National risk prediction model for perioperative mortality in non-cardiac surgery.

BACKGROUND: Many multivariable models to calculate mortality risk after surgery are limited by insufficient sample size at development or by application to cohorts distinct from derivation populations. The aims of this study were to validate the Surgical Outcome Risk Tool (SORT) for a New Zealand population and to develop an extended NZRISK model to calculate 1-month, 1-year and 2-year mortality after non-cardiac surgery. METHODS: Data from the New Zealand National Minimum Data Set for patients having surgery between January 2013 and December 2014 were used to validate SORT. A random 75 per cent split of the data was used to develop the NZRISK model, which was validated in the other 25 per cent of the data set. RESULTS: External validation of SORT in the 360 140 patients who underwent surgery in the study period showed good discrimination (area under the receiver operating characteristic curve (AUROC) value of 0·906) but poor calibration (McFadden's pseudo-R2 0·137, calibration slope 5·32), indicating it was invalid in this national surgical population. Internal validation of the NZRISK model, which incorporates sex and ethnicity in addition to the variables used in SORT for 1-month, 1-year and 2-year outcomes, demonstrated excellent discrimination with AUROC values of 0·921, 0·904 and 0·895 respectively, and excellent calibration (McFadden's pseudo-R2 0·275, 0·308 and 0·312 respectively). Calibration slopes were 1·12, 1·02 and 1·02 respectively. CONCLUSION: The SORT performed poorly in this national population. However, inclusion of sex and ethnicity in the NZRISK model improved performance. Calculation of mortality risk beyond 30 days after surgery adds to the utility of this tool for shared decision-making.

ANTECEDENTES: Muchos modelos multivariados de estimación del riesgo de mortalidad después de la cirugía están limitados por haberse desarrollado a partir de tamaños muestrales insuficientes o por haberse aplicados a cohortes distintas de las poblaciones de derivación. Los objetivos de este estudio fueron validar el Surgical Outcome Risk Tool (SORT) para una población de Nueva Zelanda y desarrollar un modelo NZRISK extendido para calcular la mortalidad al mes y a los 1 y 2 años de una cirugía no cardíaca. MÉTODOS: Para validar el SORT se utilizó el Conjunto Mínimo Básico de Datos de Nueva Zelanda para los pacientes sometidos a cirugía entre enero de 2013 y diciembre de 2014. Se realizó una división aleatoria del 75% de los datos para desarrollar el modelo NZRISK que, posteriormente, se validó en el otro 25% del conjunto de datos. RESULTADOS: La validación externa de SORT en 360.140 pacientes intervenidos en el periodo analizado mostró una buena discriminación (área bajo las curvas de característica operativa del receptor (area under the receiver-operator characteristic curves (AUROC) 0,906)) pero con una mala calibración (pseudo-R2 de McFaddens 0,137 y pendiente de calibración 5,32), lo que indicaba que SORT no era válido para esta población quirúrgica nacional. La validación interna del modelo NZRISK, que incorpora el género y la etnia además de las variables utilizadas en el SORT, para los resultados al mes y a los 1 y 2 años demostró una excelente capacidad de discriminación con una AUROC de 0,921, 0,904, 0,895 respectivamente y una calibración excelente, con una pseudo-R2 de McFaddens de 0,275, 0,308 y 0,312 respectivamente. Las pendientes de calibración fueron de 1,12, 1,02 y 1,02, respectivamente. CONCLUSIÓN: El SORT no fue útil en esta población nacional. Sin embargo, la inclusión del género y la etnia en el modelo NZRISK mejoró sus resultados. El cálculo del riesgo de mortalidad más allá de 30 días después de la cirugía añade utilidad a esta herramienta para la toma de decisiones compartida.

Systematic Review and Meta-analysis of Factors Influencing Survival Following Abdominal Aortic Aneurysm Repair.

