Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

113 Ischaemic Bowel in The North of England: Trends in Management Approach And Patient Outcomes

Aim

Bowel ischaemia is the third most common indication for emergency laparotomy in the UK and is associated with high rates of postoperative morbidity and mortality. This study describes changes in incidence, patient characteristics, management approach and outcomes for patients with bowel ischaemia over a fifteen-year period

Method

Data for patients admitted as an emergency, with a diagnosis of bowel ischaemia, to NHS hospitals in the North of England between 2002 and 2016 were collected. This included patient demographics and co-morbidities, operations performed and outcomes. The primary outcome of interest was in-hospital death within 30 days of admission for non-operatively managed patients and 30-day post-operative mortality for those who underwent an operative intervention.

Results

The incidence of bowel ischaemia has increased as a proportion of emergency general surgery admissions by 68% over fifteen years. More patients are undergoing computerised tomography (CT) imaging has (44.0% vs. 70.3%, p<0.001) and more operations are being performed within 48 hours of admission (p<0.001). The number of patients being managed operatively has fallen from 56.7% to 38.7%. Decreased 30-day mortality rates were observed for both operatively (37.5% to 26.7%, p<0.001) and non-operatively (45.7% to 26.8%, p<0.001) managed patients. Mean length of hospital stay has remained relatively unchanged over time.

Conclusions

Ischaemic bowel is becoming increasingly common. Increased usage of CT imaging has likely resulted in decreased rates of operative management due to its ability to accurately characterise intra-abdominal pathology. Improved mortality rates were observed for both operative and non-operative management strategies.

The impact of COVID-19 restrictions on pathology service utilisation

Background

Isolation and social distancing restrictions due to COVID‐19 have the potential to impact access to healthcare services.

Aims

To assess the use of pathology services during the COVID‐19 pandemic initial restrictions.

Methods

Repeated cross‐sectional study of pathology tests utilisation during a baseline time period early in 2020 compared with pre‐lockdown and lockdown due to COVID‐19 in South Australia. The outcome measure was changed in a number of pathology tests compared to baseline period, particularly change in the number of troponin tests to determine potential impacts of lockdown on urgent care presentations.

Results

In the community setting, the ratio of a number of pathology tests pre‐lockdown and post‐lockdown versus baseline period decreased from 1.02 to 0.53 respectively. The exception was microbiology molecular tests, where the number of tests was more than three times higher in the lockdown period. The number of troponin tests in emergency departments decreased in the lockdown period compared to the baseline time period; however, there was no evidence of an association between tests result (positive vs negative) and time period (odds ratio (OR) 1.09; 95% confidence interval (CI) 0.97–1.22). There was an inverse relationship between age and time period (OR 0.995; 95% CI 0.993–0.997), indicating that fewer troponin tests were conducted in older people during the lockdown compared with the baseline period.

Conclusion

COVID‐19 restrictions had a significant impact on the use of pathology testing in both urgent and non‐urgent care settings. Further studies are needed to investigate the effect on health outcomes as a result of the COVID‐19 restrictions.

The Effect of Multimorbidity Patterns and the Impact of Comorbid Anxiety and Depression on Primary Health Service Use: The Men Androgen Inflammation Lifestyle Environment and Stress (MAILES) Study

This study sought to determine patterns of multimorbidity and quantify their impact on use of primary health services in the presence and absence of anxiety and depression among a cohort of urban community-dwelling men in Australia. The analytic sample consisted of men (n = 2039; age 38–85) from the follow-up wave of a prospective cohort study of all participants of the Florey Adelaide Male Ageing Study (FAMAS; Stage 2 [2007–2010]) and age-matched men from the North-West Adelaide Health Study (NWAHS; Stage 3 [2008–2010]). Self-reported data and linkage with a national universal health coverage scheme (Medicare) provided information on the prevalence of eight chronic conditions and health service utilization information (including annual GP visits). Obesity and cardiovascular disease (CVD) were associated with the highest number of comorbid conditions. Two nonrandom multimorbidity “clusters” emerged: “CVD, Obesity, Diabetes” and “CVD, Obesity, Osteoarthritis.” Participants with conditions comorbid with CVD were more likely to have 10 or more annual GP visits, compared to multimorbidity involving other conditions. In comparison to participants without CVD, the presence of CVD increased the chance of having 10 or more annual GP visits (adjusted risk ratio: 3.7; 95% CI [2.8, 4.8]). When CVD was comorbid with anxiety and depression, having 10 or more annual GP visits was more common (adjusted risk ratio: 1.8; 95% CI [1.2, 2.5]). Multimorbidity patterns involving CVD, especially for multimorbidity that includes CVD with comorbid anxiety and depression, should be considered in developing clinical trials to better inform medical decision-making and care for patients with CVD and comorbid conditions.

