Interventions to reduce camel and small ruminant young stock morbidity and mortality in Ethiopia.

Morbidity and mortality of young stock is a challenge for livestock producers globally. In Ethiopia, where camels and small ruminants (sheep and goats) are essential smallholder and pastoral livestock, young stock losses can cause severe consequences to livelihoods. This pilot study, part of a Government-led Young Stock Mortality Reduction Consortium project, was undertaken to identify and evaluate interventions to reduce young stock mortality in mixed crop-livestock and pastoral production systems in Ethiopia. Pastoralists and mixed crop-livestock farmers were enrolled by convenience sampling across four regions. Households were sampled with questionnaire surveys to establish baseline mortality risk and prevalence of diarrhoea and respiratory disease in animals younger than one year, and followed longitudinally over a one-year period, with final evaluations conducted from March to July 2020. Mortality risk and prevalence of diarrhoea and respiratory disease before and after implementation were compared using Poisson regression models including household as random effect. Prior to intervention, median camel mortality, prevalence of diarrhoea, and respiratory disease across production systems in the different households was 0.4, 0.44 and 0.2, respectively. This compared to median pastoralist small ruminant mortality risk and prevalence of diarrhoea and respiratory disease of 0.45, 0.32 and 0.18, respectively. Post-intervention, median camel mortality, prevalence of diarrhoea and respiratory disease dropped to 0.1, 0.08 and 0. Similarly, more than half of the small ruminant households reported no mortality, and no cases of diarrhoea or respiratory disease. In camels, rate ratios of mortality risk, prevalence of diarrhoea, and respiratory disease post-intervention compared to the baseline were 0.41, 0.41 and 0.37. In small ruminants, rate ratios were 0.33, 0.35 and 0.46. All reductions were statistically significant (p < 0.01). Generally, pastoralists experienced higher mortality and disease prevalence compared to mixed crop-livestock smallholders, and the effect of intervention was slightly higher in pastoralist households. The pilot study findings demonstrated highly significant reductions in mortality and risk of diarrhoea and respiratory disease post-interventions. However, not all households benefitted from the interventions, with a few households reporting increased mortality and morbidity. Many households had very few animals which made it challenging to measure impact and the study was conducted over a single year, without a control group, so between year effects could not be accounted for in the reductions observed. These findings should contribute to improved livestock productivity in Ethiopia.

Antipsychotic drug prescribing and mortality in people with dementia before and during the COVID-19 pandemic: a retrospective cohort study in Wales, UK.

BACKGROUND: Concerns have been raised that antipsychotic drug prescribing, which has been associated with increased mortality in people with dementia, might have increased during the COVID-19 pandemic due to social restrictions imposed to limit the spread of SARS-CoV-2. We used multisource, routinely collected health-care data from Wales, UK to investigate prescribing and mortality variations in people with dementia before and during the COVID-19 pandemic. METHODS: In this retrospective cohort study, we used individual-level, anonymised, population-scale linked health data to identify adults aged 60 years and older with a diagnosis of dementia in Wales, UK. We used the CVD-COVID-UK initiative to access Welsh routinely collected electronic health record data from the Secure Anonymised Information Linkage (SAIL) Databank. Patients who were alive and registered with a SAIL general practice on Jan 1, 2016, and who received a dementia diagnosis before the age of 60 years and before or during the study period were included. We explored antipsychotic drug prescribing rate changes over 67 months, between Jan 1, 2016, and Aug 1, 2021, overall and stratified by age and dementia subtype. We used time-series analyses to examine all-cause and myocardial infarction and stroke mortality over the study period and identified the leading causes of death in people with dementia between Jan 1, 2020, and Aug 1, 2021. FINDINGS: Of 3 106 690 participants in SAIL between Jan 1, 2016 and Aug 1, 2021, 57 396 people (35 148 [61·2%] women and 22 248 [38·8%] men) met inclusion criteria for this study and contributed 101 428 person-years of follow-up. Of the 57 396 people with dementia, 11 929 (20·8%) were prescribed an antipsychotic drug at any point during follow-up. Accounting for seasonality, antipsychotic drug prescribing increased during the second half of 2019 and throughout 2020. However, the absolute difference in prescribing rates was small, ranging from 1253 prescriptions per 10 000 person-months in March, 2019, to 1305 per 10 000 person-months in September, 2020. All-cause mortality and stroke mortality increased throughout 2020, while myocardial infarction mortality declined. From Jan 1, 2020, to Aug 1, 2021, 1286 (17·1%) of 7508 participants who died had COVID-19 recorded as the underlying cause of death. INTERPRETATION: During the COVID-19 pandemic, antipsychotic drug prescribing in people with dementia in the UK increased slightly; however, it is unlikely that this was solely related to the pandemic and this increase was unlikely to be a major factor in the substantial increase in mortality during 2020. The long-term increase in antipsychotic drug prescribing in younger people and in those with Alzheimer's disease warrants further investigation using resources with access to more granular clinical data. Although deprescribing antipsychotic medications remains an essential aspect of dementia care, the results of this study suggest that changes in prescribing and deprescribing practices as a result of the COVID-19 pandemic are not required. FUNDING: British Heart Foundation (via the British Heart Foundation Data Science Centre led by Health Data Research UK), and the Scottish Neurological Research Fund.

