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.

POS0505 DEPRESSION, ANXIETY AND STRESS AMONG OUTPATIENTS WITH RHEUMATOID ARTHRITIS FOLLOWED UP AT A TERTIARY CARE HOSPITAL IN SRI LANKA; A CROSS-SECTIONAL STUDY

Background:

Increased prevalence of depression, anxiety and stress have been shown among patients with rheumatoid arthritis. Patient and disease characteristics and psychosocial factors associated with these mental health issues are shown to vary among different populations. South Asian studies comprehensively assessing the prevalence and associations of these factors are lacking.

Objectives:

To determine the prevalence of depression, anxiety and stress among patients with rheumatoid arthritis and to identify associated patient and disease factors.

Methods:

A cross-sectional study was carried out among outpatients at three specialized rheumatology clinics at the National Hospital of Sri Lanka. Individuals with a diagnosis of rheumatoid arthritis were recruited consecutively. An interviewer-administered questionnaire was used to record sociodemographic and clinical data including the Clinical Disease Activity Index. A score 10.1-22.0 was taken as moderate and more than 22.1 was taken as high disease activity. The self-administered Depression, Anxiety, Stress Scale-21 (DASS-21) tool which has been validated for the Sri Lankan population was used. Statistical analysis was done using descriptive analysis and Chi-Square.

Results:

A total of 118 participants were recruited in this study. Majority of the participants (n=105) were female and had received a secondary school education (70%). Based on the CDAI assessment most were in the moderate (39%) and high disease activity groups (36%). Prevalence of Depression, Anxiety and Stress were found to be higher than the baseline level of 1% in the general population. A breakdown of the prevalence is shown in Figure 1. Further analysis of each arm, depression anxiety and stress were carried out independently excluding the non-responders. A higher level of prevalence of all three parameters was observed with the deterioration of functional status evidenced by the inability to walk and grip a ball firmly in the palm without it falling. Prevalence of depression was associated with age > 60 years (p=0.035), increased disease activity (p=0.004) and the loss of their job due to poor health (p=0.01). Higher prevalence of anxiety was associated with increased disease activity (p=0.023). A marked increase in stress level was associated with loss of the job (p=0.009) and morning stiffness > 60 minutes (p=0.001). Several Pre-existing co-morbidities were associated with depression and anxiety (Table 1). No association was observed between stress and pre-existing comorbidities.

Table 1.

Correlation of comorbidities with depression and anxiety.

Associated FactorsDepressionAnxietyYesNoYesNoDiabetes Mellitus (%)Identified18(72)07(28)16(66)08(34)Not Identified37(45)46(55)46(55)38(45)P-value0.0160.298Ischaemic heart disease (%)Identified14(82)03(18)14(78)04(22)Not Identified41(45)50(55)48(53)42(47)P-value0.0050.056Dyslipidaemia (%)Identified20(67)10(33)25(78)07(22)Not Identified35(45)43(55)37(49)39(51)P-value0.0420.005Figure 1.

Prevalence of depression, anxiety and stress among patients with rheumatoid arthritis

Conclusion:

Prevalence of depression, anxiety and stress among patients with rheumatoid arthritis is higher than the general population. Functional deterioration, disease activity and presence of co-morbidities are associated with these mental health issues. These can guide clinicians to screen high risk individuals for the mental health issues so that measures to relieve them would potentially improve quality of life and disease outcome.

Acknowledgements:

the authors thank the consultants in charge of the Rheumatology Clinics of the National Hospital, Drs. Jeewani Rubasingha, Monica De Silva and Gunendrika Kasthurirathna. We greatly appreciate the assistance given by the staff of the Department of Community Medicine, Faculty of Medicine, University of Colombo.

Disclosure of Interests:

None declared

MORAb-202, an Antibody-Drug Conjugate Utilizing Humanized Anti-human FRα Farletuzumab and the Microtubule-targeting Agent Eribulin, has Potent Antitumor Activity