BACKGROUND: Predicting long-term survival following repair is essential to clinical decision making when offering abdominal aortic aneurysm (AAA) treatment. A systematic review and a meta-analysis of pre-operative non-modifiable prognostic risk factors influencing patient survival following elective open AAA repair (OAR) and endovascular aneurysm repair (EVAR) was performed. METHODS: MEDLINE, Embase and Cochrane electronic databases were searched to identify all relevant articles reporting risk factors influencing long-term survival (≥1 year) following OAR and EVAR, published up to April 2015. Studies with <100 patients and those involving primarily ruptured AAA, complex repairs (supra celiac/renal clamp), and high risk patients were excluded. Primary risk factors were increasing age, sex, American Society of Anaesthesiologist (ASA) score, and comorbidities such as ischaemic heart disease (IHD), cardiac failure, hypertension, chronic obstructive pulmonary disease (COPD), renal impairment, cerebrovascular disease, peripheral vascular disease (PVD), and diabetes. Estimated risks were expressed as hazard ratio (HR). RESULTS: A total of 5,749 study titles/abstracts were retrieved and 304 studies were thought to be relevant. The systematic review included 51 articles and the meta-analysis 45. End stage renal disease and COPD requiring supplementary oxygen had the worst long-term survival, HR 3.15 (95% CI 2.45-4.04) and HR 3.05 (95% CI 1.93-4.80) respectively. An increase in age was associated with HR of 1.05 (95% CI 1.04-1.06) for every one year increase and females had a worse survival than men HR 1.15 (95% CI 1.07-1.27). An increase in ASA score and the presence of IHD, cardiac failure, hypertension, COPD, renal impairment, cerebrovascular disease, PVD, and diabetes were also factors associated with poor long-term survival. CONCLUSION: The result of this meta-analysis summarises and quantifies unmodifiable risk factors that influence late survival following AAA repair from the best available published evidence. The presence of these factors might assist in clinical decision making during discussion with patients regarding repair.

Folic acid supplementation and colorectal cancer risk: a meta-analysis.

AIM: This meta-analysis aims to determine the effect of folic acid supplementation on colorectal cancer risk. METHOD: A structured search of the MEDLINE, EMBASE, Cochrane and CINAHL databases was undertaken in July 2008. All published full text English language articles were searched that included a randomized or pseudo-randomized comparison of subjects who received folate vs subjects who did not in relation to their risk of adenoma or advanced adenomatous lesions, including colorectal cancer. A weighted treatment effect (using fixed effects) was calculated across trials. RESULTS: Overall, the risk of an adenomatous lesion was not increased (odds ratio 1.09, 95% confidence interval 0.93-1.28) among patients who received folate supplementation for up to 3 years; however, for those who received folate for over 3 years, the risk of an adenomatous lesion was increased (odds ratio 1.35, 95% confidence interval 1.06-1.70). The risk associated with treatment was the highest for the occurrence of an advanced lesion (odds ratio 1.50, 95% confidence interval 1.06-2.10). There was no significant statistical heterogeneity in the analyses. CONCLUSION: At the 3-year colonoscopic follow up, folate supplementation had no effect on adenoma recurrence overall. While colonic surveillance beyond 3 years revealed an increased risk of colorectal adenoma, especially advanced adenoma, among those participants randomized to the folate group. This meta-analysis challenges the results from epidemiological studies that folate status is inversely related to the risk of developing colorectal cancer.

Computed tomographic colonography in the diagnosis of colorectal cancer.