Epilepsy-related mortality during the COVID-19 pandemic: A nationwide study of routine Scottish data.

OBJECTIVE: To examine whether epilepsy-related deaths increased during the COVID-19 pandemic and if the proportion with COVID-19 listed as the underlying cause is different between people experiencing epilepsy-related deaths and those experiencing deaths unrelated to epilepsy. METHODS: This was a Scotland-wide, population-based, cross-sectional study of routinely-collected mortality data pertaining to March-August of 2020 (COVID-19 pandemic peak) compared to the corresponding periods in 2015-2019. ICD-10-coded causes of death of deceased people of any age were obtained from a national mortality registry of death certificates in order to identify those experiencing epilepsy-related deaths (coded G40-41), deaths with COVID-19 listed as a cause (coded U07.1-07.2), and deaths unrelated to epilepsy (death without G40-41 coded). The number of epilepsy-related deaths in 2020 were compared to the mean observed through 2015-2019 on an autoregressive integrated moving average (ARIMA) model (overall, men, women). Proportionate mortality and odds ratios (OR) for deaths with COVID-19 listed as the underlying cause were determined for the epilepsy-related deaths compared to deaths unrelated to epilepsy, reporting 95% confidence intervals (CIs). RESULTS: A mean number of 164 epilepsy-related deaths occurred through March-August of 2015-2019 (of which a mean of 71 were in women and 93 in men). There were subsequently 189 epilepsy-related deaths during the pandemic March-August 2020 (89 women, 100 men). This was 25 more epilepsy-related deaths (18 women, 7 men) compared to the mean through 2015-2019. The increase in women was beyond the mean year-to-year variation seen in 2015-2019. Proportionate mortality with COVID-19 listed as the underlying cause was similar between people experiencing epilepsy-related deaths (21/189, 11.1%, CI 7.0-16.5%) and deaths unrelated to epilepsy (3,879/27,428, 14.1%, CI 13.7-14.6%), OR 0.76 (CI 0.48-1.20). Ten of 18 excess epilepsy-related deaths in women had COVID-19 listed as an additional cause. CONCLUSIONS: There is little evidence to suggest there have been any major increases in epilepsy-related deaths in Scotland during the COVID-19 pandemic. COVID-19 is a common underlying cause of both epilepsy-related and unrelated deaths.

Mortality in children with epilepsy: Cohort study using the clinical practice research datalink.

OBJECTIVE: To estimate Mortality Rate (MR) in UK children with epilepsy (CWE) compared to children without epilepsy (CWOE), describe causes of death, determine Mortality Rate Ratios (MRRs) for cause-specific mortality, and to analyse the contribution of co-morbidities (respiratory disease, neoplasm, and congenital disorders) to mortality rate. METHOD: Retrospective cohort study of children born between 1998 and 2017, using linked data from the Clinical Practice Research Datalink Gold (Set 18). Epilepsy diagnoses were identified using previously validated codes. Causes of death were defined as natural or non-natural. Epilepsy-related deaths in CWE were those where underlying or contributing cause of death was epilepsy, status epilepticus, seizures, ill-defined/unknown cause or sudden death. We used Cox proportional hazard analysis to investigate associations of epilepsy and mortality. RESULTS: There were 1,191,304 children followed for 13,994,916 person-years (median: 12) if which 9665 (0.8%) had epilepsy. Amongst CWE, 3.4% died. MR of CWE was 4.1 (95%CI 3.7-4.6)/1,000 person-years. CWE had an increased adjusted all-cause mortality (MRR 50.9,95%CI 44.8-57.7) compared to CWOE. Amongst the 330 deaths in CWE, 323 (98%) were natural, 7 (2%) non-natural, 80 (24%) epilepsy-related. MRR of non-natural deaths was 2.09 (95%CI 0.92,4.74, p = 0.08). SIGNIFICANCE: Amongst CWE, 3.4% died during the study period. All-cause mortality rate in CWE was 4/1,000 person-years representing a fifty-fold increased mortality risk, after taking into account sex and socioeconomic status, compared to similarly aged children who did not have epilepsy. Causes of death mostly were not seizure-related. Non-natural death in CWE was uncommon.

