Multiple imputation strategies for missing event times in a multi-state model analysis.

In clinical studies, multi-state model (MSM) analysis is often used to describe the sequence of events that patients experience, enabling better understanding of disease progression. A complicating factor in many MSM studies is that the exact event times may not be known. Motivated by a real dataset of patients who received stem cell transplants, we considered the setting in which some event times were exactly observed and some were missing. In our setting, there was little information about the time intervals in which the missing event times occurred and missingness depended on the event type, given the analysis model covariates. These additional challenges limited the usefulness of some missing data methods (maximum likelihood, complete case analysis, and inverse probability weighting). We show that multiple imputation (MI) of event times can perform well in this setting. MI is a flexible method that can be used with any complete data analysis model. Through an extensive simulation study, we show that MI by predictive mean matching (PMM), in which sampling is from a set of observed times without reliance on a specific parametric distribution, has little bias when event times are missing at random, conditional on the observed data. Applying PMM separately for each sub-group of patients with a different pathway through the MSM tends to further reduce bias and improve precision. We recommend MI using PMM methods when performing MSM analysis with Markov models and partially observed event times.

Hypertensive disorders of pregnancy and midlife maternal cognition in a prospective cohort study.

Hypertensive disorders of pregnancy (HDP) are associated with an increased risk of cardiovascular disorders, with recent evidence linking pre-eclampsia with vascular dementia. We examined associations of HDP with cognitive performance measured in midlife, in a prospective cohort study, the Avon Longitudinal Study of Parents and Children. Six cognitive function domains were measured 20 years after pregnancy at a mean age of 51 years. The cognition tests were repeated at clinics in the following two years. Cognitive function domains measured were immediate and delayed verbal episodic memory, working memory, processing speed, verbal intelligence, and verbal fluency. Exposures were pre-eclampsia, gestational hypertension (GH), and a combined category of any HDP, all compared to normotensive pregnancy. Of 3393 pregnancies included in the analysis, GH was experienced by 417 (12.3%) and pre-eclampsia by 57 (1.7%). GH was associated with lower verbal episodic memory, in the delayed logic memory test (-0.16 SDs; 95% CI -0.30, -0.03; p = .015) and there was weak evidence of an association with the immediate logic memory test (-0.13 SDs; -0.27, 0.001; p = .058). However, we did not see steeper declines by age for women with GH and there was no evidence of associations with other cognitive domains or for pre-eclampsia with any domains. Results were not substantially changed after controlling for midlife blood pressure. Our findings suggest that a history of GH is associated with slightly reduced episodic memory 20 years after pregnancy, but we found no evidence of a quicker age-related decline compared to women with normotensive pregnancies.

Management and outcomes of myocardial infarction in people with impaired kidney function in England.

BACKGROUND: Acute myocardial infarction (AMI) causes significant mortality and morbidity in people with impaired kidney function. Previous observational research has demonstrated reduced use of invasive management strategies and inferior outcomes in this population. Studies from the USA have suggested that disparities in care have reduced over time. It is unclear whether these findings extend to Europe and the UK. METHODS: Linked data from four national healthcare datasets were used to investigate management and outcomes of AMI by estimated glomerular filtration rate (eGFR) category in England. Multivariable logistic and Cox regression models compared management strategies and outcomes by eGFR category among people with kidney impairment hospitalised for AMI between 2015-2017. RESULTS: In a cohort of 5 835 people, we found reduced odds of invasive management in people with eGFR < 60mls/min/1.73m2 compared with people with eGFR ≥ 60 when hospitalised for non-ST segment elevation MI (NSTEMI). The association between eGFR and odds of invasive management for ST-elevation MI (STEMI) varied depending on the availability of percutaneous coronary intervention. A graded association between mortality and eGFR category was demonstrated both in-hospital and after discharge for all people. CONCLUSIONS: In England, patients with reduced eGFR are less likely to receive invasive management compared to those with preserved eGFR. Disparities in care may however be decreasing over time, with the least difference seen in patients with STEMI managed via the primary percutaneous coronary intervention pathway. Reduced eGFR continues to be associated with worse outcomes after AMI.

Comparative Effectiveness of Dynamic Treatment Strategies for Medication Use and Dosage: Emulating a Target Trial Using Observational Data.

