Hepatitis E virus in patients with decompensated chronic liver disease: a prospective UK/French study

BACKGROUND

In developed countries, hepatitis E is a porcine zoonosis caused by hepatitis E virus (HEV) genotype 3. In developing countries, hepatitis E is mainly caused by genotype 1, and causes increased mortality in patients with pre-existing chronic liver disease (CLD).

AIM

To determine the role of HEV in patients with decompensated CLD.

METHODS

Prospective HEV testing of 343 patients with decompensated CLD at three UK centres and Toulouse France, with follow-up for 6 months or death. IgG seroprevalence was compared with 911 controls.

RESULTS

11/343 patients (3.2%) had acute hepatitis E infection, and three died. There were no differences in mortality (27% vs. 26%, OR 1.1, 95% CI 0.28-4.1), age (P = 0.9), bilirubin (P = 0.5), alanine aminotransferase (P = 0.06) albumin (P = 0.5) or international normalised ratio (P = 0.6) in patients with and without hepatitis E infection. Five cases were polymerase chain reaction (PCR) positive (genotype 3). Hepatitis E was more common in Toulouse (7.9%) compared to the UK cohort (1.2%, P = 0.003). HEV IgG seroprevalence was higher in Toulouse (OR 17, 95% CI 9.2-30) and Truro (OR 2.5, 95% CI 1.4-4.6) than in Glasgow, but lower in cases, compared to controls (OR 0.59, 95% CI 0.41-0.86).

CONCLUSIONS

Hepatitis E occurs in a minority of patients with decompensated chronic liver disease. The mortality is no different to the mortality in patients without hepatitis E infection. The diagnosis can only be established by a combination of serology and PCR, the yield and utility of which vary by geographical location.

Risk factors for TB and HIV coinfection in Scotland, 2001 to 2010

The number of patients with tuberculosis (TB) increased steadily in Scotland between 2005 and 2010. Human immunodeficiency virus (HIV) infection has been a contributory factor to increases in TB in a number of comparable industrialised countries. This study investigated the extent of, and risk factors for, TB and HIV coinfection in Scotland from 2001 to 2010. Patients with TB in the national TB database were linked to those in the national HIV database using probabilistic data linkage. Patient records were anonymised to maintain confidentiality. From 2001 to 2010, 106/4, 097 (2.6%, 95% CI: 2.1 to 3.1) TB patients matched with HIV patients, equating to a 10-year incidence of 2.1 cases per million population. Patients with both TB and HIV were more often born outside the United Kingdom,were of black African ethnicity, had refugee status and had extra-thoracic lymph node involvement or cryptic/disseminated TB disease. Individuals with TB and HIV coinfection were younger and symptomatic for a shorter time before their diagnosis of TB, compared with TB patients without HIV. TB and HIV coinfection was relatively uncommon in Scotland in the study period. Clinicians should recognise the potential for HIV infection among TB patients and the importance of offering an HIV test to all TB patients.

Hepatitis E virus in Scottish blood donors

BACKGROUND AND OBJECTIVES

Published prevalence figures for hepatitis E virus (HEV) reveal significant regional differences. Several studies have reported virus transmission via blood transfusion. The aim of this study was to establish HEV seroprevalence and investigate a potential HEV RNA presence in Scottish blood donors.

MATERIALS AND METHODS

IgG and IgM were determined in individual serum samples. HEV RNA was investigated in plasma mini-pools corresponding to 43 560 individual donations using nested PCR. Samples amenable to reamplification with primers from a different region were considered confirmed positives, sequenced and analysed.

RESULTS

A total of 73 of 1559 tested individual sera (4·7%) were IgG positive, none tested positive for IgM. Plasma mini-pool testing revealed an HEV RNA frequency of 1 in 14 520 donations. Three confirmed positives belonged, as expected to genotype 3.

CONCLUSIONS

HEV IgG and RNA figures in Scottish blood donors are lower than those published for the rest of the UK, but sufficiently high to prompt further studies on potential transmission rates and effects of HEV infection, especially for immunosuppressed individuals.

Public health aspects of tuberculosis

This article covers public health aspects of the investigation and management of people who are infected with tuberculosis (TB). It contains a brief overview of the recent epidemiology of TB in Scotland, focusing on changes in Scottish TB incidence and describing some epidemiological associations. We then describe the initial public health assessment of those with suspected TB and responses that should be initiated. It does not address issues relating to the clinical treatment of patients with TB.