Microtubule-targeting agents (MTA) have been investigated for many years as payloads for antibody-drug conjugates (ADC). In many cases, these ADCs have shown limited benefits due to lack of efficacy or significant toxicity, which has spurred continued investigation into novel MTA payloads for next-generation ADCs. In this study, we have developed ADCs using the MTA eribulin, a derivative of the macrocyclic polyether natural product halichondrin B, as a payload. Eribulin ADCs demonstrated in vitro potency and specificity using various linkers and two different conjugation approaches. MORAb-202 is an investigational agent that consists of the humanized anti-human folate receptor alpha (FRA) antibody farletuzumab conjugated via reduced interchain disulfide bonds to maleimido-PEG₂-valine-citrulline-p-aminobenzylcarbamyl-eribulin at a drug-to-antibody ratio of 4.0. MORAb-202 displayed preferable biophysical properties and broad potency across a number of FRA-positive tumor cell lines as well as demonstrated improved specificity in vitro compared with farletuzumab conjugated with a number of other MTA payloads, including MMAE, MMAF, and the reducible maytansine linker-payload sulfo-SPDB-DM4. A single-dose administration of MORAb-202 in FRA-positive human tumor cell line xenograft and patient-derived tumor xenograft models elicited a robust and durable antitumor response. These data support further investigation of MORAb-202 as a potential new treatment modality for FRA-positive cancers, using the novel MTA eribulin as a payload.

Abstract 952: MORAb-202, a folate receptor-alpha (FRA)-targeting antibody-eribulin drug conjugate (ADC), exhibits durable antitumor activity and payload-mediated bystander effects on the tumor microenvironment in triple-negative breast cancer

MORAb-202 is an antibody drug conjugate (ADC) consisting of farletuzumab (humanized anti-FRA mAb) and eribulin (as a payload, which are conjugated via a cathepsin B-cleavable linker. FRA is highly over-expressed in a large number of cancers including triple negative breast cancer (TNBC). Eribulin has been approved by Phase III study 305 for metastatic breast cancer patients who have previously received at least two chemotherapies. Moreover, exploratory subpopulation analysis from combined Phase III studies of 301 and 305 found that survival benefit by eribulin treatment was observed in HER2-negative and TNBC patients. Here we show the robust anti-tumor effects of MORAb-202 against patient-derived (PDX) TNBC xenograft models.

MORAb-202 demonstrated target selectivity and favorable cytotoxic drug delivery to tumors across a series of in vitro and in vivo studies. First, we found that MORAb-202 showed highly specific cytotoxicity on FRA positive cell lines at various IC50 values (0.001~23nM) according to their FRA expression levels, with little off-target killing (IC50 >100nM) on FRA negative cells. Moreover, it demonstrated significant in vitro bystander cytotoxicity (>140-fold) in FRA negative cells co-cultured with FRA positive cells when compared to mono-cultured FRA negative cells. In vivo, a single administration of MORAb-202 (1, 2.5, 5mg/kg) in FRA positive xenograft models showed dose-dependent antitumor activity with no observable toxicity. Single administration of MORAb-202 (5mg/kg) on high FRA-expressing TNBC PDX models showed long-lasting complete tumor regression (4/8), while near-MTD dose of eribulin (3.2mg/kg) showed minimum relative tumor volume of 96%. One dose of MORAb-202 (5mg/kg) elicits partial responses even on stroma-rich, low FRA-expressing (3.7%) TNBC PDXs. Immunofluorescent staining of tumor specimens both from the pre-treatment and five days post-treatment mice revealed that MORAb-202 achieved target specific engagement to FRA-positive regions in the tumor. Notably, MORAb-202 treatment diminished the network structure of cancer associated fibroblasts. This phenomenon was confirmed in an independent FRA-positive xenograft model, collected days 3, 5, 7 and 9 post-treatment of MORAb-202.

Finally, GLP toxicology studies in cynomolgus monkeys found no adverse effects on safety pharmacology endpoints (i.e., cardiovascular, CNS, respiratory function) in the intermittent repeated-dose (Q3W×2) of MORAb-202 nor changes in electrocardiography at doses up to 6 mg/kg. This dose is believed to be about five times higher than the projected effective dose based on PDX results and eribulin dose modelling.

Cumulatively, these data strongly support MORAb-202 as a promising ADC drug candidate for FRA-positive cancers.

Citation Format: Keiji Furuuchi, Xin Cheng, Katherine Rybinski, Tomoyuki Moriyama, James Fulmer, Chris Maddage, Andrew Milinichik, Keigo Tanaka, George Lai, Mary Lou Dula, Danielle Fernando, Luigi Grasso, Earl Albone, Toshimitsu Uenaka. MORAb-202, a folate receptor-alpha (FRA)-targeting antibody-eribulin drug conjugate (ADC), exhibits durable antitumor activity and payload-mediated bystander effects on the tumor microenvironment in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 952.

