A model for malaria treatment evaluation in the presence of multiple species

Plasmodium falciparum and P. vivax are the two most common causes of malaria. While the majority of deaths and severe morbidity are due to P. falciparum, P. vivax poses a greater challenge to eliminating malaria outside of Africa due to its ability to form latent liver stage parasites (hypnozoites), which can cause relapsing episodes within an individual patient. In areas where P. falciparum and P. vivax are co-endemic, individuals can carry parasites of both species simultaneously. These mixed infections complicate dynamics in several ways: treatment of mixed infections will simultaneously affect both species, P. falciparum can mask the detection of P. vivax, and it has been hypothesised that clearing P. falciparum may trigger a relapse of dormant P. vivax. When mixed infections are treated for only blood-stage parasites, patients are at risk of relapse infections due to P. vivax hypnozoites. We present a stochastic mathematical model that captures interactions between P. falciparum and P. vivax, and incorporates both standard schizonticidal treatment (which targets blood-stage parasites) and radical cure treatment (which additionally targets liver-stage parasites). We apply this model via a hypothetical simulation study to assess the implications of different treatment coverages of radical cure for mixed and P. vivax infections and a "unified radical cure" treatment strategy where P. falciparum, P. vivax, and mixed infections all receive radical cure after screening glucose-6-phosphate dehydrogenase (G6PD) normal. In addition, we investigated the impact of mass drug administration (MDA) of blood-stage treatment. We find that a unified radical cure strategy leads to a substantially lower incidence of malaria cases and deaths overall. MDA with schizonticidal treatment was found to decrease P. falciparum with little effect on P. vivax. We perform a univariate sensitivity analysis to highlight important model parameters.

Structured, multicomponent, community-based programme for women's health and infant health and development in rural Vietnam: a parallel-group cluster randomised controlled trial

BACKGROUND

Interventions to improve early childhood development have previously addressed only one or a few risk factors. Learning Clubs is a structured, facilitated, multicomponent programme designed to address eight potentially modifiable risk factors, and offered from mid-pregnancy to 12 months post partum; we aimed to establish whether this programme could improve the cognitive development of children at 2 years of age.

METHODS

For this parallel-group cluster-randomised controlled trial, 84 of 116 communes (the clustering unit) in HaNam Province in rural Vietnam were randomly selected and randomly assigned to receive the Learning Clubs intervention (n=42) or usual care (n=42). Women aged at least 18 years who were pregnant (gestational age <20 weeks) were eligible for inclusion. Data sources were standardised, and study-specific questionnaires assessing risks and outcomes were completed in interviews in mid-pregnancy (baseline), late pregnancy (after 32 weeks of gestation), at 6-12 months post partum, and at the end of the study period when children were 2 years of age. Mixed-effects models were used to estimate trial effects, adjusting for clustering. The primary outcome was the cognitive development of children at 2 years of age, assessed by the Bayley Scales of Infant and Toddler Development Third Edition (Bayley-III) cognitive score. This trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12617000442303).

FINDINGS

Between April 28, 2018, and May 30, 2018, 1380 women were screened and 1245 were randomly assigned (669 to the intervention group and 576 to the control group). Data collection was completed on Jan 17, 2021. Data at the end of the study period were contributed by 616 (92%) of 669 women and their children in the intervention group, and by 544 (94%) of 576 women and their children in the control group. Children aged 2 years in the intervention group had significantly higher mean Bayley-III cognitive scores than those in the control group (99·6 [SD 9·7] vs 95·6 [9·4]; mean difference 4·00 [95% CI 2·56-5·43]; p<0·0001). At 2 years of age, 19 (3%) children in the intervention group had Bayley-III scores less than 1 SD, compared with 32 (6%) children in the control group, but this difference was not significant (odds ratio 0·55 [95% CI 0·26-1·17]; p=0·12). There were no significant differences between groups in maternal, fetal, newborn, or child deaths.

INTERPRETATION

A facilitated, structured, community-based, multicomponent group programme improved early childhood development to the standardised mean in rural Vietnam and could be implemented in other similarly resource-constrained settings.

FUNDING

Australian National Health and Medical Research Council and Grand Challenges Canada Saving Brains Initiative.

TRANSLATION

For the Vietnamese translation of the abstract see Supplementary Materials section.

Assessing systolic and diastolic reserves in male and female mice

Cardiac reserve is a widely used health indicator and prognostic tool. Although it is well established how to assess cardiac reserve clinically, in preclinical models, it is more challenging lacking standardization. Furthermore, although cardiac reserve incorporates both systolic (i.e., contractile reserve) and diastolic (i.e., relaxation reserve) components of the cardiac cycle, less focus has been placed on diastolic reserve. The aim of our study was to determine which technique (i.e., echocardiography, invasive hemodynamic, and Langendorff) and corresponding parameters can be used to assess the systolic and diastolic reserves in preclinical models. Healthy adult male and female CD-1 mice were administered dobutamine and evaluated by echocardiography and invasive hemodynamic, or Langendorff to establish systolic and diastolic reserves. Here, we show that systolic reserve can be assessed using all techniques in vivo and in vitro. Yet, the current indices available are ineffective at capturing diastolic reserve of healthy mice in vivo. When assessing systolic reserve, sex affects the dose response of several commonly used echocardiography parameters [i.e., fractional shortening (FS), ejection fraction (EF)]. Taken together, this study improves our understanding of how sex impacts the interpretation assessment of cardiac reserve and establishes for the first time that in healthy adult mice, the diastolic reserve cannot be assessed by currently established methods in vivo.NEW & NOTEWORTHY Cardiac reserve is a globally used health indicator and prognostic tool that is used by clinicians and preclinical scientists. In physiology, we have a long-standing appreciation of how to assess systolic reserve but lack insight into sex differences and have no frame of reference for measuring diastolic reserve to certainty across cardiac techniques or the influence of sex. Here, we show that the primary means for assessing diastolic reserve is incorrect. Furthermore, we provided proof and clarity on how to correctly measure systolic and diastolic reserve capacities. We also highlight the imperative of sex differences to the measures of both systolic and diastolic reserves using several techniques (i.e., echocardiography, invasive hemodynamics, and Langendorff) in mice.

How much of the effect of disability acquisition on mental health is mediated through employment and income? A causal mediation analysis quantifying interventional indirect effects using data from four waves of an Australian cohort study

OBJECTIVES

There is evidence that disability acquisition causes a decline in mental health, but few studies have examined the causal mechanisms through which the effect operates. This study used a novel approach to mediation analysis to quantify interventional indirect effects (IIEs) through employment and income.

DESIGN AND SETTING

We used four waves of longitudinal data (2011-2014) from the Household, Income and Labour Dynamics in Australia Survey, a nationally representative survey of Australian households.

PARTICIPANTS

Working aged individuals who acquired a disability (n=233) were compared with those who remained disability-free in all four waves (n=5419).

PRIMARY OUTCOME MEASURE

Self-reported mental health was measured using the Mental Health Inventory subscale of the Short Form 36 general health questionnaire, which measures symptoms of depression, anxiety and psychological well-being.

STATISTICAL ANALYSIS

We conducted a causal mediation analysis quantifying IIEs of disability acquisition on mental health operating through two distinct mediators: employment status and income. We used multiple imputation with 50 imputed datasets to account for missing data.

RESULTS

The total causal effect of disability acquisition on mental health was estimated to be a 4.8-point decline in mental health score (estimated mean difference: -4.8, 95% CI -7.0 to -2.7). The IIE through employment was estimated to be a 0.5-point difference (-0.5, 95% CI -1.0 to 0.0), accounting for 10.6% of the total effect, whereas there was no evidence that income explained any of the effects.

CONCLUSIONS

This study estimated that disability-related mental health inequalities could be reduced by 10.6% if employment rates were the same for people with disability as those without disability. The results suggest that employment is implicated in the relationship between disability acquisition and mental health and that more research is needed to understand the influence of other aspects of employment and other socioeconomic characteristics.

GP access to FIT increases the proportion of colorectal cancers detected on urgent pathways in symptomatic patients in Nottingham

OBJECTIVE

Service evaluation of GP access to Faecal Immunochemical Test (FIT) for colorectal cancer (CRC) detection in Nottinghamshire and use of FIT for "rule out", "rule in" and "first test selection".

DESIGN

Retrospective audit of FIT results, CRC outcomes and resource utilisation before and after introduction of FIT in Primary Care in November 2017. Data from the new pathway up to December 2018 was compared with previous experience.

RESULTS

Between November 2017 and December 2018, 6747 GP FIT test requests yielded 5733 FIT results, of which 4082 (71.2%) were <4.0 μg Hb/g faeces, 579 (10.1%) were 4.0-9.9 μg Hb/g faeces, 836 (14.6%) were 10.0-149.9 μg Hb/g faeces, and 236 (4.1%) were ≥150.0 μg Hb/g faeces. The proportion of "rule out" results <4.0 μg Hb/g faeces was significantly higher than in the Getting FIT cohort (71.2% vs 60.4%, Chi squared 42.8, p < 0.0001) and the proportion of "rule in" results ≥150.0 μg Hb/g faeces was significantly lower (4.1% vs 8.1%, Chi squared 27.3,P < 0.0001). There was a 33% rise in urgent referrals across Nottingham overall during the evaluation period. 2 CRC diagnoses were made in 4082 patients who had FIT<4.0 μg Hb/g faeces. 58.4% of new CRC diagnoses associated with a positive FIT were early stage cancers (Stage I and II). The proportion of all CRC diagnoses that follow an urgent referral s rose after introduction of FIT.

