Determining the predictive value of Read/OXMIS codes to identify incident acute myocardial infarction in the General Practice Research Database

Validation of diagnosis of acute myocardial infarction and stroke in electronic medical records: a primary care cross-sectional study in Madrid, Spain (the e-MADVEVA Study)

OBJECTIVES

To validate the diagnoses of acute myocardial infarction (AMI) and stroke recorded in electronic medical records (EMR) and to estimate the population prevalence of both diseases in people aged ≥18 years.

DESIGN

Cross-sectional validation study.

SETTING

45 primary care centres.

PARTICIPANTS

Simple random sampling of diagnoses of AMI and stroke (International Classification of Primary Care-2 codes K75 and K90, respectively) registered by 55 physicians and random age-matched and sex-matched sampling of the records that included in primary care EMRs in Madrid (Spain).

PRIMARY AND SECONDARY OUTCOME MEASURES

Sensitivity, specificity, positive and negative predictive values and overall agreement were calculated using the kappa statistic. Applied gold standards were ECGs, brain imaging studies, hospital discharge reports, cardiology reports and neurology reports. In the case of AMI, the ESC/ACCF/AHA/WHF Expert Consensus Document was also used. Secondary outcomes were the estimated prevalence of both diseases considering the sensitivity and specificity obtained (true prevalence).

RESULTS

The sensitivity of a diagnosis of AMI was 98.11% (95% CI, 96.29 to 99.03), and the specificity was 97.42% (95% CI, 95.44 to 98.55). The sensitivity of a diagnosis of stroke was 97.56% (95% CI, 95.56 to 98.68), and the specificity was 94.51% (95% CI, 91.96 to 96.28). No differences in the results were found after stratification by age and sex (both diseases). The prevalence of AMI and stroke was 1.38% and 1.27%, respectively.

CONCLUSION

The validation results show that diagnoses of AMI and stroke in primary care EMRs constitute a helpful tool in epidemiological studies. The prevalence of AMI and stroke was lower than 2% in the population aged over 18 years.

Risk Assessment of Acute Myocardial Infarction and Stroke Associated with Long-Acting Muscarinic Antagonists, Alone or in Combination, versus Long-Acting beta2-Agonists

Background

The long-acting muscarinic antagonist (LAMA) aclidinium was approved in Europe in 2012 to relieve symptoms in adult patients with chronic obstructive pulmonary disease (COPD). A post-authorization safety study was initiated to assess potential cardiovascular risks associated with LAMAs versus long-acting beta2-agonists.

Purpose

To estimate incidence rates and adjusted incidence rate ratios (IRRs) for acute myocardial infarction (AMI), stroke, and major adverse cardiac events (MACE) in new users of aclidinium, aclidinium/formoterol, tiotropium, other LAMA, long-acting beta-agonists/inhaled corticosteroids (LABA/ICS), and LAMA/LABA compared with initiators of LABA.

Patients and Methods

This population-based cohort study included patients with COPD aged ≥40 years initiating COPD medications in the UK Clinical Practice Research Datalink (CPRD) Aurum database from 2012 to 2019. Poisson regression models were used to estimate the IRR for AMI, stroke, and MACE in users of COPD medications versus LABA, adjusting for clinically relevant covariables.

Results

The study included 11,121 new users of aclidinium, 4804 of aclidinium/formoterol, 56,198 of tiotropium, 23,856 of other LAMA, 17,450 of LAMA/LABA, 70,289 of LABA/ICS, and 13,716 of LABA. During periods of continuous medication use after initiation (current use), crude incidence rates per 1000 person-years for AMI ranged from 8.7 (aclidinium/formoterol) to 12.4 (LAMA/LABA), for stroke ranged from 4.8 (aclidinium/formoterol) to 7.2 (LAMA/LABA), and for MACE ranged from 13.5 (aclidinium/formoterol) to 19.3 (LAMA/LABA). Using LABA as reference, adjusted IRRs [95% confidence intervals] were close to 1 for all study drugs for AMI (lowest for aclidinium/formoterol, 0.95 [0.60–1.52], and highest for LAMA/LABA, 1.23 [0.91–1.67]), stroke (lowest for aclidinium/formoterol, 0.64 [0.39–1.06], and highest for tiotropium, 1.02 [0.81–1.27] for tiotropium) and for MACE (lowest for aclidinium, 0.93 [0.75–1.16], and highest for LAMA/LABA, 1.24 [0.97–1.59]).

Conclusion

Risks of AMI, stroke, and MACE in current users of aclidinium, aclidinium/formoterol, tiotropium, other LAMA, LAMA/LABA, or LABA/ICS were similar to the risks among current users of LABA.

Comparative risk of acute myocardial infarction for anti-osteoporosis drugs in primary care: a meta-analysis of propensity-matched cohort findings from the UK Clinical Practice Research Database and the Catalan SIDIAP Database

The aim of this study was to evaluate the risk of acute myocardial infarction in patients taking osteoporosis medication. Patients were taken from the SIDIAP or CPRD database and were matched using propensity scores. Patients with diabetes and chronic kidney disease taking SERMs were at an increased risk. The results favour the cardiovascular safety of alendronate as a first-line choice for osteoporosis treatment.

INTRODUCTION

This study aims to evaluate the comparative safety of anti-osteoporosis drugs based on the observed risk of acute myocardial infarction while on treatment in a primary care setting.

METHODS

This is a propensity-matched cohort study and meta-analysis. This study was conducted in two primary care record databases covering UK NHS (CPRD) and Catalan healthcare (SIDIAP) patients during 1995-2014 and 2006-2014, respectively. The outcome was acute myocardial infarction while on treatment. Users of alendronate (reference group) were compared to those of (1) other oral bisphosphonates (OBP), (2) strontium ranelate (SR), and (3) selective oestrogen receptor modulator (SERM), after matching on baseline characteristics (socio-demographics, fracture risk factors, comorbidities, and concomitant drug use) using propensity scores. Multiple imputation was used to handle missing data on confounders and competing risk modelling for the calculation of relative risk (sub-distribution hazard ratios (SHR)) according to therapy. Country-specific data were analysed individually and meta-analysed.

RESULTS

A 10% increased risk of acute myocardial infarction was found in users of other bisphosphonates as compared to alendronate users within CPRD. The meta-analysis of CPRD and SIDIAP results showed a 9% increased risk in users of other bisphosphonate as compared to alendronate users. Sensitivity analysis showed SERMS users with diabetes and chronic kidney disease were at an elevated risk.

CONCLUSIONS

This study provides additional data on the risk of acute myocardial infarction in patients receiving osteoporosis treatment. The results favour the cardiovascular safety of alendronate as a first-line choice for osteoporosis treatment.

Validity of Acute Cardiovascular Outcome Diagnoses Recorded in European Electronic Health Records: A Systematic Review

BACKGROUND

Electronic health records are widely used in cardiovascular disease research. We appraised the validity of stroke, acute coronary syndrome and heart failure diagnoses in studies conducted using European electronic health records.

METHODS

Using a prespecified strategy, we systematically searched seven databases from dates of inception to April 2019. Two reviewers independently completed study selection, followed by partial parallel data extraction and risk of bias assessment. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value estimates were narratively synthesized and heterogeneity between sensitivity and PPV estimates were assessed using I2.

RESULTS

We identified 81 studies, of which 20 validated heart failure diagnoses, 31 validated acute coronary syndrome diagnoses with 29 specifically recording estimates for myocardial infarction, and 41 validated stroke diagnoses. Few studies reported specificity or negative predictive value estimates. Sensitivity was ≤66% in all but one heart failure study, ≥80% for 91% of myocardial infarction studies, and ≥70% for 73% of stroke studies. PPV was ≥80% in 74% of heart failure, 88% of myocardial infarction, and 70% of stroke studies. PPV by stroke subtype was variable, at ≥80% for 80% of ischaemic stroke but only 44% of haemorrhagic stroke. There was considerable heterogeneity (I2 >75%) between sensitivity and PPV estimates for all diagnoses.

CONCLUSION

Overall, European electronic health record stroke, acute coronary syndrome and heart failure diagnoses are accurate for use in research, although validity estimates for heart failure and individual stroke subtypes were lower. Where possible, researchers should validate data before use or carefully interpret the results of previous validation studies for their own study purposes.

Non-linear associations of 25-hydroxyvitamin D concentrations with risk of cardiovascular disease and all-cause mortality: Results from The Health Improvement Network (THIN) database

BACKGROUND

There is increasing evidence that vitamin D supplementation may only be beneficial in people with vitamin D deficiency, and the lack of sufficient people with very low vitamin D levels could explain the lack of protection against cardiovascular disease (CVD) reported in recent clinical trials of vitamin D supplementation. The aim of this study was to assess associations of low to moderate circulating concentrations of 25-hydroxyvitamin D (25(OH)D with risk of incident CVD and all-cause mortality, as well as the risk of ischaemic heart disease (IHD), cerebrovascular disease, and heart failure separately.

METHODS AND RESULTS

Longitudinal analysis of electronic health records in The Health Improvement Network (THIN), a UK primary care database. The analysis included 180,263 patients age 18 years and older without a history of CVD and with circulating concentrations of 25(OH)D. After a mean follow-up of 2.2 (SD 1.7) years, there were 3747 patients diagnosed with CVD and 3912 patients died. Compared to patients in the highest quintile of 25(OHD) (≥ 67.5 nmol/L), those in the lowest 25(OH)D quintile (<23.1 nmol/L) had a hazard ratio (HR) of 1.24 (95% CI 1.12-1.38, P <  0.001) for CVD and 1.71 (1.55-1.88, P <  0.001) for mortality. The HR for both outcomes associated with 25(OH)D concentration was non-linear, being significantly increased in patients with 25(OH)D <35 nmol/L, and highest in those with 25(OH)D <25 nmol/L, although increased for mortality at 25(OH)D ≥100 nmol/L. The increased CVD HR in the lowest 25(OH)D quintile was more from IHD (1.35, 95% CI 1.13-1.60) and heart failure (1.38, 95% CI 1.08-1.77), than from cerebrovascular disease (1.13, 95% CI 0.97-1.31).