Farletuzumab, a monoclonal antibody directed against folate receptor alpha, shows no evidence of teratogenicity in cynomolgus monkeys

Farletuzumab is a humanized monoclonal antibody targeting human folate receptor alpha, which is being developed as an anti-cancer drug. A non-human primate reproductive study was conducted to evaluate whether it could cause any embryonic or fetal abnormalities. Farletuzumab was administered intravenously to pregnant cynomolgus monkeys (n = 16/group) at doses of 0 or 67.5 mg/kg once weekly during gestation day (GD) 20 through 97. C-section was performed on GD100 ± 2, and fetuses were evaluated for morphologic (external, visceral and skeletal) effects. No farletuzumab-related changes were observed in maternal animals or fetuses, which are supported by the fact that farletuzumab has no effects on cellular uptake of folate. These data support the potential use of farletuzumab for oncologic indications during pregnancy.

Novel antibody probes for the characterization of endosialin/TEM-1

Endosialin (Tumor Endothelial Marker-1 (TEM-1), CD248) is primarily expressed on pericytes of tumor-associated microvasculature, tumor-associated stromal cells and directly on tumors of mesenchymal origin, including sarcoma and melanoma. While the function of endosialin/TEM-1 is incompletely understood, studies have suggested a role in supporting tumor growth and invasion thus making it an attractive therapeutic target. In an effort to further understand its role in cancer, we previously developed a humanized anti-endosialin/TEM-1 monoclonal antibody (mAb), called ontuxizumab (MORAb-004) for testing in preclinical and clinical studies. We herein report on the generation of an extensive panel of recombinant endosialin/TEM-1 protein extracellular domain (ECD) fragments and novel mAbs against ECD motifs. The domain-specific epitopes were mapped against ECD sub-domains to identify those that can detect distinct structural motifs and can be potentially formatted as probes suitable for diagnostic and functional studies. A number of mAbS were shown to cross-react with the murine and human protein, potentially allowing their use in human animal models and corresponding clinical trials. In addition, pairing of several mAbs supported their use in immunoassays that can detect soluble endosialin/TEM-1 (sEND) in the serum of healthy subjects and cancer patients.

Clinical audit effectively bridges the evidence-practice gap in chronic subdural haematoma management

BACKGROUND

Placement of a subdural drain after drainage of chronic subdural haematoma (CSDH) has been shown to reduce the rate of recurrence in several randomised controlled trials (RCT). The most recently published RCT was from Cambridge, UK, in 2009. Despite class I evidence for the use of subdural drains, it is unclear whether these results have been translated into clinical practice. In this clinical audit we review the use of subdural drains in our institution before and after the publication of the 2009 RCT results.

METHODS

A longitudinal retrospective study was performed on all adults having burr holes for CSDH between January 2009 and January 2014. Case notes were analysed to determine subdural drain use, re-operation for CSDH recurrence and post-operative complications. The audit loop was closed with data collected from August 2015 to January 2016.

RESULTS

Thirty-one per cent of patients had subdural drains placed at operation. Drain placement was associated with lower reoperation rates (8% vs. 17%, p = 0.021) without increasing complication rates. Drain usage doubled after publication of the Santarius et al. (2009) trial but we observed persisting and significant variability in drain utilisation by supervising consultants. The use of drains in the department increased from 35% to 75% of all cases after presentation of these results.

CONCLUSIONS

The use of subdural drains in our unit reduced recurrence rates following drainage of CSDH and reproduced the results of a 2009 clinical trial. Although the use of subdural drains doubled in the post-trial epoch, significant variability remains in practice. Clinical audit provided an effective tool necessary to drive the implementation of subdural drain placement in our unit.

Clinical presentation and risk factors of inflammatory bowel disease in Sri Lanka

BACKGROUND AND AIMS

There have been very few studies on inflammatory bowel disease (IBD) in Sri Lanka. This study was undertaken to determine the clinical presentation and whether a western style diet or infection with geo-helminths were associated with the condition.

METHODS

Three questionnaires were given to the patients: one relating to diet, one relating to clinical presentation and one relating to quality of life. The disease was confirmed endoscopically and histologically. Faeces were examined for parasites.

RESULTS

Forty four patients were enrolled (43-ulcerative colitis; 1-Crohn's Disease). All but one had ulcerative colitis. Most had no family history of disease. The peak age of onset was 21-40 y and 63% gave a history of more than 6 months symptoms prior to diagnosis. Clinical presentation was similar to cases in western countries although milder with less severe life-events. None of them had undergone surgery. All patients ate a rice-based diet and none ate bread made of refined flour. Only 2 patient was infected with a geo-helminth.

CONCLUSIONS

Eating bread made of refined flour is not related to development of IBD in these patients. The prevalence of geo-helminths in the study population corresponded to the general population average. Delay in diagnosis occurs because of an initial assumption that the cause of symptoms is infective. A National Register of non-infectious gastrointestinal disease would aid the epidemiology and allocation of funding to this inflammatory condition.