CONCLUSIONS

FIT allows GP's to select a more appropriate cohort for urgent investigation without a large number of missed diagnoses. FIT appears to promise a "stage migration" effect which may ultimately improve CRC outcomes.

Faecal immunochemical testing and blood tests for prioritization of urgent colorectal cancer referrals in symptomatic patients: a 2-year evaluation

BACKGROUND

A novel pathway incorporating faecal immunochemical testing (FIT) for rapid colorectal cancer diagnosis (RCCD) was introduced in 2017. This paper reports on the service evaluation after 2 years of pathway implementation.

METHODS

The RCCD protocol was based on FIT, blood results and symptoms to stratify adult patients in primary care. Two-week-wait (2WW) investigation was indicated for patients with rectal bleeding, rectal mass and faecal haemoglobin (fHb) level of 10 µg Hb/g faeces or above or 4 µg Hb/g faeces or more in the presence of anaemia, low ferritin or thrombocytosis, in all other symptom groups. Patients with 100 µg Hb/g faeces or above had expedited investigation . A retrospective audit of colorectal cancer detected between 2017 and 2019 was conducted, fHb thresholds were reviewed and critically assessed for cancer diagnoses.

RESULTS

In 2 years, 14788 FIT tests were dispatched with 13361 (90.4 per cent) completed returns. Overall, fHb was less than 4 µg Hb/g faeces in 9208 results (68.9 per cent), 4-9.9 µg Hb/g in 1583 (11.8 per cent), 10-99.9 µg Hb/g in 1850 (13.8 per cent) and 100 µg Hb/g faeces or above in 720 (5.4 per cent). During follow-up (median 10.4 months), 227 colorectal cancers were diagnosed. The cancer detection rate was 0.1 per cent in patients with fHb below 4 µg Hb/g faeces, 0.6 per cent in those with fHb 4-9.9 µg Hb/g faeces, 3.3 per cent for fHb 10-99.9 µg Hb/g faeces and 20.7 per cent for fHb 100 µg Hb/g faeces or above. The detection rate in the cohort with 10-19.9 µg Hb/g faeces was 1.4 per cent, below the National Institute for Health and Care Excellence threshold for urgent referral. The colorectal cancer rate in patients with fHb below 20 µg Hb/g faeces was less than 0.3 per cent.

CONCLUSION

Use of FIT to "rule out" urgent referral from primary care misses a small number of cases. The threshold for referral may be adjusted with blood results to improve stratification .

Quantitative FIT stratification is superior to NICE referral criteria NG12 in a high-risk colorectal cancer population

BACKGROUND

Guidelines for urgent investigation of colorectal cancer (CRC) are based on age and symptom-based criteria. This study aims to compare the diagnostic value of clinical features and faecal immunochemical test (FIT) results to identify those at a higher risk of CRC, thereby facilitating effective triage of patients.

METHODS

We undertook a review of all patients referred for investigation of CRC at our centre between September 2016 and June 2018. Patients were identified using a prospectively recorded local database. We performed a logistic regression analysis of factors associated with a diagnosis of CRC.

RESULTS

One-thousand-and-seven-hundred-eighty-four patients with FIT results were included in the study. Change in bowel habit (CIBH) was the most common referring clinical feature (38.3%). Patients diagnosed with CRC were significantly older than those without malignancy (74.0 years vs 68.9 years, p = 0.0007). Male patients were more likely to be diagnosed with CRC than females (6.5% vs 2.5%, Chi-squared 16.93, p < 0.0001). CRC was diagnosed in 3.5% (24/684) with CIBH compared to 8.1% (6/74) with both CIBH and iron deficiency anaemia. No individual or combination of referring clinical features was associated with an increased diagnosis of CRC (Chi-squared, 8.03, p = 0.155). Three patients with negative FIT results (< 4 µg Hb/g faeces) were diagnosed with CRC (3/1027, 0.3%). The highest proportion of cancers detected was in the ≥ 100 µg Hb/g faeces group (55/181, 30.4%).

CONCLUSION

In a multivariate model, FIT outperforms age, sex and all symptoms prompting referral. FIT has greater stratification value than any referral symptoms. FIT does have value in patients with iron deficiency anaemia.

The risk of adverse clinical outcomes following treatment of Plasmodium vivax malaria with and without primaquine in Papua, Indonesia

The widespread use of primaquine (PQ) radical cure for P. vivax, is constrained by concerns over its safety. We used routinely collected patient data to compare the overall morbidity and mortality in patients treated with and without PQ without prior testing of Glucose-6-Phosphate-Dehydrogenase (G6PD) deficiency in Papua, Indonesia, where there is a low prevalence of G6PD deficiency. Records were collated from patients older than 1 year, with P. vivax infection, who were treated with an artemisinin combination therapy (ACT). The risks of re-presentation, hospitalization, major fall in haemoglobin and death within 30 days were quantified and compared between patients treated with and without PQ using a Cox regression model. In total 26,216 patients with P. vivax malaria presented to the hospital with malaria during the study period. Overall 27.56% (95% Confidence Interval (95%CI): 26.96-28.16) of 21,344 patients treated with PQ re-presented with any illness within 30 days and 1.69% (1.51-1.88) required admission to hospital. The corresponding risks were higher in the 4,872 patients not treated with PQ; Adjusted Hazard Ratio (AHR) = 0.84 (0.79-0.91; p<0.001) and 0.54 (0.41-0.70; p<0.001) respectively. By day 30, 14.15% (12.45-16.05) of patients who had received PQ had a fall in haemoglobin (Hb) below 7g/dl compared to 20.43% (16.67-24.89) of patients treated without PQ; AHR = 0.66 (0.45-0.97; p = 0.033). A total of 75 (0.3%) patients died within 30 days of treatment with a mortality risk of 0.27% (0.21-0.35) in patients treated with PQ, compared to 0.38% (0.24-0.60) without PQ; AHR = 0.79 (0.43-1.45; p = 0.448). In Papua, Indonesia routine administration of PQ radical cure without prior G6PD testing, was associated with lower risk of all cause hospitalization and other serious adverse clinical outcomes. In areas where G6PD testing is not available or cannot be delivered reliably, the risks of drug induced haemolysis should be balanced against the potential benefits of reducing recurrent P. vivax malaria and its associated morbidity and mortality.

Thrombocytosis helps to stratify risk of colorectal cancer in patients referred on a 2-week-wait pathway

PURPOSE

Primary care studies suggest that thrombocytosis (platelet counts > 400 × 109/L) is associated with an increased risk of colorectal cancer (CRC). We aimed to establish whether this marker has significant stratification value in patients seen in secondary care.

METHODS

A retrospective review of 2991 patients referred to our colorectal 2-week-wait (2WW) pathway between August 2014 and August 2017. Patient demographics were recorded prospectively, and local electronic records systems were used to retrieve full blood counts (FBC) and cancer diagnoses. Patients with no recent platelet count at the time of referral or incomplete records were excluded.

RESULTS

2236 patients were included in this evaluation. There was no significant difference in the age distribution of those with thrombocytosis and those without. There were significantly more females in the thrombocytosis group (72.1% vs 53.9%, chi-squared 24.63, p < 0.0001). 130 CRCs were detected (5.8%) and patients with thrombocytosis were more likely to have CRC (OR 2.62, 95% CI 1.60-4.30). The CRC diagnosis rate was significantly higher in females with thrombocytosis (10.3% vs 2.9%, chi-squared 19.41, p < 0.0001) and males with thrombocytosis (16.1% vs 7.9%, chi-squared 4.62, p = 0.032).

CONCLUSION

Thrombocytosis appears to have stratification value in the 2WW population. Further evaluation of its value alone or in combination with other stratification tests is required.

Early clinical outcomes of a rapid colorectal cancer diagnosis pathway using faecal immunochemical testing in Nottingham

AIM

We introduced primary care access to faecal immunochemical testing (FIT) as a stratification tool for symptomatic patients considered to be at risk of colorectal cancer (CRC) prior to urgent referral. We aimed to evaluate clinical and pathway outcomes during the first 6 months of this novel approach.

METHOD

FIT was recommended for all patients who consulted their general practitioner with lower gastrointestinal symptoms other than rectal bleeding and rectal mass. We undertook a retrospective audit of the results of FIT, related clinical outcomes and resource utilization on prospectively logged cases between November 2017 and May 2018.