BACKGROUND: Availability of detailed data from electronic health records (EHRs) has increased the potential to examine the comparative effectiveness of dynamic treatment strategies using observational data. Inverse probability (IP) weighting of dynamic marginal structural models can control for time-varying confounders. However, IP weights for continuous treatments may be sensitive to model choice. METHODS: We describe a target trial comparing strategies for treating anemia with darbepoetin in hemodialysis patients using EHR data from the UK Renal Registry 2004 to 2016. Patients received a specified dose (microgram/week) or did not receive darbepoetin. We compared 4 methods for modeling time-varying treatment: (A) logistic regression for zero dose, standard linear regression for log dose; (B) logistic regression for zero dose, heteroscedastic linear regression for log dose; (C) logistic regression for zero dose, heteroscedastic linear regression for log dose, multinomial regression for patients who recently received very low or high doses; and (D) ordinal logistic regression. RESULTS: For this dataset, method (C) was the only approach that provided a robust estimate of the mortality hazard ratio (HR), with less-extreme weights in a fully weighted analysis and no substantial change of the HR point estimate after weight truncation. After truncating IP weights at the 95th percentile, estimates were similar across the methods. CONCLUSIONS: EHR data can be used to emulate target trials estimating the comparative effectiveness of dynamic strategies adjusting treatment to evolving patient characteristics. However, model checking, monitoring of large weights, and adaptation of model strategies to account for these is essential if an aspect of treatment is continuous.

Factors related to adverse long-term outcomes after mild traumatic brain injury in children: a scoping review.

OBJECTIVE: To identify demographic, premorbid and injury-related factors, or biomarkers associated with long-term (≥3 months) adverse outcomes in children after mild traumatic brain injury (mTBI). DESIGN: Scoping review of literature. PATIENTS: Children and adolescents with mTBI. RISK FACTORS: Any demographic, premorbid and injury-related factors, or biomarkers were included. We excluded genetic and treatment-related factors. MAIN OUTCOME MEASURES: Postconcussion syndrome (PCS), recovery. RESULTS: Seventy-three publications were included, reporting 12 long-term adverse outcomes, including PCS in 12 studies and recovery in 29 studies. Additional outcomes studied were symptom scores/severity (n=22), quality of life (n=9) and cognitive function (n=9). Forty-nine risk factors were identified across studies. Risk factors most often assessed were sex (n=28), followed by age (n=23), injury mechanism = (n=22) and prior mTBI (n=18). The influence of these and other risk factors on outcomes of mTBI were inconsistent across the reviewed literature. CONCLUSIONS: The most researched risk factors are sex, age and mechanism of injury, but their effects have been estimated inconsistently and did not show a clear pattern. The most studied outcomes are recovery patterns and symptom severity. However, these may not be the most important outcomes for clinicians and patients. Future primary studies in this area should focus on patient-important outcomes. Population-based prospective studies are needed that address prespecified hypotheses on the relationship of risk factors with given outcomes to enable reliable prediction of long-term adverse outcomes for childhood mTBI.

Preventing male suicide through a psychosocial intervention that provides psychological support and tackles financial difficulties: a mixed method evaluation.

BACKGROUND: To help resolve high suicide rates in Bristol, North Somerset and South Gloucestershire, the charity Second Step was commissioned to roll-out the Hope service offering a psychosocial intervention for men, supporting them through acute distress and addressing financial difficulties. This study evaluated the impact of the Hope service on men at risk of suicide experiencing financial and other difficulties. METHODS: Mixed methods study using: (i) a prospective cohort study design to compare depression, suicidal ideation and financial self-efficacy scores of men aged 30-64, referred to the service between October 2018 and July 2020, at baseline and 6 months follow-up and between low and moderate to high-intensity service users; and (ii) a qualitative interview study to evaluate the acceptability and impact of the Hope service to Hope service users. RESULTS: There was a 49% reduction in depression score (mean reduction - 10.0, 95% CI - 11.7 to - 8.3) and in the proportion of service users with suicidal ideation (percent reduction - 52.5, 95% CI - 64.1% to - 40.9%) at 6 months follow-up compared to baseline. Financial self-efficacy scores increased by 26% (mean increase 2.9, 95% CI 1.8 to 3.9). Qualitative accounts illustrated how 'Hope saved my life' for several men interviewed; most respondents described being able to move forward and tackle challenges with more confidence following the Hope intervention. Professional advice to tackle financial and other difficulties such as housing helped to relieve anxiety and stress and enable practical issues to be resolved. CONCLUSIONS: The Hope service offered practical and emotional support to men who have experienced suicidal feelings, redundancy, homelessness and poverty and occupies an important space between mental health and social care provision. Hope demonstrates the value of an intervention which cuts across traditional boundaries between psychiatric care and social advice agencies to provide, what is, in effect, an integrated care service.