CONCLUSION

Low 25(OH)D are associated with highest risk of CVD and mortality, and are consistent with accumulating evidence that increased risk of these diseases occurs primarily in people with vitamin D deficiency.

Variation in Cardiovascular Risk Related to Individual Antimuscarinic Drugs Used to Treat Overactive Bladder: A UK Cohort Study

BACKGROUND

Blocking muscarinic receptors could have an effect on cardiac function, especially among elderly patients with overactive bladder (OAB).

STUDY OBJECTIVE

To investigate the risk of cardiovascular (CV) events in users of antimuscarinic drugs to treat OAB.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study of new users of darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, or trospium, 18 years or older, in the United Kingdom's Clinical Practice Research Datalink (CPRD), 2004-2012.

OUTCOME MEASUREMENTS AND MAIN RESULTS

Using tolterodine as the reference, we estimated propensity-score-stratified incidence rate ratios (IRRs) for acute myocardial infarction, stroke, CV mortality, major adverse cardiac events (MACE, a combined end point of the previous three), and all-cause death for individual antimuscarinic drugs. The study cohort included 119,912 new users of OAB drugs. The mean age at cohort entry was 62 years, 70% were female, and the mean follow-up was 3.3 years. The adjusted IRR for MACE and current use of oxybutynin compared with current use of tolterodine was 1.14 (95% confidence interval [CI] 1.01-1.30). In contrast, the IRR was 0.65 (CI 0.56-0.76) for current use of solifenacin compared with tolterodine. In this study, performed with health care data, the distribution of risk factors was relatively similar across users of different OAB drugs and, although our analyses controlled for a range of measured potential confounders, residual confounding cannot be ruled out.

CONCLUSIONS

In an observational comparative study of users of medications to treat OAB conducted in routine clinical practice, the risk for CV side effects was increased in users of oxybutynin and decreased in users of solifenacin compared with users of tolterodine.

A validation study of the CirCom comorbidity score in an English cirrhosis population using the Clinical Practice Research Datalink

Purpose

The CirCom score has been developed from Danish data as a specific measure of comorbidity for cirrhosis to predict all-cause mortality. We compared its performance with the Charlson Comorbidity Index (CCI) in an English cirrhosis population.

Patients and methods

We used comorbidity scores in a survival model to predict mortality in a cirrhosis cohort in the Clinical Practice Research Datalink. The discrimination of each score was compared by age, gender, socioeconomic status, cirrhosis etiology, cirrhosis stage, and year after cirrhosis diagnosis. We also measured their ability to predict liver-related versus non-liver-related death.

Results

There was a small improvement in the C statistic from the model using the CirCom score (C=0.63) compared to the CCI (C=0.62), and there was an overall improvement in the net reclassification index of 1.5%. The improvement was more notable in younger patients, those with an alcohol etiology, and those with compensated cirrhosis. Both scores performed better (C statistic >0.7) for non-liver-related deaths than liver-related deaths (C statistic <0.6), as comorbidity was only weakly predictive of liver-related death.

Conclusion

The CirCom score provided a small improvement in performance over the CCI in the prediction of all-cause and non-liver mortality, but not liver-related mortality. Therefore, it is important to include a measure of comorbidity in studies of cirrhosis survival, alongside a measure of cirrhosis severity.

Metabolically Healthy Obese and Incident Cardiovascular Disease Events Among 3.5 Million Men and Women

BACKGROUND

Previous studies have been unclear about the cardiovascular risks for metabolically healthy obese individuals.

OBJECTIVES

This study examined the associations among metabolically healthy obese individuals and 4 different presentations of incident cardiovascular disease in a contemporary population.

METHODS

We used linked electronic health records (1995 to 2015) in The Health Improvement Network (THIN) to assemble a cohort of 3.5 million individuals, 18 years of age or older and initially free of cardiovascular disease. We created body size phenotypes defined by body mass index categories (underweight, normal weight, overweight, and obesity) and 3 metabolic abnormalities (diabetes, hypertension, and hyperlipidemia). The primary endpoints were the first record of 1 of 4 cardiovascular presentations (coronary heart disease [CHD], cerebrovascular disease, heart failure, and peripheral vascular disease).

RESULTS

During a mean follow-up of 5.4 years, obese individuals with no metabolic abnormalities had a higher risk of CHD (multivariate-adjusted hazard ratio [HR]: 1.49; 95% confidence interval [CI]: 1.45 to 1.54), cerebrovascular disease (HR: 1.07; 95% CI: 1.04 to 1.11), and heart failure (HR: 1.96; 95% CI: 1.86 to 2.06) compared with normal weight individuals with 0 metabolic abnormalities. Risk of CHD, cerebrovascular disease, and heart failure in normal weight, overweight, and obese individuals increased with increasing number of metabolic abnormalities.

CONCLUSIONS

Metabolically healthy obese individuals had a higher risk of coronary heart disease, cerebrovascular disease, and heart failure than normal weight metabolically healthy individuals. Even individuals who are normal weight can have metabolic abnormalities and similar risks for cardiovascular disease events.

Mortality gap for people with bipolar disorder and schizophrenia: UK-based cohort study 2000-2014

BackgroundBipolar disorder and schizophrenia are associated with increased mortality relative to the general population. There is an international emphasis on decreasing this excess mortality.AimsTo determine whether the mortality gap between individuals with bipolar disorder and schizophrenia and the general population has decreased.MethodA nationally representative cohort study using primary care electronic health records from 2000 to 2014, comparing all patients diagnosed with bipolar disorder or schizophrenia and the general population. The primary outcome was all-cause mortality.ResultsIndividuals with bipolar disorder and schizophrenia had elevated mortality (adjusted hazard ratio (HR) = 1.79, 95% CI 1.67-1.88 and 2.08, 95% CI 1.98-2.19 respectively). Adjusted HRs for bipolar disorder increased by 0.14/year (95% CI 0.10-0.19) from 2006 to 2014. The adjusted HRs for schizophrenia increased gradually from 2004 to 2010 (0.11/year, 95% CI 0.04-0.17) and rapidly after 2010 (0.34/year, 95% CI 0.18-0.49).ConclusionsThe mortality gap between individuals with bipolar disorder and schizophrenia, and the general population is widening.

A rule-based electronic phenotyping algorithm for detecting clinically relevant cardiovascular disease cases

Background

The implementation of electronic medical records (EMR) is becoming increasingly common. Error and data loss reduction, patient-care efficiency increase, decision-making assistance and facilitation of event surveillance, are some of the many processes that EMRs help improve. In addition, they show a lot of promise in terms of data collection to facilitate observational epidemiological studies and their use for this purpose has increased significantly over the recent years. Even though the quantity and availability of the data are clearly improved thanks to EMRs, still, the problem of the quality of the data remains. This is especially important when attempting to determine if an event has actually occurred or not. We sought to assess the sensitivity, specificity, and agreement level of a codes-based algorithm for the detection of clinically relevant cardiovascular (CaVD) and cerebrovascular (CeVD) disease cases, using data from EMRs.

Methods

Three family physicians from the research group selected clinically relevant CaVD and CeVD terms from the international classification of primary care, Second Edition (ICPC-2), the ICD 10 version 2015 and SNOMED-CT 2015 Edition. These terms included both signs, symptoms, diagnoses and procedures associated with CaVD and CeVD. Terms not related to symptoms, signs, diagnoses or procedures of CaVD or CeVD and also those describing incidental findings without clinical relevance were excluded. The algorithm yielded a positive result if the patient had at least one of the selected terms in their medical records, as long as it was not recorded as an error. Else, if no terms were found, the patient was classified as negative. This algorithm was applied to a randomly selected sample of the active patients within the hospital’s HMO by 1/1/2005 that were 40–79 years old, had at least one year of seniority in the HMO and at least one clinical encounter. Thus, patients were classified into four groups: (1) Negative patients (2) Patients with CaVD but without CeVD; (3) Patients with CeVD but without disease CaVD; (4) Patients with both diseases. To facilitate the validation process, a stratified sample was taken so that each of the groups represented approximately 25% of the sample. Manual chart review was used as the gold standard for assessing the algorithm’s performance. One-third of the patients were assigned randomly to each reviewer (Cohen’s kappa 0.91). Both coded and un-coded (free text) sections of the EMR were reviewed. This was done from the first present clinical note in the patients chart to the last one registered prior to 1/1/2005.

Results

The performance of the algorithm was compared against manual chart review. It yielded high sensitivity (0.99, 95% CI 0.938–0.9971) and acceptable specificity (0.86, 95% CI 0.818–0.895) for detecting cases of CaVD and CeVD combined. A qualitative analysis of the false positives and false negatives was performed.

Conclusions

We developed a simple algorithm, using only standardized and non-standardized coded terms within an EMR that can properly detect clinically relevant events and symptoms of CaVD and CeVD. We believe that combining it with an analysis of the free text using an NLP approach would yield even better results.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-017-2600-2) contains supplementary material, which is available to authorized users.