BACKGROUND: This study aimed to determine the sensitivity of computed tomographic colonography (CTC) in diagnosing colorectal cancer and to explore the reasons why these cancers are missed on CTC. METHODS: Patients who underwent CTC in the 56-month period from 1 January 2004 to 1 September 2008, and all cases of colorectal cancer recorded in the National Cancer Registry database from 1 January 2004 to 1 December 2008, were identified. Cases from the two data sets were then matched to identify all patients in whom CTC had been performed more than 6 weeks before a histological report was available. CTC reports and patients' records were reviewed to determine the cancer site, and images were reviewed. RESULTS: A total of 3888 patients underwent CTC over a 56-month interval. After matching with the National Cancer Registry database, colorectal cancer was identified in 131 patients, whereas it had been suspected on CTC in 123 patients. One of the patients with missed cancer was excluded, leaving seven (5.3 per cent) missed cancers, four of which were located in the caecum. Five cancers were missed because of technical limitations of CTC and two were due to perceptive errors. Systems errors and severe patient co-morbidity contributed to three of the cases. The sensitivity of CTC for colorectal cancer was 95 (95 per cent confidence interval 89 to 98) per cent. CONCLUSION: The sensitivity of 95 per cent for CTC in the diagnosis of colorectal cancer compares favourably with that of double-contrast barium enema (92 per cent) and colonoscopy (94 per cent).

Empowering knowledge generation through international data network: the IMeCCHI-DATANETWORK.

INTRODUCTION: The International Methodology Consortium for Coded Health Information (IMeCCHI) is a collaboration of health services researchers who promote methodological advances in coded health information. The IMeCCHI-DATANETWORK initiative focuses on developing a multi-purpose distributed data infrastructure and common data model (CDM) to enable cross-border data sharing and international comparisons. METHODS: IMeCCHI consortium partners from six different countries - Canada, Denmark, Italy, New Zealand, South Korea, and Switzerland - used a questionnaire to describe their original databases which differ in size, structure, content and coding systems. To standardize these data, they agreed on a CDM and mapped their population-based databases to meet the CDM specifications. At the end of this process, local data had a more homogenous content and structure, which made them syntactically and semantically interoperable. Data transformation was performed using a common data management software called TheMatrix. RESULTS: The CDM encompasses four tables of structured data (person characteristics, hospitalizations, outpatient prescription medication and death), linked at the individual level through a person identifier. It can be used to answer research questions across countries using locally converted databases, which facilitates study replication in a distributed fashion. As a proof-of-concept study, an initial research question was addressed using an agreed protocol. Local data were transformed in csv files in the CDM structure and TheMatrix was tested to transform the standardized data from each partner into local analytical datasets. This allowed results to be shared between countries, whilst maintaining local control over each region's data. CONCLUSION: The IMeCCHI-DATANETWORK, a model of a distributed data network, demonstrated that it is feasible to analyze international data using standardized analytical methods that enable independent analyses by regions, without relocating datasets thereby protecting local confidentiality obligations. The distributed data infrastructure can produce results that can be generalized to several countries, while facilitating cross-border data sharing and international comparisons. KEYWORDS: Common data model, international comparison, cross-border data sharing, interoperability, observational data.

Follow-up strategies for patients treated for non-metastatic colorectal cancer.

