Reconciliation of international administrative coding systems for comparison of colorectal surgery outcome

AIM

Significant variation in colorectal surgery outcomes exists between different countries. Better understanding of the sources of variable outcomes using administrative data requires alignment of differing clinical coding systems. We aimed to map similar diagnoses and procedures across administrative coding systems used in different countries.

METHOD

Administrative data were collected in a central database as part of the Global Comparators (GC) Project. In order to unify these data, a systematic translation of diagnostic and procedural codes was undertaken. Codes for colorectal diagnoses, resections, operative complications and reoperative interventions were mapped across the respective national healthcare administrative coding systems. Discharge data from January 2006 to June 2011 for patients who had undergone colorectal surgical resections were analysed to generate risk-adjusted models for mortality, length of stay, readmissions and reoperations.

RESULTS

In all, 52 544 case records were collated from 31 institutions in five countries. Mapping of all the coding systems was achieved so that diagnosis and procedures from the participant countries could be compared. Using the aligned coding systems to develop risk-adjusted models, the 30-day mortality rate for colorectal surgery was 3.95% (95% CI 0.86-7.54), the 30-day readmission rate was 11.05% (5.67-17.61), the 28-day reoperation rate was 6.13% (3.68-9.66) and the mean length of stay was 14 (7.65-46.76) days.

CONCLUSION

The linkage of international hospital administrative data that we developed enabled comparison of documented surgical outcomes between countries. This methodology may facilitate international benchmarking.

The principles of managing open fractures

Any fracture of a bone which communicates with the outside environment via a wound in the skin is classified as an open fracture. This may be from penetration by sharp objects from the exterior, laceration caused by the fracture fragments, or shearing forces that tear or de-glove soft tissue from a limb. These injuries vary in mechanism and severity, ranging from a broken finger caught in a bulkhead door to a catastrophic lower limb fracture suffered from an improvised explosive device (IED). We address the management principles that can be applied to all open fractures regardless of cause.

Total mesorectal excision for cancer following ventral mesh rectopexy

Since the introduction of ventral mesh rectopexy for rectal prolapse, concern exists as to how this may interfere with subsequent rectal cancer surgery. To our knowledge, this is the first report of total mesorectal excision for cancer after such a rectopexy. We discuss surgical technique, pitfalls encountered and oncological outcome.

Global comparators project: international comparison of hospital outcomes using administrative data

OBJECTIVE

To produce comparable risk-adjusted outcome rates for an international sample of hospitals in a collaborative project to share outcomes and learning.

DATA SOURCES

Administrative data varying in scope, format, and coding systems were pooled from each participating hospital for the years 2005-2010.

STUDY DESIGN

Following reconciliation of the different coding systems in the various countries, in-hospital mortality, unplanned readmission within 30 days, and "prolonged" hospital stay (>75th percentile) were risk-adjusted via logistic regression. A web-based interface was created to facilitate outcomes analysis for individual medical centers and enable peer comparisons. Small groups of clinicians are now exploring the potential reasons for variations in outcomes in their specialty.

PRINCIPAL FINDINGS

There were 6,737,211 inpatient records, including 214,622 in-hospital deaths. Although diagnostic coding depth varied appreciably by country, comorbidity weights were broadly comparable. U.S. hospitals generally had the lowest mortality rates, shortest stays, and highest readmission rates.

CONCLUSIONS

Intercountry differences in outcomes may result from differences in the quality of care or in practice patterns driven by socio-economic factors. Carefully managed administrative data can be an effective resource for initiating dialog between hospitals within and across countries. Inclusion of important outcomes beyond hospital discharge would increase the value of these analyses.

