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AIMS/HYPOTHESIS: People with type 2 diabetes are at increased risk of developing obstructive sleep apnoea. However, it is not known whether people with type 1 diabetes are also at an increased risk of obstructive sleep apnoea. This study aimed to examine whether people with type 1 diabetes are at increased risk of incident obstructive sleep apnoea compared with a matched cohort without type 1 diabetes. METHODS: We used a UK primary care database, The Health Improvement Network (THIN), to perform a retrospective cohort study between January 1995 and January 2018 comparing sleep apnoea incidence between patients with type 1 diabetes (exposed) and without type 1 diabetes (unexposed) (matched for age, sex, BMI and general practice). The outcome was incidence of obstructive sleep apnoea. Baseline covariates and characteristics were assessed at the start of the study based on the most recent value recorded prior to the index date. The Cox proportional hazards regression model was used to estimate unadjusted and adjusted hazard ratios, based on a complete-case analysis. RESULTS: In total, 34,147 exposed and 129,500 matched unexposed patients were included. The median follow-up time was 5.43 years ((IQR 2.19-10.11), and the mean BMI was 25.82 kg/m (SD 4.33). The adjusted HR for incident obstructive sleep apnoea in patients with type 1 diabetes vs those without type 1 diabetes was 1.53 (95% CI 1.25, 1.86; p<0.001). Predictors of incident obstructive sleep apnoea in patients with type 1 diabetes were older age, male sex, obesity, being prescribed antihypertensive or lipid-lowering drugs, atrial fibrillation and depression. CONCLUSIONS/INTERPRETATION: Individuals with type 1 diabetes are at increased risk of obstructive sleep apnoea compared with people without diabetes. Clinicians should suspect obstructive sleep apnoea in patients with type 1 diabetes if they are old, have obesity, are male, have atrial fibrillation or depression, or if they are taking lipid-lowering or antihypertensive drugs.

BACKGROUND: Healthcare service provision in inflammatory bowel disease (IBD) is often designed to meet targets set by healthcare providers rather than those of patients. It is unclear whether this meets the needs of patients, as assessed by patients themselves. AIMS: To assess patients' experience of IBD and the healthcare they received, aiming to identify factors in IBD healthcare provision associated with perceived high-quality care. METHODS: Using the 2019 IBD standards as a framework, a national benchmarking tool for quality assessment in IBD was developed by IBD UK, comprising a patient survey and service self-assessment. RESULTS: 134 IBD services and 9757 patients responded. Perceived quality of care was lowest in young adults and increased with age, was higher in males and those >2 years since diagnosis. No hospital services met all the national IBD standards for recommended workforce numbers. Key metrics associated with patient-reported high- quality care were: identification as a tertiary centre, patient information availability, shared decision- making, rapid response to contact for advice, access to urgent review, joint medical/surgical clinics, and access to research (all p < 0.001). Higher numbers of IBD nurse specialists in a service was strongly associated with patients receiving regular reviews and having confidence in self-management and reporting high- quality care. CONCLUSIONS: This extensive patient and healthcare provider survey emphasises the importance of aspects of care less often measured by clinicians, such as communication, shared decision- making and provision of information. It demonstrates that IBD nurse specialists are crucial to meeting the needs of people living with IBD.