BACKGROUND: It is common clinical practice to follow patients with colorectal cancer (CRC) for several years following their definitive surgery and/or adjuvant therapy. Despite this widespread practice there is considerable controversy about how often patients should be seen, what tests should be performed and whether these varying strategies have any significant impact on patient outcomes. OBJECTIVES: To review the available evidence concerning the benefits of intensive follow up of colorectal cancer patients with respect to survival. Secondary endpoints include time to diagnosis of recurrence, quality of life and the harms and costs of surveillance and investigations. SEARCH STRATEGY: Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, CANCERLIT, Cochrane Controlled Trials Register, Science Citation Index, conference proceedings, trial registers, reference lists and contact with experts in the field. SELECTION CRITERIA: Only randomised controlled trials comparing different follow-up strategies for patients with non-metastatic CRC treated with curative intent were included. DATA COLLECTION AND ANALYSIS: Trial eligibility and methodological quality were assessed independently by the three authors. MAIN RESULTS: Eight studies were included in this update of the review. There was evidence that an overall survival benefit at five years exists for patients undergoing more intensive follow up OR was 0.73 (95% CI 0.59 to 0.91); and RD -0.06 (95% CI -0.11 to -0.02). The absolute number of recurrences was similar; OR was 0.91 (95% CI 0.75 to 1.10); and RD -0.02 (95% CI -0.06 to 0.02) and although the weighted mean difference for the time to recurrence was significantly reduced by -6.75 (95% CI -11.06 to -2.44) there was significant heterogeneity between the studies. Analyses demonstrated a mortality benefit for performing more tests versus fewer tests OR was 0.64 (95% CI 0.49 to 0.85), and RD -0.09 (95%CI -0.14 to -0.03) and liver imaging versus no liver imaging OR was 0.64 (95% CI 0.49 to 0.85), and RD -0.09 (95%CI -0.14 to -0.03). There were significantly more curative surgical procedures attempted in the intensively followed arm: OR 2.41(95% CI 1.63 to 3.54), RD 0.06 (95%CI 0.04 to 0.09). No useful data on quality of life, harms or cost-effectiveness were available for further analysis. AUTHORS' CONCLUSIONS: The results of our review suggest that there is an overall survival benefit for intensifying the follow up of patients after curative surgery for colorectal cancer. Because of the wide variation in the follow-up programmes used in the included studies it is not possible to infer from the data the best combination and frequency of clinic (or family practice) visits, blood tests, endoscopic procedures and radiological investigations to maximise the outcomes for these patients. Nor is it possible to estimate the potential harms or costs of intensifying follow up for these patients in order to adopt a cost-effective approach in this clinical area. Large clinical trials underway or about to commence are likely to contribute valuable further information to clarify these areas of clinical uncertainty.

Perioperative mortality in New Zealand related to hip and knee replacement surgery: comparing administrative and registry data.

INTRODUCTION: Perioperative mortality is of considerable importance, but few national assessments are available. New Zealand has a clinical registry and an administrative dataset that both capture national information about hip and knee arthroplasties. National perioperative mortality rates were compared between the two data sources. METHOD: Data related to all patients undergoing an elective hip or knee replacement procedure (primary or revision) between 1 January 2007 and 31 December 2011 were separately extracted from the New Zealand Joint Registry and the National Minimum Dataset. The procedure date was used to define the occurrence of an event and dates were compared between datasets plus or minus 3 days. Date of death information was obtained from the National Mortality Collection and used to estimate 30 day mortality rates. RESULTS: No statistically significant differences in perioperative mortality were evident between comparisons from the two data sources although more deaths were recorded among Registry-only procedures. CONCLUSIONS: Estimates of 30 day perioperative mortality related to hip and knee arthroplasty procedures in New Zealand 2007-2011 are very similar regardless of data source. These data, coupled with perioperative mortality review using structured reports obtained from clinicians, could be used to develop a surveillance system to promote surgical safety.

Corneal ulcer due to Achromobacter xylosoxidans.

We report a case of corneal ulcer caused by the opportunistic organism Achromobacter xylosoxidans which developed during chronic topical steroid treatment of an eye with neovascular glaucoma. A. xylosoxidans has probably been underreported as a cause of ocular infection because of confusion between this organism and other Gram-negative organisms, particularly pseudomonas. A. xylosoxidans is resistant to aminoglycosides and some cephalosporins but not carbenicillin. This difference in antibiotic sensitivity patterns between A. xylosoxidans and pseudomonas makes an accurate differentiation between the 2 organisms important. This case was successfully treated after substituting topical carbenicillin for topical gentamicin and amikacin.

Follow-up strategies for patients treated for non-metastatic colorectal cancer.

