Geographic variation of mutagenic exposures in kidney cancer genomes

International differences in the incidence of many cancer types indicate the existence of carcinogen exposures that have not yet been identified by conventional epidemiology make a substantial contribution to cancer burden1. In clear cell renal cell carcinoma, obesity, hypertension and tobacco smoking are risk factors, but they do not explain the geographical variation in its incidence2. Underlying causes can be inferred by sequencing the genomes of cancers from populations with different incidence rates and detecting differences in patterns of somatic mutations. Here we sequenced 962 clear cell renal cell carcinomas from 11 countries with varying incidence. The somatic mutation profiles differed between countries. In Romania, Serbia and Thailand, mutational signatures characteristic of aristolochic acid compounds were present in most cases and but these were rare elsewhere. In Japan, a mutational signature of unknown cause was found in more than 70% of cases but in less than 2% elsewhere. A further mutational signature of unknown cause was ubiquitous but exhibited higher mutation loads in countries with higher incidence rates of kidney cancer. Known signatures of tobacco smoking correlated with tobacco consumption, but no signature was associated with obesity or hypertension, suggesting that non-mutagenic mechanisms of action underlie these risk factors. The results of this study indicate the existence of multiple, geographically variable, mutagenic exposures that potentially affect tens of millions of people and illustrate the opportunities for new insights into cancer causation through large-scale global cancer genomics.

The Complexity of Tobacco Smoke-Induced Mutagenesis in Head and Neck Cancer

Tobacco smoke, alone or combined with alcohol, is the predominant cause of head and neck cancer (HNC). Here, we further explore how tobacco exposure contributes to cancer development by mutational signature analysis of 265 whole-genome sequenced HNC from eight countries. Six tobacco-associated mutational signatures were detected, including some not previously reported. Differences in HNC incidence between countries corresponded with differences in mutation burdens of tobacco-associated signatures, consistent with the dominant role of tobacco in HNC causation. Differences were found in the burden of tobacco-associated signatures between anatomical subsites, suggesting that tissue-specific factors modulate mutagenesis. We identified an association between tobacco smoking and three additional alcohol-related signatures indicating synergism between the two exposures. Tobacco smoking was associated with differences in the mutational spectra and repertoire of driver mutations in cancer genes, and in patterns of copy number change. Together, the results demonstrate the multiple pathways by which tobacco smoke can influence the evolution of cancer cell clones.

The Mutographs biorepository: A unique genomic resource to study cancer around the world

Large-scale biorepositories and databases are essential to generate equitable, effective, and sustainable advances in cancer prevention, early detection, cancer therapy, cancer care, and surveillance. The Mutographs project has created a large genomic dataset and biorepository of over 7,800 cancer cases from 30 countries across five continents with extensive demographic, lifestyle, environmental, and clinical information. Whole-genome sequencing is being finalized for over 4,000 cases, with the primary goal of understanding the causes of cancer at eight anatomic sites. Genomic, exposure, and clinical data will be publicly available through the International Cancer Genome Consortium Accelerating Research in Genomic Oncology platform. The Mutographs sample and metadata biorepository constitutes a legacy resource for new projects and collaborations aiming to increase our current research efforts in cancer genomic epidemiology globally.

Needlestack: an ultra-sensitive variant caller for multi-sample next generation sequencing data

The emergence of next-generation sequencing (NGS) has revolutionized the way of reaching a genome sequence, with the promise of potentially providing a comprehensive characterization of DNA variations. Nevertheless, detecting somatic mutations is still a difficult problem, in particular when trying to identify low abundance mutations, such as subclonal mutations, tumour-derived alterations in body fluids or somatic mutations from histological normal tissue. The main challenge is to precisely distinguish between sequencing artefacts and true mutations, particularly when the latter are so rare they reach similar abundance levels as artefacts. Here, we present needlestack, a highly sensitive variant caller, which directly learns from the data the level of systematic sequencing errors to accurately call mutations. Needlestack is based on the idea that the sequencing error rate can be dynamically estimated from analysing multiple samples together. We show that the sequencing error rate varies across alterations, illustrating the need to precisely estimate it. We evaluate the performance of needlestack for various types of variations, and we show that needlestack is robust among positions and outperforms existing state-of-the-art method for low abundance mutations. Needlestack, along with its source code is freely available on the GitHub platform: https://github.com/IARCbioinfo/needlestack.

Circulating tumour-derived KRAS mutations in pancreatic cancer cases are predominantly carried by very short fragments of cell-free DNA

BACKGROUND

The DNA released into the bloodstream by malignant tumours· called circulating tumour DNA (ctDNA), is often a small fraction of total cell-free DNA shed predominantly by hematopoietic cells and is therefore challenging to detect. Understanding the biological properties of ctDNA is key to the investigation of its clinical relevance as a non-invasive marker for cancer detection and monitoring.