A high level estimation of the net economic benefits to small-scale livestock producers arising from animal health product distribution initiatives.

Introduction: A fundamental challenge for charities that facilitate distribution of animal health products to small-scale livestock producers (SSPs) in low and middle income countries (LMICs) is identifying the products and market mechanisms that provide the greatest positive impact for SSPs and estimating their associated impact. This paper describes a pragmatic approach to modeling the impact of market-led product distribution initiatives based on estimating the net economic benefit of administration of animal health products. Methods: The model estimates the economic impact of diseases at the individual animal level for poultry, small ruminants, and cattle. The economic impact of mortality and growth inhibition associated with disease are then estimated in conjunction with the losses averted or recovered by preventing or treating the disease. Economic benefit is estimated in 2014-2017 values and also adjusted to 2023 values. The flexible model structure allows for addition of new geographies, new products, and increased granularity of modeled production systems. Results: Applied to the Global Alliance for Livestock Veterinary Medicines (GALVmed) product distribution initiatives conducted in Africa and South Asia (SA) between 2014 and 2017, the model estimates an adjusted total net economic benefit of 139.9 million USD from sales of vaccines and poultry anthelminthics in these initiatives. Within SSA, the greatest net economic benefit was realized from East Coast fever and Newcastle disease vaccines, while in SA, peste des petits ruminants and Newcastle disease vaccines had the greatest net economic benefits. This translated to an adjusted $37.97 of net economic benefit on average per SSP customer, many of whom were small poultry producers. Discussion: While the model currently estimates impacts from mortality and growth inhibition in livestock, there is the potential to extend it to cover impacts of further initiatives, including interventions targeted at diseases that impact production of milk, eggs, and reproduction.

Case-control study developing Scottish Epilepsy Deaths Study Score to predict epilepsy-related death.

This study aimed to develop a risk prediction model for epilepsy-related death in adults. In this age- and sex-matched case-control study, we compared adults (aged ≥16 years) who had epilepsy-related death between 2009 and 2016 to living adults with epilepsy in Scotland. Cases were identified from validated administrative national datasets linked to mortality records. ICD-10 cause-of-death coding was used to define epilepsy-related death. Controls were recruited from a research database and epilepsy clinics. Clinical data from medical records were abstracted and used to undertake univariable and multivariable conditional logistic regression to develop a risk prediction model consisting of four variables chosen a priori. A weighted sum of the factors present was taken to create a risk index-the Scottish Epilepsy Deaths Study Score. Odds ratios were estimated with 95% confidence intervals (CIs). Here, 224 deceased cases (mean age 48 years, 114 male) and 224 matched living controls were compared. In univariable analysis, predictors of epilepsy-related death were recent epilepsy-related accident and emergency attendance (odds ratio 5.1, 95% CI 3.2-8.3), living in deprived areas (odds ratio 2.5, 95% CI 1.6-4.0), developmental epilepsy (odds ratio 3.1, 95% CI 1.7-5.7), raised Charlson Comorbidity Index score (odds ratio 2.5, 95% CI 1.2-5.2), alcohol abuse (odds ratio 4.4, 95% CI 2.2-9.2), absent recent neurology review (odds ratio 3.8, 95% CI 2.4-6.1) and generalized epilepsy (odds ratio 1.9, 95% CI 1.2-3.0). Scottish Epilepsy Deaths Study Score model variables were derived from the first four listed before, with Charlson Comorbidity Index ≥2 given 1 point, living in the two most deprived areas given 2 points, having an inherited or congenital aetiology or risk factor for developing epilepsy given 2 points and recent epilepsy-related accident and emergency attendance given 3 points. Compared to having a Scottish Epilepsy Deaths Study Score of 0, those with a Scottish Epilepsy Deaths Study Score of 1 remained low risk, with odds ratio 1.6 (95% CI 0.5-4.8). Those with a Scottish Epilepsy Deaths Study Score of 2-3 had moderate risk, with odds ratio 2.8 (95% CI 1.3-6.2). Those with a Scottish Epilepsy Deaths Study Score of 4-5 and 6-8 were high risk, with odds ratio 14.4 (95% CI 5.9-35.2) and 24.0 (95% CI 8.1-71.2), respectively. The Scottish Epilepsy Deaths Study Score may be a helpful tool for identifying adults at high risk of epilepsy-related death and requires external validation.