Concurrent use of long-acting bronchodilators in COPD and the risk of adverse cardiovascular events

The cardiovascular risk of concurrently using long-acting β₂-agonists (LABAs) and anticholinergics (LAMAs) in COPD is uncertain. We assessed the comparative cardiovascular and cerebrovascular safety of adding a second long-acting bronchodilator in patients with COPD.We identified a cohort of COPD patients, new users of LABA or the LAMA tiotropium during 2002-2012, from the UK Clinical Practice Research Datalink. Using high-dimensional propensity scores, each patient adding a second bronchodilator was matched with a patient who remained on monotherapy. Patients were followed for 1 year for the occurrence of acute myocardial infarction (AMI), stroke, heart failure and arrhythmia.The cohorts included up to 31 174 patients adding a bronchodilator matched to 31 174 patients remaining on bronchodilator monotherapy. Adding a long-acting bronchodilator, compared to remaining on monotherapy, was not associated with an increased risk of AMI (hazard ratio (HR) 1.12, 95% CI 0.92-1.36), stroke (HR 0.87, 95% CI 0.69-1.10) or arrhythmia (HR 1.05, 95% CI 0.81-1.36), but the risk was elevated for heart failure (HR 1.16, 95% CI 1.03-1.30).Adding a second long-acting bronchodilator in the real-world-setting treatment of COPD does not increase the risk of most cardiovascular events. The modest increase for heart failure warrants further investigation.

Risk of acute myocardial infarction with NSAIDs in real world use: bayesian meta-analysis of individual patient data

Objective To characterise the determinants, time course, and risks of acute myocardial infarction associated with use of oral non-steroidal anti-inflammatory drugs (NSAIDs).Design Systematic review followed by a one stage bayesian individual patient data meta-analysis.Data sources Studies from Canadian and European healthcare databases.Review methods Eligible studies were sourced from computerised drug prescription or medical databases, conducted in the general or an elderly population, documented acute myocardial infarction as specific outcome, studied selective cyclo-oxygenase-2 inhibitors (including rofecoxib) and traditional NSAIDs, compared risk of acute myocardial infarction in NSAID users with non-users, allowed for time dependent analyses, and minimised effects of confounding and misclassification bias. Exposure and outcomes Drug exposure was modelled as an indicator variable incorporating the specific NSAID, its recency, duration of use, and dose. The outcome measures were the summary adjusted odds ratios of first acute myocardial infarction after study entry for each category of NSAID use at index date (date of acute myocardial infarction for cases, matched date for controls) versus non-use in the preceding year and the posterior probability of acute myocardial infarction.Results A cohort of 446 763 individuals including 61 460 with acute myocardial infarction was acquired. Taking any dose of NSAIDs for one week, one month, or more than a month was associated with an increased risk of myocardial infarction. With use for one to seven days the probability of increased myocardial infarction risk (posterior probability of odds ratio >1.0) was 92% for celecoxib, 97% for ibuprofen, and 99% for diclofenac, naproxen, and rofecoxib. The corresponding odds ratios (95% credible intervals) were 1.24 (0.91 to 1.82) for celecoxib, 1.48 (1.00 to 2.26) for ibuprofen, 1.50 (1.06 to 2.04) for diclofenac, 1.53 (1.07 to 2.33) for naproxen, and 1.58 (1.07 to 2.17) for rofecoxib. Greater risk of myocardial infarction was documented for higher dose of NSAIDs. With use for longer than one month, risks did not appear to exceed those associated with shorter durations.Conclusions All NSAIDs, including naproxen, were found to be associated with an increased risk of acute myocardial infarction. Risk of myocardial infarction with celecoxib was comparable to that of traditional NSAIDS and was lower than for rofecoxib. Risk was greatest during the first month of NSAID use and with higher doses.

Serum creatinine elevation after renin-angiotensin system blockade and long term cardiorenal risks: cohort study

Objective To examine long term cardiorenal outcomes associated with increased concentrations of creatinine after the start of angiotensin converting enzyme inhibitor/angiotensin receptor blocker treatment.Design Population based cohort study using electronic health records from the Clinical Practice Research Datalink and Hospital Episode Statistics.Setting UK primary care, 1997-2014.Participants Patients starting treatment with angiotensin converting enzyme inhibitors or angiotensin receptor blockers (n=122 363).Main outcome measures Poisson regression was used to compare rates of end stage renal disease, myocardial infarction, heart failure, and death among patients with creatinine increases of 30% or more after starting treatment against those without such increases, and for each 10% increase in creatinine. Analyses were adjusted for age, sex, calendar period, socioeconomic status, lifestyle factors, chronic kidney disease, diabetes, cardiovascular comorbidities, and use of other antihypertensive drugs and non-steroidal anti-inflammatory drugs.Results Among the 2078 (1.7%) patients with creatinine increases of 30% or more, a higher proportion were female, were elderly, had cardiorenal comorbidity, and used non-steroidal anti-inflammatory drugs, loop diuretics, or potassium sparing diuretics. Creatinine increases of 30% or more were associated with an increased adjusted incidence rate ratio for all outcomes, compared with increases of less than 30%: 3.43 (95% confidence interval 2.40 to 4.91) for end stage renal disease, 1.46 (1.16 to 1.84) for myocardial infarction, 1.37 (1.14 to 1.65) for heart failure, and 1.84 (1.65 to 2.05) for death. The detailed categorisation of increases in creatinine concentrations (<10%, 10-19%, 20-29%, 30-39%, and ≥40%) showed a graduated relation for all outcomes (all P values for trends <0.001). Notably, creatinine increases of less than 30% were also associated with increased incidence rate ratios for all outcomes, including death (1.15 (1.09 to 1.22) for increases of 10-19% and 1.35 (1.23 to 1.49) for increases of 20-29%, using <10% as reference). Results were consistent across calendar periods, across subgroups of patients, and among continuing users.Conclusions Increases in creatinine after the start of angiotensin converting enzyme inhibitor/angiotensin receptor blocker treatment were associated with adverse cardiorenal outcomes in a graduated relation, even below the guideline recommended threshold of a 30% increase for stopping treatment.

Retrospective examination of lipid-lowering treatment patterns in a real-world high-risk cohort in the UK in 2014: comparison with the National Institute for Health and Care Excellence (NICE) 2014 lipid modification guidelines

BACKGROUND

In 2014, guidelines from the National Institute for Health and Care Excellence (NICE) provided updated recommendations on lipid-modifying therapy (LMT). We assessed clinical practice contemporaneous to release of these guidelines in a UK general practice setting for secondary and high-risk primary-prevention populations, and extrapolated the findings to UK nation level.

METHODS

Patients from The Health Improvement Network database with the following criteria were included: lipid profile in 2014 (index date); ≥20 years of age; ≥2 years representation in database prior to index; ≥1 statin indication either for atherosclerotic cardiovascular disease (ASCVD) or the non-ASCVD conditions high-risk diabetes mellitus and/or chronic kidney disease.

RESULTS

Overall, 183 565 patients met the inclusion criteria (n=91 479 for ASCVD, 92 086 for non-ASCVD). In those with ASCVD, 79% received statin treatment and 31% received high-intensity statin. In the non-ASCVD group, 62% were on a statin and 57% received medium-intensity or high-intensity statin. In the ASCVD and non-ASCVD cohorts, 6% and 15%, respectively, were already treated according to dosing recommendations as per updated NICE guidelines. Extrapolation to the 2014 UK population indicated that, of the 3.3 million individuals with ASCVD, 2.4 million would require statin uptitration and 680 000 would require statin initiation (31% de novo initiation, 60% reinitiation, 9% addition to non-statin LMT) to achieve full concordance with updated guidelines. Of the 3.5 million high-risk non-ASCVD individuals, 1.6 million would require statin uptitration and 1.4 million would require statin initiation (59% de novo initiation, 36% reinitiation, 5% addition to non-statin LMT).

CONCLUSIONS

A large proportion of UK individuals with ASCVD and high-risk non-ASCVD received statin treatment (79% and 62%, respectively) during the year of NICE 2014 guidelines release. Up to 94% of patients with ASCVD and 85% of high-risk non-ASCVD individuals, representing ∼3 million individuals in each group, would require statin uptitration or initiation to achieve full concordance with updated guidelines.

Using nationwide ‘big data’ from linked electronic health records to help improve outcomes in cardiovascular diseases: 33 studies using methods from epidemiology, informatics, economics and social science in the ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER) programme

Background

Electronic health records (EHRs), when linked across primary and secondary care and curated for research use, have the potential to improve our understanding of care quality and outcomes.

Objective

To evaluate new opportunities arising from linked EHRs for improving quality of care and outcomes for patients at risk of or with coronary disease across the patient journey.

Design

Epidemiological cohort, health informatics, health economics and ethnographic approaches were used.

Setting

230 NHS hospitals and 226 general practices in England and Wales.

Participants

Up to 2 million initially healthy adults, 100,000 people with stable coronary artery disease (SCAD) and up to 300,000 patients with acute coronary syndrome.

Main outcome measures

Quality of care, fatal and non-fatal cardiovascular disease (CVD) events.

Data platform and methods

We created a novel research platform [ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER)] based on linkage of four major sources of EHR data in primary care and national registries. We carried out 33 complementary studies within the CALIBER framework. We developed a web-based clinical decision support system (CDSS) in hospital chest pain clinics. We established a novel consented prognostic clinical cohort of SCAD patients.

Results

CALIBER was successfully established as a valid research platform based on linked EHR data in nearly 2 million adults with > 600 EHR phenotypes implemented on the web portal (seehttps://caliberresearch.org/portal). Despite national guidance, key opportunities for investigation and treatment were missed across the patient journey, resulting in a worse prognosis for patients in the UK compared with patients in health systems in other countries. Our novel, contemporary, high-resolution studies showed heterogeneous associations for CVD risk factors across CVDs. The CDSS did not alter the decision-making behaviour of clinicians in chest pain clinics. Prognostic models using real-world data validly discriminated risk of death and events, and were used in cost-effectiveness decision models.