LC-MS/MS analysis of vitamin D3 metabolites in human serum using a salting-out based liquid-liquid extraction and DAPTAD derivatization

LC-MS/MS has recently emerged as the best-practice for simultaneous analysis of vitamin D metabolites. We have developed and validated an LC-MS/MS method for simultaneous quantification of 25(OH)D3, 24,25(OH)2D3, and 3-epi-25(OH)D3 in human serum. These three metabolites were extracted from 50 μL of serum by acetonitrile protein precipitation followed by salting-out of acetonitrile. DAPTAD (4-(4'-dimethylaminophenyl)-1,2,4-triazoline-3,5-dione) was used to derivatize the extracted metabolites and their deuterated isotope internal standards. Chromatographic separation was achieved on a UPLC C18 column (Waters® ACQUITY 100 × 2.1 mm, 1.7 µm) utilizing 0.1% formic acid and acetonitrile as mobile phases. Limits of quantification were 1 ng/mL for 25(OH)D3 and 0.1 ng/mL for 24,25(OH)D3 and 3-epi-25(OH)D3. In-house and external Vitamin D External Quality Assessment Scheme (DEQAS) quality control sample analysis revealed satisfactory method accuracy. Within-analytical batch and between analytical batches precision were <15%. Extraction recovery for the three analytes were all ˃ 85% and all showed adequate autosampler, bench-top and freeze-thaw stability. Inter-methodological comparison of 25(OH)D3 results in patient serum samples revealed systematic and proportional differences between our method and DiaSorin® Liaison immunoassay, however a good agreement with an independent LC-MS/MS method was found.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Retrospective analysis of 30-day mortality for emergency general surgery admissions evaluating the weekend effect

Background

The weekend effect describes excess mortality associated with hospital admission on Saturday or Sunday. This study assessed whether a weekend effect exists for patients admitted for emergency general surgery.

Methods

Data for emergency general surgical admissions to National Health Service hospitals in the Northern Deanery in England between 2000 and 2014 were collected, including demographics, co-morbidities, diagnoses, operations undertaken and outcomes. The primary outcome of interest was in-hospital death within 30 days of admission. Cox regression analysis was undertaken with adjustment for co-variables.

Results

There were 12 100 in-hospital deaths within 30 days of admission (3·3 per cent). The overall 30-day mortality rate reduced significantly during the 15-year interval studied, from 5·4 per cent (2000–2004) to 4·0 per cent (2005–2009) and 2·9 per cent during 2010–2014 (P &lt; 0·001). There was no significant mortality difference for patients admitted at the weekend in adjusted Cox models (hazard ratio (HR) 1·00 for Saturday and 0·90 for Sunday, versus Wednesday). There was a significantly higher mortality for operations undertaken at the weekend (HR 1·15 for Saturday and 1·40 for Sunday; P = 0·021 and P &lt; 0·001 respectively). The significantly increased mortality that was evident for emergency surgery at the weekend compared with weekdays in 2000–2004 (HR 1·46 for Saturday and 1·55 for Sunday; both P &lt; 0·001); had reduced by 2010–2014, when the adjusted mortality risk was not significant (HR 1·18 for Saturday and 1·12 for Sunday).

Conclusion

During the past 15 years there has been a weekend effect in patients undergoing emergency general surgery based on day of operation, but not day of admission. Overall mortality for emergency general surgery has improved significantly, and in the past 5 years the increased mortality risk of weekend surgery has reduced.

Predictive value of serum testosterone for type 2 diabetes risk assessment in men

BACKGROUND

Effective prevention of type 2 diabetes (T2D) requires early identification of high-risk individuals who might benefit from intervention. We sought to determine whether low serum testosterone, a novel risk factor for T2D in men, adds clinically meaningful information beyond current T2D risk models.

METHODS

The Men Androgen Inflammation Lifestyle Environment and Stress (MAILES) study population consists of 2563 community-dwelling men aged 35-80 years in Adelaide, Australia. Of the MAILES participants, 2038 (80.0 %) provided information at baseline (2002-2006) and follow-up (2007-2010). After excluding participants with diabetes (n = 317), underweight (n = 5), and unknown BMI status (n = 11) at baseline; and unknown diabetes status (n = 50) at follow-up; 1655 participants were followed for 5 years. T2D at baseline and follow-up was defined by self-reported diabetes, or fasting plasma glucose (FPG) ≥7.0 mmol/L (126.1 mg/dL), or glycated haemoglobin (HbA1c) ≥6.5 %, or diabetes medications. Risk models were tested using logistic regression models. Sensitivity, specificity, positive predictive values (PPV) were used to identify the optimal cut-off point for low serum testosterone for incident T2D and the area under the receiver operating characteristic (AROC) curve was used to summarise the predictive power of the model. 15.5 % of men had at least one missing predictor variable; addressed through multiple imputation.