Patterns of mortality in domesticated ruminants in Ethiopia.

Background: Premature death of livestock is a problem in all ruminant production systems. While the number of premature ruminant deaths in a country is a reasonable indicator for the nation's health, few data sources exist in a country like Ethiopia that can be used to generate valid estimates. The present study aimed to establish if three different data sets, each with imperfect information on ruminant mortality, including abortions, could be combined into improved estimates of nationwide mortality in Ethiopia. Methods: We combined information from a recent survey of ruminant mortality with information from the Living Standards Measurement Study and the Disease Outbreak and Vaccination Reporting dataset. Generalized linear mixed and hurdle models were used for data analysis, with results summarized using predicted outcomes. Results: Analyses indicated that most herds experienced zero mortality and reproductive losses, with rare occasions of larger losses. Diseases causing deaths varied greatly both geographically and over time. There was little agreement between the different datasets. While the models aid the understanding of patterns of mortality and reproductive losses, the degree of variation observed limited the predictive scope. Conclusions: The models revealed some insight into why mortality rates are variable over time and are therefore less useful in measuring production or health status, and it is suggested that alternative measures of productivity, such as number of offspring raised to 1 year old per dam, would be more stable over time and likely more indicative.

Reduced dementia incidence after varicella zoster vaccination in Wales 2013-2020.

Introduction: Chronic infection with herpes viruses is a potential contributing factor to the development of dementia. The introduction of nationwide shingles (varicella zoster) vaccination in Wales might therefore be associated with reduced incident dementia. Methods: We analyzed the association of shingles vaccination with incident dementia in Wales between 2013 and 2020 using retrospectively collected national health data. Results: Vaccinated individuals were at reduced risk of dementia (adjusted hazard ratio: 0.72; 95% confidence interval: 0.69 to 0.75). The association was not modified by a reduction in shingles diagnosis and was stronger for vascular dementia than for Alzheimer's disease. Vaccination was also associated with a reduction in several other diseases and all-cause mortality. Discussion: Our study shows a clear association of shingles vaccination with reduced dementia, consistent with other observational cohort studies. The association may reflect selection bias with people choosing to be vaccinated having a higher healthy life expectancy.

Prematurity, Delivery Method, and Infant Feeding Type Are Not Associated with Paediatric-onset Inflammatory Bowel Disease Risk: A Scottish Retrospective Birth Cohort Study.

BACKGROUND AND AIMS: The incidence of paediatric-onset inflammatory bowel disease [PIBD] continues to rise globally. We aimed to determine whether mode of delivery, gestational age at birth, or type of infant feeding contribute to the development of PIBD in a nationwide cohort of Scottish children. METHODS: All children born in Scotland between 1981 and 2017 were identified using linked health administrative data to determine mode of delivery, gestational age at birth, and type of infant feeding. PIBD cases were defined as onset of Crohn's disease [CD], ulcerative colitis [UC], or IBD-unclassified [IBDU] before age 16 years. Validation was performed within an entire Scottish health board [16% of total population] via individual case-note verification. Hazard ratios [HR] were calculated for each exposure using Cox proportional hazards models. RESULTS: A study population of 2 013 851 children was identified including 1721 PIBD cases. Validation of 261 PIBD patients coded as CD and/or UC identified 242 [93%] as true positive. Children delivered vaginally did not have an altered risk of developing PIBD compared with those delivered by caesarean section, adjusted HR 0.95 [95% CI 0.84-1.08] [p = 0.46]. Compared with children born at term [≥37 weeks], children born prematurely did not have an altered risk of developing PIBD, i.e., at 24-31 weeks of gestation, HR 0.99 [95% CI 0.57-1.71] [p = 0.97] and at 32-36 weeks of gestation, HR 0.96 [95% CI 0.76-1.20] [p = 0.71]. Compared with children exclusively breastfed at age 6 weeks, children exclusively formula fed did not have an altered risk of developing PIBD: adjusted HR 0.97 [95% CI 0.81-1.15] [p = 0.69]. CONCLUSIONS: This population-based study demonstrates no association between mode of delivery, gestational age, or exclusive formula feeding at 6 weeks, and the development of PIBD.

Drug prescriptions and dementia incidence: a medication-wide association study of 17000 dementia cases among half a million participants.