METHODS

We selected 40 plasma DNA samples of pancreatic cancer cases previously reported to carry a KRAS mutation at the 'hotspot' codon 12 and re-screened the cell-free DNA using a 4-size amplicons strategy (57 bp, 79 bp, 167 bp and 218 bp) combined with ultra-deep sequencing in order to investigate whether amplicon lengths could impact on the capacity of detection of ctDNA, which in turn could provide inference of ctDNA and non-malignant cell-free DNA size distribution.

FINDINGS

Higher KRAS amplicon size (167 bp and 218 bp) was associated with lower detectable cell-free DNA mutant allelic fractions (p < 0·0001), with up to 4·6-fold (95% CI: 2·6-8·1) difference on average when comparing the 218bp- and the 57bp-amplicons. The proportion of cases with detectable KRAS mutations was also hampered with increased amplicon lengths, with only half of the cases having detectable ctDNA using the 218 bp assay relative to those detected with amplicons less than 80 bp.

INTERPRETATION

Tumour-derived mutations are carried by shorter cell-free DNA fragments than fragments of wild-type allele. Targeting short amplicons increases the sensitivity of cell-free DNA assays for pancreatic cancer and should be taken into account for optimized assay design and for evaluating their clinical performance.

FUNDING

IARC; MH CZ - DRO; MH SK; exchange program between IARC and Sao Paulo medical Sciences; French Cancer League.

Urinary TERT promoter mutations are detectable up to 10 years prior to clinical diagnosis of bladder cancer: Evidence from the Golestan Cohort Study

BACKGROUND

Detecting pre-clinical bladder cancer (BC) using urinary biomarkers may provide a valuable opportunity for screening and management. Telomerase reverse transcriptase (TERT) promoter mutations detectable in urine have emerged as promising BC biomarkers.

METHODS

We performed a nested case-control study within the population-based prospective Golestan Cohort Study (50,045 participants, followed up to 14 years) and assessed TERT promoter mutations in baseline urine samples from 38 asymptomatic individuals who subsequently developed primary BC and 152 matched controls using a Next-Generation Sequencing-based single-plex assay (UroMuTERT) and droplet digital PCR assays.

FINDINGS

Results were obtained for 30 cases and 101 controls. TERT promoter mutations were detected in 14 pre-clinical cases (sensitivity 46·67%) and none of the controls (specificity 100·00%). At an estimated BC cumulative incidence of 0·09% in the cohort, the positive and negative predictive values were 100·00% and 99·95% respectively. The mutant allelic fractions decreased with the time interval from urine collection until BC diagnosis (p = 0·033) but the mutations were detectable up to 10 years prior to clinical diagnosis.

INTERPRETATION

Our results provide the first evidence from a population-based prospective cohort study of the potential of urinary TERT promoter mutations as promising non-invasive biomarkers for early detection of BC. Further studies should validate this finding and assess their clinical utility in other longitudinal cohorts.

FUNDING

French Cancer League, World Cancer Research Fund International, Cancer Research UK, Tehran University of Medical Sciences, the International Agency for Research on Cancer, and the U.S. National Cancer Institute.

Circulating tumor DNA detection in head and neck cancer: evaluation of two different detection approaches

The use of non-invasive biomarkers such as circulating tumor DNA (ctDNA) in head and neck tumors may be of relevance in early diagnosis and eventually improved outcome. We evaluated two different approaches from two case series in Europe and South America including (i) targeted screening of ctDNA mutations, and (ii) detection of TP53 mutations in plasma and oral rinses without previous knowledge of mutational status in tumor samples. Targeted sequencing in 5 genes identified ctDNA mutations in plasma among 42% of HNSCC cases, 67% of who were early stage cases. No association was found between ctDNA mutation detection and overall survival. Sequencing of the entire coding region of the TP53 gene resulted in identification of TP53 mutations in 76% of tumor cases. However, concordance of mutation detection was low between tumor, oral rinses (11%) and plasma (2,7%) samples. Identification of 5 pathogenic TP53 mutations in oral rinses from 3 non-cancer controls gives additional evidence of mutation occurrence in individuals without a diagnosed cancer and presents an additional challenge for the development of ctDNA diagnostic assays.

Geographic heterogeneity in the prevalence of human papillomavirus in head and neck cancer

Human papillomavirus (HPV) causes oropharyngeal squamous cell carcinoma (OPSCC), although strongly divergent results have been reported regarding the prevalence of HPV16 in different countries, whether this represents important differences in etiology remains unclear. Applying rigorous protocols for sample processing, we centrally evaluated 1,420 head and neck tumors (533 oropharynx, 395 oral cavity and 482 larynx) from studies conducted in the US, Europe and Brazil for mucosal HPV DNA and p16INK4a expression to evaluate regional heterogeneity in the proportion of HPV16-associated OPSCC and other head and neck cancer, and to assess covariates associated with the risk of HPV16-positive OPSCC. While majority of OPSCC in the US (60%) were HPV16-positive, this proportion was 31% in Europe and only 4% in Brazil (p < 0.01). Similar differences were observed for other head and neck tumors, ranging from 7% in the US and 5% in Europe, to 0% in South America. The odds of HPV16-positive OPSCC declined with increasing pack years of smoking (OR: 0.75; 95% CI: 0.64-0.87) and drink years of alcohol use (OR: 0.64; 95% CI: 0.54-0.76). These results suggest that while the contribution of HPV16 is substantial for the oropharynx, it remains limited for oral cavity and laryngeal cancers.

