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Background This study assessed the impact of the first COVID-19 wave in England on outcomes for acute appendicitis, gallstone disease, intestinal obstruction, diverticular disease, and abdominal wall hernia. Methods Emergency surgical admissions for patients aged 18 years and older to 124 NHS Trust hospitals between January and June in 2019 and 2020 were extracted from Hospital Episode Statistics. The risk of 90-day mortality after admission during weeks 11–19 in 2020 (national lockdown) and 2019 (pre-COVID-19) was estimated using multilevel logistic regression with case-mix adjustment. The primary outcome was all-cause mortality at 90 days. Results There were 12 231 emergency admissions and 564 deaths within 90 days during weeks 11–19 in 2020, compared with 18 428 admissions and 542 deaths in the same interval in 2019. Overall, 90-day mortality was higher in 2020 versus 2019, with an adjusted OR of 1.95 (95 per cent c.i. 0.78 to 4.89) for appendicitis, 2.66 (1.81 to 3.92) for gallstone disease, 1.99 (1.44 to 2.74) for diverticular disease, 1.70 (1.13 to 2.55) for hernia, and 1.22 (1.01 to 1.47) for intestinal obstruction. After emergency surgery, 90-day mortality was higher in 2020 versus 2019 for gallstone disease (OR 3.37, 1.26 to 9.02), diverticular disease (OR 2.35, 1.16 to 4.73), and hernia (OR 2.34, 1.23 to 4.45). For intestinal obstruction, the corresponding OR was 0.91 (0.59 to 1.41). For admissions not leading to emergency surgery, mortality was higher in 2020 versus 2019 for gallstone disease (OR 2.55, 1.67 to 3.88), diverticular disease (1.90, 1.32 to 2.73), and intestinal obstruction (OR 1.30, 1.06 to 1.60). Conclusion Emergency admission was reduced during the first lockdown in England and this was associated with higher 90-day mortality.

Background This paper assesses variation in rates of emergency surgery (ES) amongst emergency admissions to hospital in patients with acute appendicitis, cholelithiasis, diverticular disease, abdominal wall hernia, and intestinal obstruction. Methods Records of emergency admissions between 1 April 2010 and 31 December 2019 for the five conditions were extracted from Hospital Episode Statistics for 136 acute National Health Service (NHS) trusts in England. Patients who had ES were identified using Office of Population Censuses and Surveys (OPCS) procedure codes, selected by consensus of a clinical panel. The differences in ES rates according to patient characteristics, and unexplained variations across NHS trusts were estimated by multilevel logistic regression, adjusting for year of emergency admission, age, sex, ethnicity, diagnostic subcategories, index of multiple deprivation, number of co-morbidities, and frailty. Results The cohort sizes ranged from 107 325 (hernia) to 268 253 (appendicitis) patients, and the proportion of patients who received ES from 11.0 per cent (diverticular disease) to 92.3 per cent (appendicitis). Older patients were generally less likely to receive ES, with adjusted odds ratios (ORs) of ES for those aged 75–79 versus those aged 45–49 years: 0.34 (appendicitis), 0.49 (cholelithiasis), 0.87 (hernia), and 0.91 (intestinal obstruction). Patients with diverticular disease aged 75–79 were more likely to receive ES than those aged 45–49 (OR 1.40). Variation in ES rates across NHS trusts remained after case mix adjustment and was greatest for cholelithiasis (trust median 18 per cent, 10th to 90th centile 7–35 per cent). Conclusion For patients presenting as emergency hospital admissions with common acute conditions, variation in ES rates between NHS trusts remained after adjustment for demographic and clinical characteristics. Age was strongly associated with the likelihood of ES receipt for some procedures., This study reports variation in rates of emergency surgery (ES) across National Health Service trusts amongst patients presenting as emergency admissions to hospital with acute appendicitis, cholelithiasis, diverticular disease, abdominal wall hernia, or intestinal obstruction, after adjustment for differences in patient-level characteristics. Older patients were less likely to have ES, after allowing for differences in other patient characteristics, including number of Charlson co-morbidities, level of frailty, and diagnostic subcategory. The decline in the rate of ES with increasing age was greatest for patients presenting with acute appendicitis and cholelithiasis.