RESULTS

Of the 1862 FIT kits dispatched by post 91.4% were returned, with a median return time of 7 days (range 2-110 days); however, 1.3% of returned kits could not be analysed. FIT results ≥ 150.0 μg haemoglobin (Hb)/g faeces identified patients with a significantly higher risk of CRC (30.9% vs 1.4%, chi-square 167.1, P < 0.0001). FIT results ≥ 10.0 μg Hb/g faeces identified patients with significantly higher risk of significant noncancer bowel pathology (24.1% vs 4.9%, chi-square 73.6, P < 0.0001) and FIT results < 4.0 μg Hb/g faeces identified a group more likely to have non-CRC pathology (5.1% vs 2.4%, chi-square 3.9, P < 0.05). The CRC detection rate in 531 patients investigated after a FIT result of < 4.0 μg Hb/g faeces was 0.2%. In 899 investigated patients, a FIT result with a threshold of 4.0 μg Hb/g faeces had sensitivity 97.2% (85.5-99.9% CI), specificity 61.4% (58.1-64.7% CI), negative predictive value 99.8% (98.7-100.0% CI) and positive predictive value 9.5% (8.7-10.4% CI).

CONCLUSION

A symptomatic pathway incorporating FIT is feasible and appears more clinically effective than pathways based on age and symptoms alone.

Does the effect of disability acquisition on mental health differ by employment characteristics? A longitudinal fixed-effects analysis

PURPOSE

Longitudinal studies have suggested a causal relationship between disability acquisition and mental health, but there is substantial heterogeneity in the magnitude of the effect. Previous studies have provided evidence that socioeconomic characteristics can buffer the effect but have not examined the role of employment characteristics.

METHODS

We used data from 17 annual waves of the Household, Income and Labour Dynamics in Australia Survey to compare the mental health of working age individuals before and after disability acquisition, using the Mental Health Inventory, a subscale of the SF-36 health questionnaire. Linear fixed-effects regression models were used to estimate the effect of disability acquisition on mental health. We tested for effect modification by two characteristics of people's employment prior to disability acquisition: occupational skill level and contract type. Multiple imputation using chained equations was used to handle missing data.

RESULTS

Disability acquisition was associated with a substantial decline in mental health score (estimated mean difference: - 4.3, 95% CI - 5.0, - 3.5). There was evidence of effect modification by occupational skill level, with the largest effects seen for those in low-skilled jobs (- 6.1, 95% CI - 7.6, - 4.5), but not for contract type.

CONCLUSIONS

The findings highlight the need for social and health policies that focus on increasing employment rates, improving the sustainability of employment, and providing employment services and education and training opportunities for people who acquire a disability, particularly for people in low-skilled occupations, to reduce the mental health inequalities experienced by people with disabilities.

Iron therapy for preoperative anaemia

BACKGROUND

Preoperative anaemia is common and occurs in 5% to 76% of patients preoperatively. It is associated with an increased risk of perioperative allogeneic blood transfusion, longer hospital stay, and increased morbidity and mortality. Iron deficiency is one of the most common causes of anaemia. Oral and intravenous iron therapy can be used to treat anaemia. Parenteral iron preparations have been shown to be more effective in conditions such as inflammatory bowel disease, chronic heart failure and postpartum haemorrhage due to rapid correction of iron stores. A limited number of studies has investigated iron therapy for the treatment of preoperative anaemia. The aim of this Cochrane Review is to summarise the evidence for iron supplementation, both enteral and parenteral, for the management of preoperative anaemia.

OBJECTIVES

To evaluate the effects of preoperative iron therapy (enteral or parenteral) in reducing the need for allogeneic blood transfusions in anaemic patients undergoing surgery.

SEARCH METHODS

We ran the search on 30 July 2018. We searched the Cochrane Injuries Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library), Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R), Embase Classic and Embase (Ovid), CINAHL Plus (EBSCO), PubMed, and clinical trials registries, and we screened reference lists. We ran a top-up search on 28 November 2019; one study is now awaiting classification.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that compared preoperative iron monotherapy to placebo, no treatment, standard care or another form of iron therapy for anaemic adults undergoing surgery. We defined anaemia as haemoglobin values less than 13 g/dL for males and 12 g/dL for non-pregnant females.

DATA COLLECTION AND ANALYSIS

Two review authors collected data and a third review author checked all collected data. Data were collected on the proportion of patients who receive a blood transfusion, the amount of blood transfused per patient (units), quality of life, ferritin levels and haemoglobin levels, measured as continuous variables at the following predetermined time points: pretreatment (baseline), preoperatively but postintervention, and postoperatively. We performed statistical analysis using the Cochrane software, Review Manager 5. We summarised outcome data in tables and forest plots. We used the GRADE approach to describe the quality of the body of evidence.

MAIN RESULTS

Six RCTs, with a total of 372 participants, evaluated preoperative iron therapy to correct anaemia before planned surgery. Four studies compared iron therapy (either oral (one study) or intravenous (three studies)) with no treatment, placebo or usual care, and two studies compared intravenous iron therapy with oral iron therapy. Iron therapy was delivered over a range of periods that varied from 48 hours to three weeks prior to surgery. The 372 participants in our analysis fall far short of the 819 required - as calculated by our information size calculation - to detect a 30% reduction in blood transfusions. Five trials, involving 310 people, reported the proportion of participants who received allogeneic blood transfusions. Meta-analysis of iron therapy versus placebo or standard care showed no difference in the proportion of participants who received a blood transfusion (risk ratio (RR) 1.21, 95% confidence interval (CI) 0.87 to 1.70; 4 studies, 200 participants; moderate-quality evidence). Only one study that compared oral versus intravenous iron therapy measured this outcome, and reported no difference in risk of transfusion between groups. There was no difference between the iron therapy and placebo/standard care groups for haemoglobin level preoperatively at the end of the intervention (mean difference (MD) 0.63 g/dL, 95% CI -0.07 to 1.34; 2 studies, 83 participants; low-quality evidence). However, intravenous iron therapy produced an increase in preoperative postintervention haemoglobin levels compared with oral iron (MD 1.23 g/dL, 95% CI 0.80 to 1.65; 2 studies, 172 participants; low-quality evidence). Ferritin levels were increased by intravenous iron, both when compared to standard care ((MD 149.00, 95% CI 25.84 to 272.16; 1 study, 63 participants; low-quality evidence) or to oral iron (MD 395.03 ng/mL, 95% CI 227.72 to 562.35; 2 studies, 151 participants; low-quality evidence). Not all studies measured quality of life, short-term mortality or postoperative morbidity. Some measured the outcomes, but did not report the data, and the studies which did report the data were underpowered. Therefore, uncertainty remains regarding these outcomes. The inclusion of new research in the future is very likely to change these results.

AUTHORS' CONCLUSIONS

The use of iron therapy for preoperative anaemia does not show a clinically significant reduction in the proportion of trial participants who received an allogeneic blood transfusion compared to no iron therapy. Results for intravenous iron are consistent with a greater increase in haemoglobin and ferritin when compared to oral iron, but do not provide reliable evidence. These conclusions are drawn from six studies, three of which included very small numbers of participants. Further, well-designed, adequately powered, RCTs are required to determine the true effectiveness of iron therapy for preoperative anaemia. Two studies are currently in progress, and will include 1500 randomised participants.

Early and late mortality after malaria in young children in Papua, Indonesia

BACKGROUND

In southern Papua, Indonesia, malaria is highly prevalent in young children and is a significant cause of morbidity and early mortality. The association between malaria and delayed mortality is unknown.

METHODS

Routinely-collected hospital surveillance data from southern Papua, Indonesia, were used to assess the risk of recurrent malaria and mortality within 12 months of an initial presentation with malaria in all children younger than 5 years old attending the local hospital. Analysis was primarily by Kaplan Meier and Cox regression methods.

RESULTS

In total 15,716 children presenting with malaria between April 2004 and December 2013 were included in the analysis; 6184 (39.3%) with Plasmodium falciparum, 7499 (47.7%) with P. vivax, 203 (1.3%) with P. malariae, 3 with P. ovale and 1827 (11.6%) with mixed infections. Within 1 year, 48.4% (7620/15,716) of children represented a total of 16,957 times with malaria (range 1 to 11 episodes), with the incidence of malaria being greater in patients initially presenting with P. vivax infection (1334 [95%CI 1307-1361] per 1000 patient years) compared to those with P. falciparum infection (920 [896-944]). In total 266 (1.7%) children died within 1 year of their initial presentation, 129 (48.5%) within 30 days and 137 (51.5%) between 31 and 365 days. There was no significant difference in the mortality risk in patients infected with P. vivax versus P. falciparum either before 30 days (Hazard Ratio (HR) 1.02 [0.69,1.49]) or between 31 and 365 days (HR = 1.30 [0.90,1.88]). Children who died had a greater incidence of malaria, 2280 [95%CI 1946-2671] per 1000 patient years preceding their death, compared to 1141 [95%CI 1124-1158] per 1000 patient years in those surviving.

CONCLUSIONS

Children under-5 years old with P. vivax malaria, are at significant risk of multiple representations with malaria and of dying within 1 year of their initial presentation. Preventing recurrent malaria must be a public health priority in this vulnerable population.

Multiple imputation methods for handling missing values in a longitudinal categorical variable with restrictions on transitions over time: a simulation study

Background

Longitudinal categorical variables are sometimes restricted in terms of how individuals transition between categories over time. For example, with a time-dependent measure of smoking categorised as never-smoker, ex-smoker, and current-smoker, current-smokers or ex-smokers cannot transition to a never-smoker at a subsequent wave. These longitudinal variables often contain missing values, however, there is little guidance on whether these restrictions need to be accommodated when using multiple imputation methods. Multiply imputing such missing values, ignoring the restrictions, could lead to implausible transitions.

