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We lead multidisciplinary applied research and training to rethink the way health care is delivered in general practice and across the community.
Identifying patients with suspected gastro-oesophageal cancer in primary care: Derivation and validation of an algorithm
Background: Gastro-oesphageal is one of the most common cancers worldwide. Evidence suggested that increased awareness of symptoms and earlier diagnosis could help improve treatment options and improve survival. Aim: To derive and validate an algorithm to estimate the absolute risk of having gastro-oesophageal cancer in patients in primary care with and without symptoms. Design and setting: Cohort study of 375 UK QResearch® general practices for development, and 189 for validation. Method: Included patients were aged 30-84 years, free at baseline of a diagnosis of gastro-oesophageal cancer, and without dysphagia, haematemesis, abdominal pain, appetite loss, or weight loss recorded in previous 12months. The primary outcome was incident diagnosis of gastro-oesophageal cancer recorded in the next 2 years. Risk factors examined were age, body mass index, alcohol status, smoking status, deprivation, family history of gastrointestinal cancer, dysphagia, previous diagnosis of cancer apart from gastro-oesophageal cancer, haematemesis, abdominal pain, appetite loss, weight loss, tiredness, and anaemia. Cox proportional hazards models were used to develop risk equations. Measures of calibration and discrimination assessed performance in the validation cohort. Results: There were 2527 incident cases of gastro-oesophageal cancer from 4.1 million person-years in the derivation cohort. Independent predictors were age, smoking, dysphagia, haematemesis, abdominal pain, appetite loss, weight loss, and anaemia. On validation, the algorithms explained 71% of the variation in females and 73% in males. The receiver operating curve statistics were 0.89 (females) and 0.92 (males). The D statistic was 3.2 (females) and 3.3 (males). The 10% of patients with the highest predicted risks included 77% of all gastro-oesophageal cancers diagnosed over the next 2 years. Conclusion: The algorithm has good performance and could potentially be used to help identify those at highest risk of gastro-oesophageal cancer, to facilitate early referral and investigation. ©British Journal of General Practice.
Antidepressant use and risk of adverse outcomes in older people: Population based cohort study
Objectives: To investigate the association between antidepressant treatment and risk of several potential adverse outcomes in older people with depression and to examine risks by class of antidepressant, duration of use, and dose. Design: Cohort study of people aged 65 and over diagnosed as having depression. Setting: 570 general practices in the United Kingdom supplying data to the QResearch primary care database. Participants: 60 746 patients diagnosed as having a new episode of depression between the ages of 65 and 100 years from 1 January 1996 to 31 December 2007 and followed up until 31 December 2008. Main outcome measures: Hazard ratios associated with antidepressant use for all cause mortality, attempted suicide/self harm, myocardial infarction, stroke/transient ischaemic attack, falls, fractures, upper gastrointestinal bleeding, epilepsy/seizures, road traffic accidents, adverse drug reactions, and hyponatraemia, adjusted for a range of potential confounding variables. Hazard ratios were calculated for antidepressant class (tricyclic and related antidepressants, selective serotonin reuptake inhibitors, other antidepressants), dose, and duration of use and for commonly prescribed individual drugs. Results: 54 038 (89.0%) patients received at least one prescription for an antidepressant during follow-up. A total of 1 398 359 antidepressant prescriptions were issued: 764 659 (54.7%) for selective serotonin reuptake inhibitors, 442 192 (31.6%) for tricyclic antidepressants, 2203 (0.2%) for monoamine oxidase inhibitors, and 189 305 (13.5%) for the group of other antidepressants. The associations with the adverse outcomes differed significantly between the antidepressant classes for seven outcomes. Selective serotonin reuptake inhibitors were associated with the highest adjusted hazard ratios for falls (1.66, 95% confidence interval 1.58 to 1.73) and hyponatraemia (1.52, 1.33 to 1.75) compared with when antidepressants were not being used. The group of other antidepressants was associated with the highest adjusted hazard ratios for all cause mortality (1.66, 1.56 to 1.77), attempted suicide/self harm (5.16, 3.90 to 6.83), stroke/transient ischaemic attack (1.37, 1.22 to 1.55), fracture (1.64, 1.46 to 1.84), and epilepsy/seizures (2.24, 1.60 to 3.15), compared with when antidepressants were not being used. Tricyclic antidepressants did not have the highest hazard ratio for any of the outcomes. Significantly different associations also existed between the individual drugs for the same seven outcomes; trazodone (tricyclic antidepressant), mirtazapine, and venlafaxine (both in the group of other antidepressants) were associated with the highest rates for some of these outcomes. Absolute risks over 1 year for all cause mortality were 7.04% for patients while not taking antidepressants, 8.12% for those taking tricyclic antidepressants, 10.61% for selective serotonin reuptake inhibitors, and 11.43% for other antidepressants. Conclusions: Selective serotonin reuptake inhibitors and drugs in the group of other antidepressants were associated with an increased risk of several adverse outcomes compared with tricyclic antidepressants. Among individual drugs, trazodone, mirtazapine, and venlafaxine were associated with the highest risks for some outcomes. As this is an observational study, it is susceptible to confounding by indication, channelling bias, and residual confounding, so differences in characteristics between patients prescribed different antidepressant drugs that could account for some of the associations between the drugs and the adverse outcomes may remain. Further research is needed to confirm these findings, but the risks and benefits of different antidepressants should be carefully evaluated when these drugs are prescribed to older people.