OBJECTIVE: To investigate the association of concurrent use of oral anticoagulants (OACs) and sulfonylureas and the risk of hypoglycemia in individuals with type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS: A retrospective cohort study was conducted between 2001 and 2017 using electronic primary healthcare data from the IQVIA Medical Research Data (IMRD) that incorporates data supplied by The Health Improvement Network (THIN), a propriety database of Cegedim SA. Individuals with T2DM who received OAC prescription and sulfonylureas were included. We compared the risk of hypoglycemia with sulfonylureas and OACs using propensity score matching and Cox regression. RESULTS: 109,040 individuals using warfarin and sulfonylureas and 77,296 using direct oral anticoagulants (DOACs) and sulfonylureas were identified and included. There were 285 hypoglycemia events in the warfarin with sulfonylureas group (incidence rate = 17.8 per 1,000 person-years), while in the sulfonylureas only, 304 hypoglycemia events were observed (incidence rate = 14.4 per 1,000 person-years). There were 14 hypoglycemic events in the DOACs with sulfonylureas group (incidence rates = 14.8 per 1,000 person-years), while in the sulfonylureas alone group, 60 hypoglycemia events were observed (incidence rate =23.7 per 1,000 person-years). Concurrent use of warfarin and sulfonylureas was associated with increased risk of hypoglycemia compared with sulfonylureas alone (HR 1.38; 95% CI 1.10-1.75). However, we found no evidence of an association between concurrent use of DOACs and sulfonylureas and risk of hypoglycemia (HR 0.54; 95% CI, 0.27-1.10) when compared with sulfonylureas only. CONCLUSIONS: We provide real-world evidence of possible drug-drug interactions between warfarin and sulfonylureas. The decision to prescribe warfarin with coexistent sulfonylureas to individuals with T2DM should be carefully evaluated in the context of other risk factors of hypoglycemia, and availability of alternative medications.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is small vessel vasculitis with heterogeneous clinical presentation. In the present population-based cohort study, we classified patients with GPA based on clinical features at presentation using an unsupervised clustering approach and compared their mortality, infections and frequency of comorbidities. METHODS: In this open cohort study, de-identified primary care data of patients with GPA included in the IQVIA Medical Research Data database between 1 January 1995 and 25 September 2019 was analysed retrospectively. Latent class analysis was performed to create symptom clusters of patients based on 16 categories of symptoms representing various organ involvement. All-cause mortality of resultant clusters was compared after adjusting for age, sex, Townsend deprivation quintile and smoking status at index date using extended Cox proportional hazards models. Prescription of antibiotics, considered as an indirect indicator of recurrent bacterial infection, was compared using a recurrent event model, after adjusting for quarterly use of steroid as a time-dependent covariate. Cumulative frequencies of common comorbidities were compared among the clusters at index visit, 1-year and 3-year follow-up. RESULTS: Altogether, 649 patients with GPA [median age 60.0 (IQR: 49.6-70.1)] were included. Three clusters were identified: patients with limited disease mainly with involvement of ENT and cough were classified into cluster 1 (n = 426); cluster 2 had generalised non-renal disease (n = 176); while patients in cluster 3 had renal-predominant disease (n = 47). Many patients in cluster 1 developed generalised disease at the end of 1 year. Mortality in clusters 2 and 3 was higher compared with cluster 1. Mortality in cluster 1 itself was 68% higher than the general population without GPA. The duration of antibiotics prescription and frequency of coexisting medical illnesses was also higher in clusters 2 and 3. CONCLUSIONS: In a primary care setting, patients with GPA can be classified into three distinct clusters with different prognosis, susceptibility to recurrent infections and presence of comorbidities. The tendency of cluster 1 to evolve into a more generalised disease raises questions about current immunosuppressive treatment approaches in these patients.

BACKGROUND: Chronic inflammatory conditions have been linked to dementia, but little is known about the role of atopic eczema, an inflammatory condition recently recognized to be common among older adults. OBJECTIVE: To determine whether active atopic eczema is associated with incident dementia. METHODS: A longitudinal cohort study of 1,767,667 individuals aged 60 to 99 years registered with The Health Improvement Network, a primary care cohort in the United Kingdom. The diagnoses of atopic eczema and dementia were identified using medical record codes. RESULTS: The incidence of dementia was 57 per 10,000 person-years among those with atopic eczema during follow-up (12.1% of the population) compared with 44 per 10,000 person-years in the control group. This translated to a 27% increased risk of dementia (hazard ratio, 1.27; 95% CI, 1.23-1.30) in adjusted Cox proportional hazard models. Similar associations were observed in subgroup analyses of vascular dementia and Alzheimer's disease. The association persisted after additionally adjusting for the use of systemic corticosteroids (hazard ratio, 1.29; 95% CI, 1.26-1.33) and potential mediators (hazard ratio, 1.19; 95% CI, 1.16-1.22). More severe eczema was associated with a higher risk of dementia. LIMITATIONS: Lack of detailed data on severity. CONCLUSION: Atopic eczema was associated with a small but increased risk of incident dementia. The association increased with the severity of atopic eczema.