Multiple imputation strategies for a bounded outcome variable in a competing risks analysis.

In patient follow-up studies, events of interest may take place between periodic clinical assessments and so the exact time of onset is not observed. Such events are known as "bounded" or "interval-censored." Methods for handling such events can be categorized as either (i) applying multiple imputation (MI) strategies or (ii) taking a full likelihood-based (LB) approach. We focused on MI strategies, rather than LB methods, because of their flexibility. We evaluated MI strategies for bounded event times in a competing risks analysis, examining the extent to which interval boundaries, features of the data distribution and substantive analysis model are accounted for in the imputation model. Candidate imputation models were predictive mean matching (PMM); log-normal regression with postimputation back-transformation; normal regression with and without restrictions on the imputed values and Delord and Genin's method based on sampling from the cumulative incidence function. We used a simulation study to compare MI methods and one LB method when data were missing at random and missing not at random, also varying the proportion of missing data, and then applied the methods to a hematopoietic stem cell transplantation dataset. We found that cumulative incidence and median event time estimation were sensitive to model misspecification. In a competing risks analysis, we found that it is more important to account for features of the data distribution than to restrict imputed values based on interval boundaries or to ensure compatibility with the substantive analysis by sampling from the cumulative incidence function. We recommend MI by type 1 PMM.

Cinacalcet use and the risk of cardiovascular events, fractures and mortality in chronic kidney disease patients with secondary hyperparathyroidism.

With the aim to expand the randomized controlled trial evidence of cinacalcet treatment to the unselected, general chronic kidney disease (CKD) population we analysed a large inception cohort of CKD patients in the region of Stockholm, Sweden 2006-2012 (both non-dialysis, dialysis and transplanted) with evidence of secondary hyperparathyroidism (SHPT). We used marginal structural models to account for both confounding by indication and time-dependent confounding. Over 37 months, 435/3,526 (12%) initiated cinacalcet de novo. Before cinacalcet initiation, parathyroid hormone (PTH) had increased progressively to a median of 636ng/L. After cinacalcet initiation, PTH declined, as did serum calcium and phosphate. In total, 42% of patients experienced a fatal/non-fatal cardiovascular event, 32% died and 9% had a new fracture. The unadjusted cardiovascular odds ratio (OR) associated with cinacalcet treatment was 1.01 (95% confidence interval: 0.83, 1.22). In the fully weighted model, the cardiovascular odds was lower in cinacalcet treated patients (OR 0.67: 0.48, 0.93). The adjusted ORs for all-cause mortality and for fractures were 0.79 (0.56, 1.11) and 1.08 (0.59, 1.98) respectively. Our study suggests cinacalcet treatment improves biochemical abnormalities in the wider CKD population, and adds real-world support that treating SHPT with cinacalcet may have beneficial effects on cardiovascular outcomes.

Accuracy of cystatin C for the detection of abnormal renal function in children undergoing chemotherapy for malignancy: a systematic review using individual patient data.

PURPOSE: We conducted a systematic review and individual patient data (IPD) meta-analysis to examine the utility of cystatin C for evaluation of glomerular function in children with cancer. METHODS: Eligible studies evaluated the accuracy of cystatin C for detecting poor renal function in children undergoing chemotherapy. Study quality was assessed using QUADAS-2. Authors of four studies shared IPD. We calculated the correlation between log cystatin C and GFR stratified by study and measure of cystatin C. We dichotomized the reference standard at GFR 80 ml/min/1.73m2 and stratified cystatin C at 1 mg/l, to calculate sensitivity and specificity in each study and according to age group (0-4, 5-12, and ≥ 13 years). In sensitivity analyses, we investigated different GFR and cystatin C cut points. We used logistic regression to estimate the association of impaired renal function with log cystatin C and quantified diagnostic accuracy using the area under the ROC curve (AUC). RESULTS: Six studies, which used different test and reference standard thresholds, suggested that cystatin C has the potential to monitor renal function in children undergoing chemotherapy for malignancy. IPD data (504 samples, 209 children) showed that cystatin C has poor sensitivity (63%) and moderate specificity (89%), although use of a GFR cut point of < 60 ml/min/1.73m2 (data only available from two of the studies) estimated sensitivity to be 92% and specificity 81.3%. The AUC for the combined data set was 0.890 (95% CI 0.826, 0.951). Diagnostic accuracy appeared to decrease with age. CONCLUSIONS: Cystatin C has better diagnostic accuracy than creatinine as a test for glomerular dysfunction in young people undergoing treatment for cancer. Diagnostic accuracy is not sufficient for it to replace current reference standards for predicting clinically relevant impairments that may alter dosing of important nephrotoxic agents.