BACKGROUND: Previous studies have suggested that some medications may influence dementia risk. We conducted a hypothesis-generating medication-wide association study to investigate systematically the association between all prescription medications and incident dementia. METHODS: We used a population-based cohort within the Secure Anonymised Information Linkage (SAIL) databank, comprising routinely-collected primary care, hospital admissions and mortality data from Wales, UK. We included all participants born after 1910 and registered with a SAIL general practice at ≤60 years old. Follow-up was from each participant's 60th birthday to the earliest of dementia diagnosis, deregistration from a SAIL general practice, death or the end of 2018. We considered participants exposed to a medication if they received ≥1 prescription for any of 744 medications before or during follow-up. We adjusted for sex, smoking and socioeconomic status. The outcome was any all-cause dementia code in primary care, hospital or mortality data during follow-up. We used Cox regression to calculate hazard ratios and Bonferroni-corrected p values. RESULTS: Of 551 344 participants, 16 998 (3%) developed dementia (median follow-up was 17 years for people who developed dementia, 10 years for those without dementia). Of 744 medications, 221 (30%) were associated with dementia. Of these, 217 (98%) were associated with increased dementia incidence, many clustering around certain indications. Four medications (all vaccines) were associated with a lower dementia incidence. CONCLUSIONS: Almost a third of medications were associated with dementia. The clustering of many drugs around certain indications may provide insights into early manifestations of dementia. We encourage further investigation of hypotheses generated by these results.

A national study of epilepsy-related deaths in Scotland: Trends, mechanisms, and avoidable deaths.

OBJECTIVE: This study was undertaken to investigate the trends and mechanisms of epilepsy-related deaths in Scotland, highlighting the proportion that were potentially avoidable. METHODS: This was a retrospective observational data-linkage study of administrative data from 2009-2016. We linked nationwide data encompassing mortality records, hospital admissions, outpatient attendance, antiepileptic drug (AED) prescriptions, and regional primary care attendances. Adults (aged ≥16 years) suffering epilepsy-related death were identified for study using International Classification of Diseases, 10th Revision coding combined with AED prescriptions. We reported epilepsy-related mortality rate (MR), age-specific mortality ratios, multiple cause-of-death frequencies, and the proportion of potentially avoidable deaths (identified as those with an underlying cause listed as avoidable by the Office for National Statistics). RESULTS: A total of 1921 epilepsy-related deaths were identified across Scotland; 1185 (62%) decedents were hospitalized for seizures in the years leading up to death, yet only 518 (27%) were seen in a neurology clinic during the same period. MR remained unchanged over time, ranging from 5.9 to 8.7 per 100 000 Scottish population (95% confidence interval [CI] = -.05 to .66 per 100 000 for annual change in MR). Mortality ratios were significantly increased in young adults aged 16-54 years (2.3, 95% CI = 1.8-2.8), peaking at age 16-24 years (5.3, 95% CI = 1.8-8.8). Sudden unexpected death in epilepsy (SUDEP) constituted 30% of the 553 young adult epilepsy-related deaths, with several other non-SUDEP fatal mechanisms identified including aspiration pneumonia, cardiac arrest, AED or narcotic poisoning, drowning, and alcohol dependence. Seventy-six percent of young adult epilepsy-related deaths were potentially avoidable. SIGNIFICANCE: Epilepsy-related deaths are a major public health problem in Scotland, given that they are not reducing, people are dying young, and many deaths are potentially avoidable. SUDEP is only one of several important mechanisms by which epilepsy-related deaths are occurring in young adults. Services may need to be re-evaluated to improve specialist referral following seizure-related hospital admissions.

Antiherpetic medication and incident dementia: Observational cohort studies in four countries.

BACKGROUND AND PURPOSE: Several epidemiological studies from Taiwan, all using the same data resource, found significant associations between herpes virus infection, antiherpetic medication, and subsequent dementia. We conducted a multicenter observational cohort study using health registry data from Wales, Germany, Scotland, and Denmark to investigate potential associations between antiherpetic medication and incident dementia, and also to comprehensively investigate such associations broken down according to medication type and dose, type of herpes virus, and dementia subtype. METHODS: A total of 2.5 million individuals aged 65 years or more were followed up using linked electronic health records in four national observational cohort studies. Exposure and outcome were classified using coded data from primary and secondary care. Data were analyzed using survival analysis with time-dependent covariates. RESULTS: Results were heterogeneous, with a tendency toward decreased dementia risk in individuals exposed to antiherpetic medication. Associations were not affected by treatment number, herpes subtype, dementia subtype, or specific medication. In one cohort, individuals diagnosed with herpes but not exposed to antiherpetic medication were at higher dementia risk. CONCLUSIONS: Short-term antiherpetic medication is not markedly associated with incident dementia. Because neither dementia subtype nor herpes subtype modified the association, the small but significant decrease in dementia incidence with antiherpetic administration may reflect confounding and misclassification.