Methods

We designed a simulation study based on the Longitudinal Study of Australian Children, where the target analysis was the association between (incomplete) maternal smoking and childhood obesity. We set varying proportions of data on maternal smoking to missing completely at random or missing at random. We compared the performance of fully conditional specification with multinomial and ordinal logistic imputation, and predictive mean matching, two-fold fully conditional specification, indicator based imputation under multivariate normal imputation with projected distance-based rounding, and continuous imputation under multivariate normal imputation with calibration, where each of these multiple imputation methods were applied, accounting for the restrictions using a semi-deterministic imputation procedure.

Results

Overall, we observed reduced bias when applying multiple imputation methods with restrictions, and fully conditional specification with predictive mean matching performed the best. Applying fully conditional specification and two-fold fully conditional specification for imputing nominal variables based on multinomial logistic regression had severe convergence issues. Both imputation methods under multivariate normal imputation produced biased estimates when restrictions were not accommodated, however, we observed substantial reductions in bias when restrictions were applied with continuous imputation under multivariate normal imputation with calibration.

Conclusion

In a similar longitudinal setting we recommend the use of fully conditional specification with predictive mean matching, with restrictions applied during the imputation stage.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0653-0) contains supplementary material, which is available to authorized users.

Widespread use of incorrect PCR ramp rate negatively impacts multidrug-resistant tuberculosis diagnosis (MTBDRplus)

The scale-up of rapid drug resistance testing for TB is a global priority. MTBDRplus is a WHO-endorsed multidrug-resistant (MDR)-TB PCR assay with suboptimal sensitivities and high indeterminate rates on smear-negative specimens. We hypothesised that widespread use of incorrect thermocycler ramp rate (speed of temperature change between cycles) impacts performance. A global sample of 72 laboratories was surveyed. We tested 107 sputa from Xpert MTB/RIF-positive patients and, separately, dilution series of bacilli, both at the manufacturer-recommended ramp rate (2.2 °C/s) and the most frequently reported incorrect ramp rate (4.0 °C/s). Mycobacterium tuberculosis-complex DNA (TUB-band)-detection, indeterminate results, accuracy, and inter-reader variability (dilution series only) were compared. 32 respondents did a median (IQR) of 41 (20-150) assays monthly. 78% used an incorrect ramp rate. On smear-negative sputa, 2.2 °C/s vs. 4.0 °C/s improved TUB-band positivity (42/55 vs. 32/55; p = 0.042) and indeterminate rates (1/42 vs. 5/32; p = 0.039). The actionable results (not TUB-negative or indeterminate; 41/55 vs. 28/55) hence improved by 21% (95% CI: 9-35%). Widespread use of incorrect ramp rate contributes to suboptimal MTBDRplus performance on smear-negative specimens and hence limits clinical utility. The number of diagnoses (and thus the number of smear-negative patients in whom DST is possible) will improve substantially after ramp rate correction.

Disability acquisition and mental health: effect modification by demographic and socioeconomic characteristics using data from an Australian longitudinal study

OBJECTIVES

There is evidence of a causal relationship between disability acquisition and poor mental health, but the substantial heterogeneity in the magnitude of the effect is poorly understood and may be aetiologically informative. This study aimed to identify demographic and socioeconomic factors that modify the effect of disability acquisition on mental health.

DESIGN AND SETTING

The Household, Income and Labour Dynamics in Australia Survey is a nationally representative longitudinal survey of Australian households that has been conducted annually since 2001. Four waves of data were included in this analysis, from 2011 to 2014.

PARTICIPANTS

Individuals who acquired a disability (n=387) were compared with those who remained disability-free in all four waves (n=7936).

PRIMARY OUTCOME MEASURE

Mental health was measured using the mental health subscale of the Short Form 36 (SF-36) general health questionnaire, which measures symptoms of depression, anxiety and psychological well-being.

METHODS

Linear regression models were fitted to estimate the effect of disability acquisition on mental health, testing for effect modification by key demographic and socioeconomic characteristics. To maximise causal inference, we used a propensity score approach with inverse probability of treatment weighting to control for confounding and multiple imputation using chained equations to assess the impact of missing data.

RESULTS

On average, disability acquisition was associated with a 5-point decline in mental health score (estimated mean difference: -5.1, 95% CI -7.2 to -3.0). There was strong evidence that income and relationship status modified the effect, with more detrimental effects in the lowest (-12.5, 95% CI -18.5 to -6.5) compared with highest income quintile (-1.1, 95% CI -4.9 to 2.7) and for people not in a relationship (-8.8, 95% CI -12.9 to -4.8) compared with those who were (-3.7, 95% CI -6.1 to -1.4).

CONCLUSIONS

Our results suggest that the detrimental effect of disability acquisition on mental health is substantially greater for socioeconomic disadvantaged individuals.

A comparison of multiple imputation methods for handling missing values in longitudinal data in the presence of a time-varying covariate with a non-linear association with time: a simulation study

Background

Missing data is a common problem in epidemiological studies, and is particularly prominent in longitudinal data, which involve multiple waves of data collection. Traditional multiple imputation (MI) methods (fully conditional specification (FCS) and multivariate normal imputation (MVNI)) treat repeated measurements of the same time-dependent variable as just another ‘distinct’ variable for imputation and therefore do not make the most of the longitudinal structure of the data. Only a few studies have explored extensions to the standard approaches to account for the temporal structure of longitudinal data. One suggestion is the two-fold fully conditional specification (two-fold FCS) algorithm, which restricts the imputation of a time-dependent variable to time blocks where the imputation model includes measurements taken at the specified and adjacent times. To date, no study has investigated the performance of two-fold FCS and standard MI methods for handling missing data in a time-varying covariate with a non-linear trajectory over time – a commonly encountered scenario in epidemiological studies.

Methods

We simulated 1000 datasets of 5000 individuals based on the Longitudinal Study of Australian Children (LSAC). Three missing data mechanisms: missing completely at random (MCAR), and a weak and a strong missing at random (MAR) scenarios were used to impose missingness on body mass index (BMI) for age z-scores; a continuous time-varying exposure variable with a non-linear trajectory over time. We evaluated the performance of FCS, MVNI, and two-fold FCS for handling up to 50% of missing data when assessing the association between childhood obesity and sleep problems.

Results

The standard two-fold FCS produced slightly more biased and less precise estimates than FCS and MVNI. We observed slight improvements in bias and precision when using a time window width of two for the two-fold FCS algorithm compared to the standard width of one.

Conclusion

We recommend the use of FCS or MVNI in a similar longitudinal setting, and when encountering convergence issues due to a large number of time points or variables with missing values, the two-fold FCS with exploration of a suitable time window.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0372-y) contains supplementary material, which is available to authorized users.

Randomized clinical trial of preoperative oral versus intravenous iron in anaemic patients with colorectal cancer

BACKGROUND

Treatment of preoperative anaemia is recommended as part of patient blood management, aiming to minimize perioperative allogeneic red blood cell transfusion. No clear evidence exists outlining which treatment modality should be used in patients with colorectal cancer. The study aimed to compare the efficacy of preoperative intravenous and oral iron in reducing blood transfusion use in anaemic patients undergoing elective colorectal cancer surgery.

METHODS

Anaemic patients with non-metastatic colorectal adenocarcinoma were recruited at least 2 weeks before surgery and randomized to receive oral (ferrous sulphate) or intravenous (ferric carboxymaltose) iron. Perioperative changes in haemoglobin, ferritin, transferrin saturation and blood transfusion use were recorded until postoperative outpatient review.

RESULTS

Some 116 patients were included in the study. There was no difference in blood transfusion use from recruitment to trial completion in terms of either volume of blood administered (P = 0·841) or number of patients transfused (P = 0·470). Despite this, increases in haemoglobin after treatment were higher with intravenous iron (median 1·55 (i.q.r. 0·93-2·58) versus 0·50 (-0·13 to 1·33) g/dl; P < 0·001), which was associated with fewer anaemic patients at the time of surgery (75 versus 90 per cent; P = 0·048). Haemoglobin levels were thus higher at surgery after treatment with intravenous than with oral iron (mean 11·9 (95 per cent c.i. 11·5 to 12·3) versus 11·0 (10·6 to 11·4) g/dl respectively; P = 0·002), as were ferritin (P < 0·001) and transferrin saturation (P < 0·001) levels.

CONCLUSION

Intravenous iron did not reduce the blood transfusion requirement but was more effective than oral iron at treating preoperative anaemia and iron deficiency in patients undergoing colorectal cancer surgery.

Whole genome sequencing reveals genomic heterogeneity and antibiotic purification in Mycobacterium tuberculosis isolates

BACKGROUND

Whole genome sequencing has revolutionised the interrogation of mycobacterial genomes. Recent studies have reported conflicting findings on the genomic stability of Mycobacterium tuberculosis during the evolution of drug resistance. In an age where whole genome sequencing is increasingly relied upon for defining the structure of bacterial genomes, it is important to investigate the reliability of next generation sequencing to identify clonal variants present in a minor percentage of the population. This study aimed to define a reliable cut-off for identification of low frequency sequence variants and to subsequently investigate genetic heterogeneity and the evolution of drug resistance in M. tuberculosis.