Conclusions

Emerging ‘big data’ opportunities arising from the linkage of records at different stages of a patient’s journey are vital to the generation of actionable insights into the diagnosis, risk stratification and cost-effective treatment of people at risk of, or with, CVD.

Future work

The vast majority of NHS data remain inaccessible to research and this hampers efforts to improve efficiency and quality of care and to drive innovation. We propose three priority directions for further research. First, there is an urgent need to ‘unlock’ more detailed data within hospitals for the scale of the UK’s 65 million population. Second, there is a need for scaled approaches to using EHRs to design and carry out trials, and interpret the implementation of trial results. Third, large-scale, disease agnostic genetic and biological collections linked to such EHRs are required in order to deliver precision medicine and to innovate discovery.

Study registration

CALIBER studies are registered as follows: study 2 – NCT01569139, study 4 – NCT02176174 and NCT01164371, study 5 – NCT01163513, studies 6 and 7 – NCT01804439, study 8 – NCT02285322, and studies 26–29 – NCT01162187. Optimising the Management of Angina is registered as Current Controlled Trials ISRCTN54381840.

Funding

The National Institute for Health Research (NIHR) Programme Grants for Applied Research programme (RP-PG-0407-10314) (all 33 studies) and additional funding from the Wellcome Trust (study 1), Medical Research Council Partnership grant (study 3), Servier (study 16), NIHR Research Methods Fellowship funding (study 19) and NIHR Research for Patient Benefit (study 33).

The Use of a Bayesian Hierarchy to Develop and Validate a Co-Morbidity Score to Predict Mortality for Linked Primary and Secondary Care Data from the NHS in England

Background

We have assessed whether the linkage between routine primary and secondary care records provided an opportunity to develop an improved population based co-morbidity score with the combined information on co-morbidities from both health care settings.

Methods

We extracted all people older than 20 years at the start of 2005 within the linkage between the Hospital Episodes Statistics, Clinical Practice Research Datalink, and Office for National Statistics death register in England. A random 50% sample was used to identify relevant diagnostic codes using a Bayesian hierarchy to share information between similar Read and ICD 10 code groupings. Internal validation of the score was performed in the remaining 50% and discrimination was assessed using Harrell’s C statistic. Comparisons were made over time, age, and consultation rate with the Charlson and Elixhauser indexes.

Results

657,264 people were followed up from the 1st January 2005. 98 groupings of codes were derived from the Bayesian hierarchy, and 37 had an adjusted weighting of greater than zero in the Cox proportional hazards model. 11 of these groupings had a different weighting dependent on whether they were coded from hospital or primary care. The C statistic reduced from 0.88 (95% confidence interval 0.88–0.88) in the first year of follow up, to 0.85 (0.85–0.85) including all 5 years. When we stratified the linked score by consultation rate the association with mortality remained consistent, but there was a significant interaction with age, with improved discrimination and fit in those under 50 years old (C = 0.85, 0.83–0.87) compared to the Charlson (C = 0.79, 0.77–0.82) or Elixhauser index (C = 0.81, 0.79–0.83).

Conclusions

The use of linked population based primary and secondary care data developed a co-morbidity score that had improved discrimination, particularly in younger age groups, and had a greater effect when adjusting for co-morbidity than existing scores.

A methodological comparison of two European primary care databases and replication in a US claims database: inhaled long-acting beta-2-agonists and the risk of acute myocardial infarction

PURPOSE

Results from observational studies on inhaled long-acting beta-2-agonists (LABA) and acute myocardial infarction (AMI) risk are conflicting, presumably due to variation in methodology. We aimed to evaluate the impact of applying a common study protocol on consistency of results in three databases.

METHODS

In the primary analysis, we included patients from two GP databases (Dutch-Mondriaan, UK-CPRD GOLD) with a diagnosis of asthma and/or COPD and at least one inhaled LABA or a "non-LABA inhaled bronchodilator medication" (short-acting beta-2-agonist or short-/long-acting muscarinic antagonist) prescription between 2002 and 2009. A claims database (USA-Clinformatics) was used for replication. LABA use was divided into current, recent (first 91 days following the end of a treatment episode), and past use (after more than 91 days following the end of a treatment episode). Adjusted hazard ratios (AMI-aHR) and 95 % confidence intervals (95 % CI) were estimated using time-dependent multivariable Cox regression models stratified by recorded diagnoses (asthma, COPD, or both asthma and COPD).

RESULTS

For asthma or COPD patients, no statistically significant AMI-aHRs (age- and sex-adjusted) were found in the primary analysis. For patients with both diagnoses, a decreased AMI-aHR was found for current vs. recent LABA use in the CPRD GOLD (0.78; 95 % CI 0.68-0.90) and in Mondriaan (0.55; 95 % CI 0.28-1.08), too. The replication study yielded similar results. Adjusting for concomitant medication use and comorbidities, in addition to age and sex, had little impact on the results.

CONCLUSIONS

By using a common protocol, we observed similar results in the primary analysis performed in two GP databases and in the replication study in a claims database. Regarding differences between databases, a common protocol facilitates interpreting results due to minimized methodological variations. However, results of multinational comparative observational studies might be affected by bias not fully addressed by a common protocol.

Total joint arthroplasty and the risk of myocardial infarction: a general population, propensity score-matched cohort study

OBJECTIVE

To replicate recent findings indicating that total knee arthroplasty (TKA) or total hip arthroplasty (THA) surgery will substantially reduce the risk of serious cardiovascular events among patients with osteoarthritis.

METHODS

A time-stratified, propensity score-matched cohort study was conducted to assess the incidence of myocardial infarction (MI) in a UK general population. The study population included individuals ages ≥50 years who had a UK National Health Service READ code diagnosis of knee osteoarthritis (to evaluate TKA) or hip osteoarthritis (to evaluate THA) between January 2000 and December 2012.

RESULTS

Among the patients who underwent TKA and their matched non-TKA control subjects (each n = 13,849), 306 patients and 286 control subjects developed MI during the followup. During the first postoperative month, the risk of MI was substantially increased among the TKA group compared with the non-TKA group (hazard ratio [HR] 8.75, 95% confidence interval [95% CI] 3.11-24.62), and then gradually declined during the subsequent followup. The HR for the risk of MI over the entire followup was 0.98 (95% CI 0.82-1.18). The corresponding HRs for the risk of MI in those who had undergone THA compared with the non-THA group (each n = 6,063) were 4.33 (95% CI 1.24-15.21) in the first postoperative month and 0.87 (95% CI 0.66-1.15) overall. In analyses using venous thromboembolism as a positive control outcome, both the first month and overall HRs for the risk of venous thromboembolism were substantially increased in both the TKA and THA groups.

CONCLUSION

These findings provide the first general population-based evidence to indicate that TKA and THA among osteoarthritis patients are associated with a substantially increased risk of MI during the immediate postoperative period. However, the overall long-term impact of these surgeries was null, unlike the risk of venous thromboembolism, which remained elevated years after patients had undergone the procedure.

Comparative Safety of Testosterone Dosage Forms

IMPORTANCE

Increases in testosterone use and mixed reports of adverse events have raised concerns about the cardiovascular safety of testosterone. Testosterone is available in several delivery mechanisms with varying pharmacokinetics; injections cause spikes in testosterone levels, and transdermal patches and gels cause more subtle but sustained increases. The comparative cardiovascular safety of gels, injections, and patches has not been studied.

OBJECTIVE

To determine the comparative cardiovascular safety of testosterone injections, patches, and gels.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted using administrative claims from a commercially insured (January 1, 2000, to December 31, 2012) and Medicare (January 1, 2007, to December 31, 2010) population in the United States and general practitioner records from the United Kingdom (January 1, 2000, to June 30, 2012). Participants included men (aged ≥18 years) who initiated use of testosterone patches, gels, or injections following 180 days with no testosterone use. Our analysis was conducted from December 11, 2013, to November 12, 2014.

EXPOSURES

New initiation of a testosterone dosage form, with use monitored for up to 1 year.

MAIN OUTCOMES AND MEASURES

Inpatient or outpatient medical records, diagnoses, or claims for cardiovascular and cerebrovascular events including myocardial infarction (MI), unstable angina, stroke, and composite acute event (MI, unstable angina, or stroke); venous thromboembolism (VTE); mortality; and all-cause hospitalization.

RESULTS

We identified 544,115 testosterone initiators between the 3 data sets: 37.4% injection, 6.9% patch, and 55.8% gel. The majority of men in the Medicare cohort were injection initiators (51.2%), most in the US commercially insured population were gel initiators (56.5%), and the UK database included equal proportions of injections and gel users (approximately 41%). With analysis conducted using hazard ratios and 95% CIs, compared with men using gels, injection initiators had higher hazards of cardiovascular events (ie, MI, unstable angina, and stroke) (1.26; 1.18-1.35), hospitalization (1.16; 1.13-1.19), and death (1.34; 1.15-1.56) but not VTE (0.92; 0.76-1.11). Compared with gels, patches did not confer increased hazards of cardiovascular events (1.10; 0.94-1.29), hospitalization (1.04; 1.00-1.08), death (1.02; 0.77-1.33), or VTE (1.08; 0.79-1.47).

CONCLUSIONS AND RELEVANCE

Testosterone injections were associated with a greater risk of cardiovascular events, hospitalizations, and deaths compared with gels. Patches and gels had similar risk profiles. However, this study did not assess whether patients met criteria for use of testosterone and did not assess the safety of testosterone among users compared with nonusers of the drug.