Tuberculosis and alcohol misuse in Scotland: a population-based study using enhanced surveillance data

OBJECTIVE

To identify for the first time in Scotland the epidemiological characteristics of tuberculosis (TB) patients who misuse alcohol.

DESIGN

A retrospective cohort study using Enhanced Surveillance of Mycobacterial Infections (ESMI) scheme data for adult (aged ≥ 18 years) TB cases notified in Scotland, 2001-2007. Characteristics and treatment outcomes of TB cases with and without recorded alcohol misuse were compared.

RESULTS

Of 2419 adult TB cases, alcohol misuse was recorded in 426 (18%). Alcohol misuse was associated with male sex, White ethnicity, birth in the United Kingdom, unemployment, urban residence and socio-economic deprivation. Alcohol misusers were more likely than other TB cases to have pulmonary TB (92% vs. 61%, P < 0.001), be sputum smear-positive (74% vs. 58%, P < 0.001) and be enrolled on directly observed treatment (30% vs. 3%, P < 0.001). Treatment completion rates were respectively 77% and 79% (P = 0.34) in alcohol misusers and other TB cases.

CONCLUSION

We have identified epidemiological characteristics associated with alcohol misuse among TB patients in Scotland, notably socio-economic deprivation. We suggest improvements in data collection to allow more robust findings to inform policy decisions to assist the prevention and management of alcohol misuse and reduce the TB incidence in Scotland.

Multicentre comparison of the Glasgow Blatchford and Rockall Scores in the prediction of clinical end-points after upper gastrointestinal haemorrhage

BACKGROUND

The Glasgow Blatchford Score (GBS) is increasingly being used to predict intervention and outcome following upper gastrointestinal haemorrhage (UGIH).

AIM

To compare the GBS with both the admission and full Rockall scores in predicting specific clinical end-points following UGIH.

PATIENTS AND METHODS

Data on consecutive patients presenting to four UK hospitals were collected. Admission history, clinical and laboratory data, endoscopic findings, treatment and clinical follow-up were recorded. Using ROC curves, we compared the three scores in the prediction of death, endoscopic or surgical intervention and transfusion. Results  A total of 1555 patients (mean age 56.7years) presented with UGIH during the study period. Seventy-four (4.8%) died, 223 (14.3%) had endoscopic or surgical intervention and 363 (23.3%) required transfusion. The GBS was similar at predicting death compared with both the admission Rockall (area under ROC curve 0.804 vs. 0.801) and full Rockall score (AUROC 0.741 vs. 0.790). In predicting endo-surgical intervention, the GBS was superior to the admission Rockall (AUROC 0.858 vs. 0.705; P<0.00005) and similar to the full Rockall score (AUROC 0.822 vs. 0.797). The GBS was superior to both admission Rockall (AUROC 0.944 vs. 0.756; P<0.00005) and full Rockall scores (AUROC 0.935 vs. 0.792; P<0.00005) in predicting need for transfusion.

CONCLUSIONS

Despite not incorporating age, the GBS is as effective as the admission and full Rockall scores in predicting death after UGIH. It is superior to both the admission and full Rockall scores in predicting need for transfusion, and superior to the admission Rockall score in predicting endoscopic or surgical intervention.

Should healthcare workers be screened routinely for meticillin-resistant Staphylococcus aureus? A review of the evidence

Meticillin-resistant Staphylococcus aureus (MRSA) is considered endemic in the UK National Health Service (NHS), and routine MRSA screening of hospital inpatients has recently been introduced in both Scotland and England. The UK National Screening Committee states that public pressure for widening the eligibility criteria of a proposed screening programme should be anticipated and any related decisions scientifically justifiable. A literature review was conducted to examine whether MRSA screening in Scotland should be expanded to include the routine screening of healthcare workers (HCWs). There are no published prevalence studies reporting the overall MRSA carriage rate in HCWs in NHS hospitals. Estimates of HCW carriage from the worldwide literature vary widely depending on the country, hospital specialty and setting (endemic, non-endemic or outbreak). Recent studies conducted in endemic hospital settings report non-outbreak carriage rates of 0-15%. The role of HCW carriage in the transmission of MRSA is not well understood. Persistent carriage could act as a reservoir for infection and HCWs have been implicated as the source in a number of published outbreak reports. There are no published controlled trials examining the impact of routine HCW screening as an intervention in the prevention and control of MRSA infections in the endemic hospital setting. Most of the evidence for HCW screening comes from outbreak reports where the outbreak was brought to an end following the introduction of staff screening as part of a suite of infection control measures. Further research is required before a recommendation could be made to introduce routine MRSA screening of HCWs in the NHS in Scotland.