Exposure to bisphosphonates and risk of cancer: A protocol for nested case - Control studies using the QResearch primary care database
Introduction: Bisphosphonates are becoming a common treatment for osteoporosis particularly after discovery of the association between hormone replacement therapy and increased risk of breast cancer. As osteoporosis develops with age, treatment is a long-term intervention. Randomised control trials typically have limited follow-up times, which restricts investigation of the effects of the drugs on risk of primary cancers. A few observational studies have demonstrated a reduced risk of breast cancer and possibly of endometrial cancer in bisphosphonate users. Two epidemiological studies have studied the effect of the drugs on oesophageal cancer but did not reach any definite conclusions. So far, no effects on colorectal and stomach cancer have been shown. This study will investigate the association of bisphosphonates with risks of the 10 most common primary cancers. Methods and analysis: A series of nested caseecontrol studies will be based on the general population using records from 660 UK general practices within the QResearch Database. Cases will be patients with primary cancers diagnosed between 1996 and 2011. Each case will be matched by age, sex, practice and calendar year to five controls, who are alive and registered with the practice at the time of diagnosis of the case. Exposure to bisphosphonates will be defined as at least one prescription during the study period. For the most common cancers with substantial numbers of observations, the effect of the duration of the treatment and different types of bisphosphonates will be studied. Conditional logistic regression will be applied to produce ORs adjusted for smoking status, socioeconomic status, ethnicity, cancer-specific co-morbidities and use of other medications.
Development and validation of risk prediction equations to estimate future risk of blindness and lower limb amputation in patients with diabetes: Cohort study
STUDY QUESTION: Is it possible to develop and externally validate risk prediction equations to estimate the 10 year risk of blindness and lower limb amputation in patients with diabetes aged 25-84 years? METHODS: This was a prospective cohort study using routinely collected data from general practices in England contributing to the QResearch and Clinical Practice Research Datalink (CPRD) databases during the study period 1998-2014. The equations were developed using 763 QResearch practices (n=454 575 patients with diabetes) and validated in 254 different QResearch practices (n=142 419) and 357 CPRD practices (n=206 050). Cox proportional hazards models were used to derive separate risk equations for blindness and amputation in men and women that could be evaluated at 10 years. Measures of calibration and discrimination were calculated in the two validation cohorts. STUDY ANSWER AND LIMITATIONS: Risk prediction equations to quantify absolute risk of blindness and amputation in men and women with diabetes have been developed and externally validated. In the QResearch derivation cohort, 4822 new cases of lower limb amputation and 8063 new cases of blindness occurred during follow-up. The risk equations were well calibrated in both validation cohorts. Discrimination was good in men in the external CPRD cohort for amputation (D statistic 1.69, Harrell's C statistic 0.77) and blindness (D statistic 1.40, Harrell's C statistic 0.73), with similar results in women and in the QResearch validation cohort. The algorithms are based on variables that patients are likely to know or that are routinely recorded in general practice computer systems. They can be used to identify patients at high risk for prevention or further assessment. Limitations include lack of formally adjudicated outcomes, information bias, and missing data. WHAT THIS STUDY ADDS: Patients with type 1 or type 2 diabetes are at increased risk of blindness and amputation but generally do not have accurate assessments of the magnitude of their individual risks. The new algorithms calculate the absolute risk of developing these complications over a 10 year period in patients with diabetes, taking account of their individual risk factors. FUNDING, COMPETING INTERESTS, DATA SHARING: JH-C is co-director of QResearch, a not for profit organisation which is a joint partnership between the University of Nottingham and Egton Medical Information Systems, and is also a paid director of ClinRisk Ltd. CC is a paid consultant statistician for ClinRisk Ltd.