BACKGROUND: Tramadol is a widely used weak opioid; however, the evidence for its safety profile in respiratory system needs additional information. We aimed to examine whether tramadol use is associated with an increased risk of pneumonia in the general population. METHODS: We conducted five propensity-score (PS) matched cohort studies in The Health Improvement Network database. Participants aged ≥50-years initiated tramadol were compared with those initiated one of the following analgesics: codeine (n = 144,506), naproxen (n = 113,028), diclofenac (n = 74,297), celecoxib (n = 42,538), or etoricoxib (n = 27,232). The outcome was incident pneumonia. OUTCOMES: During 6-month follow-up, 395 pneumonia (5.6/1000 person-years) occurred in the tramadol group and 414 pneumonia (5.9/1000 person-years) occurred in the PS matched codeine group. Compared with codeine group, the risk of pneumonia was lower in the tramadol group (hazard ratio [HR] = 0.63, 95% confidence interval [CI]: 0.49-0.82) during the first 30-day follow-up, but comparable between groups over the entire 6-month follow-up (HR = 0.95, 95%CI: 0.83-1.09). In addition, the risk of pneumonia was higher in the tramadol group than that in the PS matched naproxen (HR = 1.68, 95%CI: 1.37-2.06), diclofenac (HR = 1.63, 95%CI: 1.31-2.03), celecoxib (HR = 1.64, 95%CI: 1.20-2.24) or etoricoxib (HR = 1.61, 95%CI: 1.04-2.49) group. CONCLUSIONS: The present study indicated that tramadol initiators had a lower risk of incident pneumonia than codeine initiators during the short-time follow-up, but had a comparable pneumonia risk compared with codeine initiators and had a higher risk of pneumonia compared with NSAIDs initiators over the entire 6-month follow-up duration. Confirmation of the present findings and determination of the underlying mechanism will require more studies. SIGNIFICANCE: Tramadol might not be a safer alternative analgesic to codeine or NSAIDs. Both of health-care providers and patients may need to be on alert for its safety profile in respiratory system in future clinical practice.

AIM: We aimed to compare the mortality of individuals at low, moderate, and high risk of diabetic foot disease (DFD) in the context of newly diagnosed type 2 diabetes, before developing active diabetic foot problem. METHODS: This was a population-based cohort study of adults with newly diagnosed type 2 diabetes utilizing IQVIA Medical Research Data. The outcome was all-cause mortality among individuals with low, moderate, and high risk of DFD, and also in those with no record of foot assessment and those who declined foot examination. RESULTS: Of 225,787 individuals with newly diagnosed type 2 diabetes, 34,061 (15.1%) died during the study period from January 1, 2000 to December 31, 2019. Moderate risk and high risk of DFD were associated with increased mortality risk compared to low risk of DFD (adjusted hazard ratio [aHR] 1.50, 95% CI 1.42, 1.58; aHR 2.01, 95% CI 1.84, 2.20, respectively). Individuals who declined foot examination or who had no record also had increased mortality risk of 75% and 25% vs. those at low risk of DFD, respectively (aHR 1.75, 95% CI 1.51, 2.04; aHR 1.25, 95% CI 1.20, 1.30). CONCLUSION: Individuals with new-onset type 2 diabetes who had moderate to high risk of DFD were more likely to die compared to those at low risk of DFD. The associations between declined foot examination and absence of foot examinations, and increased risk of mortality further highlight the importance of assessing foot risk as it identifies not only patients at risk of diabetic foot ulceration but also mortality.