Social networks in arid Australia: a review of concepts and evidence

Arid systems are markedly different from non-arid systems. This distinctiveness extends to arid-social networks, by which we mean social networks which are influenced by the suite of factors driving arid and semi-arid regions. Neither the process of how aridity interacts with social structure, nor what happens as a result of this interaction, is adequately understood. This paper postulates three relative characteristics which make arid-social networks distinct: that they are tightly bound, are hierarchical in structure and, hence, prone to power abuses, and contain a relatively higher proportion of weak links, making them reactive to crisis. These ideas were modified from workshop discussions during 2006. Although they are neither tested nor presented as strong beliefs, they are based on the anecdotal observations of arid-system scientists with many years of experience. This paper does not test the ideas, but rather examines them in the context of five arid-social network case studies with the aim of hypotheses building. Our cases are networks related to pastoralism, Aboriginal outstations, the ‘Far West Coast Aboriginal Enterprise Network’ and natural resources in both the Lake-Eyre basin and the Murray–Darling catchment. Our cases highlight that (1) social networks do not have clear boundaries, and that how participants perceive their network boundaries may differ from what network data imply, (2) although network structures are important determinants of system behaviour, the role of participants as individuals is still pivotal, (3) and while in certain arid cases weak links are engaged in crisis, the exact structure of all weak links in terms of how they place participants in relation to other communities is what matters.

Single and serial measurements of cardiac troponin I in asymptomatic patients on chronic hemodialysis

AIMS

Coronary artery disease is the major cause of death in patients with end-stage renal failure on dialysis. This study aimed to assess the predictive value of a single cardiac troponin I (cTnI), and also the kinetics of serial values.

METHODS

Since cTnI is a potential biomarker of cardiac outcome, the present study examined single cTnI measurements (n = 88 patients) and its predictive value for future cardiac events, and a kinetic substudy of serial weekly cTnI measured for 8 weeks (n = 57) in a group of patients on hemodialysis.

RESULTS

Single cTnI measurements: 9 patients (10.2%) had a detectable cTnI at baseline and 79 patients (89.8%) had a negative baseline cTnI. There were no significant differences in age, sex, history of ischemic heart disease, diabetes, smoking or dyslipidemia between patients with detectable and negative cTnI. At the end of 9 months, the rate of combined primary endpoints, which included myocardial infarction, cardiac death and cardiac revascularization, was significantly higher in the patients with a detectable baseline cTnI (55.6%), compared to patients with a negative cTnI (6.3%) (p = 0.0007). Serial weekly cTnI measurements: significant fluctuations in cTnI were noted over time; 27% of patients with an undetectable cTnI measured at baseline had subsequent detectable levels in the serial follow-up.

CONCLUSION

A single detectable cTnI in asymptomatic patients on hemodialysis defines patients at high risk of future cardiac events. However, the incidence of detectable cTnI levels is markedly increased when serial weekly measurements are performed. The clinical significance of detectable serial measurements of cTnI is the focus of ongoing studies.

Prevalence of Helicobacter pylori in Sri Lanka as determined by PCR

Fifty-seven Sinhalese patients were investigated for the presence of Helicobacter pylori by PCR. A prevalence of 70.1%, with 47.5% positive for cagA, was demonstrated. The most common vacA allele was s1am1. There was no significant association between either the s1 allele or the cagA allele and severe gastroduodenal disease. There was an association between the s1 allele and the cagA locus.

Long-term efficacy of single-dose combinations of albendazole, ivermectin and diethylcarbamazine for the treatment of bancroftian filariasis

In a 'blinded' trial (in Sri Lanka, 1996-98) of 47 male asymptomatic microfilaraemic subjects with Wuchereria bancrofti infection, the safety, tolerability and filaricidal efficacy of 3 single-dose combination regimens were compared: albendazole 400 mg with ivermectin 200 micrograms/kg, albendazole 400 mg with diethylcarbamazine citrate (DEC) 6 mg/kg or albendazole 600 mg with ivermectin 400 micrograms/kg. Treated subjects were followed-up for 24 months. This represents the first long-term study using combinations of albendazole with DEC or ivermectin in the above doses against bancroftian filariasis. All subjects had pre-treatment microfilaria (mf) counts over 100/mL. All 3 treatments significantly reduced mf counts, with the albendazole-DEC-treated group showing the lowest mf levels at 18 and 24 months post-treatment. Filarial antigen tests suggested that all 3 treatments had significant activity against adult W. bancrofti; albendazole-DEC combination had the greatest activity according to this test, with antigen levels decreasing to 30.5% of pre-treatment antigen levels, 24 months after therapy. All 3 treatments were clinically safe and well tolerated. These results suggest that a single dose of albendazole 400 mg together with DEC 6 mg/kg is a safe and effective combination for suppression of microfilaraemia of bancroftian filariasis that could be considered for use in filariasis control programmes based on mass treatment of endemic populations.