Safety of antidepressants in adults aged under 65: Protocol for a cohort study using a large primary care database
Background: Antidepressants are among the most commonly prescribed drugs in primary care in England and their use is increasing. This is largely due to longer durations of treatment of depression. Observational studies have shown some differences in adverse outcomes associated with different antidepressant drugs but relatively little is known about their relative safety particularly with long term use. The primary aim of this study is to determine the relative and absolute risks of pre-defined adverse events comparing different classes of antidepressant drugs in adults aged under 65 years and diagnosed with depression.Methods/design: The study will identify a cohort of patients with a first recorded diagnosis of depression between 1/1/2000 and 31/07/2011, and made between the ages of 20 to 64 years using a large primary care database (QResearch). Patients will be followed up until 1/08/2012. Details of all prescriptions for antidepressants in patients in the cohort will be extracted, including the date of each prescription, the type of antidepressant drug, the dose and total quantity prescribed. Prospectively recorded data will be used to ascertain information on adverse outcomes that occurred during follow-up and after entry into the cohort. These are: all-cause mortality, suicide, attempted suicide/self-harm, sudden death, antidepressant overdose/poisoning, myocardial infarction, stroke/transient ischaemic attack, cardiac arrhythmia, epilepsy/seizures, upper gastrointestinal bleeding, falls, fractures, adverse drug reactions and motor vehicle crashes. Cox proportional hazard models will be used to estimate the association of the outcomes with class of antidepressant drug adjusting for potential confounding variables. The analyses will also examine associations by duration and dose and with the most frequently prescribed individual antidepressant drugs. Self-controlled case series analyses will be used to estimate the relative incidence of the outcomes of interest for defined time periods of antidepressant use.Discussion: The results of this study will help to establish the relative safety and balance of risks for different antidepressant drugs in people aged under 65. © 2013 Coupland et al.; licensee BioMed Central Ltd.
Exposure to bisphosphonates and risk of gastrointestinal cancers: Series of nested case-control studies with QResearch and CPRD data
Objective To investigate the association between use of bisphosphonates estimated from prescription information and risk of gastrointestinal cancers. Design Series of nested case-control studies. Setting General practices in the United Kingdom contributing to the QResearch primary care database (660) and the Clinical Practice Research Datalink (CPRD) (643). Participants Patients aged =50 with a diagnosis of a primary gastrointestinal cancer in 1997-2011, each matched with up to five controls by age, sex, practice, and calendar year. Main outcome measures Odds ratios for incident gastrointestinal cancers (colorectal, oesophageal, gastric) and use of bisphosphonates, adjusted for smoking status, ethnicity, comorbidities, and use of other drugs. Results 20 106 and 19 035 cases of colorectal cancer cases, 5364 and 5135 cases of oesophageal cancer cases, and 3155 and 3157 cases of gastric cancer were identified from QResearch and CPRD, respectively. Overall bisphosphonate use (at least one prescription) was not associated with risk of colorectal, oesophageal, or gastric cancers in either database. Adjusted odds ratios (95% confidence interval) for QResearch and CPRD were 0.97 (0.79 to 1.18) and 1.18 (0.97 to 1.43) for oesophageal cancer; 1.12 (0.87 to 1.44) and 0.79 (0.62 to 1.01) for gastric cancer; and 1.03 (0.94 to 1.14) and 1.10 (1.00 to 1.22) for colorectal cancer. Additional analyses showed no difference between types of bisphosphonate for risk of oesophageal and colorectal cancers. For gastric cancer, alendronate use was associated with an increased risk (1.47, 1.11 to 1.95; P=0.008), but only in data from the QResearch database and without any association with duration and with no definitive confirmation from sensitivity analysis. Conclusions In this series of population based case-control studies in two large primary care databases, exposure to bisphosphonates was not associated with an increased risk of common gastrointestinal cancers. © BMJ Publishing Group Ltd 2013.