A cluster of Legionnaires' disease caused by Legionella longbeachae linked to potting compost in Scotland, 2008-2009

Three cases of Legionnaires disease caused by Legionella longbeachae Sg 1 associated with potting compost have been reported in Scotland between 2008 and 2009. The exact method of transmission is still not fully understood as Legionnaires disease is thought to be acquired by droplet inhalation. The linked cases associated with compost exposure call for an introduction of compost labelling, as is already in place in other countries where L. longbeachae outbreaks have been reported.

Trends in multidrug-resistant tuberculosis in Scotland, 2000-7

Overall numbers of multidrug-resistant (MDR) tuberculosis (TB) rose sharply in the United Kingdom and Scotland in 2007. Risk factors associated with MDR TB in the United Kingdom have been identified but there has been no previous report on risk factors associated with MDR TB in Scotland. Enhanced Surveillance of Mycobacterial Infections (ESMI) data were used to examine demographic and clinical characteristics and treatment outcome of MDR TB cases notified in Scotland between 2000-7. There was a total of 11 culture-positive cases of MDR TB, five of which were notified in 2007. The majority of patients were female, 15-44 years old and unemployed. All were born outside the United Kingdom and most had arrived within the past year from or frequently travelled to their home countries in China, the Indian subcontinent or Africa. Except for one individual, our patients did not self report a history of previous diagnosis of TB which was previously identified as a risk factor for MDR TB in the United Kingdom. Only three patients received directly observed treatment (DOT). Only two patients had completed treatment at 12 months, partially due to the inadequate length of follow-up under the current ESMI system. Our results suggest that most patients had primary resistance due to transmission of MDR TB in high incidence countries and thus point to the importance of international efforts to control MDR TB in these countries. In Scotland, national efforts should be made to increase the number of MDR TB patients receiving DOT and to extend follow-up to improve monitoring of treatment outcome. It is important to identify high risk groups for MDR TB infection in order to deliver effective community-based disease control measures.

Trends in multidrug-resistant tuberculosis in Scotland, 2000-7

Overall numbers of multidrug-resistant (MDR) tuberculosis (TB) rose sharply in the United Kingdom and Scotland in 2007. Risk factors associated with MDR TB in the United Kingdom have been identified but there has been no previous report on risk factors associated with MDR TB in Scotland. Enhanced Surveillance of Mycobacterial Infections (ESMI) data were used to examine demographic and clinical characteristics and treatment outcome of MDR TB cases notified in Scotland between 2000-7. There was a total of 11 culture-positive cases of MDR TB, five of which were notified in 2007. The majority of patients were female, 15-44 years old and unemployed. All were born outside the United Kingdom and most had arrived within the past year from or frequently travelled to their home countries in China, the Indian subcontinent or Africa. Except for one individual, our patients did not self report a history of previous diagnosis of TB which was previously identified as a risk factor for MDR TB in the United Kingdom. Only three patients received directly observed treatment (DOT). Only two patients had completed treatment at 12 months, partially due to the inadequate length of follow-up under the current ESMI system. Our results suggest that most patients had primary resistance due to transmission of MDR TB in high incidence countries and thus point to the importance of international efforts to control MDR TB in these countries. In Scotland, national efforts should be made to increase the number of MDR TB patients receiving DOT and to extend follow-up to improve monitoring of treatment outcome. It is important to identify high risk groups for MDR TB infection in order to deliver effective community-based disease control measures.

Outpatient management of patients with low-risk upper-gastrointestinal haemorrhage: multicentre validation and prospective evaluation

BACKGROUND

Upper-gastrointestinal haemorrhage is a frequent reason for hospital admission. Although most risk scoring systems for this disorder incorporate endoscopic findings, the Glasgow-Blatchford bleeding score (GBS) is based on simple clinical and laboratory variables; a score of 0 identifies low-risk patients who might be suitable for outpatient management. We aimed to evaluate the GBS then assess the effect of a protocol based on this score for non-admission of low-risk individuals.