KRAS mutations in blood circulating cell-free DNA: a pancreatic cancer case-control

The utility of KRAS mutations in plasma circulating cell-free DNA (cfDNA) samples as non-invasive biomarkers for the detection of pancreatic cancer has never been evaluated in a large case-control series. We applied a KRAS amplicon-based deep sequencing strategy combined with analytical pipeline specifically designed for the detection of low-abundance mutations to screen plasma samples of 437 pancreatic cancer cases, 141 chronic pancreatitis subjects, and 394 healthy controls. We detected mutations in 21.1% (N=92) of cases, of whom 82 (89.1%) carried at least one mutation at hotspot codons 12, 13 or 61, with mutant allelic fractions from 0.08% to 79%. Advanced stages were associated with an increased proportion of detection, with KRAS cfDNA mutations detected in 10.3%, 17,5% and 33.3% of cases with local, regional and systemic stages, respectively. We also detected KRAS cfDNA mutations in 3.7% (N=14) of healthy controls and in 4.3% (N=6) of subjects with chronic pancreatitis, but at significantly lower allelic fractions than in cases. Combining cfDNA KRAS mutations and CA19-9 plasma levels on a limited set of case-control samples did not improve the overall performance of the biomarkers as compared to CA19-9 alone. Whether the limited sensitivity and specificity observed in our series of KRAS mutations in plasma cfDNA as biomarkers for pancreatic cancer detection are attributable to methodological limitations or to the biology of cfDNA should be further assessed in large case-control series.

Abstract 3156: NGS-based screening for TP53 mutations in circulating cell-free DNA: A first step towards early detection of lung cancers

Background

The US National Lung Cancer Screening Trial (NLST) demonstrated in 2011 that screening with computed tomography (CT) scans could reduce lung cancer mortality by 20%, but with important financial costs and high number of false positives. The identification of novel biomarkers is a need to obtain the maximum benefit from CT screening. Given its economical and minimally invasive nature, screening for somatic mutations in circulating tumor DNA (ctDNA) using next-generation sequencing may complement existing screening tools. However, for application in early detection, variant detection must also be done agnostically, i.e. without prior knowledge from tumour tissue of the mutations expected and unfortunately, most currently available variant callers are not adapted for this task.

Methods

We performed multiplex PCR on circulating free DNA (cfDNA) extracted from the plasma of 35 lung squamous cell carcinoma (SCC) and 64 small-cell carcinoma (SCLC) patients. We additionally included 133 hospital controls to evaluate the specificity of ctDNA. We applied (&gt;10,000X) Ion torrent targeted sequencing on the full-coding region of TP53 since this gene is known to be mutated in more than 70% and 90% of SCC and SCLC, respectively. Each amplification, library preparation, and sequencing was performed in duplicate to control for amplification and sequencing errors. Detecting mutations on ctDNA raises important statistical and bioinformatics challenges as it represents only a small fraction of cfDNA. We therefore developed and applied a method based on the idea that a data-derived model of sequencing errors has the potential to improve our ability to detect low-allelic fraction (AF) somatic variants.

Results

We detected TP53 non-synonymous coding mutations with AFs between 0.04% and 85% (median 1.7%) in 8 (23%) SCC patients, 28 (44%) SCLC patients, and 8 (6%) controls. We estimated odds ratios of 4.6 (p = 0.006) for SCC and 12.0 (p = 6.7×10-10) for SCLC. Observations in controls are surprising, but in this instance there was no information regarding a subsequent cancer diagnosis.

Conclusion

We show that it is possible to detect ctDNA in the cfDNA of lung cancer patients. Since only patients with early stage (I-IIA) SCC tumours were included, these results support the potential utility of the approach for early detection. Nevertheless, if such mutations are found prior to diagnosis has not been explored in a prospective study design with pre-diagnostic plasma samples and individuals without a cancer diagnosis through a follow-up period.

Citation Format: Patrice H. Avogbe, Tiffany Delhomme, Noémie Leblay, Florence Le Calvez-Kelm, Priscilia Chopard, Valérie Gaborieau, Ghislaine Scelo, Behnoush Abedi-Ardekani, David Zaridze, Anush Mukeria, Graham Byrnes, Paul Brennan, Lynnette Fernandez-Cuesta, Matthieu Foll, James D. McKay. NGS-based screening for TP53 mutations in circulating cell-free DNA: A first step towards early detection of lung cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3156.