Antidepressant use and risk of adverse outcomes in people aged 20-64 years: Cohort study using a primary care database
Background: Antidepressants are one of the most commonly prescribed medications in young and middle-aged adults, but there is relatively little information on their safety across a range of adverse outcomes in this age group. This study aimed to assess associations between antidepressant treatment and several adverse outcomes in people aged 20-64 years diagnosed with depression. Methods: We conducted a cohort study in 238,963 patients aged 20-64 years registered with practices across the UK contributing to the QResearch primary care database. Only patients with a first diagnosis of depression were included. Outcomes were falls, fractures, upper gastrointestinal bleed, road traffic accidents, adverse drug reactions and all-cause mortality recorded during follow-up. Cox proportional hazards models were used to estimate hazard ratios associated with antidepressant exposure adjusting for potential confounding variables. Results: During 5 years of follow-up, 4651 patients had experienced a fall, 4796 had fractures, 1066 had upper gastrointestinal bleeds, 3690 had road traffic accidents, 1058 had experienced adverse drug reactions, and 3181 patients died. Fracture rates were significantly increased for selective serotonin reuptake inhibitors (adjusted hazard ratio 1.30, 95% CI 1.21-1.39) and other antidepressants (1.28, 1.11-1.48) compared with periods when antidepressants were not used. All antidepressant drug classes were associated with significantly increased rates of falls. Rates of adverse drug reactions were significantly higher for tricyclic and related antidepressants (1.54, 1.25-1.88) and other antidepressants (1.61, 1.22-2.12) compared with selective serotonin reuptake inhibitors. Trazodone was associated with a significantly increased risk of upper gastrointestinal bleed. All-cause mortality rates were significantly higher for tricyclic and related antidepressants (1.39, 1.22-1.59) and other antidepressants (1.26, 1.08-1.47) than for selective serotonin reuptake inhibitors over 5 years but not 1 year, and were significantly reduced after 85 or more days of treatment with selective serotonin reuptake inhibitors. Mirtazapine was associated with significantly increased mortality rates over 1 and 5 years of follow-up. Conclusions: Selective serotonin reuptake inhibitors had higher rates of fracture than tricyclic and related antidepressants but lower mortality and adverse drug reaction rates than the other antidepressant drug classes. The association between mirtazapine and increased mortality merits further investigation. These risks should be carefully considered and balanced against potential benefits for individual patients when the decision to prescribe an antidepressant is made.
Derivation, validation, and evaluation of a new QRISK model to estimate lifetime risk of cardiovascular disease: Cohort study using QResearch database
Objective: To develop, validate, and evaluate a new QRISK model to estimate lifetime risk of cardiovascular disease. Design: Prospective cohort study with routinely collected data from general practice. Cox proportional hazards models in the derivation cohort to derive risk equations accounting for competing risks. Measures of calibration and discrimination in the validation cohort. Setting: 563 general practices in England and Wales contributing to the QResearch database. Subjects: Patients aged 30-84 years who were free of cardiovascular disease and not taking statins between 1 January 1994 and 30 April 2010: 2 343 759 in the derivation dataset, and 1 267 159 in the validation dataset. Main outcomes measures: Individualised estimate of lifetime risk of cardiovascular disease accounting for smoking status, ethnic group, systolic blood pressure, ratio of total cholesterol:high density lipoprotein cholesterol, body mass index, family history of coronary heart disease in first degree relative aged <60 years, Townsend deprivation score, treated hypertension, rheumatoid arthritis, chronic renal disease, type 2 diabetes, and atrial fibrillation. Age-sex centile values for lifetime cardiovascular risk compared with 10 year risk estimated using QRISK2 (2010). Results: Across all the 1 267 159 patients in the validation dataset, the 50th, 75th, 90th, and 95th centile values for lifetime risk were 31%, 39%, 50%, and 57% respectively. Of the 10% of patients in the validation cohort classified at highest risk with either the lifetime risk model or the 10 year risk model, only 18 385(14.5%) were at high risk on both measures. Patients identified as high risk with the lifetime risk approach were more likely to be younger, male, from ethnic minority groups, and have a positive family history of premature coronary heart disease than those identified with the 10 year QRISK2 score. The lifetime risk calculator is available at www.qrisk.org/lifetime/. Conclusions: Compared with using a 10 year QRISK2 score, a lifetime risk score will tend to identify patients for intervention at a younger age. Although lifestyle interventions at an earlier age could be advantageous, there would be small gains under the age of 65, and medical interventions carry risks as soon as they are initiated. Research is needed to examine closely the cost effectiveness and acceptability of such an approach.