BACKGROUND: It is common clinical practise to follow patients with colorectal cancer (CRC) for several years following their definitive surgery and/or adjuvant therapy. Despite this widespread practice there is considerable controversy about how often patients should be seen, what tests should be performed and whether these varying strategies have any significant impact on patient outcomes. OBJECTIVES: To review the available evidence concerning the benefits of intensive follow-up of colorectal cancer patients with respect to survival. Secondary endpoints include time to diagnosis of recurrence, quality of life and the harms and costs of surveillance and investigations. SEARCH STRATEGY: Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, CANCERLIT, Cochrane Controlled Trials Register, Science Citation Index, conference proceedings, trial registers, reference lists and contact with experts in the field. SELECTION CRITERIA: Only randomised controlled trials comparing different follow-up strategies for patients with non-metastatic CRC treated with curative intent were included. DATA COLLECTION AND ANALYSIS: Trial eligibility and methodological quality were assessed independently by the three reviewers. MAIN RESULTS: Five trials were included. There was evidence that an overall survival benefit at 5 years exists for patients undergoing more intensive follow-up (OR = 0.67, 95% confidence interval 0.53 - 0.84; RD = -0.07, CI -0.12 - -0.02). The absolute number of recurrences was similar (OR = 0.91; 95% confidence interval 0.72 - 1.14; RD = 0.00, CI -0.07 - 0.07) and although the weighted mean difference for the time to recurrence was significantly reduced by 6.75 (95% confidence interval -11.06 - -2.44) there was significant heterogeneity between the studies. Analyses demonstrated a mortality benefit for performing more tests versus fewer tests (OR = 0.66; 95% confidence interval 0.46 - 0.95) and liver imaging versus no liver imaging (OR = 0.66; 95% confidence interval 0.46 - 0.95). However when both these results are expressed as a risk difference this significance is lost (RD = -0.06; CI -0.25 - 0.13). No useful data on quality of life, harms or cost-effectiveness were available for further analysis. REVIEWER'S CONCLUSIONS: The results of our review suggest that there is an overall survival benefit for intensifying the follow-up of patients after curative surgery for colorectal cancer. Because of the wide variation in the follow-up programmes used in the included studies it is not possible to infer from the data the best combination and frequency of clinic (or family practice) visits, blood tests, endoscopic procedures and radiological investigations to maximise the outcomes for these patients. Nor is it possible to estimate the potential harms or costs of intensifying follow-up for these patients in order to adopt a cost-effective approach in this clinical area. Large clinical trials underway or about to commence are likely to contribute valuable further information to clarify these areas of clinical uncertainty.

The epidemiology of emergency department attendances in Christchurch.

AIM: To describe the characteristics of patients who attended Christchurch Hospital's emergency department (ED) in 1998. METHODS: Non-identifiable data about all the attendances to the ED during 1998 were obtained from Christchurch Hospital's management information services database. Demographic data, time and date of arrival, source of referral, diagnosis, triage category, and discharge destination were analysed. RESULTS: In 1998 there were 65,024 attendances, on average 178 people per day (95% confidence interval 145-211). Children and the elderly were the most frequent attenders except in weekends when visits by young people were more common. The elderly had the highest age specific rates of attendance. Most attendances were between 8am and midnight, and Mondays and July were the day and month with most attendances respectively. 43% of people referred themselves and 38% were referred by their general practitioner (GP). GP referrals were significantly more common during the day, the working week and in the winter. The elderly frequently presented with medical problems, their attendances were classified as more urgent and 75% of their visits resulted in hospital admission. CONCLUSIONS: These findings are generally consistent with the few previously published descriptions of ED attendance in New Zealand and most overseas studies. ED attendance data have important implications for funders and providers of ED services and a national dataset should be established.

Frequent attenders at Christchurch Hospital's emergency department.

AIM: To describe the characteristics of adult frequent attenders presenting to a major urban emergency department during a twelve month period. METHODS: A retrospective study was performed of all frequent attenders (presenting ten of more times during twelve months) to the Emergency Department (ED) at Christchurch Hospital. RESULTS: The proportion of visits to the ED by frequent attenders increased from 1.38% to 2.08% of all visits between 1996 to 2000. A computer search identified 86 frequent attenders between 1 November 1998 and 31 October 1999: 1,395 visits were made by these patients. The median age was 35 years, both sexes were equally represented and most frequent attenders were single. The most common presenting problem was medical (40%) or psychological (36%), and (86%) had secondary problems related to each attendance. CONCLUSION: This study's findings are generally consistent with those from two previous descriptions of frequent attenders. Evidence from overseas trials suggests that case management may provide the best outcomes for these patients, but further research is needed.