Socio-economic predictors of time to care home admission in people living with dementia in Wales: A routine data linkage study.

OBJECTIVES: Limited research has shown that people with dementia (PwD) from lower socio-economic backgrounds can face difficulties in accessing the right care at the right time. This study examined whether socio-economic status (SES) and rural versus urban living location are associated with the time between diagnosis and care home admission in PwD living in Wales, UK. METHODS/DESIGN: This study linked routine health data and an e-cohort of PwD who have been admitted into a care home between 2000 and 2018 living in Wales. Survival analysis explored the effects of SES, living location, living situation, and frailty on the time between diagnosis and care home admission. RESULTS: In 34,514 PwD, the average time between diagnosis and care home admission was 1.5 (±1.4) years. Cox regression analysis showed that increased age, living alone, frailty, and living in less disadvantaged neighbourhoods were associated with faster rate to care home admission. Living in rural regions predicted a slower rate until care home admission. CONCLUSIONS: This is one of the first studies to show a link between socio-economic factors on time to care home admission in dementia. Future research needs to address variations in care needs between PwD from different socio-economic and geographical backgrounds.

Validating the accuracy of administrative healthcare data identifying epilepsy in deceased adults: A Scottish data linkage study.

BACKGROUND: We investigate the case-ascertainment accuracy for potentially active epilepsy of four administrative healthcare datasets used to identify deceased adults in Scotland. METHODS: In this diagnostic accuracy study, unique patient identifiers were used to link administrative healthcare data for adults (aged 16 years and over) who died in Scotland between 01/01/09-01/01/16. Cases were ascertained from linking mortality records, hospital admissions, antiepileptic drug (AED) prescriptions, and primary care attendances. We assessed ICD-10 codes G40 (epilepsy), G41 (status epilepticus), and R56.8 (seizures) listed as causes of death and as hospital admission reasons, various AEDs, and F25 primary care epilepsy Read codes. These epilepsy indicators were searched through 01/01/09-01/01/16, suggesting active epilepsy during a maximal period of seven years before death. They were compared to epilepsy diagnoses made from medical records reviewed by a senior epileptologist, with a second senior epileptologist independently reviewing the medical records in a 10 % sample to check for specialist interrater agreement in epilepsy diagnoses. We validated how accurately epilepsy was identified by each dataset alone and when combined, calculating positive predictive value (PPV) and sensitivity (with 95 % confidence intervals (CIs)). RESULTS: 159,032 deceased potential epilepsy cases were captured across the four datasets. Medical records reviewed in a random sample of 936 confirmed that epilepsy was present in 614 and absent in 322. Specialist interrater diagnostic agreement was substantial (100 medical records reviewed in duplicate, kappa = 0.72, CI 0.58-0.86). G40-41 cause of death codes had a PPV of 86 % (CI 84-89 %) and sensitivity of 73 % (CI 69-76 %). Adding R56.8 lowered PPV to 69 % (CI 65-72 %) and raised sensitivity to 87 % (CI 84-90 %). The optimal algorithm combining two datasets consisted of F25 Read codes paired with AEDs (PPV 86 % (CI 80-92 %), sensitivity 93 % (CI 88-97 %)). Also effective was pairing G40-41 and/or R56.8 cause of death codes with AEDs (PPV 91 % (CI 89-94 %), sensitivity 81 % (CI 77-84 %)). Whilst algorithms combining three datasets raised PPV to as high as 93-95 %, the associated sensitivities were low (71 % at most). CONCLUSIONS: Routinely-collected Scottish data can accurately identify epilepsy in deceased adults. It may be necessary to combine the diagnostic coding used with AEDs to ensure optimal case-ascertainment. The results help inform the design of future Scottish epilepsy mortality studies recruiting from administrative data sources.

A nationwide, retrospective, data-linkage, cohort study of epilepsy and incident dementia.