RESULTS

The incidence rate of T2D was 8.9 % (147/1655) over a median follow-up of 4.95 years (interquartile range: 4.35-5.00). Serum testosterone level predicted incident T2D (relative risk 0.96 [95 % CI: 0.92,1.00], P = 0.032) independent of current risk models including the AUSDRISK, but did not improve corresponding AROC statistics. A cut-off point of <16 nmol/L for low serum testosterone, which classified about 43 % of men, returned equal sensitivity (61.3 % [95 % CI: 52.6,69.4]) and specificity (58.3 % [95 % CI: 55.6,60.9) for predicting T2D risk, with a PPV of 12.9 % (95 % CI: 10.4,15.8).

CONCLUSIONS

Low serum testosterone predicts an increased risk of developing T2D in men over 5 years independent of current T2D risk models applicable for use in routine clinical practice. Screening for low serum testosterone in addition to risk factors from current T2D risk assessment models or tools, including the AUSDRISK, would identify a large subgroup of distinct men who might benefit from targeted preventive interventions.

Characterization of comorbid factors in hip fracture related in-hospital mortality

It is important to delineate factors which influence in-hospital mortality rates following a hip fracture. The current study aimed to identify the nature and frequency of comorbidities prevalent in this patient cohort. A retrospective chart review of cases of in-patient mortality following admission for a hip fracture was performed. These cases (n=127) were characterized for comorbidities, complications, medical status indicators, and other contributory factors. Cardiovascular 104 (81.9%), respiratory 66 (52.0%), genitourinary 41 (32.3%), psychiatric 41 (32.3%), vascular 40 (31.5%), and gastrointestinal 40 (31.5%), are the physiological systems, most commonly associated with comorbidity amongst hip fracture patients who succumb to in-hospital mortality. Renal failure, pneumonia, sepsis, myocardial infarction, congestive cardiac failure (CCF), respiratory failure, and Clostridium difficile infection are conditions which are associated with postoperative complications leading to in-patient mortality. Analysis of medical status indicators illustrated an inverse correlation between ASA scores and postoperative survival time, in this cohort-of hip fracture patients (R2 = 0.9485).

Predictors of sexual dysfunction incidence and remission in men

INTRODUCTION

The progress and determinants of sexual dysfunction in middle-aged and elderly men remain unclear.

AIM

To describe the incidence or remission and biopsychosocial predictors of erectile dysfunction (ED) and low sexual desire (SD).

MAIN OUTCOME MEASURES

Erectile function (International Index of Erectile Function) and sexual desire (Sexual Desire Inventory 2) were assessed at follow-up. Sociodemographic, lifestyle, and health-related factors were examined in multivariate models of ED and low SD.

METHODS

Data were collected from 810 randomly selected men residing in northern and western Adelaide, Australia, and aged 35-80 years at baseline, who made clinic visits 5 years apart.

RESULTS

At baseline, 23.2% (n = 123) of men had ED. ED incidence and remission were observed in 31.7% (n = 179) and 29.0% (n = 71) of eligible men, respectively. At baseline, 19.2% (n = 165) had low solitary sexual desire, and 6.0% (n = 50) had low dyadic sexual desire; incidence of low sexual desire occurred in 17.6% (n = 83) (solitary) and 8.3% (n = 51) (dyadic), while remission occurred in 15.4% (n = 68) (solitary) and 22.6% (n = 40) (dyadic) of men. In the final regression models, predictors of incident ED were higher age, lower income, higher abdominal fat mass, low alcohol intake, higher risk of obstructive sleep apnea (OSA) risk, voiding lower urinary tract symptoms (LUTS), depression, and diabetes. Predictors of ED remission were lower age, current employment, and absence of voiding LUTS, angina, diabetes, and dyslipidemia. Predictors of low dyadic SD incidence included higher age, never having been married, widowhood, being unemployed, being retired, insufficient physical activity, and low alcohol intake. Predictors of low dyadic SD remission were being married, not being widowed, higher income, lower abdominal fat mass, lower OSA risk, and higher plasma testosterone. Predictors of low solitary SD included never having been married, being unemployed, low alcohol intake, lower testosterone, storage LUTS, and hypertension. Predictors of low solitary SD remission were being married, being employed, higher income, higher physical activity, moderate alcohol intake, and depression.