The Diagnosis of Urinary Tract Infection in Young Children (DUTY) Study Clinical Rule: Economic Evaluation.

OBJECTIVE: To estimate the cost-effectiveness of a two-step clinical rule using symptoms, signs and dipstick testing to guide the diagnosis and antibiotic treatment of urinary tract infection (UTI) in acutely unwell young children presenting to primary care. METHODS: Decision analytic model synthesising data from a multicentre, prospective cohort study (DUTY) and the wider literature to estimate the short-term and lifetime costs and healthcare outcomes (symptomatic days, recurrent UTI, quality adjusted life years) of eight diagnostic strategies. We compared GP clinical judgement with three strategies based on a 'coefficient score' combining seven symptoms and signs independently associated with UTI and four strategies based on weighted scores according to the presence/absence of five symptoms and signs. We compared dipstick testing versus laboratory culture in children at intermediate risk of UTI. RESULTS: Sampling, culture and antibiotic costs were lowest in high-specificity DUTY strategies (£1.22 and £1.08) compared to clinical judgement (£1.99). These strategies also approximately halved urine sampling (4.8% versus 9.1% in clinical judgement) without reducing sensitivity (58.2% versus 56.4%). Outcomes were very similar across all diagnostic strategies. High-specificity DUTY strategies were more cost-effective than clinical judgement in the short- (iNMB = £0.78 and £0.84) and long-term (iNMB =£2.31 and £2.50). Dipstick tests had poorer cost-effectiveness than laboratory culture in children at intermediate risk of UTI (iNMB = £-1.41). CONCLUSIONS: Compared to GPs' clinical judgement, high specificity clinical rules from the DUTY study could substantially reduce urine sampling, achieving lower costs and equivalent patient outcomes. Dipstick testing children for UTI is not cost-effective.

Comparison of microbiological diagnosis of urinary tract infection in young children by routine health service laboratories and a research laboratory: Diagnostic cohort study.

OBJECTIVES: To compare the validity of diagnosis of urinary tract infection (UTI) through urine culture between samples processed in routine health service laboratories and those processed in a research laboratory. POPULATION AND METHODS: We conducted a prospective diagnostic cohort study in 4808 acutely ill children aged <5 years attending UK primary health care. UTI, defined as pure/predominant growth ≥105 CFU/mL of a uropathogen (the reference standard), was diagnosed at routine health service laboratories and a central research laboratory by culture of urine samples. We calculated areas under the receiver-operator curve (AUC) for UTI predicted by pre-specified symptoms, signs and dipstick test results (the "index test"), separately according to whether samples were obtained by clean catch or nappy (diaper) pads. RESULTS: 251 (5.2%) and 88 (1.8%) children were classified as UTI positive by health service and research laboratories respectively. Agreement between laboratories was moderate (kappa = 0.36; 95% confidence interval [CI] 0.29, 0.43), and better for clean catch (0.54; 0.45, 0.63) than nappy pad samples (0.20; 0.12, 0.28). In clean catch samples, the AUC was lower for health service laboratories (AUC = 0.75; 95% CI 0.69, 0.80) than the research laboratory (0.86; 0.79, 0.92). Values of AUC were lower in nappy pad samples (0.65 [0.61, 0.70] and 0.79 [0.70, 0.88] for health service and research laboratory positivity, respectively) than clean catch samples. CONCLUSIONS: The agreement of microbiological diagnosis of UTI comparing routine health service laboratories with a research laboratory was moderate for clean catch samples and poor for nappy pad samples and reliability is lower for nappy pad than for clean catch samples. Positive results from the research laboratory appear more likely to reflect real UTIs than those from routine health service laboratories, many of which (particularly from nappy pad samples) could be due to contamination. Health service laboratories should consider adopting procedures used in the research laboratory for paediatric urine samples. Primary care clinicians should try to obtain clean catch samples, even in very young children.