Phase Ib study of RG7112 with doxorubicin (D) in advanced soft tissue sarcoma (ASTS)

10514

Background: Preclinical data demonstrate p53-dependent MIC-1 activation by both D and the MDM2 inhibitor RG7112. This study evaluated the tolerability of combining D with RG7112 in ASTS patients (pts) and pharmacokinetic (PK) and pharmacodynamic (PD) parameters of the combination. Methods: A phase 1b 3+3 dose escalation study was designed. Pts with ASTS in whom D was considered appropriate were eligible. D was administered IV at either 50 mg/m2 or 60 mg/m2on day 1 with RG7112 administered orally 500 or 1000 mg QD for 3 or 5 days (d1-3 or d1-5) in 28-d treatment cycles. Safety, PK and PD, including serum MIC-1 (an indicator of p53 activation), were assessed. Results: As of January 15, 2013, enrollment was complete with 23 pts with ASTS accrued; safety data for cycle 1 was available for preliminary review in 20 pts. Growth factor support was mandated following the first dosing group (D 60 mg/m2and RG7112 500 mg x 5d) due to febrile neutropenia or grade 4 neutropenia. Of the 20 pts for which cycle 1 safety data is available, 13 pts reported neutropenia (12 grade 3/4); 5 reported grade 3/4 febrile neutropenia (3 following mandatory GCSF prophylaxis); 12 pts developed thrombocytopenia (9 grade 3/4). PK parameters of the combination therapy are similar to single agent values and did not demonstrate evidence of drug-drug interactions. Serum MIC-1 rapidly increased to levels greater than for either agent alone. Best response to date is stable disease in 8/16 pts who have had interim evaluations. Conclusions: Combination therapy with D and RG7112 resulted in a high rate of grade 3/4 neutropenia (60%) or thrombocytopenia (45%). PK analysis does not suggest this is due to changes in the metabolism of either drug. This combination demonstrates apparent potentiation of p53 activation demonstrated by increased MIC-1 levels greater than additive effects of the single agents. Biomarker analyses, safety, PK, and MIC-1 data will be presented. Clinical trial information: NCT01605526. [Table: see text]

Abstract LB-201: Clinical pharmacology characterization of RG7112, an MDM2 antagonist, in patients with advanced solid tumors

MDM2 is overproduced as a mechanism to impair p53 function in many cancers. By reactivating p53, antagonists of p53-MDM2 interaction could offer a novel approach to treatment of solid tumors and leukemias. RG7112, the first potent and selective small-molecule MDM2 antagonist in clinical testing, is an oral p53 activator and is currently in phase I. To optimize its dose and schedule, a number of clinical pharmacology characteristics were explored in this multi-center trial in patients (pts) with advanced solid tumors. In Part I, the impact of high-energy/high-fat meal and formulation (crystalline versus amorphous) was examined in cross-over design. In Part II, schedule optimization (4 schedules of drug adm under fasting condition and 1 cohort with liquid supplementation) was investigated in parallel, dose escalation design. Clinical endpoints were PK/PD and safety/tolerability including platelet reduction (a potential target-mediated hematological toxicity indicator).

A total of 76 pts (42F and 34M, mean age 60 yr) participated in the study. In their first-cycle treatment, 36 pts received weekly x3 (26 with food/formulation evaluation), 15 pts daily x5, 6 pts daily x20, and 19 pts daily x3 (3 with food evaluation) doses; daily doses ranged from 500-4500 mg. The most commonly reported AEs (> 20%) were GI-related. Twelve pts have reported 21 SAEs, of which, 4 events in 2 pts (1 pt with G4 thrombocytopenia, anemia, and neutropenia; 1 pt with G3 delirium) were related to study treatment.

A high-energy (∼1000 kcal)/high-fat (∼60 g) meal and a reduced energy (∼500 kcal)/fat (∼30 g) liquid supplementation both enhanced overall bioavailability (BA) of tested formulations by 2-fold, with inter-pt variability reduced by half. At steady-state, amorphous formulation also reduced PK variability by half from the crystalline formulation. High-dose consecutive daily dosing for 5 and 3 d yielded highest drug concentrations on the last day of treatment. On the other hand, both weekly and low-dose/long-duration (20-day) schedules yielded lower peak concentrations (note that the per-cycle exposure was comparable to, or higher than, high-dose 5x and 3x daily schedules).