METHODS

Our study was undertaken at four hospitals in the UK. We calculated GBS and admission (pre-endoscopy) and full (post-endoscopy) Rockall scores for consecutive patients presenting with upper-gastrointestinal haemorrhage. With receiver-operating characteristic (ROC) curves, we compared the ability of these scores to predict either need for clinical intervention or death. We then prospectively assessed at two hospitals the introduction of GBS scoring to avoid admission of low-risk patients.

FINDINGS

Of 676 people presenting with upper-gastrointestinal haemorrhage, we identified 105 (16%) who scored 0 on the GBS. For prediction of need for intervention or death, GBS (area under ROC curve 0.90 [95% CI 0.88-0.93]) was superior to full Rockall score (0.81 [0.77-0.84]), which in turn was better than the admission Rockall score (0.70 [0.65-0.75]). When introduced into clinical practice, 123 patients (22%) with upper-gastrointestinal haemorrhage were classified as low risk, of whom 84 (68%) were managed as outpatients without adverse events. The proportion of individuals with this condition admitted to hospital also fell (96% to 71%, p<0.00001).

INTERPRETATION

The GBS identifies many patients presenting to general hospitals with upper-gastrointestinal haemorrhage who can be managed safely as outpatients. This score reduces admissions for this condition, allowing more appropriate use of in-patient resources.

Upper gastrointestinal bleeding and the changing use of COX-2 non-steroidal anti-inflammatory drugs and low-dose aspirin

BACKGROUND

Rofecoxib was withdrawn in 2004.

AIM

To assess the incidence of upper gastrointestinal bleeding in the context of the changing use of cyclo-oxygenase-2 non-steroidal anti-inflammatory drugs and low-dose aspirin.

METHODS

We examined the characteristics of patients developing upper gastrointestinal bleeding in a defined population in south-west Scotland. The primary comparisons were made between two calendar years, preceding and following the withdrawal of rofecoxib.

RESULTS

The overall incidence of upper gastrointestinal bleeding rose from 98.7 in 2002 to 143 per 10(5) of the population per annum in 2005 (chi(2) = 21.1; P < 0.001). The rise in the incidence was associated with using low-dose aspirin, from 26.6 to 38.4 per 10(5) (chi(2) = 5.4; P = 0.02), other antithrombotic drugs, from 12.1 to 30.2 per 10(5) (chi(2) = 19.6; P < 0.001), and excess alcohol, from 23.5 to 36.4 per 10(5) (chi(2) = 7.1; P = 0.008), but insignificantly with using non-steroidal anti-inflammatory drugs, from 13.3 to 16.1 per 10(5) (chi(2) = 0.64; P = 0.4). After adjustment for the concomitant use of these drugs, there was no significant trend in the incidence of upper gastrointestinal bleeding associated with non-steroidal anti-inflammatory drugs over the period of 1996-2005.

CONCLUSION

The rise in the incidence of upper gastrointestinal bleeding was weakly related to the change in use of non-steroidal anti-inflammatory drugs. Instead, it probably reflected the increasing use of low-dose aspirin, other antithrombotic drugs and alcohol.

Clinical outcome in upper gastrointestinal bleeding complicating low-dose aspirin and antithrombotic drugs

BACKGROUND

The current risk stratification systems in upper gastrointestinal bleeding do not correct for the intake of low-dose aspirin and other antithrombotic drugs.

AIM

To test the Blatchford scores in evaluating the clinical outcome in bleeders using these drugs.

METHODS

We calculated the Blatchford scores in 510 bleeders, including 123 on low-dose aspirin, 44 on other antithrombotic drugs, and 68 on non-steroidal anti-inflammatory drugs.

RESULTS

The median clinical scores distributed according to aetiological risk factors were as follows: no risk factors, 5; non-steroidal anti-inflammatory drugs, 8; aspirin, 7; other antithrombotics, 6; excess alcohol, 4; multiple risk factors, 7; (P = 0.003, Kruskal-Wallis test). Scores correlated positively with the duration of admission in the entire group (r(s) = 0.285; P < 0.001) and in those taking aspirin and antithrombotics (r(s) = 0.211; P = 0.029). The median scores in patients requiring the blood transfusion were 10 in the entire group and 11 in users of aspirin or antithrombotics, compared with 3 and 4, respectively, in those not transfused (P < 0.001).