Aims To assess variation in use of emergency surgery (ES) for emergency hospital admissions with acute appendicitis, cholelithiasis, diverticular disease, abdominal wall hernia or intestinal obstruction. Methods Cohorts were extracted from Hospital Episode Statistics for 136 acute NHS trusts in England. Clinical panel consensus defined ES for emergency admissions between 1/4/2010 and 31/12/2019. The association of socio-demographic characteristics with ES use was estimated by multivariable logistic regression, with adjustment for comorbidity, frailty, diagnosis and trust. Results The cohort sizes ranged from 49,385 (hernia) to 184,777 (appendicitis) patients. ES was less likely for: patients aged over 80, with odds ratios (ORs) across conditions from 0.15 to 0.84 versus those aged under 40; the most deprived, ORs 0.83 to 0.92, versus least deprived; and Asian patients, ORs 0.72 to 0.88, versus White patients. Black patients were less likely to have emergency surgery for appendicitis (OR 0.78) and cholelithiasis (OR 0.78). Females were less likely to have ES for appendicitis (OR 0.94 versus males), but more likely to have surgery for intestinal obstruction (OR 1.29), hernia (OR 1.13) and cholelithiasis (OR 1.22). Unexplained variation in ES across trusts, remained after case-mix adjustment, and was greatest for cholelithiasis (median of 16%, 10 to 90 centile 5%-34%), and hernia (61%, 52%-71%), followed by intestinal obstruction (29%, 24%-36%). appendicitis (93%, 89%-95%), and diverticular disease (15%, 11%-20%). Conclusions The socio-demographic characteristics of emergency admissions are associated with the likelihood of receiving ES. Variation in ES use between NHS trusts remained after adjustment for demographic and clinical characteristics.

Background Uncomplicated acute appendicitis can be managed with non-operative (antibiotic) treatment, but laparoscopic appendicectomy remains the first-line management in the UK. During the COVID-19 pandemic the practice altered, with more patients offered antibiotics as treatment. A large-scale observational study was designed comparing operative and non-operative management of appendicitis. The aim of this study was to evaluate 90-day follow-up. Methods A prospective, cohort study at 97 sites in the UK and Republic of Ireland included adult patients with a clinical or radiological diagnosis of appendicitis that either had surgery or non-operative management. Propensity score matching was conducted using age, sex, BMI, frailty, co-morbidity, Adult Appendicitis Score and C-reactive protein. Outcomes were 90-day treatment failure in the non-operative group, and in the matched groups 30-day complications, length of hospital stay (LOS) and total healthcare costs associated with each treatment. Results A total of 3420 patients were recorded: 1402 (41 per cent) had initial antibiotic management and 2018 (59 per cent) had appendicectomy. At 90-day follow-up, antibiotics were successful in 80 per cent (1116) of cases. After propensity score matching (2444 patients), fewer overall complications (OR 0.36 (95 per cent c.i. 0.26 to 0.50)) and a shorter median LOS (2.5 versus 3 days, P < 0.001) were noted in the antibiotic management group. Accounting for interval appendicectomy rates, the mean total cost was €1034 lower per patient managed without surgery. Conclusion This study found that antibiotics is an alternative first-line treatment for adult acute appendicitis and can lead to cost reductions., Adult appendicitis is the most common emergency general surgery condition worldwide, and is normally treated with laparoscopic appendicectomy despite evidence that it can be treated safely with antibiotics. The authors followed up patients who received operative treatment and non-operative treatment with antibiotics during the first wave of the COVID-19 pandemic. Non-operative management was associated with a shorter length of hospital stay, fewer complications and a significant health cost reduction compared with operative management.