Derivation and validation of updated QFracture algorithm to predict risk of osteoporotic fracture in primary care in the United Kingdom: Prospective open cohort study
Objective: To develop and validate an updated version of the QFracture algorithm for estimating the risk of a patient sustaining an osteoporotic fracture or hip fracture in a primary care population. Design: Prospective open cohort study using routinely collected data from 420 general practices in the United Kingdom to develop updated QFracture scores and 207 practices to validate scores. Cox's proportional hazards model was used in the derivation cohort to derive risk equations using several explanatory variables. We calculated measures of calibration and discrimination using the validation cohort. Participants: 3 142 673 patients in derivation cohort and 1 583 373 in validation cohort, aged 30-100 years, who contributed 23 608 337 and 11 732 106 person years of observation, respectively. We identified 59 772 incident diagnoses of osteoporotic fracture in the derivation cohort and 28 685 in the validation cohort. Outcomes: Incident diagnosis of osteoporotic fracture (vertebral, distal radius, proximal humerus, or hip) and incident hip fracture recorded in general practice records or linked cause of death records. Results: We found significant independent associations with overall fracture risk in women for age, body mass index, ethnic origin, alcohol intake, smoking status, chronic obstructive pulmonary disease or asthma, any cancer, cardiovascular disease, dementia, diagnosis or treatment for epilepsy, history of falls, chronic liver disease, Parkinson's disease, rheumatoid arthritis or systemic lupus erythematosus, chronic renal disease, type 1 diabetes, type 2 diabetes, previous fracture, endocrine disorders, gastrointestinal malabsorption, any antidepressants, corticosteroids, unopposed hormone replacement therapy, and parental history of osteoporosis. Risk factors for hip fracture in women were similar except for gastrointestinal malabsorption and parental history of hip fracture. Risk factors for men were largely the same as those for women but also included care home residence. The updated hip fracture algorithm explained 71.7% (95% confidence interval 71.1% to 72.3%) of the variation in women and 70.4% (69.3% to 71.5%) in men. D statistic values for hip fracture were high for women (3.26, 3.21 to 3.31) and men (3.15, 3.06 to 3.24), and higher than for osteoporotic fracture. Values for the area under the receiver operating characteristics curves for hip fracture were 0.89 for women and 0.88 for men, compared with 0.79 and 0.71 for osteoporotic fracture, respectively. The updated algorithms performed better than the 2009 algorithms. Conclusions: Two QFracture algorithms were updated to predict risk of osteoporotic and hip fracture in primary care populations to include ethnic origin, all classes of antidepressants, chronic obstructive pulmonary disease, epilepsy, dementia, Parkinson's disease, cancer, systemic lupus erythematosus, chronic renal disease, type 1 diabetes, previous fragility fracture, and care home residence. These updated algorithms showed improved performance compared with previous QFracture algorithms reported in 2009.
Exposure to bisphosphonates and risk of common non-gastrointestinal cancers: Series of nested case-control studies using two primary-care databases
Background: Bisphosphonates are the most commonly prescribed osteoporosis drugs but long-term effects are unclear, although antitumour properties are known from preclinical studies. Methods: Nested case-control studies were conducted to investigate bisphosphonate use and risks of common non-gastrointestinal cancers (breast, prostate, lung, bladder, melanoma, ovarian, pancreas, uterus and cervical). Patients 50 years and older, diagnosed with primary cancers between 1997 and 2011, were matched to five controls using the UK practice-based QResearch and Clinical Practice Research Datalink (CPRD) databases. The databases were analysed separately and the results combined.Results:A total of 91 556 and 88 845 cases were identified from QResearch and CPRD, respectively. Bisphosphonate use was associated with reduced risks of breast (odds ratio (OR): 0.92, 95% confidence interval (CI): 0.87-0.97), prostate (OR: 0.87, 95% CI: 0.79-0.96) and pancreatic (OR: 0.79, 95% CI: 0.68-0.93) cancers in the combined analyses, but no significant trends with duration. For alendronate, reduced risk associations were found for prostate cancer in the QResearch (OR: 0.81, 95% CI: 0.70-0.93) and combined (OR: 0.84, 95% CI: 0.75-0.93) analyses (trend with duration P-values 0.009 and 0.001). There were no significant associations from any of the other analyses. Conclusion: In this series of large population-based case-control studies, bisphosphonate use was not associated with increased risks for any common non-gastrointestinal cancers. © 2013 Cancer Research UK. All rights reserved.
