Alex Bottle

Systematic review of discharge coding accuracy

INTRODUCTION Routinely collected data sets are increasingly used for research, financial reimbursement and health service planning. High quality data are necessary for reliable analysis. This study aims to assess the published accuracy of routinely collected data sets in Great Britain. METHODS Systematic searches of the EMBASE, PUBMED, OVID and Cochrane databases were performed from 1989 to present using defined search terms. Included studies were those that compared routinely collected data sets with case or operative note review and those that compared routinely collected data with clinical registries. RESULTS Thirty-two studies were included. Twenty-five studies compared routinely collected data with case or operation notes. Seven studies compared routinely collected data with clinical registries. The overall median accuracy (routinely collected data sets versus case notes) was 83.2% (IQR: 67.3-92.1%). The median diagnostic accuracy was 80.3% (IQR: 63.3-94.1%) with a median procedure accuracy of 84.2% (IQR: 68.7-88.7%). There was considerable variation in accuracy rates between studies (50.5-97.8%). Since the 2002 introduction of Payment by Results, accuracy has improved in some respects, for example primary diagnoses accuracy has improved from 73.8% (IQR: 59.3-92.1%) to 96.0% (IQR: 89.3-96.3), P= 0.020. CONCLUSION Accuracy rates are improving. Current levels of reported accuracy suggest that routinely collected data are sufficiently robust to support their use for research and managerial decision-making.

Use of administrative data or clinical databases as predictors of risk of death in hospital: comparison of models

Objective To compare risk prediction models for death in hospital based on an administrative database with published results based on data derived from three national clinical databases: the national cardiac surgical database, the national vascular database and the colorectal cancer study. Design Analysis of inpatient hospital episode statistics. Predictive model developed using multiple logistic regression. Setting NHS hospital trusts in England. Patients All patients admitted to an NHS hospital within England for isolated coronary artery bypass graft (CABG), repair of abdominal aortic aneurysm, and colorectal excision for cancer from 1996-7 to 2003-4. Main outcome measures Deaths in hospital. Performance of models assessed with receiver operating characteristic (ROC) curve scores measuring discrimination (<0.7=poor, 0.7-0.8=reasonable, >0.8=good) and both Hosmer-Lemeshow statistics and standardised residuals measuring goodness of fit. Results During the study period 152 523 cases of isolated CABG with 3247 deaths in hospital (2.1%), 12 781 repairs of ruptured abdominal aortic aneurysm (5987 deaths, 46.8%), 31 705 repairs of unruptured abdominal aortic aneurysm (3246 deaths, 10.2%), and 144 370 colorectal resections for cancer (10 424 deaths, 7.2%) were recorded. The power of the complex predictive model was comparable with that of models based on clinical datasets with ROC curve scores of 0.77 (v 0.78 from clinical database) for isolated CABG, 0.66 (v 0.65) and 0.74 (v 0.70) for repairs of ruptured and unruptured abdominal aortic aneurysm, respectively, and 0.80 (v 0.78) for colorectal excision for cancer. Calibration plots generally showed good agreement between observed and predicted mortality. Conclusions Routinely collected administrative data can be used to predict risk with similar discrimination to clinical databases. The creative use of such data to adjust for case mix would be useful for monitoring healthcare performance and could usefully complement clinical databases. Further work on other procedures and diagnoses could result in a suite of models for performance adjusted for case mix for a range of specialties and procedures.

Systematic review of comorbidity indices for administrative data.