Abstract 3137: NGS-based detection of KRAS hotspot mutations in plasma cell-free DNA of pancreatic cancer cases

Background: Pancreatic ductal adenocarcinoma (PDAC) is characterized by hotspot mutations in the KRAS gene (codons 12, 13 or 61) in 85-90% of cases. Codon 12 KRAS mutations have been detected in pancreatic juice, blood and stool samples from pancreatic cancer cases and represent promising biomarkers for early detection. However, the proportion of tumor-derived KRAS mutations in cell-free DNA fragments (cfDNA) has shown large variations, probably because of the heterogeneity in biosamples and assays tested. Deep sequencing technologies (NGS) allow the identification of low-abundance somatic variants, but have not previously been applied to the detection of KRAS hotspot mutations in cfDNA of PDAC cases. Moreover, variant calling methods have rarely been tested against cancer-free individuals so the proportion of false positives is unknown. We investigated whether deep sequencing of KRAS mutations at codons 12, 13 and 61 in plasma samples could represent a robust assay to distinguish pancreatic cancer from chronic pancreatitis and healthy controls.

Methods: We developed an Ion Torrent-based NGS KRAS assay (partial exons 2 and 3, totalling 208bp) to screen cfDNA from plasma samples of 461 PDAC cases, 154 individuals with chronic pancreatitis and 421 healthy controls. cfDNA extraction (&gt;4ng) and sequencing (&gt;1000x coverage on average, and absence of systematic high sequencing error rates on the 208bp) performed well on 431 (93%) PDAC cases, 138 (90%) chronic pancreatitis, and 388 (95%) controls. We fit a robust negative-binomial regression to estimate the distribution of the sequencing errors at each DNA bp position and identified outlying samples, which were considered as KRAS positive when q-value&lt;10-3. We also estimated the detection threshold of our assay using serial dilutions of DNA from SW480 KRAS mutated cell-line (p.G12V) in wild-type DNA.

Results: Sequencing of the serial dilutions of KRAS p.G12V mutated DNA indicated a detection threshold at a minor allele frequency of 0.2%. KRAS mutations in cfDNA were detected in 83 (19.3%) PDAC cases (73 on codon 12; 8 on codon 61; 1 on codon 13; and 1 multiple codons, i.e., similar in proportions as reported in tumor tissue from the International Cancer Genomic Consortium); 3 (2.2%) chronic pancreatitis (all on codon 12); and 8 (2.1%) healthy controls (4 on codon 12 and 4 on codon 61). Stage was significantly associated with the proportion of detected mutations in cancer cases (chi-squared p = 0.0005): the proportions of cases with detectable KRAS mutations in plasma were 7.9%, 14.9%, and 31.1% for local, regional, and advanced stages, respectively.

Conclusions: The NGS-based KRAS mutation screening is a sensitive approach to detect low allelic fraction in plasma cfDNA, although its utility for early detection is still limited. However, it has the capacity to identify specific KRAS mutations, which could be useful in a panel of other non-invasive biomarkers.

Citation Format: Florence Le Calvez-Kelm, Matthieu Foll, Magdalena B. Wozniak, Geoffroy Durand, Priscilia Chopard, Maroulio Pertesi, Tiffany Delhomme, Ivana Holcatova, Lenka Foretova, Vladimir Janout, Eleonora Fabianova, Maxime P. Vallée, Paul Brennan, James D. McKay, Graham Byrnes, Ghislaine Scélo. NGS-based detection of KRAS hotspot mutations in plasma cell-free DNA of pancreatic cancer cases. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3137.

Aristolochic acid exposure in Romania and implications for renal cell carcinoma

BACKGROUND

Aristolochic acid (AA) is a nephrotoxicant associated with AA nephropathy (AAN) and upper urothelial tract cancer (UUTC). Whole-genome sequences of 14 Romanian cases of renal cell carcinoma (RCC) recently exhibited mutational signatures consistent with AA exposure, although RCC had not been previously linked with AAN and AA exposure was previously reported only in localised rural areas.

METHODS

We performed mass spectrometric measurements of the aristolactam (AL) DNA adduct 7-(deoxyadenosin-N(6)-yl) aristolactam I (dA-AL-I) in nontumour renal tissues of the 14 Romanian RCC cases and 15 cases from 3 other countries.

RESULTS

We detected dA-AL-I in the 14 Romanian cases at levels ranging from 0.7 to 27 adducts per 10(8) DNA bases, in line with levels reported in Asian and Balkan populations exposed through herbal remedies or food contamination. The 15 cases from other countries were negative.

INTERPRETATION

Although the source of exposure is uncertain and likely different in AAN regions than elsewhere, our results demonstrate that AA exposure in Romania exists outside localised AAN regions and provide further evidence implicating AA in RCC.

Adequacy of venous thromboprophylaxis in acutely ill medical patients (IMPART): multisite comparison of different clinical decision support systems

BACKGROUND

The adequacy of thromboprophylaxis prescriptions in acutely ill hospitalized medical patients needs improvement.