Risks and benefits of direct oral anticoagulants versus warfarin in a real world setting: cohort study in primary care
OBJECTIVE: To investigate the associations between direct oral anticoagulants (DOACs) and risks of bleeding, ischaemic stroke, venous thromboembolism, and all cause mortality compared with warfarin. DESIGN: Prospective open cohort study. SETTING: UK general practices contributing to QResearch or Clinical Practice Research Datalink. PARTICIPANTS: 132 231 warfarin, 7744 dabigatran, 37 863 rivaroxaban, and 18 223 apixaban users without anticoagulant prescriptions for 12 months before study entry, subgrouped into 103 270 patients with atrial fibrillation and 92 791 without atrial fibrillation between 2011 and 2016. MAIN OUTCOME MEASURES: Major bleeding leading to hospital admission or death. Specific sites of bleeding and all cause mortality were also studied. RESULTS: In patients with atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (adjusted hazard ratio 0.66, 95% confidence interval 0.54 to 0.79) and intracranial bleeding (0.40, 0.25 to 0.64); dabigatran was associated with a decreased risk of intracranial bleeding (0.45, 0.26 to 0.77). An increased risk of all cause mortality was observed in patients taking rivaroxaban (1.19, 1.09 to 1.29) or on lower doses of apixaban (1.27, 1.12 to 1.45). In patients without atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (0.60, 0.46 to 0.79), any gastrointestinal bleeding (0.55, 0.37 to 0.83), and upper gastrointestinal bleeding (0.55, 0.36 to 0.83); rivaroxaban was associated with a decreased risk of intracranial bleeding (0.54, 0.35 to 0.82). Increased risk of all cause mortality was observed in patients taking rivaroxaban (1.51, 1.38 to 1.66) and those on lower doses of apixaban (1.34, 1.13 to 1.58). CONCLUSIONS: Overall, apixaban was found to be the safest drug, with reduced risks of major, intracranial, and gastrointestinal bleeding compared with warfarin. Rivaroxaban and low dose apixaban were, however, associated with increased risks of all cause mortality compared with warfarin.
A study of the safety and harms of antidepressant drugs for older people: A cohort study using a large primary care database
Objectives: The aim of this study was to establish the relative safety and balance of risks for antidepressant treatment in older people. The study objectives were to (1) determine relative and absolute risks of predefined adverse events in older people with depression, comparing classes of antidepressant drugs [tricyclic and related antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs) and other antidepressants] and commonly prescribed individual drugs with non-use of antidepressant drugs; (2) directly compare the risk of adverse events for SSRIs with TCAs; (3) determine associations with dose and duration of antidepressant medication; (4) describe patterns of antidepressant use in older people with depression; and (5) estimate costs of antidepressant medication and primary care visits. Design: A cohort study of patients aged 65 years and over diagnosed with depression. Setting: The study was based in 570 general practices in the UK supplying data to the QResearch database. Participants: Patients diagnosed with a new episode of depression between the ages of 65 and 100 years, from 1 January 1996 to 31 December 2007. Participants were followed up until 31 December 2008. Interventions: The exposure of interest was treatment with antidepressant medication. Antidepressant drugs were grouped into the major classes and commonly prescribed individual drugs were identified. Main outcome measures: There were 13 predefined outcome measures: all-cause mortality, sudden cardiac death, suicide, attempted suicide/self-harm, myocardial infarction, stroke/transient ischaemic attack (TIA), falls, fractures, upper gastrointestinal bleeding, epilepsy/seizures, road traffic accidents, adverse drug reactions and hyponatraemia. Results: In total, 60,746 patients were included in the study cohort. Of these, 54,038 (89.0%) received at least one prescription for an antidepressant during follow-up. The associations with the adverse outcomes were significantly different between the classes of antidepressant drugs for seven outcomes. SSRIs were associated with the highest adjusted hazard ratios (HRs) for falls [1.66, 95% confidence interval (CI) 1.58 to 1.73] and hyponatraemia (1.52, 95% CI 1.33 to 1.75), and the group of other antidepressants was associated with the highest HRs