METHODS

Genomic DNA was isolated from single colonies from 14 rifampicin mono-resistant M. tuberculosis isolates, as well as the primary cultures and follow up MDR cultures from two of these patients. The whole genomes of the M. tuberculosis isolates were sequenced using either the Illumina MiSeq or Illumina HiSeq platforms. Sequences were analysed with an in-house pipeline.

RESULTS

Using next-generation sequencing in combination with Sanger sequencing and statistical analysis we defined a read frequency cut-off of 30% to identify low frequency M. tuberculosis variants with high confidence. Using this cut-off we demonstrated a high rate of genetic diversity between single colonies isolated from one population, showing that by using the current sequencing technology, single colonies are not a true reflection of the genetic diversity within a whole population and vice versa. We further showed that numerous heterogeneous variants emerge and then disappear during the evolution of isoniazid resistance within individual patients. Our findings allowed us to formulate a model for the selective bottleneck which occurs during the course of infection, acting as a genomic purification event.

CONCLUSIONS

Our study demonstrated true levels of genetic diversity within an M. tuberculosis population and showed that genetic diversity may be re-defined when a selective pressure, such as drug exposure, is imposed on M. tuberculosis populations during the course of infection. This suggests that the genome of M. tuberculosis is more dynamic than previously thought, suggesting preparedness to respond to a changing environment.

Lennie: a smartphone application with novel implications for the management of animal colonies

Researchers rely on animals for their clinical applicability and ease of monitoring. However, careful management is required to ensure the animal and financial costs are minimized. The incorporation of 'smartphone' technology in research has increased exponentially, with a focus on the development of innovative research-based applications. We have developed a smartphone application designed to address the needs of modern researchers in the management of their colonies. 'Lennie' introduces a new method for the management of small to medium-sized animal colonies. Lennie allows users wireless access to their colonies with the ability to create and edit from virtually anywhere. Lennie also offers the ability to manage colonies based on experiments by assigning animals based on priority. Experimental time-points are also recorded with integrated scheduling options using the calendar function. Lennie represents an alternative to current large-scale software options, as the application design is simple, and requires no training or manuals. As the technological landscape is constantly evolving, we must continue to find ways to improve upon current practices to ensure that research is completed with efficiency and efficacy. With this new method of animal management, researchers are able to spend less time record keeping and can focus their efforts on continued innovation.

Paracetamol exposure in pregnancy and early childhood and development of childhood asthma: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

While paracetamol exposure in pregnancy and early infancy has been associated with asthma, it remains unclear whether this is confounded by respiratory tract infections, which have been suggested as an alternative explanation. We undertook a systematic review and meta-analysis of longitudinal studies that reported the association between paracetamol exposure during pregnancy or infancy and the subsequent development of childhood asthma (≥5 years).

METHODS

Two independent researchers searched the databases EMBASE and PUBMED on 12 August 2013 for relevant articles using predefined inclusion and exclusion criteria. Study quality was assessed and results were pooled using fixed effect models or random effect models when moderate between-study heterogeneity was observed. We explicitly assessed whether the observed associations are due to confounding by respiratory tract infections.

RESULTS

Eleven observational cohort studies met the inclusion criteria. Any paracetamol use during the first trimester was related to increased risk of childhood asthma (5 studies, pooled OR=1.39, 95% CI 1.01 to 1.91) but there was marked between-study heterogeneity (I(2)=63%) and only one of these studies adjusted for maternal respiratory tract infections. Increasing frequency of use of paracetamol during infancy was associated with increased odds of childhood asthma (3 studies, pooled OR=1.15, 95% CI 1.00 to 1.31 per doubling of days exposure), but in these same three studies adjusting for respiratory tract infections reduced this association (OR=1.06, 95% CI 0.92 to 1.22).

DISCUSSION

The association during early pregnancy exposure was highly variable between studies and exposure during infancy appears to be moderately confounded by respiratory tract infections. There is insufficient evidence to warrant changing guidelines on early life paracetamol exposure at this time.

Population pharmacokinetics of intravenous artesunate: a pooled analysis of individual data from patients with severe malaria

There are ~660,000 deaths from severe malaria each year. Intravenous artesunate (i.v. ARS) is the first-line treatment in adults and children. To optimize the dosing regimen of i.v. ARS, the largest pooled population pharmacokinetic study to date of the active metabolite dihydroartemisinin (DHA) was performed. The pooled dataset consisted of 71 adults and 195 children with severe malaria, with a mixture of sparse and rich sampling within the first 12 h after drug administration. A one-compartment model described the population pharmacokinetics of DHA adequately. Body weight had the greatest impact on DHA pharmacokinetics, resulting in lower DHA exposure for smaller children (6–10 kg) than adults. Post hoc estimates of DHA exposure were not significantly associated with parasitological outcomes. Comparable DHA exposure in smaller children and adults after i.v. ARS was achieved under a dose modification for intramuscular ARS proposed in a separate analysis of children.

The feasibility and clinical efficacy of intravenous iron administration for preoperative anaemia in patients with colorectal cancer

AIM

The study aimed to analyse the feasibility and efficacy of administration of a single intravenous iron infusion (IVI) in the preoperative optimization of colorectal cancer patients with anaemia.

METHOD

Twenty patients were recruited at least 14 days before the planned date of surgery. A single 1000 mg dose of ferric carboxymaltose (Ferinject) was administered as an outpatient procedure. Blood samples were taken at recruitment prior to drug administration (REC), on the day of surgery prior to any intervention (DOS) and on the first postoperative day. Allogeneic red blood cell transfusions (ARBT) and outcomes were recorded from recruitment throughout the study period.

RESULTS

There was a significant median rise in haemoglobin levels (Hb) from REC to DOS of 1.8 g/dl [interquartile range (IQR) 0.75-2.45, P < 0.001] for the entire cohort. Two patients received ARBT preoperatively, and for those not transfused preoperatively (n = 18), this incremental Hb rise remained significant (P < 0.001, median 1.65 g/dl, IQR 0.5-2.3). Of these patients, those who responded to IVI had higher erythropoietin (EPO) levels at recruitment (P < 0.01) and lower recruitment Hb values, transferrin-saturation (TSAT) and C-reactive protein (CRP) levels (P < 0.05). REC Hb (Rs = -0.62, P < 0.01), REC TSAT levels (Rs = -0.67, P < 0.01) and REC EPO (Rs = 0.69, P < 0.01) correlated with the magnitude of treatment change in Hb levels. Five patients received ARBT until the fourth postoperative day, which was significantly fewer than predicted (P < 0.05).

CONCLUSION

IVI can be administered preoperatively in the outpatient clinic to colorectal cancer patients with anaemia, with associated reduction in ARBT use and increase in Hb levels.

The influence of laparoscopy on incisional hernia rates: a retrospective analysis of 1057 colorectal cancer resections

AIM

The aim of this study was to evaluate the incidence of incisional hernia formation after laparoscopic and open surgery for colorectal cancer.

METHOD

A retrospective analysis was conducted of 1057 colorectal cancer resection cases (289 laparoscopic, 768 open) performed in a single national laparoscopic training centre between January 2006 and December 2011. Clinical notes and serial computed tomography scans were reviewed, with any incisional hernia including those at a surgical incision, port site, stoma and stoma closure site identified and the size of the defect measured.

RESULTS

The overall incisional hernia rate was 14.8%. There was no significant difference between the open and laparoscopic groups (14.4% vs 15.9%, P = 0.566). Excluding stoma-related hernia, 10.7% of the open group developed a surgical wound hernia, and 11.1% of the laparoscopic group developed a hernia at a port site, extraction site or surgical midline incision. There was no statistical difference between the two groups (P = 0.853). The defects were smaller in the laparoscopic group (P < 0.005). There were significantly more parastomal hernias in the laparoscopic group (40%) than in the open group (12.7%, P < 0.001).

CONCLUSION

The incidence of incisional hernia formation was similar after laparoscopic or open surgery for colorectal cancer. Parastomal hernia was more frequent after laparoscopic surgery.

Hypoxia, not hypercapnia, induces cardiorespiratory failure in rats

Mechanical respiratory loads induce cardiorespiratory failure, presumably by increasing O2 demand concurrently with decreases in O2 availability (decreased PaO2). We tested the hypothesis that asphyxia alone can cause cardiorespiratory failure ("failure") in pentobarbital-anesthetized rats. We also tested the hypothesis that hypoxia, not hypercapnia, is responsible by supplying supplemental O2 during mechanical loading in a separate group of rats. Asphyxia (mean PaO2 and PaCO2 of 43 and 69mmHg, respectively) resulted in failure, evident as a slowing of mean respiratory frequency (133-83breaths/min) and a sudden and large drop in mean arterial pressure (71-47mmHg), after 214±66min (n=16; range 117-355min). Neither respiratory drive nor heart rate decreased, indicating that failure was peripheral, not central. Of 8 rats tested after 3h of asphyxia for the presence in blood of cardiac troponin T, all were positive. In an additional 6 rats, normocapnic hypoxia (mean PaCO2 and PaO2 were 39±2.2 and 41±3.1mmHg, respectively) caused failure after an average 205min (range 181-275min), no different from that of asphyxic rats. In the 6 rats that breathed O2 during an initially moderate inspiratory resistive load, endurances exceeded 7h (failure occurring only because we increased the load after 6h) and tracheal pressure and left ventricular dP/dt were maintained despite supercarbia (PaCO2>150mmHg). Thus, asphyxia alone can induce failure, the failure is due to hypoxia, not hypercapnia, and hypercapnia has minimal effects on cardiac and respiratory muscle function in the presence of hyperoxia.

