Survival after liver transplantation in the United Kingdom and Ireland compared with the United States

<b>Background and Aim</b>: Surgical mortality in the US is widely perceived to be superior to that in the UK. However, previous comparisons of surgical outcome in the two countries have often failed to take sufficient account of case-mix or examine long-term outcome. The standardised nature of liver transplantation practice makes it uniquely placed for undertaking reliable international comparisons of surgical outcome. The objective of this study is to undertake a risk-adjusted disease-specific comparison of both short- and long-term survival of liver transplant recipients in the UK and Ireland with that in the US. <b>Design, setting and participants</b>: Multi-centre cohort study using two high quality national databases including all adults who underwent a first single organ liver transplant in the UK and Ireland (n=5,925) and the US (n=41,866) between March 1994 and March 2005. <b>Main outcome measures</b>: Post-transplant mortality during the first 90 days, 90 days-1 year and beyond the first year, adjusted for donor and recipient characteristics. <b>Results</b>: Risk-adjusted mortality in the UK and Ireland was generally higher than in the US during the first 90 days (hazard ratio 1.17 95%CI 1.07-1.29), both for patients transplanted for acute liver failure (hazard ratio 1.27 95%CI 1.01-1.60) as well as those transplanted for chronic liver disease (hazard ratio 1.18 95% CI 1.07- 1.31). Between 90 days and 1 year post-transplantation, no statistically significant differences in overall risk- adjusted mortality were noted between the two cohorts. Survivors of the first post-transplant year in the UK and Ireland had lower overall risk-adjusted mortality than those transplanted in the US (hazard ratio 0.88 95% CI 0.81- 0.96). This difference was observed among patients transplanted for chronic liver disease (hazard ratio 0.88 95%CI 0.81-0.96) but not those transplanted for acute liver failure (hazard ratio 1.02 95%CI 0.70- 1.50). <b>Conclusions</b>: Whilst risk adjusted mortality is higher in the UK and Ireland during the first 90 days following liver transplantation, it is higher in the US among those liver transplant recipients who survived the first post- transplant year. Our results are consistent with the notion that the US has superior acute peri-operative care whereas the UK appears to provide better quality chronic care following liver transplantation surgery

Aldosterone status associates with insulin resistance in patients with heart failure-data from the ALOFT study

<b>Background</b>: Aldosterone plays a key role in the pathophysiology of heart failure. In around 50% of such patients, aldosterone 'escapes' from inhibition by drugs that interrupt the renin-angiotensin axis; such patients have a worse clinical outcome. Insulin resistance is a risk factor in heart failure and cardiovascular disease. The relationship between aldosterone status and insulin sensitivity was investigated in a cohort of heart failure patients. <b>Methods</b>: 302 patients with New York Heart Association (NYHA) class II-IV heart failure on conventional therapy were randomized in ALiskiren Observation of heart Failure Treatment study (ALOFT), designed to test the safety of a directly acting renin inhibitor. Plasma aldosterone and 24-hour urinary aldosterone excretion as well as fasting insulin and Homeostasis model assessment of insulin resistance (HOMA-IR) were measured. Subjects with aldosterone escape and high urinary aldosterone were identified according to previously accepted definitions. <b>Results</b>: Twenty per-cent of subjects demonstrated aldosterone escape and 34% had high urinary aldosterone levels. At baseline, there was a positive correlation between fasting insulin and plasma(r=0.22 p<0.01) and urinary aldosterone(r=0.19 p<0.03). Aldosterone escape and high urinary aldosterone subjects both demonstrated higher levels of fasting insulin (p<0.008, p<0.03), HOMA-IR (p<0.06, p<0.03) and insulin-glucose ratios (p<0.006, p<0.06) when compared to low aldosterone counterparts. All associations remained significant when adjusted for potential confounders. <b>Conclusions</b>: This study demonstrates a novel direct relationship between aldosterone status and insulin resistance in heart failure. This observation merits further study and may identify an additional mechanism that contributes to the adverse clinical outcome associated with aldosterone escape