Erythropoiesis-stimulating agent dosing, haemoglobin and ferritin levels in UK haemodialysis patients 2005-13.

Background: Erythropoiesis-stimulating agents (ESAs) with intravenous iron supplementation are the main treatment for anaemia in patients with chronic kidney disease. Although observational studies suggest better outcomes for patients who achieve higher haemoglobin (Hb) levels, randomized controlled trials comparing higher and lower Hb targets have led to safety concerns over higher targets and to changes in treatment guidelines. Methods: Quarterly data from 2005 to 2013 were obtained on 28 936 haemodialysis patients from the UK Renal Registry. We examined trends in ESA use and average dose, Hb and ferritin values over time and Hb according to the UK Renal Association guideline range. Results: The average ESA dose declined over time, with sharper decreases of epoetin seen towards the end of 2006 and from 2009. Average Hb for patients on ESAs was 114.1 g/L [95% confidence interval (CI) 113.7, 114.6] in the first quarter of 2005, which decreased to 109.6 g/L (95% CI 109.3, 109.9) by the end of 2013. Average serum ferritin was 353 µg/L (95% CI 345, 360) at the start of 2005, increasing to 386 µg/L (95% CI 380, 392) in the final quarter of 2013. The percentage of patients with Hb in the range of 100-120 g/L increased from 46.1 at the start of 2005 to 57.6 at the end of 2013. Conclusions: Anaemia management patterns for haemodialysis patients changed in the UK between 2005 and 2013. These patterns most likely reflect clinician response to emerging trial evidence and practice guidelines. Registries play an important role in continued observation of anaemia management and will monitor further changes as new evidence on optimal care emerges.

Improving the Diagnosis and Treatment of Urinary Tract Infection in Young Children in Primary Care: Results from the DUTY Prospective Diagnostic Cohort Study.

PURPOSE: Up to 50% of urinary tract infections (UTIs) in young children are missed in primary care. Urine culture is essential for diagnosis, but urine collection is often difficult. Our aim was to derive and internally validate a 2-step clinical rule using (1) symptoms and signs to select children for urine collection; and (2) symptoms, signs, and dipstick testing to guide antibiotic treatment. METHODS: We recruited acutely unwell children aged under 5 years from 233 primary care sites across England and Wales. Index tests were parent-reported symptoms, clinician-reported signs, urine dipstick results, and clinician opinion of UTI likelihood (clinical diagnosis before dipstick and culture). The reference standard was microbiologically confirmed UTI cultured from a clean-catch urine sample. We calculated sensitivity, specificity, and area under the receiver operator characteristic (AUROC) curve of coefficient-based (graded severity) and points-based (dichotomized) symptom/sign logistic regression models, and we then internally validated the AUROC using bootstrapping. RESULTS: Three thousand thirty-six children provided urine samples, and culture results were available for 2,740 (90%). Of these results, 60 (2.2%) were positive: the clinical diagnosis was 46.6% sensitive, with an AUROC of 0.77. Previous UTI, increasing pain/crying on passing urine, increasingly smelly urine, absence of severe cough, increasing clinician impression of severe illness, abdominal tenderness on examination, and normal findings on ear examination were associated with UTI. The validated coefficient- and points-based model AUROCs were 0.87 and 0.86, respectively, increasing to 0.90 and 0.90, respectively, by adding dipstick nitrites, leukocytes, and blood. CONCLUSIONS: A clinical rule based on symptoms and signs is superior to clinician diagnosis and performs well for identifying young children for noninvasive urine sampling. Dipstick results add further diagnostic value for empiric antibiotic treatment.

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness.