BACKGROUND: Meta-analyses of test accuracy studies may provide estimates that are highly improbable in clinical practice. Tailored meta-analysis produces plausible estimates for the accuracy of a test within a specific setting by tailoring the selection of included studies compatible with a specific setting using information from the target setting. The aim of this study was to validate the tailored meta-analysis approach by comparing outcomes from tailored meta-analysis with outcomes from a setting specific test accuracy study. METHODS: A retrospective cohort study of primary care electronic health records provided setting-specific data on the test positive rate and disease prevalence. This was used to tailor the study selection from a review of faecal calprotectin testing for inflammatory bowel disease for meta-analysis using the binomial method and the Mahalanobis distance method. Tailored estimates were compared to estimates from a study of test accuracy in primary care using the same routine dataset. RESULTS: Tailoring resulted in the inclusion of 3/14 (binomial method) and 9/14 (Mahalanobis distance method) studies in meta-analysis. Sensitivity and specificity from tailored meta-analysis using the binomial method were 0.87 (95% CI 0.77 to 0.94) and 0.65 (95% CI 0.60 to 0.69) and 0.98 (95% CI 0.83 to 0.999) and 0.68 (95% CI 0.65 to 0.71), respectively using the Mahalanobis distance method. The corresponding estimates for the conventional meta-analysis were 0.94 (95% CI 0.90 to 0.97) and 0.67 (95% CI 0.57 to 0.76) and for the FC test accuracy study of primary care data 0.93 (95%CI 0.89 to 0.96) and 0.61 (95% CI 0.6 to 0.63) to detect IBD at a threshold of 50 μg/g. Although the binomial method produced a plausible estimate, the tailored estimates of sensitivity and specificity were not closer to the primary study estimates than the estimates from conventional meta-analysis including all 14 studies. CONCLUSIONS: Tailored meta-analysis does not always produce estimates of sensitivity and specificity that lie closer to the estimates derived from a primary study in the setting in question. Potentially, tailored meta-analysis may be improved using a constrained model approach and this requires further investigation.

Primary care databases extract and combine routine data from the electronic patient records of various participating practices on a regular basis. These databases can be used for innovative and relevant addiction research, but such use requires a thorough understanding of how data were originally collected and how they need to be processed and statistically analysed to produce sound scientific evidence. The aims of this paper are therefore to (1) make a case for why primary care databases should be considered more frequently for addiction research; (2) provide an overview of how primary care databases are constructed; (3) highlight important methodological and statistical strengths and weaknesses of using primary care databases for research; and (4) give practical advice about how a researcher can get access to databases. Three major primary care databases from the UK serve as examples: Clinical Practice Research Datalink (CPRD), The Health Improvement Network (THIN), and QResearch.

OBJECTIVES: To investigate effects of appropriately and inappropriately dosed apixaban/rivaroxaban versus warfarin on effectiveness and safety outcomes in patients with non-valvular atrial fibrillation (NVAF). DESIGN: Cohort study with nested case-control analyses using primary care electronic health records (IQVIA Medical Research Data UK database). SETTING: UK primary care. PARTICIPANTS: Patients aged ≥18 years with NVAF newly prescribed apixaban (N=14 701), rivaroxaban (N=14 288) or warfarin (N=16 175) between 1 January 2012 and 30 June 2018, and followed up to 31 December 2018. PRIMARY AND SECONDARY OUTCOME MEASURES: Incident cases of ischaemic stroke/systemic embolism (IS/SE) and intracranial bleeding (ICB). Cases were matched to controls on age, sex and OAC naïve status. Using logistic regression, adjusted ORs with 95% CIs were calculated for the outcomes comparing apixaban/rivaroxaban use (appropriate or inappropriate dosing based on the product label criteria) and warfarin. RESULTS: For IS/SE, ORs (95% CIs) for apixaban versus warfarin were 1.19 (0.92-1.52) for appropriate dose and 1.01 (0.67-1.51) for inappropriate dose; for rivaroxaban versus warfarin, estimates were 1.07 (0.83-1.37) for appropriate dose and 1.21 (0.78-1.88) for inappropriate dose. For ICB, ORs (95% CIs) for apixaban versus warfarin were 0.67 (0.44-1.00) for appropriate dose and 0.45 (0.21-0.95) for inappropriate dose; for rivaroxaban versus warfarin, estimates were 0.81 (0.55-1.20) for appropriate dose and 1.14 (0.56-2.31) for inappropriate dose. CONCLUSIONS: Dosing appropriateness in NVAF was not associated with a significant difference in IS/SE risk or increase in ICB risk versus warfarin. These findings may reflect residual confounding and biases that were difficult to control, as also seen in other observational studies. They should, therefore, be interpreted with caution, and prescribers should adhere to the dosing instructions in the respective Summary of Product Characteristics. Further studies on this topic from real-world populations are needed.

