggests that EHRs could provide a complementary role for investigating malaria trends over time.

Relative and Absolute Risk of Tendon Rupture with Fluoroquinolone and Concomitant Fluoroquinolone/Corticosteroid Therapy: Population-Based Nested Case-Control Study.

Background and ObjectiveTendon rupture can result from fluoroquinolone exposure. The objective of this study was to quantify relative and absolute risk and determine how risk is affected by timing of exposure.MethodsThe UK Health Improvement Network primary care database was used to perform a nested case–control study measuring the association between fluoroquinolone exposure and tendon rupture. Adults with tendon rupture were matched on age, sex, general practice and calendar time to four controls selected from a cohort prescribed systemic fluoroquinolone or co-amoxiclav antibiotics. The relative and absolute risk of tendon rupture with fluoroquinolone exposure was calculated.ResultsCurrent fluoroquinolone exposure was associated with an increased risk of any tendon rupture (adjusted incidence rate ratio [aIRR] 1.61, 95% CI 1.25–2.09) and Achilles tendon rupture (aIRR 3.14, 95% CI 2.11–4.65) that persisted for 60 days. Risk increased with cumulative exposure and was greatest when co-prescribed with oral corticosteroids (aIRR 19.36, 95% CI 7.78–48.19 for Achilles tendon rupture). The adjusted rate difference (aRD) with fluoroquinolone exposure was 2.9 and 2.1 per 10,000 patients for any and Achilles tendon rupture, respectively, and was greatest in people aged ≥ 60 years prescribed concomitant oral corticosteroid therapy (aDR 19.6 for any tendon and 6.6 Achilles tendon rupture per 10,000). No association was seen with co-amoxiclav or statin exposure, or with biceps or other tendon ruptures.ConclusionsRisk of tendon rupture with fluoroquinolones depends on timing, cumulative dose and concomitant exposure to oral corticosteroids. Absolute risk significantly varied by age and concomitant corticosteroid exposure, affecting elderly patients the greatest.Electronic supplementary materialThe online version of this article (10.1007/s40261-018-0729-y) contains supplementary material, which is available to authorized users.

Contemporary epidemiology of systemic sclerosis: A population-based cohort study in the United Kingdom

ObjectiveTo estimate the contemporary epidemiology of systemic sclerosis (SSc) in the UK and to explore the validity of using The Health Improvement Network (THIN) primary care database to study SSc. Methods4,520,299 individuals (2000–2012) aged 1–99 years were followed to identify potential incident cases of SSc; potential prevalent cases were identified at start of follow-up. Patient profiles, including free-text comments, were manually reviewed to verify cases of SSc, and case validation was undertaken for a sample (n = 100) using questionnaires to primary care physicians. Incidence, prevalence and mortality rates were calculated. ResultsFollowing manual review, we identified 1321 cases of SSc (689 incident and 632 prevalent) over a mean follow-up of 7.6 years; mean age at diagnosis 59.1 years. Using information from 91/100 valid questionnaires returned, the positive predictive value of SSc diagnoses in THIN following manual review was 94%. Incidence rates of SSc per 100,000 person-years (95% CI) were 2.02 (1.87–2.17) overall, [3.36 (3.09–3.64) in females, 0.61 (0.49–0.74) in males], ranging from 1.53 (1.11–2.06) to 2.56 (1.78–3.56) across calendar years. Prevalence of SSc per 100,000 (95% CI) increased from 17.13 (14.97–19.51) to 25.38 (23.68–27.16) over the study period, and was higher in females. Using Poisson regression, the adjusted mortality rate ratio was 2.82 (95% CI: 2.55–3.13) among SSc cases versus the general population. ConclusionsTHIN enables precise and valid estimates of SSc occurrence to be determined. The observed increase in SSc prevalence has not been driven by increasing incidence.

Incidence of Upper and Lower Gastrointestinal Bleeding in New Users of Low-Dose Aspirin

There are few data on the incidence of upper and lower gastrointestinal bleeding (UGIB and LGIB) from observational studies of low-dose aspirin users. We aimed to estimate incidence rates of UGIB and LGIB in a large cohort of new users of low-dose aspirin in the United Kingdom, with subanalyses of hospitalization status and fatalities. We performed a population-based study of 199,079 new users of low-dose aspirin (median age, 64.0 years) identified from the Health Improvement Network primary care database (2000-2012). Individuals were followed for a median 5.4 years (maximum, 14 years) to identify new cases of UGIB and LGIB. Following multistep validation, we calculated overall and age- and sex-specific incidence rates; we performed subanalyses for health care use and death within 30 days of GIB. We also estimated rates within a matched (1:1) cohort of nonusers of low-dose aspirin at the start of the follow-up period. The low-dose aspirin users had 1115 UGIB events and 1936 LGIB events; most subjects with UGIB events (58.9%) were hospitalized, whereas most subjects with LGIB events were referred to secondary care (72.8%). Crude incidence rates of GIB per 1000 person-years were 0.97 for subjects with UGIB (95% CI, 0.91-1.02) and 1.68 for subjects with LGIB (95% CI, 1.60-1.75). Incidence rates per 1000 person-years for patients hospitalized for GIB were 0.57 for UGIB (95% CI, 0.53-0.61) and 0.45 for LGIB (95% CI, 0.42-0.49); for referred (but not hospitalized) cases, these values were 0.39 for UGIB (95% CI, 0.36-0.43) and 1.22 for LGIB (1.16-1.29). Incidence rates per 1000 person-years were 0.06 for fatal UGIB (95% CI, 0.04-0.07), 0.01 for fatal LGIB (95% CI, 0.01-0.02), 0.91 for nonfatal UGIB (95% CI, 0.86-0.97), and 1.66 for nonfatal LGIB (95% CI, 1.59-1.74). Among nonusers of low-dose aspirin, incidence rates per 1000 person-years were 0.67 (95% CI, 0.63-0.75) for UGIB and 0.76 (95% CI, 0.72-0.82) for LGIB. In a population-based study of low-dose aspirin users, the incidence of LGIB was higher than the incidence of UGIB. However, incidence rates of hospitalized GI bleeds and 30-day mortality rates were lower for LGIB than for UGIB. These estimates are valuable for benefit-risk assessments of low-dose aspirin for cardiovascular and colorectal cancer prevention.