Author(s): Keele, L; Harris, S; Pimentel, SD; Grieve, R | Abstract: Instrumental variable methods, subject to appropriate identification assumptions, enable consistent estimation of causal effects in the presence of unobserved confounding. Near–far matching has been proposed as one analytic method to improve inference by strengthening the effect of the instrument on the exposure and balancing observable characteristics between groups of subjects with low and high values of the instrument. However, in settings with hierarchical data (e.g. patients nested within hospitals), or where several covariate interactions must be balanced, conventional near–far matching algorithms may fail to achieve the requisite covariate balance. We develop a new matching algorithm, that combines near–far matching with refined covariate balance, to balance large numbers of nominal covariates while also strengthening the instrumental variable. This extension of near–far matching is motivated by a case-study that aims to identify the causal effect of prompt admission to an intensive care unit on 7-day and 28-day mortality.

Summary In randomized controlled trials with treatment non-compliance, instrumental variable approaches are used to estimate complier average causal effects. We extend these approaches to cost-effectiveness analyses, where methods need to recognize the correlation between cost and health outcomes. We propose a Bayesian full likelihood approach, which jointly models the effects of random assignment on treatment received and the outcomes, and a three-stage least squares method, which acknowledges the correlation between the end points and the endogeneity of the treatment received. This investigation is motivated by the REFLUX study, which exemplifies the setting where compliance differs between the randomized controlled trial and routine practice. A simulation is used to compare the methods’ performance. We find that failure to model the correlation between the outcomes and treatment received correctly can result in poor confidence interval coverage and biased estimates. By contrast, Bayesian full likelihood and three-stage least squares methods provide unbiased estimates with good coverage.

Background There is a growing prevalence of diabetes worldwide in patients in the general population, including those with prior myocardial infarction (MI). Purpose To describe the characteristics, health status, resource utilization and clinical adverse events of stable post-MI patients with diabetes. Methods The long-Term rIsk, clinical manaGement and healthcare Resource utilization of stable coronary artery dISease (TIGRIS) prospective observational study (NCT01866904) obtained data from 8985 stable patients 1–3 years post-MI from 369 centres in 25 countries, who provided diabetes status (no, yes, insulin-treated) and follow-up. Diabetes status, other patient characteristics, medications, medical history and healthcare resource utilization were recorded at enrolment. Health status was assessed at enrolment, 1 and 2 years by EQ-5D-3L and converted to an EQ-5D score. Deaths, cardiovascular (CV) events, bleeding events and related hospitalizations were recorded during 2 years of follow-up. Results Diabetes mellitus (DM) was prevalent at enrolment in 2966 (33%) patients of whom 872 (29%) were insulin-treated. Compared to patients without DM, those with DM had a higher mean body mass index (28.2 vs 26.6kg/m2) and heart rate (71 vs 67bpm), were more likely to have had ≥2 prior MIs (12% vs 10%), chronic kidney disease (10% vs 6%), peripheral artery disease (10% vs 5%), heart failure (15% vs 10%), anaemia (4% vs 2%), angina (12% vs 9%), stroke (6% vs 4%) and chronic obstructive pulmonary disease (9% vs 7%). Patients with DM reported more problems for each domain of the EQ-5D (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), which resulted in a lower mean EQ-5D utility score at enrolment (0.83±0.22 for no-diabetes vs 0.86±0.19 for diabetes). Moreover, they also had higher CV hospitalization rates in the 6 months prior to enrolment (6.4% vs 5%). All these measures were more marked in insulin-dependent diabetics. The incidences of all-cause death, CV death and the composite of CV death, MI and stroke were all significantly higher in patients with DM, especially those on insulin (see Figure). For CV death, MI and stroke the 2-year risk ratios, compared to patients without DM, were 2.64 (P Figure 1 Conclusions Within a global population of stable post-MI patients, those with DM (especially those on insulin) have poorer health status and EQ-5D utility score, higher hospitalization rates and worse clinical outcomes compared with those without DM. Thus, in cardiac clinics worldwide, patients with DM require particularly close attention. Acknowledgement/Funding The study was funded by AstraZeneca