CONCLUSIONS

Sexual dysfunction in aging men is a dynamic disorder whose incidence and remission are predicted by a range of modifiable risk factors.

Longitudinal changes in testosterone over five years in community-dwelling men

CONTEXT

There are few population-based studies reporting longitudinal changes in total T, LH, FSH, and SHBG levels, and there is limited information on risk factors for their change.

OBJECTIVE

The objective of the study was to examine 5-year changes in serum T, LH, FSH, and SHBG levels among Australian men.

DESIGN

The study initially included a randomly selected, community-based cohort of 1588 men age 35 years or older at recruitment (mean age, 54 ± 11 y) with available data at 2 visits. Men on medications known to affect, or with established pathology of, the hypothalamo-pituitary gonadal axis were excluded, leaving 1382 for analysis.

RESULTS

Mean baseline and follow-up T levels were 16.2 ± 1.4 and 15.6 ± 1.4 nmol/L, a change of -0.13 nmol/L/y. Annualized T changes were associated with obesity, being unmarried, and smoking at baseline, but not with diabetes, hypertension, or cardiovascular disease. T declined in men who had persistent depression or developed chronic disease, and it increased in men who were married, as compared to unmarried, at both time points. In the multivariate analysis, smoking cessation, development of central obesity (waist ≥ 100 cm), or generalized obesity (body mass index ≥ 30 kg/m(2)) resulted in T decreases of 0.36, 0.25, and 0.20 nmol/L/y, respectively. Quitting smoking, developing obesity, and having persisting depression were inversely related to SHBG change.

CONCLUSIONS

An age-related decline in T levels is not inevitable but is largely explained by smoking behavior and intercurrent changes in health status, particularly obesity and depression.

Screening for subclinical Cushing's syndrome in type 2 diabetes mellitus: low false-positive rates with nocturnal salivary cortisol

The diagnosis of subclinical Cushing's syndrome (SCS) is important, but its relative rarity amongst patients with common metabolic disorders requires a simple test with a low false-positive rate. Using nocturnal salivary cortisol (NSC), which we first validated in patients with suspected and proven Cushing's syndrome, we screened 106 overweight patients with type 2 diabetes mellitus, a group at high risk of SCS and nontumoral hypothalamic-pituitary-adrenal axis perturbations. Our hypothesis was that a lower false-positive rate with NSC was likely, compared with that reported with the dexamethasone suppression test (DST) (10-20%), currently the foundation of diagnosis of SCS. No participant had clinically apparent Cushing's syndrome. Three participants had an elevated NSC but further testing excluded SCS. In this study, NSC had a lower false-positive rate (3%) than previously reported for the DST. Given the reported excellent performance of NSC in detection of hypercortisolism, the low false-positive rate in SCS suggests NSC may be superior to the DST for SCS screening. The NSC and DST should be compared directly in metabolic disorder patients; although our data suggest the patient group will need to be substantially larger to definitively determine the optimal screening test.

Antineoplastic agents target the 25-hydroxyvitamin D3 24-hydroxylase messenger RNA for degradation: implications in anticancer activity

Calcitriol or 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] has antitumor activity and hence its levels in patients may play an important role in disease outcome. Here, we report that the antineoplastic agents, daunorubicin hydrochloride, etoposide, and vincristine sulfate inhibited the ability of 1,25(OH)(2)D(3) to cause the accumulation of mRNA for kidney 25-hydroxyvitamin D(3) 24-hydroxylase (CYP24), an enzyme which catabolizes this hormone. This was not due to a drug-induced cytotoxic effect, reduction in the expression of the vitamin D receptor or inhibition of the vitamin D receptor-mediated activation of the mitogen-activated protein kinases or CYP24 promoter activity. Interestingly, there was selective degradation of CYP24 mRNA in the presence of the drugs. This was accompanied by an enhancement in the levels of 1,25(OH)(2)D(3) in cells incubated with 25-hydroxy vitamin D(3). These data identify a novel mechanism of action of some commonly used antineoplastic agents which by decreasing the stability of CYP24 mRNA would prolong the bioavailability of 1,25(OH)(2)D(3) for anticancer actions.

Circulating RANKL is inversely related to RANKL mRNA levels in bone in osteoarthritic males

Introduction

The relationship of circulating levels of receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) with the expression of these molecules in bone has not been established. The objective of this study was to measure, in humans, the serum levels of RANKL and OPG, and the corresponding levels in bone of mRNA encoding these proteins.