Sex differences in incidence, mortality, and survival in individuals with stroke in Scotland, 1986 to 2005

<p><b>Background and Purpose:</b> The aim of this study was to examine the effect of sex across different age groups and over time for stroke incidence, 30-day case-fatality, and mortality.</p> <p><b>Methods:</b> All first hospitalizations for stroke in Scotland (1986 to 2005) were identified using linked morbidity and mortality data. Age-specific rate ratios (RRs) for comparing women with men for both incidence and mortality were modeled with adjustment for study year and socioeconomic deprivation. Logistic regression was used to model 30-day case-fatality.</p> <p><b>Results:</b> Women had a lower incidence of first hospitalization than men and size of effect varied with age (55 to 64 years, RR=0.65, 95% CI 0.63 to 0.66; 85 years, RR=0.94, 95% CI 0.91 to 0.96). Women aged 55 to 84 years had lower mortality than men and again size of effect varied with age (65 to 74 years, RR=0.79, 95% CI 0.76 to 0.81); 75 to 84 years, RR=0.94, 95% CI 0.92 to 0.95). Conversely, women aged 85 years had 15% higher stroke mortality than men (RR=1.15, 95% CI 1.12 to 1.18). Adjusted risk of death within 30 days was significantly higher in women than men, and this difference increased over the 20-year period in all age groups (adjusted OR in 55 to 64 year olds 1.23, 95% CI 1.14 to 1.33 in 1986 and 1.51, 95% CI 1.39 to 1.63 in 2005).</p> <p><b>Conclusions:</b> We observed lower rates of incidence and mortality in younger women than men. However, higher numbers of older women in the population mean that the absolute burden of stroke is greater in women. Short-term case-fatality is greater in women of all ages and, worryingly, these differences have increased from 1986 to 2005.</p&gt

Hypothesis testing in unbalanced experimental designs

SIGLEAvailable from British Library Document Supply Centre-DSC:DX209197 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Impact of NICE guidance on rates of haemorrhage after tonsillectomy: an evaluation of guidance issued during an ongoing national tonsillectomy audit

Background: The National Institute for Health and Clinical Excellence (NICE) issued guidance on surgical techniques for tonsillectomy during a national audit of surgical practice and postoperative complications. Objective: To assess the impact of the guidance on tonsillectomy practice and outcomes. Design: An interrupted time-series analysis of routinely collected Hospital Episodes Statistics data, and an analysis of longitudinal trends in surgical technique using data from the National Prospective Tonsillectomy Audit. Participants: Patients undergoing tonsillectomy in English NHS hospitals between January 2002 and December 2004. Main outcome measure: Postoperative haemorrhage within 28 days. Results: The rate of haemorrhage increased by 0.5% per year from 2002, reaching 6.4% when the guidance was published. After publication, the rate of haemorrhage fell immediately to 5.7% (difference 0.7%: 95% CI −1.3% to 0.0%) and the rate of increase appeared to have stopped. Data from the National Prospective Tonsillectomy Audit showed that the fall coincided with a shift in surgical techniques, which was consistent with the guidance. Conclusion: NICE guidance influenced surgical tonsillectomy technique and in turn produced an immediate fall in postoperative haemorrhage. The ongoing national audit and strong support from the surgical specialist association may have aided its implementation

A study of simple unbalanced factorial designs that use type ii and type iii sums of squares

Methods for analysing unbalanced factorial designs can be traced back to the work of Frank Yates in the 1930s . Yet, still today the question on how his methods of fitting constants (Type II) and weighted squares of means (Type III) behave when negligible or insignificant interactions exist, is still unanswered. In this paper, by means of a simulation study, Type II and Type III ANOVA results are examined for all unbalanced structures originating from a 2x3 balanced factorial design within homogeneous groups (design types) accounting for structure, number of observations lost and which cells contained the missing observations. The two level factor is further analysed to test the null hypothesis, for both Type II and Type III analyses, that the unbalanced structures within each design type provide comparable F values. These results are summarised and the conclusion shows that this work agrees with statements made by Yates Burdick and Herr and Shaw and Mitchell-Olds, but there are some results which require further investigation