Perinatal common mental disorders among women and the social and emotional development of their infants in rural Vietnam

BACKGROUND

Little is known about the effect of common mental disorders (CMD) among women in the perinatal period on infant development in low-income countries. The aim of this study was to examine the effect of exposures to maternal symptoms of ante- and post-natal CMD on infant social-emotional development in a low-income setting.

METHODS

A prospective community-based investigation in which a cohort of pregnant women was recruited in rural northern Vietnam and followed until 6 months postpartum. Psychosocial and biological data were collected in four assessment waves. The outcome was 6-month old infants' scores on the Bayley Scales of Infant and Toddler Development Social-Emotional Questionnaire. Direct and indirect effects of maternal CMD on the outcome were tested simultaneously with path analysis.

RESULTS

Complete data were available for 378 mother-infant dyads. There were no direct effects of ante- or post-natal CMD on infant Social-Emotional scores. However, there was an indirect pathway (path coefficient -1.11, 95% CI -1.79 to -0.42) in which antenatal CMD were associated with increased likelihood of postnatal CMD, which were associated with reduced parenting self-efficacy and less affectionate and warm parenting practices, which were associated with lower infant social-emotional scores. Parenting self-efficacy and practices also mediated the adverse effects of a woman being young or of high parity or experiencing poverty, intimate partner violence, a poor relationship with her own mother, non-economic life adversity and insufficient breastmilk, on infant social-emotional development.

LIMITATIONS

We acknowledge some limitations including (1) a moderate rate of attrition, (2) the use of a screening test for perinatal CMD, (3) the Bayley scales are not yet validated for use in Vietnam and (4) possible response bias in which maternal perceptions of their infants were influenced by their mood.

CONCLUSIONS

These data indicate that women's antenatal and postnatal mental health is a crucial but currently inadequately understood determinant of the social and emotional development of infants in low-income settings.

Same-day assessment and management of urgent (2-week wait) colorectal referrals: an analysis of the outcome of 1606 patients attending an endoscopy unit-based colorectal clinic

AIM

The Rapid Access Diagnosis and Remedy (RADAR) clinic combines 2-week wait (TWW) specialist consultation with 'straight-to-test' flexible sigmoidoscopy (FS) for left-sided 'red-flag' TWW criteria (excluding right-sided mass or iron-deficiency anaemia). The study aims were to determine the effectiveness of RADAR in differentiating colorectal cancer from benign disease and to evaluate the need for whole colonic investigation (WCI) following FS, in symptomatic patients.

METHOD

Prospectively collated data of all RADAR patients from November 2005 to November 2009 were analysed, excluding patients referred internally for a FS. The local histology database was later interrogated to detect any missed cancers.

RESULTS

Of 1690 patients (729 men; median (range) age: 68 (18-96) years) assessed in RADAR, 84 were excluded. Colorectal cancer (CRC) was diagnosed in 117 (7.3%). Eighty-seven cancers were diagnosed on the day of attendance and a further 13 within a week (88.9% overall). Two patients after a cancer-free FS were found to have a right-sided CRC on WCI (0.24%) and one synchronous cancer was found. No patient with a cancer-free FS having a WCI was subsequently found to have CRC at a median of 35 (12-58) months.

CONCLUSION

Flexible sigmoidoscopy, in the context of an endoscopy unit TWW clinic, allows same-day diagnosis of most patients referred with left-sided symptoms, and immediate reassurance and treatment of most benign diagnoses. For these patients, the use of routine WCI following a cancer-free FS does not appear to be beneficial. Adopting this system would significantly reduce the number of barium enemas and colonoscopies currently performed.

Outcomes after biological mesh reconstruction of the pelvic floor following extra-levator abdominoperineal excision of rectum (APER)

BACKGROUND

Extra-levator abdominoperineal excision of the rectum (ELAPER) for low rectal cancer is used to avoid the adverse oncological outcomes of inadvertent perforation and a positive circumferential resection margin associated with the conventional APER technique. This wider excision creates a large defect requiring pelvic floor reconstruction, and there is still controversy regarding the best method of closure. The aim of this study is to present outcomes of biological mesh pelvic floor reconstruction following ELAPER.

METHODS

Prospective data on consecutive patients having ELAPER for low rectal cancer at a single UK institution between October 2008 and March 2013 were collected. The perineum was reconstructed using a biological mesh and the short-term outcomes were evaluated, focusing particularly on perineal wound complications and perineal hernias.

RESULTS

Thirty-four patients were included [median age 62 years, range 40-72 years, 27 males (79 %)]. The median operative time was 248 min (range 120-340 min). The median length of hospital stay was 9 days (range 4-20 days). There were three perineal complications (9 %) requiring surgical intervention, but no meshes were removed. There were no perineal hernias. The median length of follow-up was 21 months (range 1-54 months). The overall mortality was 9 % from distant metastases.

CONCLUSIONS

Our series adds to the increasing evidence that good outcomes can be achieved for pelvic floor reconstruction with biological mesh following ELAPER without the additional use of myocutaneous flaps. The low serious complication rate, good outcomes in perineal wound healing and the absence of perineal hernias demonstrates that this is a safe and feasible procedure.

Impact on infants' cognitive development of antenatal exposure to iron deficiency disorder and common mental disorders

Objectives

The aim of this study was to examine the effects of antenatal exposure to iron deficiency anemia (IDA) and common mental disorders (CMD) on cognitive development of 6 months old infants in a developing country.

Methods

A prospective population-based study in a rural province in Vietnam, which enrolled pregnant women at 12–20 weeks gestation and followed them up with their infants until six months postpartum. Criteria for IDA were Hb <11 g/dL and serum ferritin <15 ng/mL. CMD symptoms were assessed by the Edinburgh Postnatal Depression Scale-Vietnam validation. Infant cognitive development was assessed by Bayley Scales of Infant and Toddler Development, 3^rd Ed. Path analyses were performed to determine the direct and indirect, partly or fully mediated, causal effects of the antenatal exposures.

Results

A total of 497 pregnant women were recruited, of those 378 women provided complete data which were included in the analyses. Statistically significant direct adverse effects of persistent antenatal IDA (estimated difference of −11.62 points; 95% CI −23.01 to −0.22) and antenatal CMD (−4.80 points; 95% CI: −9.40 to −0.20) on infant Bayley cognitive scores at six months were found. Higher birthweight, household wealth, and self-rated sufficient supply of breastmilk were associated with higher cognitive scores. Maternal age >30 years and primiparity had an indirect adverse effect on infants’ Bayley cognitive scores.

Conclusions

These findings suggest that antenatal IDA and CMD both have adverse effects on child cognitive development, which if unrecognized and unaddressed are likely to be lasting. It is crucial that both these risks are considered by policy makers, clinicians, and researchers seeking to improve child cognitive function in developing countries.

A Novel Spore Collection Device for Sampling Exposure Pathways: A Case Study of Puccinia psidii

A device comprising a filter attached to a vacuum cleaner was purpose-built to sample rust spores from three potentially high-risk pathways in Australia: passengers, fresh flowers, and sea cargo. The proportion of spores recovered from eight surfaces comparable with those on each pathway (cotton, denim, roses, carnations, chrysanthemums, wood, plastic, and metal) was estimated in the laboratory. Spore recovery percentages were highest for denim clothing (61% Puccinia triticina Erikss. and 62% Uromycladium tepperianum) and lowest for carnations (4% P. triticina Erikss. and 5% U. tepperianum). Subsequently, the device was tested at several locations on the Central Coast of New South Wales, Australia, recently affected by a "myrtle rust" outbreak. Symptomatic and asymptomatic myrtle rust hosts, myrtle rust nonhosts, and inanimate objects (e.g., clothing and vehicles) were sampled in conjunction with the emergency response to the outbreak. A polymerase chain reaction (PCR) assay developed for P. psidii established the presence of myrtle rust, and visual inspections provided spore count estimations. All samples from symptomatic myrtle rust hosts produced positive PCR results and spore count estimations were generally much greater. Several samples from asymptomatic myrtle rust hosts, myrtle rust nonhosts, and inanimate objects also produced positive PCR results; however, there were discrepancies between PCR results and spore count estimations in some of these samples, all of which had <100 spores. This study highlights the utility of the device and analytical methodology, especially during the early stages of a disease outbreak when infection symptoms on plants and contamination on objects is not visible upon gross examination.

Adult serum cytokine concentrations and the persistence of asthma

BACKGROUND

Cytokines play a pivotal role in regulating the development and persistence of the inflammatory process in asthma. Our aim was to investigate whether asthma persistence or remission is associated with a specific cytokine profile.