Background:Adjustment for comorbidities is common in performance benchmarking and risk prediction. Despite the exponential upsurge in the number of articles citing or comparing Charlson, Elixhauser, and their variants, no systematic review has been conducted on studies comparing comorbidity measures in use with administrative data. We present a systematic review of these multiple comparison studies and introduce a new meta-analytical approach to identify the best performing comorbidity measures/indices for short-term (inpatient+⩽30 d) and long-term (outpatient+>30 d) mortality. Methods:Articles up to March 18, 2011 were searched based on our predefined terms. The bibliography of the chosen articles and the relevant reviews were also searched and reviewed. Multiple comparisons between comorbidity measures/indices were split into all possible pairs. We used the hypergeometric test and confidence intervals for proportions to identify the comparators with significantly superior/inferior performance for short-term and long-term mortality. In addition, useful information such as the influence of lookback periods was extracted and reported. Results:Out of 1312 retrieved articles, 54 articles were eligible. The Deyo variant of Charlson was the most commonly referred comparator followed by the Elixhauser measure. Compared with baseline variables such as age and sex, comorbidity adjustment methods seem to better predict long-term than short-term mortality and Elixhauser seems to be the best predictor for this outcome. For short-term mortality, however, recalibration giving empirical weights seems more important than the choice of comorbidity measure. Conclusions:The performance of a given comorbidity measure depends on the patient group and outcome. In general, the Elixhauser index seems the best so far, particularly for mortality beyond 30 days, although several newer, more inclusive measures are promising.

Day of week of procedure and 30 day mortality for elective surgery: retrospective analysis of hospital episode statistics

Objectives To assess the association between mortality and the day of elective surgical procedure. Design Retrospective analysis of national hospital administrative data. Setting All acute and specialist English hospitals carrying out elective surgery over three financial years, from 2008-09 to 2010-11. Participants Patients undergoing elective surgery in English public hospitals. Main outcome measure Death in or out of hospital within 30 days of the procedure. Results There were 27 582 deaths within 30 days after 4 133 346 inpatient admissions for elective operating room procedures (overall crude mortality rate 6.7 per 1000). The number of weekday and weekend procedures decreased over the three years (by 4.5% and 26.8%, respectively). The adjusted odds of death were 44% and 82% higher, respectively, if the procedures were carried out on Friday (odds ratio 1.44, 95% confidence interval 1.39 to 1.50) or a weekend (1.82, 1.71 to 1.94) compared with Monday. Conclusions The study suggests a higher risk of death for patients who have elective surgical procedures carried out later in the working week and at the weekend.

Weekend mortality for emergency admissions. A large, multicentre study

Background Several studies have identified higher mortality for patients admitted as emergencies at the weekend compared with emergency admissions during the week, but most have focused on specific conditions or have had a limited sample size. Methods Using routinely collected hospital administrative data, we examined in-hospital deaths for all emergency inpatient admissions to all public acute hospitals in England for 2005/2006. Odds of death were calculated for admissions at the weekend compared to admissions during the week, adjusted for age, sex, socioeconomic deprivation, comorbidity and diagnosis. Results Of a total of 4 317 866 emergency admissions, we found 215 054 in-hospital deaths with an overall crude mortality rate of 5.0% (5.2% for all weekend admissions and 4.9% for all weekday admissions). The overall adjusted odds of death for all emergency admissions was 10% higher (OR 1.10, 95% CI 1.08 to 1.11) in those patients admitted at the weekend compared with patients admitted during a weekday (p<0.001). Conclusions This is the largest study published on weekend mortality and highlights an area of concern in relation to the delivery of acute services.

Short-term outcomes following open versus minimally invasive esophagectomy for cancer in England: a population-based national study.