BACKGROUND: It is not clear which young children presenting acutely unwell to primary care should be investigated for urinary tract infection (UTI) and whether or not dipstick testing should be used to inform antibiotic treatment. OBJECTIVES: To develop algorithms to accurately identify pre-school children in whom urine should be obtained; assess whether or not dipstick urinalysis provides additional diagnostic information; and model algorithm cost-effectiveness. DESIGN: Multicentre, prospective diagnostic cohort study. SETTING AND PARTICIPANTS: Children < 5 years old presenting to primary care with an acute illness and/or new urinary symptoms. METHODS: One hundred and seven clinical characteristics (index tests) were recorded from the child's past medical history, symptoms, physical examination signs and urine dipstick test. Prior to dipstick results clinician opinion of UTI likelihood ('clinical diagnosis') and urine sampling and treatment intentions ('clinical judgement') were recorded. All index tests were measured blind to the reference standard, defined as a pure or predominant uropathogen cultured at ≥ 10(5) colony-forming units (CFU)/ml in a single research laboratory. Urine was collected by clean catch (preferred) or nappy pad. Index tests were sequentially evaluated in two groups, stratified by urine collection method: parent-reported symptoms with clinician-reported signs, and urine dipstick results. Diagnostic accuracy was quantified using area under receiver operating characteristic curve (AUROC) with 95% confidence interval (CI) and bootstrap-validated AUROC, and compared with the 'clinician diagnosis' AUROC. Decision-analytic models were used to identify optimal urine sampling strategy compared with 'clinical judgement'. RESULTS: A total of 7163 children were recruited, of whom 50% were female and 49% were < 2 years old. Culture results were available for 5017 (70%); 2740 children provided clean-catch samples, 94% of whom were ≥ 2 years old, with 2.2% meeting the UTI definition. Among these, 'clinical diagnosis' correctly identified 46.6% of positive cultures, with 94.7% specificity and an AUROC of 0.77 (95% CI 0.71 to 0.83). Four symptoms, three signs and three dipstick results were independently associated with UTI with an AUROC (95% CI; bootstrap-validated AUROC) of 0.89 (0.85 to 0.95; validated 0.88) for symptoms and signs, increasing to 0.93 (0.90 to 0.97; validated 0.90) with dipstick results. Nappy pad samples were provided from the other 2277 children, of whom 82% were < 2 years old and 1.3% met the UTI definition. 'Clinical diagnosis' correctly identified 13.3% positive cultures, with 98.5% specificity and an AUROC of 0.63 (95% CI 0.53 to 0.72). Four symptoms and two dipstick results were independently associated with UTI, with an AUROC of 0.81 (0.72 to 0.90; validated 0.78) for symptoms, increasing to 0.87 (0.80 to 0.94; validated 0.82) with the dipstick findings. A high specificity threshold for the clean-catch model was more accurate and less costly than, and as effective as, clinical judgement. The additional diagnostic utility of dipstick testing was offset by its costs. The cost-effectiveness of the nappy pad model was not clear-cut. CONCLUSIONS: Clinicians should prioritise the use of clean-catch sampling as symptoms and signs can cost-effectively improve the identification of UTI in young children where clean catch is possible. Dipstick testing can improve targeting of antibiotic treatment, but at a higher cost than waiting for a laboratory result. Future research is needed to distinguish pathogens from contaminants, assess the impact of the clean-catch algorithm on patient outcomes, and the cost-effectiveness of presumptive versus dipstick versus laboratory-guided antibiotic treatment. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Nappy pad urine samples for investigation and treatment of UTI in young children: the 'DUTY' prospective diagnostic cohort study.

BACKGROUND: The added diagnostic utility of nappy pad urine samples and the proportion that are contaminated is unknown. AIM: To develop a clinical prediction rule for the diagnosis of urinary tract infection (UTI) based on sampling using the nappy pad method. DESIGN AND SETTING: Acutely unwell children <5 years presenting to 233 UK primary care sites. METHOD: Logistic regression to identify independent associations of symptoms, signs, and urine dipstick test results with UTI; diagnostic utility quantified as area under the receiver operator curves (AUROC). Nappy pad rule characteristics, AUROC, and contamination, compared with findings from clean-catch samples. RESULTS: Nappy pad samples were obtained from 3205 children (82% aged <2 years; 48% female), culture results were available for 2277 (71.0%) and 30 (1.3%) had a UTI on culture. Female sex, smelly urine, darker urine, and the absence of nappy rash were independently associated with a UTI, with an internally-validated, coefficient model AUROC of 0.81 (0.87 for clean-catch), which increased to 0.87 (0.90 for clean-catch) with the addition of dipstick results. GPs' 'working diagnosis' had an AUROC 0.63 (95% confidence intervals [CI] = 0.53 to 0.72). A total of 12.2% of nappy pad and 1.8% of clean-catch samples were 'frankly contaminated' (risk ratio 6.66; 95% CI = 4.95 to 8.96; P<0.001). CONCLUSION: Nappy pad urine culture results, with features that can be reported by parents and dipstick tests, can be clinically useful, but are less accurate and more often contaminated compared with clean-catch urine culture.