Methods

Fasting blood samples were obtained on the day of surgery from patients presenting for hip replacement surgery for primary osteoarthritis (OA). Intraoperatively, samples of intertrochanteric trabecular bone were collected for analysis of OPG and RANKL mRNA, using real time RT-PCR. Samples were obtained from 40 patients (15 men with age range 50 to 79 years, and 25 women with age range 47 to 87 years). Serum total RANKL and free OPG levels were measured using ELISA.

Results

Serum OPG levels increased over the age range of this cohort. In the men RANKL mRNA levels were positively related to age, whereas serum RANKL levels were negatively related to age. Again, in the men serum RANKL levels were inversely related (r = -0.70, P = 0.007) to RANKL mRNA levels. Also in the male group, RANKL mRNA levels were associated with a number of indices of bone structure (bone volume fraction relative to bone tissue volume, specific surface of bone relative to bone tissue volume, and trabecular thickness), bone remodelling (eroded surface and osteoid surface), and biochemical markers of bone turnover (serum alkaline phosphatase and osteocalcin, and urinary deoxypyridinoline).

Conclusion

This is the first report to show a relationship between serum RANKL and the expression of RANKL mRNA in bone.

Reduced maternal corticosteroid-binding globulin and cortisol levels in pre-eclampsia and gamete recipient pregnancies

OBJECTIVE

To measure and contrast maternal cortisol and corticosteroid-binding globulin (CBG) levels in pregnancies with normal outcomes, pre-eclampsia, intrauterine growth restriction (IUGR) and in gamete recipients.

STUDY DESIGN

Prospective study of 93 women at high risk of pre-eclampsia, including gamete recipients (n = 22) and 33 controls. Plasma total and free cortisol and CBG were measured every 2 weeks from 16 weeks' gestation until delivery.

RESULTS

Forty-two per cent of the high-risk group had complications, including pre-eclampsia (n = 11), gestational hypertension (n = 16) and small-for-gestational-age (SGA) neonates (n = 12). There were no complications in the controls. In all groups, plasma CBG concentrations increased progressively across gestation (P < 0.05), in parallel to total cortisol, but fell significantly from 36 weeks' gestation onwards, with a corresponding rise in free cortisol concentrations. In pre-eclampsia and gestational hypertension, plasma CBG, and total and free cortisol concentrations were lower from 36 weeks onwards (P < 0.05). In IUGR, plasma CBG concentrations were suppressed from 28 weeks' gestation until delivery (P < 0.05), but with no significant difference in plasma total and free cortisol. Gamete recipients had significantly lower plasma CBG from 20 weeks' gestation onwards, and plasma total and free cortisol were reduced at 24 and 32 weeks onwards, respectively.

CONCLUSIONS

Maternal plasma CBG, total and free cortisol concentrations are reduced in pre-eclampsia/gestational hypertension, and markedly reduced in gamete recipients. Low CBG may be due to reduced synthesis or enhanced inflammation-driven degradation. Low maternal cortisol may be due to a lack of placental corticotropin-releasing hormone or reduced maternal ACTH, driving cortisol production. Low maternal cortisol may influence the foetal hypothalamic-pituitary-adrenal axis and disease patterns later in life following complicated pregnancy.

Detection of HBsAg mutants in a population with a low prevalence of hepatitis B virus infection

Two independent studies were conducted to evaluate performance of two HBsAg immunoassay products performed on the Abbott ARCHITECT and Bayer ADVIA Centaur immunoassay analyzers. One was a retrospective study of 484 stored samples and the second was a prospective study of 349 samples from random population. In the process of the evaluation, a number of discordant samples from HBsAg-positive patients were found which led to the discovery of a number of HBsAg mutants in the general Australian population. Following viral DNA sequencing, these were identified as HBsAg escape mutants. Whilst the existence of HBsAg mutants has been well documented in various regions of the world, this is surprising in an area of low endemicity and demonstrates the necessity of an HBsAg assay to detect mutants reliably in a diagnostic situation where HBsAg is used as the only marker to detect an HBV infection. These studies demonstrate the ability of the Abbott ARCHITECT and AxSYM HBsAg immunoassays to detect these HBsAg mutations which were not detected by the Bayer ADVIA Centaur.

Comparison of the Gen-Probe APTIMA Combo 2 assay to the AMPLICOR CT/NG assay for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in urine samples from Australian men and women

The performance of the APTIMA Combo 2 assay (AC2) for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae infections in urine samples was compared to that of the AMPLICOR CT/NG assay (AMP). The AC2 performance was superior to that of AMP for both organisms in this study.