Serum profiles of MIC-1, a secreted protein that is strongly induced by activated p53, showed similar patterns to the PK when the clinical pharmacology conditions were varied.

The first-cycle platelet profiles indicate that the weekly schedule didn't cause platelet reduction, while the daily schedules showed a trend of dose- and length-dependent platelet reduction with daily x 5 at high doses being the most pronounced (1 pt resulted in G-4 thrombocytopenia).

In conclusion, RG7112 is well tolerated with or without food in the therapeutically relevant dose range, food enhanced BA with reduced variability, and high-dose consecutive daily for 3-5 d is superior in yielding sufficiently high PK exposure and PD effects potentially required for cancer treatment efficacy.

Citation Format: Amita Patnaik, Anthony Tolcher, Muralidhar Beeram, John Nemunaitis, Glen Weiss, Gwen Nichols, Steven Middleton, Nenad Sarapa, Anna Beryozkina, Jianguo Zhi. Clinical pharmacology characterization of RG7112, an MDM2 antagonist, in patients with advanced solid tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-201. doi:10.1158/1538-7445.AM2013-LB-201

PP162. sFlt-1 controlled by CPAP in a pregnant patient with chronic hypertension

INTRODUCTION

Preeclampsia is recognised as the leading cause of perinatal mortality and morbidity worldwide. Interest has been increasing recently as to the possible impact of sleep disordered breathing (SDB) on the mechanisms of preeclampsia, possibly by augmenting placental hypoxia during sleep. A biomarker of preeclampsia, sFlt-1, has also come to prominence in recent years and is postulated to be a good predictor of preeclampsia as well as a strong indicator of the severity of the disease.

OBJECTIVES

The aim of this study was to investigate the effect of CPAP treatment for SDB on sFlt-1 concentrations during pregnancy.

METHODS

Patients were recruited from the outpatients' clinic in Campbelltown Hospital, Campbelltown, NSW in the first half of 2011. The levels of sFlt-1 in four pregnant women, with or without hypertensive disorders of pregnancy, and with or without SDB were measured using ELISA.

RESULTS

Women with SDB and chronic hypertension or preeclampsia had higher levels of sFlt-1 and a greater percentage increase of this marker, and CPAP treatment appeared to attenuate the rise of sFlt-1 as shown in the table below.

CONCLUSION

Elevated sFlt-1 was associated with untreated SDB in those with chronic hypertension. This study provides feasibility for a larger scale study to occur, to further examine the validity of the hypothesis that CPAP treatment has a beneficial effect on sFLt-1 levels and therefore, may lower the risk and severity of preeclampsia.

PP154. Relationship between recorded and reported snoring during pregnancy: Objective measurement versus questionnaire responses

INTRODUCTION

Snoring is a common symptom of sleep disordered breathing (SDB), a condition that is present in 4% of the general population. SDB is identified by snoring and repetitive cessation of breathing during sleep accompanied by repetitive hypoxia and has been found to be associated with hypertension, stroke and heart attack. There is not depth of knowledge examining the association between SDB and pregnancy outcomes.

OBJECTIVES

To examine the prevalence of self reported snoring in pregnancy and the potential association between self reported snoring and the development of Hypertensive Disorders of Pregnancy (HDP) within a larger cohort from a prevalence of SDB in pregnancy study.

METHODS

Questionnaires were administered to pregnant women attending an outpatient's antenatal clinic. The self reported snoring is a component of the Epworth scale. Pregnancy progression and outcome data were collected on all participants and analyse by IBM SPSS v.20™ utilising Chi-square analysis, Student T test and logistic regression analysis. HDP diagnoses were in alignment with the SOMANZ (2009) diagnostic criteria.