A study of type ii and type iii power for testing hypotheses from unbalanced factorial designs

Methods for analysing unbalanced factorial designs are well documented when there is at least one observation for all treatment combinations. The Type II and Type III methods, as they have become known, are the methods of choice for hypothesis testing purposes, but there is no consensus about which is more suitable. The aim of this paper is to assess how the deterioration of the balanced structure in a given designinfluences Type II and Type III power, both when negligible/ insignificant interactions and no interactions exist. A simulation study was set up using 726 unbalanced designs which stem from a 23 factorial design with three replicates per cell. The sampling scheme was chosen so that the interaction effect was negligible and associated with low power. A separate study investigated a 20% random sample of the unbalanced designs identified above, but fixing the interaction effect to be zero. The results from the simulation study showed that, regardless of how many observations were lost from the balanced design, the median Type II power was greater and the inter-quartile range of Type II power wider than the corresponding values for Type III power. This is an important message for practitioners, namely that the Type II method is, on average, more powerful than the Type III method but is also more influenced by cell patterning than the Type III method. There was also some evidence to suggest that up to a certain point, which is particular to the factorial design set-up, as more observations are lost the Type II method will be increasingly more powerful than the Type III method

Comparing outcomes of percutaneous transluminal coronary angioplasty with coronary artery bypass grafting: can routine health service data complement and enhance randomised controlled trials?

Aim To compare outcomes of percutaneous transluminal coronary angioplasty (PTCA) with coronary artery bypass graft surgery (CABG) for a population stemming from routinely collected data, in order to assess the merits of such data sources as a complement, and possible enhancement, to randomized controlled trial results.<p></p> Methods and Results A population of Scottish patients were taken from a routine discharge summary and from this data source patients comparable to those from randomized controlled trial settings were identified. Between 1989 and 1995, 12238 pseudo randomized controlled trial patients were identified from the routine data set, of which 3714 (30·3%) received PTCA and 8524 (69·7%) received CABG. The baseline characteristics of the pseudo randomized controlled trial and randomized controlled trial patients were similar. The evidence from both the randomized controlled trials and routine data indicate that for 1 year follow-up the risk of cardiac death and/or non-fatal myocardial infarction is not significantly different between the two treatment groups.<p></p> Conclusion The outcomes expected of PTCA and CABG following trial evidence have been realized in the routine data which are representative of a complete, non-selective population. Due to the size of the routine data set it would be possible to set up hypotheses for potential subgroup effects at the outset.<p></p&gt

Using routine data to complement and enhance the results of randomised controlled trials

No abstract available

Mathematical coupling may account for the association between baseline severity and minimally important difference values

Objective: To generate anchor-based values for the “minimally important difference” (MID) for a number of commonly used patient-reported outcome (PRO) measures and to examine whether these values could be applied across the continuum of preoperative patient severity. Study Design and Setting: Six prospective cohort studies of patients undergoing elective surgery at hospitals in England and Wales. Patients completed questionnaires about their health and health-related quality of life before and after surgery. MID values were calculated using the mean change score for a reference group of patients who reported they were “a little better” after surgery minus the mean change score for those who said they were “about the same.” Pearson's correlation was used to examine the association between baseline severity and change scores in the reference group. Baseline severity was expressed in two ways: first in terms of preoperative scores and second in terms of the average of pre- and postoperative scores (Oldham's method). Results: Of the 10 PRO measures examined, eight demonstrated a moderate or high positive association between preoperative scores and MID values. Only two measures demonstrated such an association when Oldham's measure of baseline severity was used. Conclusion: In general, there is little association between baseline severity and MID values. However, a moderate association persists for some measures, and it is recommended that researchers continue to test for this relationship when generating anchor-based MID values from change scores