OBJECTIVE: To determine the association of epilepsy with incident dementia by conducting a nationwide, retrospective data-linkage, cohort study to examine whether the association varies according to dementia subtypes and to investigate whether risk factors modify the association. METHODS: We used linked health data from hospitalization, mortality records, and primary care consultations to follow up 563,151 Welsh residents from their 60th birthday to estimate dementia rate and associated risk factors. Dementia, epilepsy, and covariates (medication, smoking, comorbid conditions) were classified with the use of previously validated code lists. We studied rate of dementia and dementia subtypes in people with epilepsy (PWE) and without epilepsy using (stratified) Kaplan-Meier plots and flexible parametric survival models. RESULTS: PWE had a 2.5 (95% confidence interval [CI] 2.3-2.6) times higher hazard of incident dementia, a 1.6 (95% CI 1.4-1.8) times higher hazard of incident Alzheimer disease (AD), and a 3.1 (95% CI 2.8-3.4) times higher hazard of incident Vascular dementia (VaD). A history of stroke modified the increased incidence in PWE. PWE who were first diagnosed at ≤25 years of age had a dementia rate similar to that of those diagnosed later in life. PWE who had ever been prescribed sodium valproate compared to those who had not were at higher risk of dementia (hazard ratio [HR] 1.6, 99% CI 1.4-1.9) and VaD (HR 1.7, 99% CI 1.4-2.1) but not AD (HR 1.2, 99% CI 0.9-1.5). CONCLUSION: PWE compared to those without epilepsy have an increased dementia risk.

Accuracy of identifying incident stroke cases from linked health care data in UK Biobank.

OBJECTIVE: In UK Biobank (UKB), a large population-based prospective study, cases of many diseases are ascertained through linkage to routinely collected, coded national health datasets. We assessed the accuracy of these for identifying incident strokes. METHODS: In a regional UKB subpopulation (n = 17,249), we identified all participants with ≥1 code signifying a first stroke after recruitment (incident stroke-coded cases) in linked hospital admission, primary care, or death record data. Stroke physicians reviewed their full electronic patient records (EPRs) and generated reference standard diagnoses. We evaluated the number and proportion of cases that were true-positives (i.e., positive predictive value [PPV]) for all codes combined and by code source and type. RESULTS: Of 232 incident stroke-coded cases, 97% had EPR information available. Data sources were 30% hospital admission only, 39% primary care only, 28% hospital and primary care, and 3% death records only. While 42% of cases were coded as unspecified stroke type, review of EPRs enabled a pathologic type to be assigned in >99%. PPVs (95% confidence intervals) were 79% (73%-84%) for any stroke (89% for hospital admission codes, 80% for primary care codes) and 83% (74%-90%) for ischemic stroke. PPVs for small numbers of death record and hemorrhagic stroke codes were low but imprecise. CONCLUSIONS: Stroke and ischemic stroke cases in UKB can be ascertained through linked health datasets with sufficient accuracy for many research studies. Further work is needed to understand the accuracy of death record and hemorrhagic stroke codes and to develop scalable approaches for better identifying stroke types.

The accuracy of using administrative healthcare data to identify epilepsy cases: A systematic review of validation studies.

Our objective was to undertake a systematic review ascertaining the accuracy of using administrative healthcare data to identify epilepsy cases. We searched MEDLINE and Embase from 01/01/1975 to 03/07/2018 for studies evaluating the diagnostic accuracy of routinely collected healthcare data in identifying epilepsy cases. Any disease coding system in use since the International Classification of Diseases, Ninth Revision (ICD-9) was permissible. Two authors independently screened studies, extracted data, and quality-assessed studies. We assessed positive predictive value (PPV), sensitivity, negative predictive value (NPV), and specificity. The primary analysis was a narrative synthesis of review findings. Thirty studies were included, published between 1989 and 2018. Risks of bias were low, high, and unclear in 4, 14, and 12 studies, respectively. Coding systems included ICD-9, ICD-10, and Read Codes, with or without antiepileptic drugs (AEDs). PPVs included ranges of 5.2%-100% (Canada), 32.7%-96.0% (USA), 47.0%-100% (UK), and 37.0%-88.0% (Norway). Sensitivities included ranges of 22.2%-99.7% (Canada), 12.2%-97.3% (USA), and 79.0%-94.0% (UK). Nineteen studies contained at least one algorithm with a PPV >80%. Sixteen studies contained at least one algorithm with a sensitivity >80%. PPV was highest in algorithms consisting of disease codes (ICD-10 G40-41, ICD-9 345) in combination with one or more AEDs. The addition of symptom codes to this (ICD-10 R56; ICD-9 780.3, 780.39) lowered PPV. Sensitivity was highest in algorithms consisting of symptom codes with one or more AEDs. Although using AEDs alone achieved high sensitivities, the associated PPVs were low. Most NPVs and specificities were >90%. We conclude that it is reasonable to use administrative data to identify people with epilepsy (PWE) in epidemiological research. Studies prioritizing high PPVs should focus on combining disease codes with AEDs. Studies prioritizing high sensitivities should focus on combining symptom codes with AEDs. We caution against the use of AEDs alone to identify PWE.