RESULTS

Questionnaires were administered and outcomes collected on 2023 pregnancies. Snoring was reported by 49.2% of women. HDP affected 10.1% of the cohort, 3.3% of whom were preeclamptic. Of the pregnancies affected by HDP self reported snoring occurred in 57.7% in comparison to 43.3% who do not report snoring (p<0.001).

CONCLUSION

This would indicate that there is an association between self reported snoring and the development of HDP. Further analysis will be undertaken to model the effect of other potential risk factors such as maternal age, parity, pre-pregnancy BMI and other co morbidities.

A phase I study of MDM2 antagonist RG7112 in patients (pts) with relapsed/refractory solid tumors

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Background: RG7112 is a small molecule MDM2 antagonist, designed to non-genotoxically activate p53. A phase I dose escalation (DE) was performed, followed by a sarcoma biomarker extension (EXT) in pts with wild type TP53. Methods: 106 pts (58M, 48 F), median age 57.9 yrs (range 22-84) participated; 76 in 9 cohorts (DE) from 20 to 1800 mg/m2, orally QD x 10 q28 days. 30 pts with sarcoma were treated at MTD (2500 mg) (EXT) with pre-and on dose (d5+/-2) biopsies. Analyses included TP53 mutation (AmpliChip), MDM2 amplification (ISH), p53 and p21 IHC, MDM2 RT-PCR, Ki-67, TUNEL and [18F]-FLT-PET. Blood was obtained for PK and MIC-1, a PD marker of p53 activation. Results: DE: MTD was1440 mg/m2/d (2500 mg flat dose). PK was ~dose linear (t½ 1-1.5 d) with high variability (CV~70%) in AUC and Cmax . Adverse events included nausea/GI and exposure-related neutropenia/thrombocytopenia. 3 DLTs: diarrhea, pancytopenia, hyponatremia occurred (at ≥ 640 mg/m2). Evidence of activity included: 1) concentration dependent increase in plasma MIC-1 (% baseline), 2) decrease in [18F]-FLT PET and PR each in liposarcoma pts at 1800 mg/m2 and 1440 mg/m2, respectively. EXT: Grade3/ 4 cytopenias at MTD precluded subsequent cycles in 6/8 pts (10 day schedule). Dosing was changed to 5 days, and only 3 patients had Gr3/4 cytopenias. 8/22 pts remained on study for >4 cycles, including 2 pts with SD for 7 and 9 cycles respectively. 3 of 4 EXT pts had decreased [18F]-FLT-PET activity. Biopsies (pre- and on treatment) demonstrated: 1) increase in p53 (median 1.5 fold change (X) by IHC, n=15); 2) increase in p21 (median 2.7X by IHC, n=14); 3) increase in MDM2 (median 2.5X by RT-PCR, n = 27); 4) decrease in % Ki-67(+) cells (median % change from baseline -65.4%, range -91% to +275%, n=17 ); 5) increase in TUNEL(+) cells of 9.0 (density of + cells/mm2, range -26.2 to +45.5, n=22). These results were seen both in tumors with and without MDM2 gene amplification, and in multiple sarcoma subtypes. Conclusions: RG7112 has manageable AEs (GI ) and cytopenias correlating with AUC. Single agent disease control, and biomarker activity was seen in both MDM2 amplified and non-amplified, heavily pretreated soft tissue sarcoma pts, with changes reflecting activation of p53-related pathways.

Influence of signalment on developing cranial cruciate rupture in dogs in the UK

OBJECTIVES

To investigate risk factors associated with cranial cruciate ligament rupture in dogs.

METHODS

Retrospective case-control study: medical records of a first-opinion veterinary practice were searched for dogs diagnosed with cranial cruciate ligament rupture (1995 to 2007). For each case, six unaffected dogs were randomly selected from all dogs presenting that day for comparison. Multi-variable binary logistic regression was performed to assess the association of variables on likelihood of cruciate rupture.