Objective: To compare short-term outcomes of open and minimally invasive esophagectomy (MIE) for cancer. Background Data: Numerous studies have demonstrated the safety and possible advantages of MIE in selected cohorts of patients. The increasing use of MIE is not coupled with conclusive evidence of its benefits over “open” esophagectomy, especially in the absence of randomized trials. Methods: Hospital Episode Statistics data were analyzed from April 2005 to March 2010. This is a routinely collected database of all English National Health Service Trusts. Office of Population Censuses and Surveys Classification of Surgical Operations and Procedures, 4th revision (OPCS-4), procedure codes were used to identify index resections and International Statistical Classification of Diseases, 10th Revision (ICD-10), diagnostic codes were used to ascertain comorbidity status and complications. Thirty-day in-hospital mortality, medical complications, and surgical reinterventions were analyzed. Unadjusted and risk-adjusted regression analyses were undertaken. Results: Seven thousand five hundred and two esophagectomies were undertaken; of these, 1155 (15.4%) were MIE. In 2009–2010, 24.7% of resections were MIE. There was no difference in 30-day mortality (4.3% vs 4.0%; P = 0.605) and overall medical morbidity (38.0% vs 39.2%; P = 0.457) rates between open and MIE groups, respectively. A higher reintervention rate was associated with the MIE group than with the open group (21% vs 17.6%, P = 0.006; odds ratio, 1.17; 95% confidence interval, 1.00–1.38; P = 0.040). Conclusions: Minimally invasive esophagectomy is increasingly performed in the United Kingdom. Although the study confirmed the safety of MIE in a population-based national data, there are no significant benefits demonstrated in mortality and overall morbidity. Minimally invasive esophagectomy is associated with higher reintervention rate. Further evidence is needed to establish the long-term survival of MIE.

Ten-year trends in hospital admissions for adverse drug reactions in England 1999–2009

Summary Objectives Adverse drug reactions (ADR) are an important cause of morbidity and mortality. We analysed trends in hospital admissions associated with ADRs in English hospitals between 1999 and 2008. Design Data from the Hospital Episode Statistics database were examined for all English hospital admissions (1999–2008) with a primary or secondary diagnosis of an ADR recorded. Setting All NHS (public) hospitals in England. Main outcome measures The number of admissions and in-hospital mortality rate with a primary (codes including ‘adverse drug reaction’, ‘drug-induced’, ‘due to drug’, ‘due to medicament’ or ‘drug allergy’) or secondary diagnosis of ADR (ICD-10 Y40-59) were obtained and analysed. Further analysis for the year 2008–2009 was performed with regard to age, gender, proportion aged >65 yrs and total bed-days. Results Between 1999 and 2008, there were 557,978 ADR-associated admissions, representing 0.9% of total hospital admissions. Over this period the annual number of ADRs increased by 76.8% (from 42,453 to 75,076), and in-hospital mortality rate increased by 10% (from 4.3% to 4.7%). In 2008, there were 6,830,067 emergency admissions of which 75,076 (1.1%) were drug-related. Systemic agents were most commonly implicated (19.2%), followed by analgesics (13.3%) and cardiovascular drugs (12.9%).There has been a near two-fold increase in nephropathy and cardiovascular consequences secondary to drugs and a 6.8% fall in mental and behavioural disorders due to drugs. Conclusions ADRs have a major impact on public health. Our data suggest the number of ADR admissions has increased at a greater rate than the increase in total hospital admissions; some of this may be due to improved diagnostic coding. However, in-hospital mortality due to ADR admissions also increased during the period. Our findings should prompt policymakers to implement further measures to reduce ADR incidence and their associated in-hospital mortality, and methods to improve the recording of ADRs.

Impact of the seven-valent pneumococcal conjugate vaccination (PCV7) programme on childhood hospital admissions for bacterial pneumonia and empyema in England: national time-trends study, 1997–2008