AIMS: Previous studies reported proton pump inhibitor (PPI) use may increase the risk of fracture; however, the findings may be susceptible to indication bias because peptic ulcer disease (PUD), 1 major indication for PPIs, may affect skeletal health. Determining whether PUD would increase hip fracture risk may help identify high-risk populations and explore risk factors. METHODS: We conducted a cohort study using data from The Health Improvement Network (THIN) in the United Kingdom. THIN contains patient information such as disease diagnosis and medicine prescriptions. Up to 5 non-PUD individuals (n = 138 265) were matched to each case of incident PUD (n = 27 653) by age, sex, and body mass index. We examined the association between PUD and hip fracture by a multivariable Cox proportional hazard model. We repeated the same analysis among individuals with incident PUD and gastroesophageal reflux disease (GERD) (n = 27 160), another disease with similar indication for PPIs, as a positive control exposure. RESULTS: Over a mean of 5.6 years of follow-up, hip fracture occurred in 589 individuals with PUD and 2015 individuals without PUD (3.8 vs 2.6/1000 person-years), with a multivariable-adjusted hazard ratio (HR) being 1.44 (95% confidence interval [CI], 1.31-1.58). The association persisted among subgroups stratified by sex and age. In positive control exposure analysis, the hip fracture risk was also higher in PUD than GERD (3.8 vs 2.4/1000 person-years; multivariable-adjusted HR = 1.65; 95% CI, 1.45-1.7). CONCLUSIONS: This general population-based cohort study suggests, after controlling for acid-lowering medication and other potential risk factors, PUD is independently associated with an increased risk of hip fracture.

BACKGROUND: With multimorbidity becoming the norm rather than the exception, the management of multiple chronic diseases is a major challenge facing healthcare systems worldwide. METHODS: Using a large, nationally representative database of electronic medical records from the United Kingdom spanning the years 2005-2016 and consisting over 4.5 million patients, we apply statistical methods and network analysis to identify comorbid pairs and triads of diseases and identify clusters of chronic conditions across different demographic groups. Unlike many previous studies, which generally adopt cross-sectional designs based on single snapshots of closed cohorts, we adopt a longitudinal approach to examine temporal changes in the patterns of multimorbidity. In addition, we perform survival analysis to examine the impact of multimorbidity on mortality. RESULTS: The proportion of the population with multimorbidity has increased by approximately 2.5 percentage points over the last decade, with more than 17% having at least two chronic morbidities. We find that the prevalence and the severity of multimorbidity, as quantified by the number of co-occurring chronic conditions, increase progressively with age. Stratifying by socioeconomic status, we find that people living in more deprived areas are more likely to be multimorbid compared to those living in more affluent areas at all ages. The same trend holds consistently for all years in our data. In general, hypertension, diabetes, and respiratory-related diseases demonstrate high in-degree centrality and eigencentrality, while cardiac disorders show high out-degree centrality. CONCLUSIONS: We use data-driven methods to characterize multimorbidity patterns in different demographic groups and their evolution over the past decade. In addition to a number of strongly associated comorbid pairs (e.g., cardiac-vascular and cardiac-metabolic disorders), we identify three principal clusters: a respiratory cluster, a cardiovascular cluster, and a mixed cardiovascular-renal-metabolic cluster. These are supported by established pathophysiological mechanisms and shared risk factors, and largely confirm and expand on the results of existing studies in the medical literature. Our findings contribute to a more quantitative understanding of the epidemiology of multimorbidity, an important pre-requisite for developing more effective medical care and policy for multimorbid patients.