The combination of DPP-4 inhibitors versus sulfonylureas with metformin after failure of first-line treatment in the risk for major cardiovascular events and death

OBJECTIVE

To determine whether the combination of dipeptidyl-peptidase 4 (DPP-4) inhibitors vs. sulfonylureas with metformin after failure of first-line treatment is associated with a decreased risk for major adverse cardiovascular events (myocardial infarction and stroke) and for all-cause mortality.

METHOD

Using the UK Clinical Practice Research Datalink, a cohort of patients newly treated with metformin or sulfonylurea monotherapy between January 1, 1988, and December 31, 2011, was identified and was followed until December 31, 2012. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models to compare the DPP-4 inhibitor-metformin combination to the sulfonylurea-metformin combination so as to study the risk for a composite endpoint consisting of myocardial infarction, stroke and all-cause mortality. The models were adjusted for high-dimensional propensity score deciles.

RESULTS

The cohort consisted of 11,807 patients that included 2286 on a DPP-4 inhibitor-metformin combination and 9521 on a sulfonylurea-metformin combination. The crude incidence rates (95% CIs) of the composite endpoint were 1.2% (0.8% to 1.7%) and 2.2% (1.9% to 2.5%) per year for the DPP-4 inhibitor-metformin and sulfonylurea-metformin combinations, respectively. In the high-dimensional propensity score-adjusted model, the use of the DPP-4 inhibitor-metformin combination was associated with a 38% decreased risk for the composite endpoint (adjusted HR: 0.62; 95% CI 0.40 to 0.98), compared with the sulfonylurea-metformin combination.

CONCLUSIONS

The use of a DPP-4 inhibitor combination with metformin, compared with a sulfonylurea-metformin combination, was associated with decreased risks for major cardiovascular events and all-cause mortality.

Evaluating the validity of clinical codes to identify cataract and glaucoma in the UK Clinical Practice Research Datalink

PURPOSE

The aim of this study is to determine (i) the positive predictive value (PPV) of an algorithm using clinical codes to identify incident glaucoma and cataract events in the Clinical Practice Research Datalink (CPRD) and (ii) the ability to capture the correct timing of these clinical events.

METHODS

A total of 21,339 and 5349 potential cataract and glaucoma cases, respectively, were identified in CPRD between 1 January 1990 and 31 December 2010. Questionnaires were sent to the general practitioners (GP) of 1169 (5.5%) cataract and 1163 (21.7%) glaucoma cases for validation. GPs were asked to verify the diagnosis and the timing of the diagnosis and to provide other supporting information.

RESULTS

A total of 986 (84.3%) valid cataract questionnaires and 863 (74.2%) glaucoma questionnaires were completed. 92.1% and 92.4% of these used information beyond EMR to verify the diagnosis. Cataract and glaucoma diagnoses were confirmed in the large majority of the cases. The PPV (95% CI) of the cataract and glaucoma Read code algorithm were 92.0% (90.3-93.7%) and 84.1% (81.7-86.6%), respectively. However, timing of diagnosis was incorrect for a substantial proportion of the cases (20.3% and 32.8% of the cataract and glaucoma cases, respectively) among whom 30.4% and 49.2% had discrepancies in diagnosis timing greater than 1 year.

CONCLUSIONS

High PPV suggests that the algorithms based on the clinical Read codes are sufficient to identify the cataract and glaucoma cases in CPRD. However, these codes alone may not be able to accurately identify the timing of the diagnosis of these eye disorders. Ltd.

Risk of major cardiovascular events in patients with psoriatic arthritis, psoriasis and rheumatoid arthritis: a population-based cohort study

OBJECTIVES

We aimed to quantify the risk of major adverse cardiovascular events (MACE) among patients with psoriatic arthritis (PsA), rheumatoid arthritis (RA) and psoriasis without known PsA compared with the general population after adjusting for traditional cardiovascular risk factors.

METHODS

A population-based longitudinal cohort study from 1994 to 2010 was performed in The Health Improvement Network (THIN), a primary care medical record database in the UK. Patients aged 18-89 years of age with PsA, RA or psoriasis were included. Up to 10 unexposed controls matched on practice and index date were selected for each patient with PsA. Outcomes included cardiovascular death, myocardial infarction, cerebrovascular accidents and the composite outcome (MACE). Cox proportional hazards models were used to calculate the HRs for each outcome adjusted for traditional risk factors. A priori, we hypothesised an interaction between disease status and disease-modifying antirheumatic drug (DMARD) use.

RESULTS

Patients with PsA (N=8706), RA (N=41 752), psoriasis (N=138 424) and unexposed controls (N=81 573) were identified. After adjustment for traditional risk factors, the risk of MACE was higher in patients with PsA not prescribed a DMARD (HR 1.24, 95% CI 1.03 to 1.49), patients with RA (No DMARD: HR 1.39, 95% CI 1.28 to 1.50, DMARD: HR 1.58, 95% CI 1.46 to 1.70), patients with psoriasis not prescribed a DMARD (HR 1.08, 95% CI 1.02 to 1.15) and patients with severe psoriasis (DMARD users: HR 1.42, 95% CI 1.17 to 1.73).

CONCLUSIONS

Cardiovascular risk should be addressed with all patients affected by psoriasis, PsA or RA.

External validation of the UKPDS risk engine in incident type 2 diabetes: a need for new type 2 diabetes-specific risk equations

OBJECTIVE

To evaluate the performance of the UK Prospective Diabetes Study Risk Engine (UKPDS-RE) for predicting the 10-year risk of cardiovascular disease end points in an independent cohort of U.K. patients newly diagnosed with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a retrospective cohort study using routine health care data collected between April 1998 and October 2011 from ∼350 U.K. primary care practices contributing to the Clinical Practice Research Datalink (CPRD). Participants comprised 79,966 patients aged between 35 and 85 years (388,269 person-years) with 4,984 cardiovascular events. Four outcomes were evaluated: first diagnosis of coronary heart disease (CHD), stroke, fatal CHD, and fatal stroke.

RESULTS

Accounting for censoring, the observed versus predicted 10-year event rates were as follows: CHD 6.1 vs. 16.5%, fatal CHD 1.9 vs. 10.1%, stroke 7.0 vs. 10.1%, and fatal stroke 1.7 vs. 1.6%, respectively. The UKPDS-RE showed moderate discrimination for all four outcomes, with the concordance index values ranging from 0.65 to 0.78.

CONCLUSIONS

The UKPDS stroke equations showed calibration ranging from poor to moderate; however, the CHD equations showed poor calibration and considerably overestimated CHD risk. There is a need for revised risk equations in type 2 diabetes.

Ischaemic cardiac events and use of strontium ranelate in postmenopausal osteoporosis: a nested case-control study in the CPRD

We explored the cardiac safety of the osteoporosis treatment strontium ranelate in the UK Clinical Practice Research Datalink. While known cardiovascular risk factors like obesity and smoking were associated with increased cardiac risk, use of strontium ranelate was not associated with any increase in myocardial infarction or cardiovascular death.

INTRODUCTION

It has been suggested that strontium ranelate may increase risk for cardiac events in postmenopausal osteoporosis. We set out to explore the cardiac safety of strontium ranelate in the Clinical Practice Research Datalink (CPRD) and linked datasets.

METHODS

We performed a nested case-control study. Primary outcomes were first definite myocardial infarction, hospitalisation with myocardial infarction, and cardiovascular death. Cases and matched controls were nested in a cohort of women treated for osteoporosis. The association with exposure to strontium ranelate was analysed by multivariate conditional logistic regression.

RESULTS

Of the 112,445 women with treated postmenopausal osteoporosis, 6,487 received strontium ranelate. Annual incidence rates for first definite myocardial infarction (1,352 cases), myocardial infarction with hospitalisation (1,465 cases), and cardiovascular death (3,619 cases) were 3.24, 6.13, and 14.66 per 1,000 patient-years, respectively. Obesity, smoking, and cardiovascular treatments were associated with significant increases in risk for cardiac events. Current or past use of strontium ranelate was not associated with increased risk for first definite myocardial infarction (odds ratio [OR] 1.05, 95 % confidence interval [CI] 0.68-1.61 and OR 1.12, 95 % CI 0.79-1.58, respectively), hospitalisation with myocardial infarction (OR 0.84, 95 % CI 0.54-1.30 and OR 1.17, 95 % CI 0.83-1.66), or cardiovascular death (OR 0.96, 95 % CI 0.76-1.21 and OR 1.16, 95 % CI 0.94-1.43) versus patients who had never used strontium ranelate.

CONCLUSIONS

Analysis in the CPRD did not find evidence for a higher risk for cardiac events associated with the use of strontium ranelate in postmenopausal osteoporosis.

Determining the predictive value of Read codes to identify congenital cardiac malformations in the UK Clinical Practice Research Datalink

PURPOSES

The purposes of this study were to determine (i) the positive predictive value (PPV) of multiple Read codes used to identify congenital cardiac malformation (CCM) cases in the UK Clinical Practice Research Datalink (CPRD); (ii) the accuracy of the diagnosis date; and (iii) the source of information that the general practitioners (GPs) use for validating the diagnosis suggested by the code.

METHODS

Eight hundred eighty-eight records with Read diagnostic and procedures codes for CCM, between January 1996 and November 2010, were identified from CPRD. Questionnaires were sent to GPs to verify the diagnoses and date of the code-identified events.

RESULTS

A total of 719 questionnaires were returned (81% response rate). The PPV of the CCM codes was 93% (670/719). Thirty-one percent of cases had a different event date than the one recorded in the electronic medical record (EMR); 10% of these differing dates were within 30 days of the code-identified CCM date. GPs used a variety of data sources to confirm CCM diagnoses. Although the EMR was the most frequently used data source (70%), 66% reported using consultation letters, 9% reported using clinical notes or paper charts, and 35% of GPs reported using the hospital record to confirm the CCM diagnosis.