for all-cause mortality (1.66, 95% CI 1.56 to 1.77), attempted suicide/self-harm (5.16, 95% CI 3.90 to 6.83), stroke/TIA (1.37, 95% CI 1.22 to 1.55), fracture (1.63, 95% CI 1.45 to 1.83) and epilepsy/seizures (2.24, 95% CI 1.60 to 3.15) compared with when antidepressants were not being used. TCAs did not have the highest HR for any of the outcomes. There were also significantly different associations between the individual drugs for seven outcomes, with trazodone, mirtazapine and venlafaxine associated with the highest rates for several of these outcomes. The mean incremental cost (for all antidepressant prescriptions) ranged between £51.58 (amitriptyline) and £641.18 (venlafaxine) over the 5-year post-diagnosis period. Conclusions: This study found associations between use of antidepressant drugs and a number of adverse events in older people. There was no evidence that SSRIs or drugs in the group of other antidepressants were associated with a reduced risk of any of the adverse outcomes compared with TCAs; however, they may be associated with an increased risk for certain outcomes. Among individual drugs trazodone, mirtazapine and venlafaxine were associated with the highest rates for some outcomes. Indication bias and residual confounding may explain some of the study findings. The risks of prescribing antidepressants need to be weighed against the potential benefits of these drugs. © Queen's Printer and Controller of HMSO 2011.
Derivation and validation of QStroke score for predicting risk of ischaemic stroke in primary care and comparison with other risk scores: A prospective open cohort study
Objective: To develop and validate a risk algorithm (QStroke) to estimate risk of stroke or transient ischaemic attack in patients without prior stroke or transient ischaemic attack at baseline; to compare (a) QStroke with CHADS 2 and CHA2DS2VASc scores in patients with atrial fibrillation and (b) the performance of QStroke with the Framingham stroke score in the full population free of stroke or transient ischaemic attack. Design: Prospective open cohort study using routinely collected data from general practice during the study period 1 January 1998 to 1 August 2012. Setting: 451 general practices in England and Wales contributing to the national QResearch database to develop the algorithm and 225 different QResearch practices to validate the algorithm. Participants: 3.5 million patients aged 25-84 years with 24.8 million person years in the derivation cohort who experienced 77 578 stroke events. For the validation cohort, we identified 1.9 million patients aged 25-84 years with 12.7 million person years who experienced 38 404 stroke events. We excluded patients with a prior diagnosis of stroke or transient ischaemic attack and those prescribed oral anticoagulants at study entry. Main outcome measures: Incident diagnosis of stroke or transient ischaemic attack recorded in general practice records or linked death certificates during follow-up. Risk factors: Self assigned ethnicity, age, sex, smoking status, systolic blood pressure, ratio of total serum cholesterol to high density lipoprotein cholesterol concentrations, body mass index, family history of coronary heart disease in first degree relative under 60 years, Townsend deprivation score, treated hypertension, type 1 diabetes, type 2 diabetes, renal disease, rheumatoid arthritis, coronary heart disease, congestive cardiac failure, valvular heart disease, and atrial fibrillation Results: The QStroke algorithm explained 57% of the variation in women and 55% in men without a prior stroke. The D statistic for QStroke was 2.4 in women and 2.3 in men. QStroke had improved performance on all measures of discrimination and calibration compared with the Framingham score in patients without a prior stroke. Among patients with atrial fibrillation, levels of discrimination were lower, but QStroke had some improved performance on all measures of discrimination compared with CHADS2 and CHA2DS 2VASc. Conclusion: QStroke provides a valid measure of absolute stroke risk in the general population of patients free of stroke or transient ischaemic attack as shown by its performance in a separate validation cohort. QStroke also shows some improvement on current risk scoring methods, CHADS 2 and CHA2DS2VASc, for the subset of patients with atrial fibrillation for whom anticoagulation may be required. Further research is needed to evaluate the cost effectiveness of using these algorithms in primary care.