BACKGROUND: Since changes in the national guidance in 2011, prophylactic antibiotics for women undergoing caesarean section are recommended prior to skin incision, rather than after the baby's umbilical cord has been clamped. Evidence from randomised controlled trials conducted outside the UK has shown that this reduces maternal infectious morbidity; however, the prophylactic antibiotics also cross the placenta, meaning that babies are exposed to them around the time of birth. Antibiotics are known to affect the gut microbiota of the babies, but the long-term effects of exposure to high-dose broad-spectrum antibiotics around the time of birth on allergy and immune-related diseases are unknown. OBJECTIVES: We aimed to examine whether or not in-utero exposure to antibiotics immediately prior to birth compared with no pre-incisional antibiotic exposure increases the risk of (1) asthma and (2) eczema in children born by caesarean section. DESIGN: This was a controlled interrupted time series study. SETTING: The study took place in primary and secondary care. PARTICIPANTS: Children born in the UK during 2006-18 delivered by caesarean section were compared with a control cohort delivered vaginally. INTERVENTIONS: In-utero exposure to antibiotics immediately prior to birth. MAIN OUTCOME MEASURES: Asthma and eczema in children in the first 5 years of life. Additional secondary outcomes, including other allergy-related conditions, autoimmune diseases, infections, other immune system-related diseases and neurodevelopmental conditions, were also assessed. DATA SOURCES: The Health Improvement Network (THIN) and the Clinical Practice Research Datalink (CPRD) primary care databases and the Hospital Episode Statistics (HES) database. Previously published linkage strategies were adapted to link anonymised data on mothers and babies in these databases. Duplicate practices contributing to both THIN and the CPRD databases were removed to create a THIN-CPRD data set. RESULTS: In the THIN-CPRD and HES data sets, records of 515,945 and 3,945,351 mother-baby pairs were analysed, respectively. The risk of asthma was not significantly higher in children born by caesarean section exposed to pre-incision antibiotics than in children whose mothers received post-cord clamping antibiotics, with an incidence rate ratio of 0.91 (95% confidence interval 0.78 to 1.05) for diagnosis of asthma in primary care and an incidence rate ratio of 1.05 (95% confidence interval 0.99 to 1.11) for asthma resulting in a hospital admission. We also did not find an increased risk of eczema, with an incidence rate ratio of 0.98 (95% confidence interval 0.94 to1.03) and an incidence rate ratio of 0.96 (95% confidence interval 0.71 to 1.29) for diagnosis in primary care and hospital admissions, respectively. LIMITATIONS: It was not possible to ascertain the exposure to pre-incision antibiotics at an individual level. The maximum follow-up of children was 5 years. CONCLUSIONS: There was no evidence that the policy change from post-cord clamping to pre-incision prophylactic antibiotics for caesarean sections during 2006-18 had an impact on the incidence of asthma and eczema in early childhood in the UK. FUTURE WORK: There is a need for further research to investigate if pre-incision antibiotics have any impact on developing asthma and other allergy and immune-related conditions in older children. STUDY REGISTRATION: This study is registered as researchregistry3736. FUNDING: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in ; Vol. 26, No. 30. See the NIHR Journals Library website for further project information.

To examine the relationship between maternal postnatal depression and completion of infant vaccinations. We conducted a cohort study using data from The Health Improvement Network (THIN), a large UK primary care electronic health record database. We identified 196,329 mother-infant pairs in which the infant was born between 2006 and 2015. Postnatal depression was identified through antidepressant prescriptions or diagnoses or symptoms of depression in first year after childbirth. Primary outcome was completion of three 5-in-1 vaccination doses in infants before 1 year of age; this vaccine protects against diphtheria, tetanus, whooping cough, polio, and type b. We used Poisson regression models to compare likelihood of infant 5-in-1 vaccine uptake among children of women with a record of postnatal depression to likelihood among those without. Of the 196,329 women, 20,802 (10.6%) had a record of postnatal depression and/or antidepressant prescription. There was no difference in infants' 5-in-1 vaccination completion between those of mothers with a record and those of mothers' without (adjusted incidence rate ratio [IRR]  = 1.01; 95% CI, 0.99-1.02). Those from more socially deprived areas were less likely to complete infant vaccinations compared to those from the least deprived areas (IRR = 0.92; 95% CI, 0.90-0.93). Likelihood of completing infant vaccination decreased over time, comparing 2014-2015 to 2006-2007 (IRR = 0.90; 95% CI, 0.89-0.92). Among mothers who engage with primary care, maternal postnatal depression is not associated with lower rates of infant vaccination, though more research is needed to conclude if either more severe depression or unrecognized depression is associated with lower completion rates.