Summary In randomized controlled trials with non-adherence, instrumental variable (IV) methods are frequently used to report the complier average causal effect. With binary outcomes, many of the available IV estimation methods impose distributional assumptions. We develop a randomization-inference-based method of IV estimation for binary outcomes. The method is non-parametric and is based on Fisher's exact test, and estimates can be easily calculated from a set of 2×2 or 2×2×2 tables. Although we retain the standard IV identification assumptions for confidence regions and point estimates, the IV estimand under randomization inference is sample specific and does not assume that the randomized controlled trials participants are a random sample from the target population. We illustrate the method with the ‘IMPROVE’ trial that compares emergency endovascular versus open surgical repair for patients with ruptured aortic aneurysms.

Summary Randomized controlled trials (RCTs) can provide unbiased estimates of sample average treatment effects. However, a common concern is that RCTs may fail to provide unbiased estimates of population average treatment effects. We derive the assumptions that are required to identify population average treatment effects from RCTs. We provide placebo tests, which formally follow from the identifying assumptions and can assess whether they hold. We offer new research designs for estimating population effects that use non-randomized studies to adjust the RCT data. This approach is considered in a cost-effectiveness analysis of a clinical intervention: pulmonary artery catheterization.

Summary Guidelines for good practice in cost-effectiveness analyses (CEAs) are available from the UK's National Institute for Health and Clinical Excellence, which address the scope of the CEA study, appropriateness of the data used and how to account for model as well as statistical uncertainty. Within these three broad headings, we identify 10 specific issues that may affect materially the CEA of a public health intervention for which injecting drug users are a major target group. The 10 issues relate to injecting drug users' under-representation in randomized controlled trials; their risk of blood-borne viruses—such as human immunodeficiency virus and hepatitis C virus—which have long-term chronic sequelae, their markedly higher age-specific mortality than in the general population and the relapsing–remitting nature of opiate dependence with its associated risk of overdose. We consider how adequately three key UK CEAs accounted for the relevant injecting drug user specific issues that we have highlighted. The three case-studies are antiviral treatment of carriage of hepatitic C virus, opiate substitution therapy and needle and syringe programmes.

Summary Public policy makers use cost effectiveness analyses (CEAs) to decide which health and social care interventions to provide. Missing data are common in CEAs, but most studies use complete-case analysis. Appropriate methods have not been developed for handling missing data in complex settings, exemplified by CEAs that use data from cluster randomized trials. We present a multilevel multiple-imputation approach that recognizes the hierarchical structure of the data and is compatible with the bivariate multilevel models that are used to report cost effectiveness. We contrast this approach with single-level multiple imputation and complete-case analysis, in a CEA alongside a cluster randomized trial. The paper highlights the importance of adopting a principled approach to handling missing values in settings with complex data structures.

Background: there is a need for more information on the costs of different ways of managing stroke. Methods to compare the costs of stroke care in different countries have not been previously developed. Objective: to develop and use a method to compare the costs of acute stroke care across Europe. Setting: acute hospitals in 13 different European centres. Subjects and methods: we included in the study stroke patients hospitalized during 1996–7 at 13 centres across Europe (n=2072). We recorded the duration of acute hospital stay and use of investigations. Mean costs for each centre were predicted using linear regression analysis to adjust for case‐mix differences. Results: the average acute hospital stay ranged from 9 days (Spain) to 35 days (UK; P 74 ranged from $220 (95% confidence interval 191–254) in Latvia to $5164 (4294–6191) in Austria. Conclusions: differences in the acute costs of stroke exist across Europe because of differences in clinical practice and unit costs. This methodology will be used to capture the costs incurred by a broad range of care providers. These estimates will then be suitable for using in cost‐effectiveness analysis.