OBJECTIVE

To prospectively assess the efficacy of thromboprophylaxis adequacy of various clinical decision support systems (CDSS) with the aim of increasing the use of explicit criteria for thromboprophylaxis prescription in nine Swiss medical services.

METHODS

We randomly assigned medical services to a pocket digital assistant program (PDA), pocket cards (PC) and no CDSS (controls). In centers using an electronic chart, an e-alert system (eAlerts) was developed. After 4 months, we compared post-CDSS with baseline thromboprophylaxis adequacy for the various CDSS and control groups.

RESULTS

Overall, 1085 patients were included (395 controls, 196 PC, 168 PDA, 326 eAlerts), 651 pre- and 434 post-CDSS implementation: 472 (43.5%) presented a risk of VTE justifying thromboprophylaxis (31.8% pre, 61.1% post) and 556 (51.2%) received thromboprophylaxis (54.2% pre, 46.8% post). The overall adequacy (% patients with adequate prescription) of pre- and post-CDSS implementation was 56.2 and 50.7 for controls (P = 0.29), 67.3 and 45.3 for PC (P = 0.002), 66.0 and 64.9 for PDA (P = 0.99), 50.5 and 56.2 for eAlerts (P = 0.37), respectively, eAlerts limited overprescription (56% pre, 31% post, P = 0.01).

CONCLUSION

While pocket cards and handhelds did not improve thromboprophylaxis adequacy, eAlerts had a modest effect, particularly on the reduction of overprescription. This effect only partially contributes to the improvement of patient safety and more work is needed towards institution-tailored tools.

Measuring quality of patient information documents with an expanded EQIP scale

OBJECTIVE

To develop an expanded version of the ensuring quality information for patients (EQIP) scale to measure quality of patient information documents.

METHODS

We added 16 new items to the 20-item EQIP scale. The 36 items addressed document content, structure, and identification data. The new tool was used to rate the quality of 73 leaflets describing medical care procedures, used at a university hospital. Assessment rules were clarified on 25 documents; the remaining 48 leaflets were independently rated by two assessors.

RESULTS

Inter-rater reliability was very good (mean item-specific kappa statistic on 48 documents=0.84). The intraclass correlation coefficient for the global score was 0.95. The mean global conformity score on all items was 44 (range: 21-76, S.D.=10). Most documents stated the purpose of the medical intervention (74% fully adequate), described qualitative risks (64%), used a respectful tone (80%), provided clear information (64%) in a logical order (73%). Fewer quantified risks (7%), were balanced (33%), used everyday language (22%), provided contact details (28%), identified authors (25%) and funding sources (4%). None gave evidence-based references nor clearly mentioned patient participation.

CONCLUSIONS

The expanded EQIP scale was reliable, and proved useful for analysis of patient information documents. Documents partially met international standards for quality patient information.

PRACTICE IMPLICATIONS

Document producers' efforts should focus on respecting guidelines and including patients.

Drug selection errors in relation to medication labels: a simulation study

The aim of this study was to assess the impact of differences in drug label information on injectable drug selection errors. Differences in the display of drug strength information were assessed in a randomised controlled trial involving ward nurses, intensive care nurses, nurse anaesthetists, ward physicians, and anaesthetists. A set of 24 on-screen tasks were constructed. For each task, a label corresponding to an instruction consisting of two from three possible pieces of information (concentration, quantity, volume) had to be selected from a list of 10 items. The set was presented three times to participants using three different label formats. Format A provided two pieces of strength information different from those in the instruction. Format B and C provided all three pieces in a random and a fixed sequence, respectively. The frequency of errors was statistically higher with formats A and B than with format C, and greater in nurses than in anaesthetists. Regulatory bodies should therefore implement a standard requiring that the concentration (expressed in 'mg x ml(-1)'), the amount and the volume of drug be displayed on medication labels in fixed locations.

Measuring human-error probabilities in drug preparation: a pilot simulation study

OBJECTIVES

Designing a safe medication process requires the ability to model its reliability using methods such as probabilistic risk assessment (PRA). However, lack of data, especially on human-error probabilities (HEPs), limits its use. To assess whether small-scale simulations could help generate HEP data, a pilot study was conducted among nurses and anaesthetists. It focused on two core activities, namely, the manual preparation of medications and the arithmetic necessary to prepare drugs. Its specific objectives were to evaluate whether HEPs could be high enough to be measurable and to determine whether these HEPs could be sensitive to individuals and task details. These would give some insight into the level of detail required by PRA analysis.

METHODS

Thirty nurse and 28 anaesthetist volunteers were involved in the experiment. Nurses and anaesthetists had to prepare medications for 20 patients and 22 syringes of various drugs, respectively. Both groups had to perform 22 calculations relating to the preparation of drugs. HEPs, distribution of HEPs and dependency of HEPs on individuals and task details were assessed.