Predicting incident dementia 3-8 years after brief cognitive tests in the UK Biobank prospective study of 500,000 people.

INTRODUCTION: Prospective studies reporting associations between cognitive performance and subsequent incident dementia have been subject to attrition bias. Furthermore, the extent to which established risk factors account for such associations requires further elucidation. METHODS: We used UK Biobank baseline cognitive data (n ≤ 488,130) and electronically linked hospital inpatient and death records during three- to eight-year follow-up, to estimate risk of total dementia (n = 1051), Alzheimer's disease (n = 352), and vascular dementia (n = 169) according to four brief cognitive tasks, with/without adjustment for constitutional and modifiable risk factors. RESULTS: We found associations of cognitive task performance with all-cause and cause-specific dementia (P <  .01); these were not accounted for by established risk factors. Cognitive data added up to 5% to the discriminative accuracy of receiver operating characteristic curve models; areas under the curve ranged from 82% to 86%. DISCUSSION: This study offers robust evidence that brief cognitive testing could be a valuable addition to dementia prediction models.

Identifying Parkinson's disease and parkinsonism cases using routinely collected healthcare data: A systematic review.

BACKGROUND: Population-based, prospective studies can provide important insights into Parkinson's disease (PD) and other parkinsonian disorders. Participant follow-up in such studies is often achieved through linkage to routinely collected healthcare datasets. We systematically reviewed the published literature on the accuracy of these datasets for this purpose. METHODS: We searched four electronic databases for published studies that compared PD and parkinsonism cases identified using routinely collected data to a reference standard. We extracted study characteristics and two accuracy measures: positive predictive value (PPV) and/or sensitivity. RESULTS: We identified 18 articles, resulting in 27 measures of PPV and 14 of sensitivity. For PD, PPV ranged from 56-90% in hospital datasets, 53-87% in prescription datasets, 81-90% in primary care datasets and was 67% in mortality datasets. Combining diagnostic and medication codes increased PPV. For parkinsonism, PPV ranged from 36-88% in hospital datasets, 40-74% in prescription datasets, and was 94% in mortality datasets. Sensitivity ranged from 15-73% in single datasets for PD and 43-63% in single datasets for parkinsonism. CONCLUSIONS: In many settings, routinely collected datasets generate good PPVs and reasonable sensitivities for identifying PD and parkinsonism cases. However, given the wide range of identified accuracy estimates, we recommend cohorts conduct their own context-specific validation studies if existing evidence is lacking. Further research is warranted to investigate primary care and medication datasets, and to develop algorithms that balance a high PPV with acceptable sensitivity.

Identifying dementia outcomes in UK Biobank: a validation study of primary care, hospital admissions and mortality data.

Prospective, population-based studies that recruit participants in mid-life are valuable resources for dementia research. Follow-up in these studies is often through linkage to routinely-collected healthcare datasets. We investigated the accuracy of these datasets for dementia case ascertainment in a validation study using data from UK Biobank-an open access, population-based study of > 500,000 adults aged 40-69 years at recruitment in 2006-2010. From 17,198 UK Biobank participants recruited in Edinburgh, we identified those with ≥ 1 dementia code in their linked primary care, hospital admissions or mortality data and compared their coded diagnoses to clinical expert adjudication of their full-text medical record. We calculated the positive predictive value (PPV, the proportion of cases identified that were true positives) for all-cause dementia, Alzheimer's disease and vascular dementia for each dataset alone and in combination, and explored algorithmic code combinations to improve PPV. Among 120 participants, PPVs for all-cause dementia were 86.8%, 87.3% and 80.0% for primary care, hospital admissions and mortality data respectively and 82.5% across all datasets. We identified three algorithms that balanced a high PPV with reasonable case ascertainment. For Alzheimer's disease, PPVs were 74.1% for primary care, 68.2% for hospital admissions, 50.0% for mortality data and 71.4% in combination. PPV for vascular dementia was 43.8% across all sources. UK routinely-collected healthcare data can be used to identify all-cause dementia in prospective studies. PPVs for Alzheimer's disease and vascular dementia are lower. Further research is required to explore the geographic generalisability of these findings.