RESULTS

Frequency of cranial cruciate ligament rupture was 1·19% [95% confidence interval (CI) 1·02 to 1.36%]. West Highland white terriers (n=17), Yorkshire terriers (n=14) and Rottweilers (n=11) were at significantly increased risk of cranial cruciate ligament rupture (P≤0·002). Rottweilers were at five times greater risk compared with other pure breeds (OR 5·12, 95% CI 2·281 to 11·494, P<0·001), obesity quadrupled the risk of cranial cruciate ligament rupture (OR 3·756, 95% CI 1·659 to 8·502, P=0·001) and females were twice as likely to suffer cranial cruciate ligament failure compared to males (OR 2·054, 95% CI 1·467 to 2·877, P<0·001). Dogs less than two years old were statistically less likely to sustain cranial cruciate ligament rupture than dogs older than eight years (OR 0·246, 95% CI 0·127 to 0·477, P<0·001). There was no significant difference in median weights (in kilograms) of neutered dogs, compared to their entire counterparts in either the case group (P=0·994) or in the control group (P=0·630). There was also no significant difference in body condition (-underweight/normal weight/overweight/obese) of neutered versus entire dogs among the cases (P=0·243), or the controls (P=0·211).

CLINICAL SIGNIFICANCE

Cranial cruciate ligament rupture is more likely in Rottweilers and in female dogs, older dogs and obese dogs. Following multi-variable analysis, it was established that neutering was not associated with increased risk of cranial cruciate ligament rupture.

NMDA receptor-dependent switching between different gamma rhythm-generating microcircuits in entorhinal cortex

Local circuits in the medial entorhinal cortex (mEC) and hippocampus generate gamma frequency population rhythms independently. Temporal interaction between these areas at gamma frequencies is implicated in memory-a phenomenon linked to activity of NMDA-subtype glutamate receptors. While blockade of NMDA receptors does not affect frequency of gamma rhythms in hippocampus, it exposes a second, lower frequency (25-35 Hz) gamma rhythm in mEC. In experiment and model, NMDA receptor-dependent mEC gamma rhythms were mediated by basket interneurons, but NMDA receptor-independent gamma rhythms were mediated by a novel interneuron subtype-the goblet cell. This cell was distinct from basket cells in morphology, intrinsic membrane properties and synaptic inputs. The two different gamma frequencies matched the different intrinsic frequencies in hippocampal areas CA3 and CA1, suggesting that NMDA receptor activation may control the nature of temporal interactions between mEC and hippocampus, thus influencing the pathway for information transfer between the two regions.

Recruitment of parvalbumin-positive interneurons determines hippocampal function and associated behavior

Perisomatic inhibition provided by a subgroup of GABAergic interneurons plays a critical role in timing the output of pyramidal cells. To test their contribution at the network and the behavioral level, we generated genetically modified mice in which the excitatory drive was selectively reduced either by the knockout of the GluR-D or by conditional ablation of the GluR-A subunit in parvalbumin-positive cells. Comparable cell type-specific reductions of AMPA-mediated currents were obtained. Kainate-induced gamma oscillations exhibited reduced power in hippocampal slices from GluR-D-/- and GluR-A(PVCre-/-) mice. Experimental and modeling data indicated that this alteration could be accounted for by imprecise spike timing of fast-spiking cells (FS) caused by smaller interneuronal EPSPs. GluR-D-/- and GluR-A(PVCre-/-) mice exhibited similar impairments in hippocampus-dependent tasks. These findings directly show the effects of insufficient recruitment of fast-spiking cells at the network and behavioral level and demonstrate the role of this subpopulation for working and episodic-like memory.