RESULTS

In the preparation tasks, overall HEP was 3.0% for nurses and 6.5% for anaesthetists. In the arithmetic tasks, overall HEP was 23.8% for nurses and 8.9% for anaesthetists. A statistically significant difference was noted between the two groups. In both preparation and arithmetic tasks, HEPs were dependent on individual nurses but not on individual anaesthetists. In every instance, HEPs were dependent on task details.

CONCLUSION

Our study illustrates that small-scale simulations represent an interesting way of generating HEPs. HEPs are, indeed, in the range of 10(-2) and 10(-1). But in most cases, HEPs depend heavily on operators and task details. This dependency means that the influence of these parameters must be determined before advanced PRA analysis. There is therefore an urgent need to develop experimental research into assessing this influence by means of randomised controlled trials.

Venous thromboembolism prophylaxis in acutely ill medical patients: definite need for improvement

AIM OF THE STUDY

To examine the frequency and adequacy of thromboprophylaxis in acutely ill medical patients hospitalized in eight Swiss medical hospitals.

METHODS

A cross-sectional study of 1372 patients from eight Swiss hospitals was carried out. After exclusion of patients (275) given therapeutic anticoagulation, 1097 patients were audited. The adequacy of thromboprophylaxis was assessed by comparison with predefined explicit criteria.

RESULTS

Of 1097 patients, 542 (49.4%) received thromboprophylaxis. According to the explicit criteria, 644 (58.7%) should have been on prophylaxis (P < 0.001, when compared with the rate observed). The rate of prevention differed widely between hospitals (from 29.4 to 88.6%) with no difference between teaching and nonteaching hospitals. According to the explicit criteria, a substantial proportion (44.9%) of the patients who should have been treated were not. Conversely, 41.3% of the patients were unnecessarily treated.

CONCLUSIONS

Even though the appropriateness of the explicit criteria used could be challenged, our data suggest that the current practice is associated with important uncertainty leading to both overuse and underuse of thromboprophylaxis in patients hospitalized in medical wards. More efforts are urgently needed to develop new or endorse existing explicit, evidence-based criteria and guidelines for thromboprophylaxis in this population of patients.

Relationship between hospital length of stay and quality of care in patients with congestive heart failure

OBJECTIVE

To determine the relationship between hospital length of stay (LOS) and quality of care in patients admitted for congestive heart failure (CHF).

METHODS

This observational study was conducted in the medical wards of the Geneva University Hospitals, Geneva, Switzerland. A random sample of 371 patients was drawn from the 1084 patients discharged alive with a principal diagnosis of CHF between January 1997 and December 1998. Explicit criteria grouped into three scores were used to assess the quality of processes of care: admission work-up (admission score); evaluation and treatment during the stay (treatment score); and readiness for discharge (discharge score). The association between LOS and quality of care was analysed using linear regression with adjustment for clinical characteristics.

RESULTS

The mean proportion of criteria met were 80% for the admission score, 66% for the treatment score, and 76% for the discharge score. Mean (SD) LOS was 13.2 (8.8) days. The admission score was not associated with LOS, but the treatment score increased by 0.5% (95% CI 0.3 to 0.7; p < 0.001) with each additional day in hospital and the discharge score increased by 2.5% (95% CI 1.6 to 3.3; p < 0.001) per day from admission to day 10 but remained unchanged thereafter. Adjustment for potential confounders did not substantially modify these relationships.

CONCLUSIONS

In patients with CHF there is a significant association between LOS and the quality of the treatment provided, as well as with readiness for discharge. Appropriate reorganisation of processes of care should accompany attempts at reducing LOS to avoid detrimental effects on quality of care.

Unplanned readmissions of patients with congestive heart failure: do they reflect in-hospital quality of care or patient characteristics?

PURPOSE

To determine if early unplanned readmissions of patients hospitalized for heart failure are associated with suboptimal in-hospital care or with the clinical and demographic characteristics of the patient.

SUBJECT AND METHODS

We performed a case-control study among patients discharged with a principal diagnosis of heart failure. Cases included all patients unexpectedly readmitted within 31 days of discharge; controls were randomly selected from among those not readmitted. Quality of care was measured using explicit criteria reflecting the admission work-up, evaluation and treatment, and readiness for discharge.

RESULTS

Ninety-one cases and 351 controls were included. There was no significant association between early unplanned readmissions and the scores for quality of the admission work-up or evaluation and treatment during the stay. There was a significant association between readiness for discharge and subsequent early readmission: for each 10% decrease in the proportion of fulfilled criteria, the odds of readmission increased by 14% (95% confidence interval [CI] 1. 01 to 1.28, P = 0.04) for all-cause readmissions and by 19% (95% CI: 1.04 to 1.36, P = 0.01) for heart-failure-related readmissions. In a multiple logistic regression model, previous diagnosis of heart failure (odds ratio [OR] = 2.9, 95% CI: 1.7 to 4.8, P <0.001), age (OR = 3.3, 95% CI: 1.3 to 8.5, P = 0.01 for patients aged 65 to 79 years and OR = 4.1, 95% CI: 1.6 to 11, P = 0.004 for patients aged 80 years and older), and history of cardiac revascularization (OR = 2.1, 95% CI: 1.2 to 3.9, P = 0.01) showed a stronger association with early unplanned all-cause readmissions than the readiness-for-discharge score (OR = 1.16, 95% CI: 1.02 to 1.31, P = 0.02). Similar findings were seen for heart failure-related readmissions.