An evaluation of a multi-component adult weight management on referral intervention in a community setting.

BACKGROUND: National Institute for Health and Care Excellence (NICE) guidance on adult weight management recommends interventions are multi-component. We aimed to assess the implementation and health benefits of a primary care referral to an adult multi-component weight management intervention in a community setting. The intervention was offered through Primary care in National Health Service (NHS) South Gloucestershire, UK, from Oct 2008 to Nov 2010, in partnership with statutory, community and commercial providers. The scheme offered 12 weeks' community based concurrent support of dietary (Weight Watchers, WW), physical activity (Exercise on Prescription, EOP) and behavioural change (motivational interviewing) components to obese adults. Funding was available for 600 places. RESULTS: Five hundred and fifty nine participants engaged with the intervention, mean age 48 years, 88% female. Mean weight loss for all engagers was 3.7 kg (95 % confidence interval 3.4, 4.1). Participants completing the intervention achieved the largest weight reduction (mean loss 5.9 kg; 5.3, 6.6). Achievement of 5% weight loss was higher in completers (58%; 50, 65) compared to non-completers (19%; 12, 26) and people who only participated in one commercial component of the intervention (either WW or EOP; 19%; 13, 24). CONCLUSION: A multi-component weight management programme may be beneficial for weight loss, but a randomized controlled trial is needed to establish effectiveness and to evaluate cost.

Injection Drug Use and Hepatitis C as Risk Factors for Mortality in HIV-Infected Individuals: The Antiretroviral Therapy Cohort Collaboration.

BACKGROUND: HIV-infected individuals with a history of transmission through injection drug use (IDU) have poorer survival than other risk groups. The extent to which higher rates of hepatitis C (HCV) infection in IDU explain survival differences is unclear. METHODS: Adults who started antiretroviral therapy between 2000 and 2009 in 16 European and North American cohorts with >70% complete data on HCV status were followed for 3 years. We estimated unadjusted and adjusted (for age, sex, baseline CD4 count and HIV-1 RNA, AIDS diagnosis before antiretroviral therapy, and stratified by cohort) mortality hazard ratios for IDU (versus non-IDU) and for HCV-infected (versus HCV uninfected). RESULTS: Of 32,703 patients, 3374 (10%) were IDU; 4630 (14%) were HCV+; 1116 (3.4%) died. Mortality was higher in IDU compared with non-IDU [adjusted HR 2.71; 95% confidence interval (CI): 2.32 to 3.16] and in HCV+ compared with HCV- (adjusted HR 2.65; 95% CI: 2.31 to 3.04). The effect of IDU was substantially attenuated (adjusted HR 1.57; 95% CI: 1.27 to 1.94) after adjustment for HCV, while attenuation of the effect of HCV was less substantial (adjusted HR 2.04; 95% CI: 1.68 to 2.47) after adjustment for IDU. Both IDU and HCV were strongly associated with liver-related mortality (adjusted HR 10.89; 95% CI: 6.47 to 18.3 for IDU and adjusted HR 14.0; 95% CI: 8.05 to 24.5 for HCV) with greater attenuation of the effect of IDU (adjusted HR 2.43; 95% CI: 1.24 to 4.78) than for HCV (adjusted HR 7.97; 95% CI: 3.83 to 16.6). Rates of CNS, respiratory and violent deaths remained elevated in IDU after adjustment for HCV. CONCLUSIONS: A substantial proportion of the excess mortality in HIV-infected IDU is explained by HCV coinfection. These findings underscore the potential impact on mortality of new treatments for HCV in HIV-infected people.

Predictive models for kidney disease: improving global outcomes (KDIGO) defined acute kidney injury in UK cardiac surgery.