CONCLUSIONS

The Blatchford scores are significantly elevated in users of non-steroidal anti-inflammatory drugs, low-dose aspirin, and other antithrombotic drugs. They correlate positively with the duration of admission and the need for blood transfusion.

Upper gastrointestinal mucosal abnormalities and blood loss complicating low-dose aspirin and antithrombotic therapy

BACKGROUND

Little is known about the site and nature of bleeding lesions related to low-dose aspirin and other antithrombotic agents.

AIM

To describe the mucosal abnormalities in patients presenting with upper gastrointestinal bleeding while being treated with these drugs.

METHODS

The endoscopic findings and clinical details were analysed in all patients presenting with haematemesis and/or melaena at a single centre during three calendar years. Associations between endoscopic findings and risk factors, including the intake of non-steroidal anti-inflammatory drugs, low-dose aspirin (75 mg daily) and other antithrombotic drugs including warfarin, clopidogrel, and dipyridamole, were assessed by logistic regression analysis.

RESULTS

In 674 upper gastrointestinal bleeders, we found that the odds ratio for the presence of erosive oesophagitis in aspirin users was 2 (95% CI, 1-3; P = 0.03) and 3 (2-5; P = 0.0003) in patients taking other antithrombotic agents. In 41 patients with oesophagitis and taking these drugs, 36 (88%) had cardiovascular disease and only 4 (10%) had peptic symptoms.

CONCLUSIONS

Erosive oesophagitis is common in patients with upper gastrointestinal bleeding taking low-dose aspirin or antithrombotic agents, and could potentially be confused with the coexisting heart disease.

Upper gastrointestinal haemorrhage associated with low-dose aspirin and anti-thrombotic drugs - a 6-year analysis and comparison with non-steroidal anti-inflammatory drugs

BACKGROUND

Low-dose aspirin and other anti-thrombotic therapy has been increasingly used for vascular protection.

AIM

To assess the possibility that the incidence of upper gastrointestinal blood loss has changed in subjects using these agents in comparison with non-steroidal anti-inflammatory drugs.

METHODS

We studied the characteristics of all patients with acute upper gastrointestinal haemorrhage and attending a single hospital at 3 points over a 6-year period: 1996 (n = 204), 1999 (n = 224) and in 2002 (n = 252).

RESULTS

The incidence of haemorrhage in subjects taking low-dose aspirin rose from 15 per 100 000 of the population per annum in 1996, to 18 in 1999 and 27 in 2002 (P = 0.004). The respective incidence in subjects taking other anti-thrombotic drugs was 4, 8, and 12 (P < 0.001). No significant change was detected in non-steroidal anti-inflammatory drug users. However, acute myocardial infarction mortality was 216 per 100 000 in 1996, 221 in 1999 and fell to 169 in 2002 (P < 0.001).

CONCLUSIONS

The incidence of upper gastrointestinal haemorrhage in users of low-dose aspirin and other anti-thrombotic drugs has been steadily rising. This has been paralleled by a fall in cardiac mortality.

A risk score to predict need for treatment for upper-gastrointestinal haemorrhage

BACKGROUND

Current risk-stratification systems for patients with acute upper-gastrointestinal bleeding discriminate between patients at high or low risks of dying or rebleeding. We therefore developed and prospectively validated a risk score to identify a patient's need for treatment.

METHODS

Our first study used data from 1748 patients admitted for upper-gastrointestinal haemorrhage. By logistic regression, we derived a risk score that predicts patients' risks of needing blood transfusion or intervention to control bleeding, rebleeding, or dying. From this score, we developed a simplified fast-track screen for use at initial presentation. In a second study, we prospectively validated this score using receiver operating characteristic (ROC) curves--a measure of the validity of a scoring system--and chi2 goodness-of-fit testing with data from 197 patients. We also validated the quicker screening tool.

FINDINGS

We calculated risk scores from patients' admission haemoglobin, blood urea, pulse, and systolic blood pressure, as well as presentation with syncope or melaena, and evidence of hepatic disease or cardiac failure. The score discriminated well with a ROC curve area of 0.92 (95% CI 0.88-0.95). The score was well calibrated for patients needing treatment (p=0.84).