CONCLUSIONS

Among patients with heart failure, early unplanned readmissions were not associated with suboptimal admission work-up or evaluation and treatment but were weakly associated with readiness for discharge. However, they were strongly associated with the patients' clinical and demographic characteristics.

Predictors of inappropriate hospital days in a department of internal medicine

BACKGROUND

This study aimed to identify predictors of inappropriate hospital days in a department of internal medicine, as a basis for quality improvement interventions.

METHODS

The appropriateness of 5665 hospital days contributed by 500 patients admitted to the Department of Internal Medicine, Geneva University Hospitals, Switzerland, was assessed by means of the Appropriateness Evaluation Protocol. Predictor variables included patient's age and sex, manner of admission and discharge, and characteristics of hospital days (weekend, holiday, sequence).

RESULTS

Overall, 15% of hospital admissions and 28% of hospital days were rated as inappropriate. In multivariate models, inappropriate hospital days were more frequent among patients whose admission was inappropriate (odds ratio [OR] = 5.3, 95% CI: 3.1-8.4) and among older patients (80-95 years: OR = 3.6, 95% CI: 1.7-7.0, versus <50 years). The likelihood of inappropriateness also increased with each subsequent hospital day, culminating on the day of discharge, regardless of the total length of stay.

CONCLUSIONS

This study identified both the admission and the discharge processes as important sources of inappropriate hospital use in a department of internal medicine. The oldest patients were also at high risk of remaining in the hospital inappropriately. Surprisingly, long hospital stays did not generate a higher proportion of inappropriate days than short hospital stays. This information proved useful in developing interventions to improve the hospitalization process.

Risk factors for a medically inappropriate admission to a Department of Internal Medicine

OBJECTIVE

To identify patient- and admission-related risk factors for a medically inappropriate admission to a department of internal medicine.

METHODS

Cross-sectional study of a systematic sample of 500 admissions to the department of internal medicine of an urban teaching hospital. The appropriateness of each admission and reasons for inappropriate admissions were assessed using the Appropriateness Evaluation Protocol. Risk factors included the time (day of week and holidays) and manner (through emergency department or direct admission) of admission, patient age and sex, health status of patient and spouse, living arrangements, formal home care services, and informal support from family or friends.

RESULTS

Overall, 76 (15.2%) hospital admissions were rated as medically inappropriate by the Appropriateness Evaluation Protocol. In multivariate analysis, the likelihood of an inappropriate admission was increased by better physical functioning of the patient (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.1-2.1 [for 1 SD in Physical Functioning scores]), lower mental health status of the patient's spouse (OR, 2.6; 95% CI, 1.3-5.6), receipt of informal help from family or friends (OR, 3.3; 95% CI, 1.5-7.2), and hospitalization by one's physician (OR, 3.6; 95% CI, 1.7-7.5). Receiving formal adult home care was not associated with inappropriateness of hospitalization.

CONCLUSIONS

Inappropriate admissions to internal medicine wards are determined by a mix of factors, including the patient's health and social environment. In addition, the private practitioners' discretionary ability to hospitalize their patients directly may also favor medically inappropriate admissions.

[Cancers in children in the Auvergne area: retrospective study from 1986 to 1991]

BACKGROUND

The specificity of childhood cancers led to the creation of regional childhood cancer registries. An epidemiological study of childhood cancers in the Auvergne area was carried out over a 6 year-period (1986-1991) in order to create a registry.

POPULATION AND METHODS

The population of our study was 252,820 children (0-15 years old), living in the Auvergne region. All malignant neoplasms were included together with brain tumours (whatever grading). Data were collected from medical and administrative sources.

RESULTS

The data of 153 cases were collected during this period. World age standardized overall incidence rate was 120.5 cases/milion/year. Age standardized incidence rates were: leukemias 37.6 (ALL 28.01), central nervous system tumours 18.34 (medulloblastomas 4.6, astrocytomas 4.6, ependymomas 3.8), lymphomas 10.0, neuroblastomas 18.6, soft tissue tumors 8.3, bone tumours 6.1 (Ewing's sarcomas 4.1, osteosarcomas 2.0), nephroblastomas 5.5, retinoblastomas 3.1, liver tumours 0.5 and others 0.5.

CONCLUSIONS

Our data base in the Auvergne area might be a source of information for epidemiological studies on the role of etiological factors, the survival, the sequelae and the incidence trends.