Pattern of accidents and injuries involving three-wheelers

OBJECTIVE

To study the pattern of injuries and some causative factors of three-wheeler related accidents.

DESIGN

Prospective descriptive study.

SETTING

Accident unit, Colombo South Teaching Hospital, Kalubowila.

METHODS

One hundred patients admitted to Colombo South Teaching Hospital with three-wheeler related accidents were interviewed, examined within 24 hours of admission and followed up by using a standard questionnaire. Detailed descriptions of the accident and the types of injuries were recorded.

RESULTS

54 accidents took place during daytime 07.00 h to 19.00 h) and the passengers were the commonest victims (40%). Soft tissue injury was the commonest injury observed (75%). The second commonest type of injury was long bone fractures (21%). Toppling due to a sudden turn of the vehicle accounted for 30% of accidents. Of 28 drivers in the study group, 25 admitted breaking the handle-lock to increase the vehicle's turning angle. Toppling due to a sudden turn was identified as the cause of the accident in all those who had interfered with the handle-lock. At the time of the accident, 89% of the drivers and 28.1% of pedestrians were under the influence of alcohol. Alcohol was related to 67.4% of the night accidents.

CONCLUSIONS

Alcohol consumption was recognised as a major contributory factor, in particular for night accidents. A strong association was observed between mechanical alteration of the vehicle's handle-lock and the risk of accident. Introduction of legislation to prohibit handle-lock alteration and strict implementation of the law regarding driving under the influence of alcohol would help to reduce three-wheeler related accidents.

Comparison of some clinical and histological features of colorectal carcinoma occurring in patients below and above 40 years

OBJECTIVE

To determine the clinicopathological features of colorectal malignancies in Sri Lankan patients aged 40 years or younger, and to compare them with those of older patients.

METHODS

The clinicopathological features of 60 colorectal malignancies which occurred in patients aged 40 years or younger were compared with 245 malignant colorectal tumours in older patients. These tumours had been diagnosed at a University Department of Pathology over 15 years.

RESULTS

19.7% of colorectal malignancies occurred in patients aged 40 years or younger. (Male:Female ratio = 1.6:1). The mean duration from onset of symptoms to diagnosis was 4.2 months. There was no statistically significant difference between young and old patients in the presenting symptoms, site of tumour and Dukes' staging of colorectal malignancies. A statistically significant proportion of tumours in young patients was mucoid (13.3%) or signet ring cell (5%) type. 3.3% of young patients with colorectal carcinoma gave a family history of similar malignancy. A history of predisposing conditions (ulcerative colitis) was present in 3.3% of young patients.

CONCLUSIONS

The clinical presentation of colorectal malignancies in Sri Lankan patients below 40 years of age does not differ from that in older patients. Mucoid and signet ring cell carcinomas are commoner in the young.

Selective enzyme-mediated extraction of capsaicinoids and caratenoids from chili guajillo puya (Capsicum annum L.) using ethanol as solvent

The selective extraction of capsaicinoids and carotenoids from chili guajillo "puya" flour was studied. When ethanol was used as solvent, 80% of capsaicinoids and 73% of carotenoids were extracted, representing an interesting alternative for the substitution of hexane in industrial processes. Additionally, when the flour was pretreated with enzymes that break the cell wall and then dried, extraction in ethanol increased to 11 and 7% for carotenoid and capsaicinoid, respectively. A selective two-stage extraction process after the treatment with enzymes is proposed. The first step uses 30% (v/v) ethanol and releases up to 60% of the initial capsaicinoids, and the second extraction step with industrial ethanol permits the recovery of 83% of carotenoids present in the flour.

Linking injection drug users to medical services: role of street outreach referrals

Street outreach workers in HIV prevention have expanded their role to include referring injection drug users to medical services. However, little is known about whether drug users act on these referrals. The study discussed in this article examined the level of exposure to street outreach reported by injection drug users, the most common medical referrals acted on as a result of such contacts, and the predictors of acting on these referrals. Findings indicate that injection drug users with four or more contacts with street outreach workers during the preceding six months were more likely to report acting on referrals. To maximize the relevance of outreach for encouraging medical treatment, both street outreach workers and social workers in health care could benefit from cross training that focuses on strengthening the referral process.