INTRODUCTION: Acute kidney injury (AKI) risk prediction scores are an objective and transparent means to enable cohort enrichment in clinical trials or to risk stratify patients preoperatively. Existing scores are limited in that they have been designed to predict only severe, or non-consensus AKI definitions and not less severe stages of AKI, which also have prognostic significance. The aim of this study was to develop and validate novel risk scores that could identify all patients at risk of AKI. METHODS: Prospective routinely collected clinical data (n = 30,854) were obtained from 3 UK cardiac surgical centres (Bristol, Birmingham and Wolverhampton). AKI was defined as per the Kidney Disease: Improving Global Outcomes (KDIGO) Guidelines. The model was developed using the Bristol and Birmingham datasets, and externally validated using the Wolverhampton data. Model discrimination was estimated using the area under the ROC curve (AUC). Model calibration was assessed using the Hosmer-Lemeshow test and calibration plots. Diagnostic utility was also compared to existing scores. RESULTS: The risk prediction score for any stage AKI (AUC = 0.74 (95% confidence intervals (CI) 0.72, 0.76)) demonstrated better discrimination compared to the Euroscore and the Cleveland Clinic Score, and equivalent discrimination to the Mehta and Ng scores. The any stage AKI score demonstrated better calibration than the four comparison scores. A stage 3 AKI risk prediction score also demonstrated good discrimination (AUC = 0.78 (95% CI 0.75, 0.80)) as did the four comparison risk scores, but stage 3 AKI scores were less well calibrated. CONCLUSIONS: This is the first risk score that accurately identifies patients at risk of any stage AKI. This score will be useful in the perioperative management of high risk patients as well as in clinical trial design.

Childhood milk consumption is associated with better physical performance in old age.

BACKGROUND: studies have shown that milk and dairy consumption in adulthood have beneficial effects on health. METHODS: we examined the impact of childhood and adult diet on physical performance at age 63-86 years. The Boyd Orr cohort (n = 405) is a 65-year prospective study of children who took part in a 1930's survey; the Caerphilly Prospective Study (CaPS; n = 1,195) provides data from mid-life to old age. We hypothesised that higher intakes of childhood and adult milk, calcium, protein, fat and energy would be associated with a better performance. RESULTS: in fully adjusted models, a standard deviation (SD) increase in natural log-transformed childhood milk intake was associated with 5% faster walking times from the get-up and go test in Boyd Orr (95% CI: 1 to 9) and 25% lower odds of poor balance (OR: 0.75; 0.55 to 1.02). Childhood calcium intake was positively associated with walking times (4% faster per SD; 0 to 8) and a higher protein intake was associated with lower odds of poor balance (OR: 0.71; 0.54 to 0.92). In adulthood, protein intake was positively associated with walking times (2% faster per SD; 1 to 3; Boyd Orr and CaPS pooled data). CONCLUSION: this is the first study to show positive associations of childhood milk intake with physical performance in old age.

Associations of insulin and insulin-like growth factors with physical performance in old age in the Boyd Orr and Caerphilly studies.

OBJECTIVE: Insulin and the insulin-like growth factor (IGF) system regulate growth and are involved in determining muscle mass, strength and body composition. We hypothesised that IGF-I and IGF-II are associated with improved, and insulin with worse, physical performance in old age. METHODS: Physical performance was measured using the get-up and go timed walk and flamingo balance test at 63-86 years. We examined prospective associations of insulin, IGF-I, IGF-II and IGFBP-3 with physical performance in the UK-based Caerphilly Prospective Study (CaPS; n = 739 men); and cross-sectional insulin, IGF-I, IGF-II, IGFBP-2 and IGFBP-3 in the Boyd Orr cohort (n = 182 men, 223 women). RESULTS: In confounder-adjusted models, there was some evidence in CaPS that a standard deviation (SD) increase in IGF-I was associated with 1.5% faster get-up and go test times (95% CI: -0.2%, 3.2%; p = 0.08), but little association with poor balance, 19 years later. Coefficients in Boyd Orr were in the same direction as CaPS, but consistent with chance. Higher levels of insulin were weakly associated with worse physical performance (CaPS and Boyd Orr combined: get-up and go time = 1.3% slower per SD log-transformed insulin; 95% CI: 0.0%, 2.7%; p = 0.07; OR poor balance 1.13; 95% CI; 0.98, 1.29; p = 0.08), although associations were attenuated after controlling for body mass index (BMI) and co-morbidities. In Boyd Orr, a one SD increase in IGFBP-2 was associated with 2.6% slower get-up and go times (95% CI: 0.4%, 4.8% slower; p = 0.02), but this was only seen when controlling for BMI and co-morbidities. There was no consistent evidence of associations of IGF-II, or IGFBP-3 with physical performance. CONCLUSIONS: There was some evidence that high IGF-I and low insulin levels in middle-age were associated with improved physical performance in old age, but estimates were imprecise. Larger cohorts are required to confirm or refute the findings.