METHODS

The Tasmanian Longitudinal Health Study followed participants from 7 to 44 years of age. Serum concentrations of interleukin (IL)-4, IL-5, IL-6, IL-8, IL-10 and tumor necrosis factor-alpha (TNF-α) were measured at age 44 years. Participants were categorized into five phenotypes (early-onset noncurrent asthma, early-onset current asthma, late-onset noncurrent asthma and late-onset current asthma). Those who had never had asthma formed the reference group. Multivariable linear regression was used to compare serum cytokine concentrations between each phenotype and the reference group.

RESULTS

IL-10 concentrations were significantly lower in serum from the early-onset current asthma group than in the reference group (ratio of geometric means 0.58; 95% confidence interval 0.33-0.99; p = 0.048). IL-6 concentrations for the late-onset remitted group were also significantly lower than in the reference group (p = 0.009). The TNF-α concentrations were significantly lower for both early-and late-onset remitted asthma phenotypes when compared with the reference group. No associations were detected between serum concentrations of IL-4, IL-5 or IL-8 and these specific longitudinal asthma phenotypes.

CONCLUSION

Our findings suggest a possible role for deficient IL-10 responses in the persistence of early-onset asthma. Lower IL-6 and TNF-α concentrations in serum from those with remitted asthma suggest that these proinflammatory cytokines may be actively suppressed during asthma remission.

Prevalence and risk factors for symptoms of common mental disorders in early and late pregnancy in Vietnamese women: a prospective population-based study

BACKGROUND

Little is known about the prevalence of and risk factors for common mental disorders (CMD) in pregnant women in low-income countries. The aim of this study was to establish the prevalence of and psychosocial risk factors for clinically significant symptoms of CMD in early and late pregnancy in women in rural Viet Nam.

METHODS

A population-based sample of women was surveyed in early and late pregnancy. CMD were assessed by the Edinburgh Postnatal Depression Scale-Viet Nam Validation and psychosocial risks by study-specific structured interviews.

RESULTS

In total 497/523 (97%) eligible women were recruited and 419 (84%) provided complete data. Prevalence of CMD only in early pregnancy was 22.4% (95% CI 18.4-26.4); only in late pregnancy was 10.7% (95% CI 7.8-13.7) and at both assessment waves was 17.4% (95% CI 13.8-21.1). Non-economic and economic coincidental life adversity, intimate partner violence, past pregnancy loss, and childhood abuse were positively associated with persistent antenatal CMD. Older age, having a preference for the baby's sex, and nulli- or primiparity were risk factors for CMD in early pregnancy.

CONCLUSIONS

Persistent antenatal CMD are prevalent in rural areas of Viet Nam. Psychosocial risk factors play a major role in this significant public health problem.

Adverse effects of falciparum and vivax malaria and the safety of antimalarial treatment in early pregnancy: a population-based study

Background

The effects of malaria and its treatment in the first trimester of pregnancy remain an area of concern. We aimed to assess the outcome of malaria-exposed and malaria-unexposed first-trimester pregnancies of women from the Thai–Burmese border and compare outcomes after chloroquine-based, quinine-based, or artemisinin-based treatments.

Methods

We analysed all antenatal records of women in the first trimester of pregnancy attending Shoklo Malaria Research Unit antenatal clinics from May 12, 1986, to Oct 31, 2010. Women without malaria in pregnancy were compared with those who had a single episode of malaria in the first trimester. The association between malaria and miscarriage was estimated using multivariable logistic regression.

Findings

Of 48 426 pregnant women, 17 613 (36%) met the inclusion criteria: 16 668 (95%) had no malaria during the pregnancy and 945 (5%) had a single episode in the first trimester. The odds of miscarriage increased in women with asymptomatic malaria (adjusted odds ratio 2·70, 95% CI 2·04–3·59) and symptomatic malaria (3·99, 3·10–5·13), and were similar for Plasmodium falciparum and Plasmodium vivax. Other risk factors for miscarriage included smoking, maternal age, previous miscarriage, and non-malaria febrile illness. In women with malaria, additional risk factors for miscarriage included severe or hyperparasitaemic malaria (adjusted odds ratio 3·63, 95% CI 1·15–11·46) and parasitaemia (1·49, 1·25–1·78 for each ten-fold increase in parasitaemia). Higher gestational age at the time of infection was protective (adjusted odds ratio 0·86, 95% CI 0·81–0·91). The risk of miscarriage was similar for women treated with chloroquine (92 [26%] of 354), quinine (95 [27%) of 355), or artesunate (20 [31%] of 64; p=0·71). Adverse effects related to antimalarial treatment were not observed.

Interpretation

A single episode of falciparum or vivax malaria in the first trimester of pregnancy can cause miscarriage. No additional toxic effects associated with artesunate treatment occurred in early pregnancy. Prospective studies should now be done to assess the safety and efficacy of artemisinin combination treatments in early pregnancy.

Funding

Wellcome Trust and Bill & Melinda Gates Foundation.

Meat consumption and risk of primary hip and knee joint replacement due to osteoarthritis: a prospective cohort study

BACKGROUND

There is emerging evidence for a beneficial effect of meat consumption on the musculoskeletal system. However, whether it affects the risk of knee and hip osteoarthritis is unknown. We performed a prospective cohort study to examine the relationship between meat consumption and risk of primary hip and knee replacement for osteoarthritis.

METHODS

Eligible 35,331 participants were selected from the Melbourne Collaborative Cohort Study recruited during 1990-1994. Consumption of fresh red meat, processed meat, chicken, and fish was assessed using a food frequency questionnaire. Primary hip and knee replacement for osteoarthritis during 2001-2005 was determined by linking the cohort records to the Australian National Joint Replacement Registry.

RESULTS

There was a negative dose-response relationship between fresh red meat consumption and the risk of hip replacement (hazard ratio (HR) 0.94 per increase in intake of one time/week, 95% confidence interval (CI) 0.89-0.98). In contrast, there was no association with knee replacement risk (HR 0.98, 95% CI 0.94-1.02). Consumption of processed meat, chicken and fish were not associated with risk of hip or knee replacement.

CONCLUSION

A high level consumption of fresh red meat was associated with a decreased risk of hip, but not knee, joint replacement for osteoarthritis. One possible mechanism to explain these differential associations may be via an effect of meat intake on bone strength and hip shape. Further confirmatory studies are warranted.

Is physical activity a risk factor for primary knee or hip replacement due to osteoarthritis? A prospective cohort study

OBJECTIVE

To estimate prospectively any association between measures of physical activity and the risk of either primary knee or hip replacement due to osteoarthritis (OA).

METHODS

Eligible subjects (n = 39,023) were selected from participants in a prospective cohort study recruited 1990-1994. Primary knee and hip replacement for OA during 2001-2005 was determined by linking the cohort records to the National Joint Replacement Registry. A total physical activity level was computed, incorporating both intensity and frequency for different forms of physical activity obtained by questionnaire at baseline attendance.

RESULTS

There was a dose-response relationship between total physical activity level and the risk of primary knee replacement [hazards ratio (HR) 1.04, 95% CI 1.01-1.07 for an increase of 1 level in total physical activity]. Although vigorous activity frequency was associated with an increased risk of primary knee replacement (HR 1.42, 95% CI 1.08-1.86) for 1-2 times/week and HR 1.24 (95% CI 0.90-1.71) for ≥ 3 times/week), the p for trend was marginal (continuous HR 1.08, 95% CI 1.00-1.16, p = 0.05). The frequency of less vigorous activity or walking was not associated with the risk of primary knee replacement, nor was any measure of physical activity associated with the risk of primary hip replacement.

CONCLUSION

Increasing levels of total physical activity are positively associated with the risk of primary knee but not hip replacement due to OA. Physical activity might affect the knee and hip joints differently depending on the preexisting health status and anatomy of the joint, as well as the sort of physical activity performed.

Electrons and Protons Accelerated in Mercury's Magnetic Field

Fluxes of protons with energies of approximately 550 kev and electrons with energies of approximately 300 kev which exceed approximately 10(4) and 10(5) cm(-2) sec(-1), respectively, have been discovered in the magnetosphere of Mercury. Electron fluxes > 10(3) cm(-2) sec(-1) also are observed in the outbound pass of the Mariner 10 spacecraft throuigh the magnetosheath. The intensity versus time profiles of the particle fluxes in the magnetosphere appear with sudden onsets of approximately 10(4) cm(-2) sec(-1) beginning at interplanetary background levels and persisting for times equivalent to their being distriblited spatially over regions having a scale size comparable to the planetary radius. For a spectral form dJ/dE alpha E-gamma, where J is the differential particle intensity and E is the kinetic energy, the typical values of gamma are gamma(p) = 5.5 for protons above 500 kev and gamma(e) >/= 9 for electrons above 170 kev. Large coherent electron intensity oscillations (variations of factors of 10 to 100) have been discovered with characteristic periods of approximately 6 seconds and with higher frequency components. In some cases proton bursts are found in phase with these oscillations. On the basis of the experimental evidence and a knowledge of the general magnetic field intensities and directions along the trajectory of Mariner 10 provided by the magnetic field observations, it is shown that the radiation events observed in the magnetosphere and magnetosheath are transient and are not interpretable in terms of stable trapped particle populations. Furthermtiore, experimental evidence strongly supports the view that the particles are impulsively accelerated and that the acceleration source is not more distant from the point of observation along lines of force than approximately 8 x 10(3) to 16 x 10(3) kilometers (3 to 6.5 units of Mercury's radius). Candidates for the regions most likely to be sources of particle acceleration are discussed, namely, the magnetotail and the magnetosheath. It is pointed out that the phenomena discovered at Mercury will place more stringent conditions on allowed mnodels for electron and proton acceleration than have heretofore been possible in studies within the earth's magnetosphere.