A controlled study of inhaled pentamidine for primary prevention of Pneumocystis carinii pneumonia

BACKGROUND

Current recommendations for prophylaxis of Pneumocystis carinii pneumonia (PCP) are based on data from patients who have had at least one episode of PCP (secondary prevention). We designed a study to determine the efficacy and side effects of inhaled pentamidine in the primary prevention of PCP.

METHODS

Two hundred twenty-three patients sero-positive for human immunodeficiency virus (HIV) who had the acquired immunodeficiency syndrome (AIDS) but not PCP, who had advanced AIDS-related complex, or who had less than 0.2 x 10(9) CD4-positive lymphocytes per liter received either 300 mg of pentamidine isethionate or 300 mg of sodium isethionate every 28 days by inhaler. The proportion of patients surviving without PCP was analyzed with the log-rank test as a function of time spent in the trial, according to the intention to treat with either placebo or pentamidine.

RESULTS

The third of five planned interim analyses showed a significant difference in the occurrence of PCP, with 8 cases in pentamidine group and 23 in the placebo group (nominal P value = 0.0021). There were no deaths within 60 days of the diagnosis of PCP and no significant differences in survival between groups. Approximately 53 inhalations were needed to prevent one episode of pneumonia. Thirty-eight of 114 patients given pentamidine (33 percent) and 7 of 109 given placebo (6 percent) had moderate-to-severe coughing during inhalations (two-tailed P less than 0.00001), which caused 4 patients given pentamidine (3.5 percent) to discontinue taking it.

CONCLUSIONS

A dose of 300 mg of aerosolized pentamidine given every four weeks was well tolerated and 60 to 70 percent effective in preventing a first episode of PCP in patients with HIV infection.

Primary prevention of Pneumocystis carinii pneumonia by inhalation of pentamidine. Preliminary results from a placebo-controlled randomized trial. Swiss Group for Clinical Studies on AIDS

Patients with AIDS but without pneumocystis carinii pneumonia, patients with advanced AIDS-related complex (ARC), and asymptomatic patients with less than 200 CD4-positive lymphocytes/mm3 were randomized to one of two groups: group I: Inhalation of 300 mg of pentamidine every 28 days; group II: Inhalation of placebo (300 mg of Na isethionate) every 28 days. From May to November 28, 1989, 160 patients have entered the trial. Inhalations were well tolerated, with only a 6% use of bronchodilators and a 15% incidence of cough. Until now five patients died, none of them drug related. So far, six patients have developed pneumocystis carinii pneumonia; four of these were on pentamidine, and two on placebo. Five of the six cases occurred before the second inhalation. Recruitment will continue until 250 patients are enrolled.

Extended intestinal aganglionosis in siblings

In this paper we report two cases of extended intestinal aganglionosis in siblings, a condition that could be considered a severe variety of Hirschsprung's disease.

[Familial tubulopathy associating hypercalciuria and saline diabetes. Favorable results of indomethacin therapy]

The association of hypercalciuria, salt losing renal disease, and a defect in urine concentrating ability with high renin and aldosterone levels is described in two brothers. One child had marked nephrocalcinosis by the age of 3 and the other severe growth retardation. In one child all the abnormalities were abolished with indomethacin which was responsible for a marked decrease in urinary. The data and the family study suggest that this condition is a proximal tubular disorder with atuosomal recessive inheritance.

Studies on circulating immunoreactive calcitonin in low birth weight infants during the first 48 hours of life

Serum immunoreactive calcitonin (iCT), serum immunoreactive parathyroid hormone (iPTH) and serum Ca, Mg, P and total protein levels were determined sequentially at 5 given periods of time from 1 to 48 h of age in 16 low birth weight infants. Mean +/- SD serum Ca levels decreased from 8.99 +/- 0.79 mg/100 ml at time 1--2 h to 7.00 +/- 0.51 mg/100 ml at time 12--14 h; there was a small further decrease at time 22--26 h: 6.79 +/- 1.07 mg/100 ml. There was no significant change in serum Mg, P or total protein during the same periods of time. Serum iPTH levels increased steadily from time 1--2 h to time 44--48 h reaching above normal range values. Serum iCT levels were non detectable (less than 150 pg/ml) in 11 among 15 infants at time 1--2 h. A marked increase in mean +/- SD serum iCT levels was observed at time 12--14 h (1850 +/- 872 pg/ml) and time 22--26 h (1462 +/- 806 pg/ml) followed by a decrease at time 44--48 h. A negative correlation was found between serum iCT levels and respectively gestational age (p less than 0.01) and serum Ca levels (p less than 0.01) at time 22--26 h while serum iCT levels correlated positively with serum iPTH levels (p less than 0.05). Evidence obtained from this study indicates that a secretion of calcitonin takes place during the early neonatal period in low birth weight infants and that this secretion is a contributing factor of the socalled "early-type" neonatal hypocalcemia.