CONCLUSIONS

Clinical Practice Research Datalink Read codes for CCMs have 93% PPV and most likely point to true cases. However, the accuracy of diagnosis dates and the age at diagnosis may not be as reliable. The findings of this study indicate that GPs use information beyond what is available for researchers in the EMR to confirm clinical diagnoses when responding to validation questionnaires. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Type and timing of heralding in ST-elevation and non-ST-elevation myocardial infarction: an analysis of prospectively collected electronic healthcare records linked to the national registry of acute coronary syndromes

AIMS

It is widely thought that ST-elevation myocardial infarction (STEMI) is more likely to occur without warning (i.e. an unanticipated event in a previously healthy person) than non-ST-elevation myocardial infarction (NSTEMI), but no large study has evaluated this using prospectively collected data. The aim of this study was to compare the evolution of atherosclerotic disease and cardiovascular risk between people going on to experience STEMI and NSTEMI.

METHODS

We identified patients experiencing STEMI and NSTEMI in the national registry of myocardial infarction for England and Wales (Myocardial Ischaemia National Audit Project), for whom linked primary care records were available in the General Practice Research Database (as part of the CALIBER collaboration). We compared the prevalence and timing of atherosclerotic disease and major cardiovascular risk factors including smoking, hypertension, diabetes, and dyslipidaemia, between patients later experiencing STEMI to those experiencing NSTEMI.

RESULTS

A total of 8174 myocardial infarction patients were included (3780 STEMI, 4394 NSTEMI). Myocardial infarction without heralding by previously diagnosed atherosclerotic disease occurred in 71% STEMI (95% CI 69-72%) and 50% NSTEMI patients (95% CI 48-51%). The proportions of myocardial infarctions with no prior atherosclerotic disease, major risk factors, or chest pain was 14% (95% CI 13-16%) in STEMI and 9% (95% CI 9-10%) in NSTEMI. The rate of heralding coronary diagnoses was particularly high in the 12 months before infarct; 4.1-times higher (95% CI 3.3-5.0) in STEMI and 3.6-times higher (95% CI 3.1-4.2) in NSTEMI compared to the rate in earlier years.

CONCLUSIONS

Acute myocardial infarction occurring without prior diagnosed coronary, cerebrovascular, or peripheral arterial disease was common, especially for STEMI. However, there was a high prevalence of risk factors or symptoms in patients without previously diagnosed disease. Better understanding of the antecedents in the year before myocardial infarction is required.

Risk and predictors of cardiovascular disease in psoriasis: a population-based study

BACKGROUND

Emerging evidence suggests that severe psoriasis is associated with increased risk of cardiovascular disease. The goal of this study was to examine the risk and predictors of clinical cardiovascular events in psoriasis.

METHODS

We performed a historical cohort and a nested case-cohort study using the population-based resources in Olmsted County, Minnesota. The study population included a population-based incidence cohort of patients with psoriasis first diagnosed between January 1, 1970, and January 1, 2000, and 2678 age- and sex-matched non-psoriasis subjects. Cardiovascular events, including hospitalized myocardial infarction, coronary revascularization procedures, stroke, heart failure, and cardiovascular death.

RESULTS

Psoriasis was associated with an increased risk of myocardial infarction based on diagnostic codes (hazard ratio 1.26; 95% confidence intervals: 1.01, 1.58) but not when the analyses were restricted to validated myocardial infarction (hazard ratio 1.18; 95% confidence intervals: 0.80, 1.74). Psoriasis was not associated with an increased risk of heart failure or cardiovascular death. Traditional cardiovascular risk factors were significantly associated with cardiovascular risk in psoriasis. Each 1% increase in Framingham risk score at psoriasis incidence corresponded with a 5-10% increase in risk of cardiovascular events.

CONCLUSION

In this large incidence cohort of patients with psoriasis representing the full disease severity spectrum, psoriasis was not associated with an increased cardiovascular risk.

The incidence of eating disorders in the UK in 2000-2009: findings from the General Practice Research Database

OBJECTIVES

Few studies have investigated the incidence of eating disorders (EDs). Important questions about changes in the incidence of diagnosed disorders in recent years, disorder and gender-specific onset and case detection remain unanswered. Understanding changes in incidence is important for public health, clinical practice and service provision. The aim of this study was to estimate the annual (age-specific, gender-specific and subtype-specific) incidence of diagnosed ED: anorexia nervosa (AN), bulimia nervosa (BN) and eating disorder not otherwise specified (EDNOS) in primary care over a 10-year period in the UK (2000-2009); to examine the changes within the study period; and to describe peak age at diagnosis.

DESIGN

Register-based study.

SETTING

Primary care. Data were obtained from a primary care register, the General Practice Research Database, which contains anonymised records representing about 5% of the UK population.

PARTICIPANTS

All patients with a first-time diagnosis of AN, BN and EDNOS were identified.

PRIMARY OUTCOME

Annual crude and age-standardised incidence rates were calculated.

RESULTS

A total of 9072 patients with a first-time diagnosis of an ED were identified. The age-standardised annual incidence rate of all diagnosed ED for ages 10-49 increased from 32.3 (95% CI 31.7 to 32.9) to 37.2 (95% CI 36.6 to 37.9) per 100 000 between 2000 and 2009. The incidence of AN and BN was stable; however, the incidence of EDNOS increased. The incidence of the diagnosed ED was highest for girls aged 15-19 and for boys aged 10-14.

CONCLUSIONS

The age-standardised incidence of ED increased in primary care between 2000 and 2009. New diagnoses of EDNOS increased, and EDNOS is the most common ED in primary care.

Completeness and diagnostic validity of recording acute myocardial infarction events in primary care, hospital care, disease registry, and national mortality records: cohort study

OBJECTIVE

To determine the completeness and diagnostic validity of myocardial infarction recording across four national health record sources in primary care, hospital care, a disease registry, and mortality register.

DESIGN

Cohort study.

PARTICIPANTS

21 482 patients with acute myocardial infarction in England between January 2003 and March 2009, identified in four prospectively collected, linked electronic health record sources: Clinical Practice Research Datalink (primary care data), Hospital Episode Statistics (hospital admissions), the disease registry MINAP (Myocardial Ischaemia National Audit Project), and the Office for National Statistics mortality register (cause specific mortality data).

SETTING

One country (England) with one health system (the National Health Service).

MAIN OUTCOME MEASURES

Recording of acute myocardial infarction, incidence, all cause mortality within one year of acute myocardial infarction, and diagnostic validity of acute myocardial infarction compared with electrocardiographic and troponin findings in the disease registry (gold standard).

RESULTS

Risk factors and non-cardiovascular coexisting conditions were similar across patients identified in primary care, hospital admission, and registry sources. Immediate all cause mortality was highest among patients with acute myocardial infarction recorded in primary care, which (unlike hospital admission and disease registry sources) included patients who did not reach hospital, but at one year mortality rates in cohorts from each source were similar. 5561 (31.0%) patients with non-fatal acute myocardial infarction were recorded in all three sources and 11 482 (63.9%) in at least two sources. The crude incidence of acute myocardial infarction was underestimated by 25-50% using one source compared with using all three sources. Compared with acute myocardial infarction defined in the disease registry, the positive predictive value of acute myocardial infarction recorded in primary care was 92.2% (95% confidence interval 91.6% to 92.8%) and in hospital admissions was 91.5% (90.8% to 92.1%).

CONCLUSION

Each data source missed a substantial proportion (25-50%) of myocardial infarction events. Failure to use linked electronic health records from primary care, hospital care, disease registry, and death certificates may lead to biased estimates of the incidence and outcome of myocardial infarction.

TRIAL REGISTRATION

NCT01569139 clinicaltrials.gov.

Opioid use for noncancer pain and risk of myocardial infarction amongst adults

BACKGROUNDS

With increasing use of opioids for chronic noncancer pain comes concern about safety of this class of drugs. Opioid-induced hypogonadism, which could increase the risk for myocardial infarction (MI), has recently come to the attention of clinicians. To evaluate this concern we examined the association between opioid use for noncancer pain and risk of MI amongst adults.

METHODS

We conducted a nested case-control study using the UK General Practice Research Database. Amongst 1.7 million opioid users during 1990-2008, we identified 11 693 incident MI cases aged 18-80 years, and randomly selected up to four controls matched by age, gender, index date (date of onset symptoms or diagnosis of first-ever MI) and general practice via risk-set sampling. Cases and controls were required to have no cancer and no major risk factors for MI before the index date. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from conditional logistic regression.

RESULTS

Compared with nonuse, current use of opioids was associated with a 1.28-fold (95% CI 1.19-1.37) risk of MI. Cumulative use of opioids with 11-50 (OR = 1.38, 95% CI: 1.28-1.49) or > 50 (OR = 1.25, 95% CI: 1.11-1.40) prescriptions, was also marginally associated with increased risk of MI. The risk was particularly increased in users of morphine (OR = 1.71, 95% CI: 1.09-2.68), meperidine (OR = 2.15, 95% CI: 1.24-3.74) and polytherapy (OR = 1.46, 95% CI: 1.22-1.76).

CONCLUSIONS

Current use of any opioids and cumulative use of 11 or more prescriptions are associated with a small increased risk for MI compared to nonuse and the risk was greater in morphine, meperidine and polytherapy users. Residual confounding, particularly confounding by indication, should be considered in interpreting our results.

Validation of acute myocardial infarction in the Food and Drug Administration's Mini-Sentinel program

PURPOSE

To validate an algorithm based upon International Classification of Diseases, 9(th) revision, Clinical Modification (ICD-9-CM) codes for acute myocardial infarction (AMI) documented within the Mini-Sentinel Distributed Database (MSDD).