Beta rhythms (15-20 Hz) generated by nonreciprocal communication in hippocampus

Generation of gamma rhythms in reciprocally connected areas of cortex produces synchronous neuronal firing, although little is known about the consequences of gamma rhythms when generated in nonreciprocally connected regions. This nonreciprocity exists in hippocampus, where gamma rhythms are generated in area CA3 in vitro and in vivo and nonreciprocally projected to area CA1 by the Schaffer collateral pathway. Here we demonstrate how this CA3 gamma rhythm generates two different patterns of local CA1 oscillation dependent on the degree of output from area CA1. 1) In conditions where activity projected to area CA1 produces only very low principal cell recruitment the local population rhythm mimics the gamma rhythm projected from CA3. This activity is generated predominantly by recruitment of CA1 basket cells in a manner dependent on phasic, feedforward excitation of this interneuron subclass. Interneurons in stratum oriens, not receiving CA3 feedforward input, fired at theta frequencies. 2) In the presence of serotonin CA1 principal cell recruitment was appreciably enhanced, resulting in dual activation of CA1 basket cells through both feedforward and feedback excitations. Feedback excitation to CA1 stratum oriens interneurons was also enhanced. The resulting change in interneuron network dynamics generated a beta-frequency CA1 rhythm (as a near-subharmonic of the gamma rhythm projected from CA3). These findings demonstrate that in nonreciprocally connected networks, the frequency of population rhythms in target areas serves to code for degree of principal cell recruitment by afferent input.

Region-specific reduction in entorhinal gamma oscillations and parvalbumin-immunoreactive neurons in animal models of psychiatric illness

Psychiatric illnesses, particularly schizophrenia, are associated with disrupted markers for interneuronal function and interneuron-mediated brain rhythms such as gamma frequency oscillations. Here we investigate a possible link between these two observations in the entorhinal cortex and hippocampus by using a genetic and an acute model of psychiatric illness. Lysophosphatidic acid 1 receptor-deficient (LPA1-deficient) mice show psychomotor-gating deficits and neurochemical changes resembling those seen in postmortem schizophrenia studies. Similar deficits are seen acutely with antagonism of the NMDA subtype of glutamate receptor. Neither model induced any change in power or frequency of gamma rhythms generated by kainate in hippocampal slices. In contrast, a dramatic decrease in the power of gamma oscillations was seen in superficial, but not deep, medial entorhinal cortex layers in both models. Immunolabeling for GABA, parvalbumin, and calretinin in medial entorhinal cortex from LPA1-deficient mice showed an approximately 40% reduction in total GABA- and parvalbumin-containing neurons, but no change in the number of calretinin-positive neurons. This deficit was specific for layer II (LII). No change in the number of neurons positive for these markers was seen in the hippocampus. Acute NMDA receptor blockade, which selectively reduces synaptic drive to LII entorhinal interneurons, also disrupted gamma rhythms in a similar manner in superficial entorhinal cortex, but not in hippocampus. These data demonstrate an area-specific deficit in gamma rhythmogenesis in animal models of psychiatric illness and suggest that loss, or reduction in function, of interneurons having a large NMDA receptor expression may underlie the network dysfunction that is seen.

A software module for the adaptive estimation of steady state auditory evoked potentials

A graphical user interface (GUI) implementing a novel technique of fast estimation of steady state auditory evoked potentials (SSAEPs) for rapid assessment of the functionality of the human auditory nervous system is presented. The proposed signal estimator has shown great promise in the fast extraction of weak signals buried under large amounts of noise such as the case with SSAEP signals. Currently, the main technical impediment in the widespread clinical use of the SSAEP testing for hearing assessment is the excessively long measurement time needed for the estimation process due to the presence of large amounts of background noise. The presented software module that is publicly disseminated through the Internet is meant to facilitate the use of an efficient signal processing technique by the hearing researchers. The software environment allows for loading previously recorded SSAEP signals into the workspace for analysis. Moreover, it enables the user to add simulated SSAEP signals to the background EEG for the purpose of testing the capability of the underlying signal processing algorithm.