Adherence to asthma management guidelines by middle-aged adults with current asthma

BACKGROUND

With the increasing burden of asthma worldwide, much effort has been given to developing and updating management guidelines. Using data from the Tasmanian Longitudinal Health Study (TAHS), the adequacy of asthma management for middle-aged adults with asthma was investigated.

METHODS

Information about spirometry, medication history and current asthma status was collected by the most recent TAHS when participants were in their mid 40s. Only those who reported ever having asthma were eligible for analysis.

RESULTS

Of the 702 participants who reported ever having asthma, 50% had current asthma (n = 351) of whom 71% were categorised as having persistent asthma (n = 98 mild, n = 92 moderate, n = 58 severe). The majority (85.2%) of participants with current asthma had used some form of asthma medication in the past 12 months, but the proportion of the use of minimally adequate preventer medication was low (26%). Post-bronchodilator airflow obstruction increased progressively from mild to severe persistent asthma for those inadequately managed, but not for those on adequate therapy.

CONCLUSION

Appropriate use of asthma medication by this middle-aged group of adults with current asthma was inadequate, especially for those with adult-onset moderate or severe persistent disease and without a family history of asthma. These results suggest that proper use of preventer medication could protect against the progressive decline in lung function associated with increasing severity. This has implications not just for poor quality of life, but also for the development of fixed airflow obstruction.

Relationship between body adiposity measures and risk of primary knee and hip replacement for osteoarthritis: a prospective cohort study

INTRODUCTION

Total joint replacement is considered a surrogate measure for symptomatic end-stage osteoarthritis. It is unknown whether the adipose mass and the distribution of adipose mass are associated with the risk of primary knee and hip replacement for osteoarthritis. The aim of the present investigation was to examine this in a cohort study.

METHODS

A total of 39,023 healthy volunteers from Melbourne, Australia were recruited for a prospective cohort study during 1990 to 1994. Their body mass index, waist circumference, and waist-to-hip ratio were obtained from direct anthropometric measurements. The fat mass and percentage fat were estimated from bioelectrical impedance analysis. Primary knee and hip replacements for osteoarthritis between 1 January 2001 and 31 December 2005 were determined by data linkage to the Australian Orthopaedic Association National Joint Replacement Registry. Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) for primary joint replacement associated with each adiposity measure.

RESULTS

Comparing the fourth quartile with the first, there was a threefold to fourfold increased risk of primary joint replacement associated with body weight (HR = 3.44, 95% confidence interval (CI) = 2.83 to 4.18), body mass index (HR = 3.44, 95% CI = 2.80 to 4.22), fat mass (HR = 3.51, 95% CI = 2.87 to 4.30), and percentage fat (HR = 2.99, 95% CI = 2.46 to 3.63). The waist circumference (HR = 2.77, 95% CI = 2.26 to 3.39) and waist-to-hip ratio (HR = 1.46, 95% CI = 1.21 to 1.76) were less strongly associated with the risk. Except for the waist-to-hip ratio, which was not significantly associated with hip replacement risk, all adiposity measures were associated with the risk of both knee and hip joint replacement, and were significantly stronger risk factors for knee.

CONCLUSIONS

Risk of primary knee and hip joint replacement for osteoarthritis relates to both adipose mass and central adiposity. This relationship suggests both biomechanical and metabolic mechanisms associated with adiposity contribute to the risk of joint replacement, with stronger evidence at the knee rather than the hip.

Smoking and inadequate housing: results from an Australian national survey

OBJECTIVES

To examine the effect of: (a) the smoking status of the household; and (b) the amount spent on smoking by the household on inadequate housing.

STUDY DESIGN

This was a cross-sectional study using data from the first wave of the Household Income and Labour Dynamics in Australia survey.

METHODS

A total of 7673 households were eligible for analysis. The outcome, inadequate housing, was derived from a questionnaire item asking respondents about the adequacy of their housing with respect to their housing needs in general. A house was defined as a smoking household if at least one member smoked. Amongst smoking households, the total amount spent on smoking per week was calculated. Other factors included in the analyses were education, occupation and age of the head of the household, household size, household disposable income and housing tenure.

RESULTS

There was evidence for an unadjusted association between being a smoking household and having inadequate housing [odds ratio (OR) 1.64, 95% confidence interval (CI) 1.32-2.03, P<0.001]; however, after adjusting for indicators of socio-economic status and age, evidence for the association became much weaker (OR 1.15, 95% CI 0.90-1.47, P=0.262). For smoking households, there was little evidence for an association between inadequate housing and the amount spent on smoking by the household, either unadjusted or adjusted.

CONCLUSIONS

It appears that antismoking policies will not enhance housing adequacy, which is predominantly affected by indicators of socio-economic status.

Fatty acid composition of milk of refugee Karen and urban Korean mothers. Is the level of DHA in breast milk of Western women compromised by high intake of saturated fat and linoleic acid?

BACKGROUND

Lower proportions of docosahexaenoic acid (DHA) and total n-3 metabolites have been reported in breast milk of European, Australian and North American women compared with milk of mothers from non-Western countries. This difference is not always explained by intakes of marine products.

OBJECTIVE

We investigated the possibility that the relative composition of DHA and total n-3 metabolites in breast milk of non-Western mothers with low fat intakes is higher than the levels commonly reported in their Western counterparts.

SUBJECTS

Mature milk of refugee Karen women from two different camps in Thailand (n=26 and n=53), and transition milk from urban Korean mothers (n=12) in Seoul was collected. In common with their respective community, the mothers have low fat intake, which is predominately of plant origin.

RESULTS

The percentage levels of DHA and n-3 metabolites in the milk of the Karen mothers were 0.52 +/- 0.14 and 0.85 +/- 0.24 (camp 1) and 0.54 +/- 0.22 and 0.92 +/- 0.42 (camp 2). In the Korean milk, DHA was 0.96 +/- 0.21 and total n-3 metabolites 1.51 +/- 0.3.

CONCLUSION

We postulate that the levels of DHA and total n-3 metabolites may be compromised in breast milk of mothers on the Western high fat diet. This calls into question the use of DHA composition of such milk as a reference for the formulation of milk designed, for infant feed or, to test the function of DHA in neuro-visual development.

A comparison of estradiol levels between women with a hysterectomy and ovarian conservation and women with an intact uterus

OBJECTIVES

To compare the distribution of estradiol levels between women with a hysterectomy and ovarian conservation and women with an intact uterus.

METHODS

A large cross-sectional study of women aged between 40 and 69 years, residing in Melbourne, Australia. Estradiol levels were available for 152 women with a hysterectomy and ovarian conservation and 1423 women with an intact uterus. All of the women were 'never-users' of hormone replacement therapy.

RESULTS

For women under 55 years of age, we observed that those with a hysterectomy and ovarian conservation had slightly higher estradiol levels compared with those with an intact uterus after adjustment for age, body mass index, smoking status and alcohol intake (ratio of geometric means of estradiol levels = 1.24; 95% confidence interval = 1.00-1.53). For women who were 55 years or greater, the distribution of estradiol levels varied little by hysterectomy status.

CONCLUSIONS

Our data do not suggest that women with hysterectomy and ovarian conservation have markedly different estradiol levels compared to women with an intact uterus.

Statistical approaches for assessing the relative validity of a food-frequency questionnaire: use of correlation coefficients and the kappa statistic

OBJECTIVE

To compare different statistical methods for assessing the relative validity of a self-administered, 150-item, semi-quantitative food-frequency questionnaire (FFQ) with 4-day weighed diet records (WR).

DESIGN

Subjects completed the Scottish Collaborative Group FFQ and carried out a 4-day WR. Relative agreement between the FFQ and WR for energy-adjusted nutrient intakes was assessed by Pearson and Spearman rank correlation coefficients, the percentages of subjects classified into the same and opposite thirds of intake, and Cohen's weighted kappa.

SUBJECTS

Forty-one men, mean age 36 (range 21-56) years, and 40 women, mean age 33 (range 19-58) years, recruited from different locations in Aberdeen, Scotland.

RESULTS

Spearman correlation coefficients tended to be lower than Pearson correlation coefficients, and were above 0.5 for 10 of the 27 nutrients in men and 17 of the 27 nutrients in women. For nutrients with Spearman correlation coefficients above 0.5, the percentage of subjects correctly classified into thirds ranged from 39 to 78%, and weighted kappa values ranged from 0.23 to 0.66.

CONCLUSIONS

Both Spearman correlation coefficients and weighted kappa values are useful in assessing the relative validity of estimates of nutrient intake by FFQs. Spearman correlation coefficients above 0.5, more than 50% of subjects correctly classified and less than 10% of subjects grossly misclassified into thirds, and weighted kappa values above 0.4 are recommended for nutrients of interest in epidemiological studies.