METHODS

Using an ICD-9-CM-based algorithm (hospitalized patients with 410.x0 or 410.x1 in primary position), we identified a random sample of potential cases of AMI in 2009 from four Data Partners participating in the Mini-Sentinel Program. Cardiologist reviewers used information abstracted from hospital records to assess the likelihood of an AMI diagnosis based on criteria from the Joint European Society of Cardiology and American College of Cardiology Global Task Force. Positive predictive values (PPVs) of the ICD-9-based algorithm were calculated.

RESULTS

Of the 153 potential cases of AMI identified, hospital records for 143 (93%) were retrieved and abstracted. Overall, the PPV was 86.0% (95% confidence interval; 79.2%, 91.2%). PPVs ranged from 76.3% to 94.3% across the four Data Partners.

CONCLUSIONS

The overall PPV of potential AMI cases, as identified using an ICD-9-CM-based algorithm, may be acceptable for safety surveillance; however, PPVs do vary across Data Partners. This validation effort provides a contemporary estimate of the reliability of this algorithm for use in future surveillance efforts conducted using the Food and Drug Administration's MSDD.

Influenza infection and risk of acute myocardial infarction in England and Wales: a CALIBER self-controlled case series study

Background. An association between infections and vascular events has been observed, but the specific effect of influenza and influenza-like illnesses on triggering acute myocardial infarction (AMI) is unclear.

Methods. Episodes of first AMI from 1 January 2003 through 31 July 2009 were identified using linked anonymized electronic medical records from the Myocardial Ischaemia National Audit Project and the General Practice Research Database. Self-controlled case series analysis was used to investigate AMI risks after consultation for acute respiratory infection. Infections were stratified by influenza virus circulation, diagnostic code, and vaccination status to assess whether influenza was more likely than other infections to trigger AMI.

Results. Of 22 024 patients with acute coronary syndrome, 11 208 met the criterion of having had their first AMI at the age of ≥40 years, and 3927 had also consulted for acute respiratory infection. AMI risks were significantly raised during days 1–3 after acute respiratory infection (incidence ratio, 4.19 [95% confidence interval, 3.18–5.53], with the effect tapering over time. The effect was greatest in those aged ≥80 years (P = .023). Infections occurring when influenza was circulating and those coded as influenza-like illness were associated with consistently higher incidence ratios for AMI (P = .012).

Conclusions. Influenza and other acute respiratory infections can act as a trigger for AMI. This effect may be stronger for influenza than for other infections.

Clinical trials registration. NCT01106196.

The risk of cardiovascular disease in systemic sclerosis: a population-based cohort study

OBJECTIVES

To evaluate the risk of incident myocardial infarction (MI), stroke and peripheral vascular disease (PVD) in individuals with systemic sclerosis (SSc) in a general population context.

METHODS

We conducted a cohort study using a UK primary care database containing records from 1986 to 2011. SSc diagnoses, outcomes and cardiovascular risk factors were identified from electronic medical records. We conducted two cohort analyses: (1) MI and stroke, and (2) PVD, excluding individuals with prevalent disease at baseline for each analysis. We estimated HRs comparing SSc with age-, sex- and entry time-matched comparison cohorts, adjusting for potential cardiovascular risk factors.

RESULTS

Among 865 individuals with SSc (85.8% women, mean age 58.7 years), the incidence rates (IRs) of MI and stroke were 4.4 and 4.8 per 1000 person-years (PY), versus 2.5 and 2.5 per 1000 PY in the comparison cohort. The corresponding adjusted HRs were 1.80 (95% CI 1.07 to 3.05) for MI and 2.61 (95% CI 1.54 to 4.44) for stroke. Among 858 individuals with SSc (85.3% female, mean age 58.9 years), the IR of PVD was 7.6 per 1000 PY versus 1.9 per 1000 PY in the comparison cohort, with an adjusted HR of 4.35 (95% CI 2.74 to 6.93).

CONCLUSIONS

These findings provide the first general population-based evidence that SSc is associated with an increased risk of developing MI, stroke and PVD. Further insight into disease mechanisms, as well as how disease subtype, organ involvement and medication use may alter these increased risks, is needed.

Risk of self-harm in physically ill patients in UK primary care

OBJECTIVE

To examine self-harm risk across the adult age range in patients diagnosed with various physical illnesses using the General Practice Research Database - a broadly representative sample of all people registered with a family practice in the United Kingdom.

METHODS

We conducted a large nested case-control study sampled from the whole primary care cohort. During 2001-2008 we studied 2306 cases of self-harm and 46,120 age and gender-matched controls without such an episode recorded. Relative risks were estimated against reference patients with none of the examined physical illnesses. Additionally, we assessed confounding by recorded depression, effect modification by gender and multi-morbidity effects.

RESULTS

Risk was significantly elevated in relation to any of the physical illnesses (male OR 1.35, 95% CI 1.18-1.54; female OR 1.62, 95% CI 1.40-1.86). For both genders combined, risk was raised with each specific illness. Effects sizes were consistently larger in women. Adjustment for recorded depression explained much of the elevated risk, but not so in women with asthma, back pain, diabetes, epilepsy or hypertension. Raised risk was seen in younger adults and during middle age, but not among older people. There was a dose-response relationship with increasing number of physical illnesses, and in women this was independent of depression.

CONCLUSION

Heightened risk was seen with a variety of physical illnesses. The findings indicate a need for tackling psychological distress and reducing self-harm risk in physically ill patients who attend primary healthcare services for non-psychiatric reasons, particularly so for women and younger and middle aged adults.

Risk of myocardial infarction associated with chronic hepatitis C virus infection: a population-based cohort study

Hepatitis C virus (HCV) infection is associated with systemic inflammation and metabolic complications that might predispose patients to atherosclerosis. However, it remains unclear if HCV infection increases the risk of acute myocardial infarction (MI). To determine whether HCV infection is an independent risk factor for acute MI among adults followed in general practices in the United Kingdom (UK), a retrospective cohort study was conducted in The Health Improvement Network, from 1996 through 2008. Patients ≥18 years of age with at least 6 months of follow-up and without a prior history of MI were eligible for study inclusion. HCV-infected individuals, identified with previously validated HCV diagnostic codes (n = 4809), were matched on age, sex and practice with up to 15 randomly selected patients without HCV (n = 71 668). Rates of incident MI among patients with and without a diagnosis of HCV infection were calculated. Adjusted hazard ratios were estimated using Cox proportional hazards regression, controlling for established cardiovascular risk factors. During a median follow-up of 3.2 years, there was no difference in the incidence rates of MI between HCV-infected and -uninfected patients (1.02 vs 0.92 events per 1000 person-years; P = 0.7). HCV infection was not associated with an increased risk of incident MI (adjusted HR, 1.10; 95% confidence interval [CI], 0.67-1.83). Sensitivity analyses including the exploration of a composite outcome of acute MI and coronary interventions yielded similar results (adjusted HR, 1.16; 95% CI, 0.77-1.74). In conclusion, HCV infection was not associated with an increased risk of incident MI.

Clinical importance of the drug interaction between statins and CYP3A4 inhibitors: a retrospective cohort study in The Health Improvement Network

OBJECTIVE

To compare the relative hazard of muscle toxicity, renal dysfunction, and hepatic dysfunction associated with the drug interaction between statins and concomitant medications that inhibit the CYP3A4 isoenzyme.

BACKGROUND

Although statins provide important clinical benefits related to mitigating the risk of cardiovascular events, this class of medications also has the potential for severe adverse reactions. The risk for adverse events may be potentiated by concomitant use of medications that interfere with statin metabolism.

METHODS

Data from The Health Improvement Network (THIN) from 1990 to 2008 were used to conduct a retrospective cohort study. Cohorts were created to evaluate each outcome (muscle toxicity, renal dysfunction, and hepatic dysfunction) independently. Each cohort included new statin initiators and compared the relative hazard of the outcome. The interaction ratio (I*R) was the primary contrast of interest. The I*R represents the relative effect of each statin type (statin 3A4 substrate vs. statin non-3A4 substrate) with a CYP3A4 inhibitor, independent of the effect of the statin type without a CYP3A4 inhibitor. We adjusted for confounding variables using the multinomial propensity score.

RESULTS

The median follow-up time per cohort was 1.5 years. There were 7889 muscle toxicity events among 362,809 patients and 792,665 person-years. The adjusted muscle toxicity I*R was 1.22 (95% confidence interval [CI] = 0.90-1.66). There were 1449 renal dysfunction events among 272,099 patients and 574,584 person-years. The adjusted renal dysfunction I*R was 0.91 (95%CI = 0.58-1.44). There were 1434 hepatic dysfunction events among 367,612 patients and 815,945 person-years. The adjusted hepatic dysfunction I*R was 0.78 (95%CI = 0.45-1.31).

CONCLUSIONS

Overall, this study found no difference in the relative hazard of muscle toxicity, renal dysfunction, or hepatic dysfunction for patients prescribed a statin 3A4 substrate versus a statin non-3A4 substrate with CYP3A4 inhibitor concomitancy.

Accuracy of pneumonia hospital admissions in a primary care electronic medical record database

PURPOSE

When using electronic medical record data to study drug use, hospitalizations are markers of severe outcomes. To identify events within a specified time window, it is important to validate hospitalization diagnoses and dates. Our objective was to validate pneumonia hospitalizations and their dates identified using hospitalization codes in The Health Improvement Network (THIN), a UK primary care electronic medical record.