INTERPRETATION

Our score identified patients at low or high risk of needing treatment to manage their bleeding. This score should assist the clinical management of patients presenting with upper-gastrointestinal haemorrhage, but requires external validation.

Infectious health care workers: should patients be told?

The risk of transmission of HIV or hepatitis B from infectious health care workers to patients is low. However, inadvertent exposure causes great concern amongst patients of an infected health care worker. The patients of a Scottish dentist diagnosed hepatitis B e antigen positive were informed by letter of their exposure. A sample of patients was sent a postal questionnaire. Most (56%) respondents reported feeling anxious on receiving the letter but almost all (93%) thought patients should always be informed following treatment by an infectious health care worker, although the risk was very small. We discuss clinical and ethical factors relating to informing patients following exposure to an infectious health care worker. We suggest that a balance should be struck between patients' wishes to know of risks to which they have been exposed, however small, and the professional view that when risks are negligible, patients need not be informed.

Emergency medical admissions in Glasgow: general practices vary despite adjustment for age, sex, and deprivation

BACKGROUND

Emergency admission rates have been rising rapidly in Britain. Studies defining the underlying factors are needed.

AIM

To determine the principal diagnoses, demographic, and socioeconomic factors associated with emergency medical admissions.

METHOD

Cohort study based on the Greater Glasgow Health Board population of 810,423 adults. A fully anonymized dataset linkage of 43,247 adult emergency admissions to Glasgow medical beds in 1997 was obtained. Emergency admission rates were analysed by diagnosis, age, sex, Carstairs' deprivation category, and by individual general practices (after adjustment for other factors).

RESULTS

The commonest principal diagnoses were chest pain (9.6%), chronic obstructive airways disease (5.6%), angina (5.4%), heart failure (4.1%), and acute myocardial infarction (3.9%). Twenty-one per cent of patients were coded as having 'ill-defined signs or symptoms'. Emergency medical admission rates rose with the age of the patient, doubling with every two decades' age increase. Admission rates for patients from deprived areas were twice those from affluent areas. Males were more frequently admitted than females (adjusted odds ratio = 1.19). After adjustment for age, sex, and deprivation, the general practices' emergency medical admission rates showed an almost twofold difference between the top and bottom deciles.

CONCLUSION

Emergency medical admission rates are higher among the elderly, males, and deprived populations. This has implications for equitable resource distribution in the National Health Service. Admissions for exclusion of myocardial disease were common; however, myocardial infarction was not the final diagnosis in two-thirds of these patients. The large variation between the general practices' admission rates requires further investigation.

Acute upper gastrointestinal haemorrhage in west of Scotland: case ascertainment study

OBJECTIVES

To determine the incidence and case fatality of acute upper gastrointestinal haemorrhage in the west of Scotland and to identify associated factors.

DESIGN

Case ascertainment study.

SETTING

All hospitals treating adults with acute upper gastrointestinal haemorrhage in the west of Scotland.

SUBJECTS

1882 patients aged 15 years and over treated in hospitals for acute upper gastrointestinal haemorrhage during a six month period.

MAIN OUTCOME MEASURES

Incidence of acute upper gastrointestinal haemorrhage per 100,000 population per year, and case fatality.

RESULTS

The annual incidence was 172 per 100,000 people aged 15 and over. The annual population mortality was 14.0 per 100,000. Both were higher among elderly people, men, and patients resident in areas of greater social deprivation. Overall case fatality was 8.2%. This was higher among those who bled as inpatients after admission for other reasons (42%) and those admitted as tertiary referrals (16%). Factors associated with increased case fatality were age, uraemia, pre-existing malignancy, hepatic failure, hypotension, cardiac failure, and frank haematemesis or a history of syncope at presentation. Social deprivation, sex, and anaemia were not associated with increased case fatality after adjustment for other factors.

CONCLUSIONS

The incidence of acute upper gastrointestinal haemorrhage was 67% greater than the highest previously reported incidence in the United Kingdom, which may be partially attributable to the greater social deprivation in the west of Scotland and may be related to the increased prevalence of Helicobacter pylori. Fatality after acute upper gastrointestinal haemorrhage was associated with age, comorbidity, hypotension, and raised blood urea concentrations on admission. Although deprivation was associated with increased incidence, it was not related to the risk of fatality.