Diabetes mellitus in a Christchurch working population.

Using criteria recommended by the World Health Organisation, prevalence rates for diabetes mellitus have been determined in a Christchurch working population of adults aged 15-65 years. Ninety-three percent of 1047 workers employed by a large industrial group were screened for diabetes mellitus using 75 G oral glucose tolerance tests. Three point one percent of the survey group were diabetic--1.55% were known to have diabetes and a further 1.55% were new cases. In addition, 0.31% were considered to have gestational diabetes mellitus. Blood glucose elevations not diagnostic for diabetes mellitus were present in another 0.93%. By applying the criteria of the National Diabetes Data Group, slightly different prevalence rates were found--3.0% for diabetes mellitus and 1.14% for impaired glucose tolerance.

Detection of cytomegalovirus antibody with latex agglutination.

Transfusion-acquired cytomegalovirus (CMV) infections should be prevented in seronegative immunocompromised patients by providing blood products from donors who are also seronegative. Latex agglutination was investigated as a simple and rapid method for detecting antibody against CMV. Latex beads were coated with CMV antigen, incubated for 8 min at room temperature with 25 microliter of sera, and examined for agglutination. The sensitivity and specificity of latex agglutination was compared with that of indirect hemagglutination (IHA, Cetus Corp., Emeryville, Calif.) and enzyme immunoassay (EIA) with sera from 604 random blood donors or patients. Of 327 serum samples shown to be seronegative by EIA and IHA, 327 had a latex agglutination titer of less than 1:4 (specificity, 100%). Of 236 serum samples with detectable antibody by EIA and IHA, 228 had a latex agglutination titer of 1:4 or greater (sensitivity, 97%). Plasma collected with EDTA, heparin, or citrate was satisfactory for latex agglutination. Latex agglutination results correlated quantitatively with those of EIA, and the test also detected fourfold or greater rises in antibody with paired sera from six patients with posttransfusion CMV infections. Latex agglutination is a sensitive and specific assay that is rapid and simple to perform and should be effective in selecting seronegative blood donors to prevent posttransfusion CMV infections in seronegative recipients.

Use of the directigen latex agglutination test for detection of Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis antigens in cerebrospinal fluid from meningitis patients.

Cerebrospinal fluid specimens from 257 persons were tested for the presence of bacterial antigens by counterimmunoelectrophoresis and the Directigen meningitis test (Hynson, Westcott & Dunning, Div. Becton Dickinson & Co., Baltimore, Md.). The specimens were obtained from 162 patients with meningitis caused by Haemophilus influenzae type b, Streptococcus pneumoniae, or Neisseria meningitidis serogroups A and C and from 95 patients without bacterial meningitis or meningitis caused by other bacterial agents. Directigen detected H. influenzae type b antigen in 83% (69 of 83) of the specimens obtained from patients with H. influenzae disease, pneumococcal antigen in 77% (30 of 39) of the specimens from patients with pneumococcal disease, and N. meningitidis antigen in 93% (37 of 40) of the specimens from patients with disease caused by N. meningitidis serogroups A and C. The comparable figures for counterimmunoelectrophoresis were 66% (55 of 83), 79% (31 of 39), and 78% (31 of 40), respectively. No false-positive reactions were reported with the Directigen reagents. Nonspecific reactions (agglutination with more than one of the four Directigen latex reagents) were noted with five specimens. The nonspecific reactions were resolved in four of the five specimens by heating (100 degrees C for 3 min). The accumulated data demonstrate that the sensitivity of the Directigen meningitis test is better than or at least equivalent to the sensitivity of counterimmunoelectrophoresis for the detection of antigens in cerebrospinal fluid.