METHODS

This cross-sectional study used a cohort of THIN adult visits for acute nonspecific respiratory infections from June 1985 to August 2006. Pneumonia hospitalizations within 30 days after the visit were identified using THIN diagnosis and hospitalization codes; 60 participants were randomly selected for validation. Patients' general practitioners (GPs) returned de-identified hospital summaries and consultants' letters regarding overnight hospitalizations within a 180-day window around the THIN hospitalization. Positive predictive value (PPV) was the number of GP-validated hospitalizations divided by THIN documented hospitalizations.

RESULTS

GPs returned 59 of 60 patient records; 52 had confirmed hospitalizations. PPV of THIN hospitalization documentation was 88% (95%CI = 77-95). One admission was not for pneumonia; PPV of THIN-documented pneumonia admission was 86% (95%CI = 75-94). Of 52 valid THIN hospitalizations, 50 were actually admitted within 14 days of the documented THIN date (range = -2 to +18). The absolute median difference between THIN and validated admission dates was +0.5 days, and the absolute mean difference was +3.1 days. In 16 of 52 admitted patients, the THIN admission date was the actual discharge date.

CONCLUSIONS

THIN hospitalization codes performed well in identifying acute pneumonia hospitalizations and their timing. Admission date validity might be better for conditions associated with shorter versus longer hospitalizations.

Attributable risk estimate of severe psoriasis on major cardiovascular events

BACKGROUND

Recent studies suggest that psoriasis, particularly if severe, may be a risk factor for major adverse cardiac events, such as myocardial infarction, stroke, and mortality from cardiovascular disease. We compared the risk of major adverse cardiac events between patients with psoriasis and the general population and estimated the attributable risk of severe psoriasis.

METHODS

We performed a cohort study in the General Practice Research Database. Severe psoriasis was defined as receiving a psoriasis diagnosis and systemic therapy (N=3603). Up to 4 patients without psoriasis were selected from the same practices and start dates for each patient with psoriasis (N=14,330).

RESULTS

Severe psoriasis was a risk factor for major adverse cardiac events (hazard ratio 1.53; 95% confidence interval, 1.26-1.85) after adjusting for age, gender, diabetes, hypertension, tobacco use, and hyperlipidemia. After fully adjusted analysis, severe psoriasis conferred an additional 6.2% absolute risk of 10-year major adverse cardiac events.

CONCLUSION

Severe psoriasis confers an additional 6.2% absolute risk of a 10-year rate of major adverse cardiac events compared with the general population. This potentially has important therapeutic implications for cardiovascular risk stratification and prevention in patients with severe psoriasis. Future prospective studies are needed to validate these findings.

Threshold haemoglobin levels and the prognosis of stable coronary disease: two new cohorts and a systematic review and meta-analysis

BACKGROUND

Low haemoglobin concentration has been associated with adverse prognosis in patients with angina and myocardial infarction (MI), but the strength and shape of the association and the presence of any threshold has not been precisely evaluated.

METHODS AND FINDINGS

A retrospective cohort study was carried out using the UK General Practice Research Database. 20,131 people with a new diagnosis of stable angina and no previous acute coronary syndrome, and 14,171 people with first MI who survived for at least 7 days were followed up for a mean of 3.2 years. Using semi-parametric Cox regression and multiple adjustment, there was evidence of threshold haemoglobin values below which mortality increased in a graded continuous fashion. For men with MI, the threshold value was 13.5 g/dl (95% confidence interval [CI] 13.2-13.9); the 29.5% of patients with haemoglobin below this threshold had an associated hazard ratio for mortality of 2.00 (95% CI 1.76-2.29) compared to those with haemoglobin values in the lowest risk range. Women tended to have lower threshold haemoglobin values (e.g, for MI 12.8 g/dl; 95% CI 12.1-13.5) but the shape and strength of association did not differ between the genders, nor between patients with angina and MI. We did a systematic review and meta-analysis that identified ten previously published studies, reporting a total of only 1,127 endpoints, but none evaluated thresholds of risk.

CONCLUSIONS

There is an association between low haemoglobin concentration and increased mortality. A large proportion of patients with coronary disease have haemoglobin concentrations below the thresholds of risk defined here. Intervention trials would clarify whether increasing the haemoglobin concentration reduces mortality.

Using free text information to explore how and when GPs code a diagnosis of ovarian cancer: an observational study using primary care records of patients with ovarian cancer

BACKGROUND

Primary care databases provide a unique resource for healthcare research, but most researchers currently use only the Read codes for their studies, ignoring information in the free text, which is much harder to access.

OBJECTIVES

To investigate how much information on ovarian cancer diagnosis is 'hidden' in the free text and the time lag between a diagnosis being described in the text or in a hospital letter and the patient being given a Read code for that diagnosis.

DESIGN

Anonymised free text records from the General Practice Research Database of 344 women with a Read code indicating ovarian cancer between 1 June 2002 and 31 May 2007 were used to compare the date at which the diagnosis was first coded with the date at which the diagnosis was recorded in the free text. Free text relating to a diagnosis was identified (a) from the date of coded diagnosis and (b) by searching for words relating to the ovary.

RESULTS

90% of cases had information relating to their ovary in the free text. 45% had text indicating a definite diagnosis of ovarian cancer. 22% had text confirming a diagnosis before the coded date; 10% over 4 weeks previously. Four patients did not have ovarian cancer and 10% had only ambiguous or suspected diagnoses associated with the ovarian cancer code.

CONCLUSIONS

There was a vast amount of extra information relating to diagnoses in the free text. Although in most cases text confirmed the coded diagnosis, it also showed that in some cases GPs do not code a definite diagnosis on the date that it is confirmed. For diseases which rely on hospital consultants for diagnosis, free text (particularly letters) is invaluable for accurate dating of diagnosis and referrals and also for identifying misclassified cases.

The effect of influenza vaccination on risk of acute myocardial infarction: self-controlled case-series study

Acute myocardial infarction (AMI) peaks in winter months, partly linked to epidemic influenza. This implies that influenza vaccination may prevent some cases of AMI. This study investigated the association between influenza vaccination and AMI using the self-controlled case-series method. We identified 8180 cases of first AMI aged 40 years and over at time of diagnosis. The incidence of AMI was significantly reduced in the 60 days following vaccination (compared with the baseline period), ranging from a reduction of 32% (IRR 0.68; 95% CI 0.60-0.78) at 1-14 days after vaccination, to 18% (IRR 0.82; 95% CI 0.75-0.90) at 29-59 days after vaccination. Reductions in AMI incidence were more pronounced for early seasonal vaccinations before mid-November.

Constituent country inequalities in myocardial infarction incidence and case fatality in men and women in the United Kingdom, 1996-2005

BACKGROUND

Understanding myocardial infarction (MI) incidence and case fatality trends across the four UK constituent countries is of importance following devolution of the government of health-care services.

METHODS

Retrospective cohort study using a primary care database (5.19 million patients) examining trends in incidence of first MI and 30-day case fatality.

RESULTS

From 1996 to 2005, the incidence of MI decreased in all countries, but reductions were greater in England (men, -3.1%; women, -2.8%) and Wales (men, -3.3%; women, -4.6%) than in Scotland (men, -1.9%; women, -0.6%) and Northern Ireland (men no change, women, -0.8%) (average annual percentage change). Greater reductions in England and Wales than Scotland and Northern Ireland meant a widening of north-south difference in MI incidence over the study period. Downward trends in 30-day case fatality were found in each country but less regional variation was evident (England men, -12.0%, women, -11.0%; Wales men, -18.4%, women, -12.6%; Scotland men, -9.5%, women, -9.0%; Northern Ireland men, -8.6%, women, -13.0%).

CONCLUSION

From 1996 to 2005, downward trends in the incidence of first MI and 30-day case fatality were evident in each constituent country. Greater improvements in case fatality, compared with incidence, were found within each country.

Validity of diagnostic coding within the General Practice Research Database: a systematic review

BACKGROUND

The UK-based General Practice Research Database (GPRD) is a valuable source of longitudinal primary care records and is increasingly used for epidemiological research.

AIM

To conduct a systematic review of the literature on accuracy and completeness of diagnostic coding in the GPRD.

DESIGN OF STUDY

Systematic review.

METHOD

Six electronic databases were searched using search terms relating to the GPRD, in association with terms synonymous with validity, accuracy, concordance, and recording. A positive predictive value was calculated for each diagnosis that considered a comparison with a gold standard. Studies were also considered that compared the GPRD with other databases and national statistics.

RESULTS

A total of 49 papers are included in this review. Forty papers conducted validation of a clinical diagnosis in the GPRD. When assessed against a gold standard (validation using GP questionnaire, primary care medical records, or hospital correspondence), most of the diagnoses were accurately recorded in the patient electronic record. Acute conditions were not as well recorded, with positive predictive values lower than 50%. Twelve papers compared prevalence or consultation rates in the GPRD against other primary care databases or national statistics. Generally, there was good agreement between disease prevalence and consultation rates between the GPRD and other datasets; however, rates of diabetes and musculoskeletal conditions were underestimated in the GPRD.

CONCLUSION

Most of the diagnoses coded in the GPRD are well recorded. Researchers using the GPRD may want to consider how well the disease of interest is recorded before planning research, and consider how to optimise the identification of clinical events.

Psoriasis and cardiovascular risk: strength in numbers

In this issue, Wakkee and colleagues report a self-described exploratory cohort study and conclude that psoriasis may not be an independent risk factor for ischemic heart disease (IHD) hospitalization and that there is only a slight and borderline increased risk of ischemic heart disease among psoriasis patients. This negative result should be interpreted in light of the study's limitations, the complex relationship among levels of psoriasis severity, patient age, and cardiovascular (CV) risk, and the context of the rapidly growing literature.