Defining the appropriateness and inappropriateness of antibiotic prescribing in primary care.

To assess the appropriateness of prescribing systemic antibiotics for different clinical conditions in primary care, and to quantify 'ideal' antibiotic prescribing proportions in conditions for which antibiotic treatment is sometimes but not always indicated. Prescribing guidelines were consulted to define the appropriateness of antibiotic therapy for the conditions that resulted in antibiotic prescriptions between 2013 and 2015 in The Health Improvement Network (THIN) primary care database. The opinions of subject experts were then formally elicited to quantify ideal antibiotic prescribing proportions for 10 common conditions. Of the antibiotic prescriptions in THIN, 52.5% were for conditions that could be assessed using prescribing guidelines. Among these, the vast majority of prescriptions (91.4%) were for conditions where antibiotic appropriateness is conditional on patient-specific indicators. Experts estimated low ideal prescribing proportions in acute, non-comorbid presentations of many of these conditions, such as cough (10% of patients), rhinosinusitis (11%), bronchitis (13%) and sore throat (13%). Conversely, antibiotics were believed to be appropriate in 75% of non-pregnant women with non-recurrent urinary tract infection. In impetigo and acute exacerbation of chronic obstructive pulmonary disease, experts clustered into distinct groups that believed in either high or low prescribing. In English primary care, most antibiotics are prescribed for conditions that only sometimes require antibiotic treatment, depending on patient-specific indicators. Experts estimated low ideal prescribing proportions in many of these conditions. Incomplete prescribing guidelines and disagreement about prescribing in some conditions highlight further research needs.

Statins and the Risk of Intracerebral Hemorrhage in Patients With Previous Ischemic Stroke or Transient Ischemic Attack

Although there is no overall association between statin use and intracerebral hemorrhage (ICH), whether there is an increased risk among those with a history of ischemic stroke (IS) or transient ischemic attack (TIA) remains controversial. We evaluated the relationship of preadmission statin use with the risk of ICH in patients with a history of IS or TIA in a population-based cohort. The Health Improvement Network primary care database in the United Kingdom was used to identify new users of low-dose aspirin and a matched comparison. Both cohorts were followed to identify incident cases of ICH, with validation by manual review of patient records and linkage to hospitalization data. In a nested case-control study, we compared the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for ICH based on statin use in the subgroup of individuals with history of IS/TIA. Last statin use within 1 year of ICH (OR, 0.92; 95% CI [confidence interval], 0.60-1.4), last use between 8 days and 1 year (OR, 1.81; 95% CI, 0.99-3.28), and statin use at the time of ICH (OR, 0.77; 95% CI, 0.49-1.21) were not associated with the overall ICH risk among 157 patients with ICH and 884 controls with a history of IS/TIA. There was also no difference in 30-day rates of fatal (OR, 0.82; 95% CI, 0.41-1.64) or nonfatal (OR, 0.90; 95% CI, 0.51-1.57) ICH. Statin use was not associated with an increased risk of ICH among patients with a previous history of IS/TIA.

Development and Validation of an Algorithm to Accurately Identify Atopic Eczema Patients in Primary Care Electronic Health Records from the UK

Electronic health records hold great promise for clinical and epidemiologic research. Undertaking atopic eczema (AE) research using such data is challenging because of its episodic and heterogeneous nature. We sought to develop and validate a diagnostic algorithm that identifies AE cases based on codes used for electronic records used in the UK Health Improvement Network. We found that at least one of five diagnosis codes plus two treatment codes for any skin-directed therapy were likely to accurately identify patients with AE. To validate this algorithm, a questionnaire was sent to the physicians of 200 randomly selected children and adults. The primary outcome, positive predictive value for a physician-confirmed diagnosis of AE, was 86% (95% confidence interval = 80–91). Additional criteria increased the PPV up to 95% but would miss up to 89% of individuals with physician-confirmed AE. The first and last entered diagnosis codes for individuals showed good agreement with the physician-confirmed age at onset and last disease activity; the mean difference was 0.8 years (95% confidence interval = –0.3 to 1.9) and –1.3 years (95% confidence interval = –2.5 to –0.1), respectively. A combination of diagnostic and prescription codes can be used to reliably estimate the diagnosis and duration of AE from The Health Improvement Network primary care electronic health records in the UK.