Background Childhood bacterial pneumonia and empyema rates have reportedly increased in recent years in Europe. In September 2006 the seven-valent pneumococcal conjugate vaccination (PCV7) was introduced to the childhood national immunisation programme in England following a successful PCV7 campaign in the USA. The aim of this study was to report national time trends in hospital admissions for childhood bacterial pneumonia and empyema in England before and after the introduction of PCV7. Methods A population-based time-trend analysis of Hospital Episode Statistics data of children aged <15 years admitted to all NHS hospitals in England, with a primary diagnosis of bacterial pneumonia and empyema from 1997 to 2008 was performed. Annual crude and age-sex standardised hospital admission rates for bacterial pneumonia and empyema were calculated. Results Admission rates for bacterial pneumonia and empyema increased from 1997 to 2006, then declined to 2008. Bacterial pneumonia rates decreased to 1079 (95% CI 1059 to 1099) per million children and empyema rates decreased to 14 (95% CI 11 to 16) per million children. The RR for bacterial pneumonia admissions was 1.19 (95% CI 1.16 to 1.22) in 2006 compared with 2004 and 0.81 (95% CI 0.79 to 0.83) in 2008 compared with 2006. For empyema, the corresponding RRs were 1.77 (95% CI 1.38 to 2.28) in 2006 compared with 2004 and 0.78 (95% CI 0.62 to 0.98) in 2008 compared with 2006. Conclusion Childhood bacterial pneumonia and empyema admission rates were increasing prior to 2006 and decreased by 19% and 22% respectively between 2006 and 2008, following the introduction of the PCV7 pneumococcal conjugate vaccination to the national childhood immunisation programme.

Changes in the Incidence of Lower Extremity Amputations in Individuals With and Without Diabetes in England Between 2004 and 2008

OBJECTIVE To describe recent trends in the incidence of nontraumatic amputations among individuals with and without diabetes and estimate the relative risk of amputations among individuals with diabetes in England. RESEARCH DESIGN AND METHODS We identified all patients aged >16 years who underwent any nontraumatic amputation in England between 2004 and 2008 using national hospital activity data from all National Health Service hospitals. Age- and sex-specific incidence rates were calculated using the total diabetes population in England every year. To test for time trend, we fitted Poisson regression models. RESULTS The absolute number of diabetes-related amputations increased by 14.7%, and the incidence decreased by 9.1%, from 27.5 to 25.0 per 10,000 people with diabetes, during the study period (P > 0.2 for both). The incidence of minor and major amputations did not significantly change (15.7–14.9 and 11.8–10.2 per 10,000 people with diabetes; P = 0.66 and P = 0.29, respectively). Poisson regression analysis showed no statistically significant change in diabetes-related amputation incidence over time (0.98 decrease per year [95% CI 0.93–1.02]; P = 0.12). Nondiabetes-related amputation incidence decreased from 13.6 to 11.9 per 100,000 people without diabetes (0.97 decrease by year [0.93–1.00]; P = 0.059). The relative risk of an individual with diabetes undergoing a lower extremity amputation was 20.3 in 2004 and 21.2 in 2008, compared with that of individuals without diabetes. CONCLUSIONS This national study suggests that the overall population burden of amputations increased in people with diabetes at a time when the number and incidence of amputations decreased in the aging nondiabetic population.

Uptake of the NHS Health Checks programme in a deprived, culturally diverse setting: cross-sectional study

BACKGROUND The UK is embarking on a national cardiovascular risk assessment programme called NHS Health Checks; in order to be effective, high and equitable uptake is paramount. METHODS A cross-sectional study, using data extracted from electronic medical records of persons aged 35-74 years estimated to be at a high risk of developing cardiovascular disease, to examine the uptake of the Health Checks using logistic regression and statin prescribing. RESULTS A total of 44.8% of high risk patients invited for a Health Check attended. Uptake was lower among younger men but higher among patients from south Asian (AOR = 1.71 [1.29-2.27] compared with white) or mixed ethnic backgrounds (AOR = 2.42 [1.50-3.89]), and patients registered with smaller practices (AOR = 2.53 [1.09-5.84] <3000 patients compared with 3000-5999). The percentage of patients confirmed to be at high risk of CVD prescribed a statin increased from 24.7 to 44.8%. CONCLUSIONS Uptake of cardiovascular risk assessment and prescribing of statins in high risk patients was considerably lower than projected in the first year of NHS Health Checks programme. Targeting efforts to increase uptake and adherence to interventions in high risk populations and reinvesting resources into population wide strategies to reduce obesity, smoking and salt intake may prove more cost-effective in reducing the burden of cardiovascular disease in the UK.