Chapter 3: Liver disease: Reducing amenable mortality
Chronic Liver Disease
Scotland has one of the fastest growing Chronic Liver Disease ( CLD) mortality rates in the world at a time when rates in most of Western Europe are falling 19,20 (Figure 1). Deaths from CLD now account for 1 in 50 of all Scottish deaths 21. These rising rates also contrast with falling mortality rates in recent years from the major diseases in Scotland (Coronary Heart Disease, Cerebrovascular Disease and Cancer) 22. CLD includes a range of conditions which include cirrhosis but exclude primary liver cancer.
The liver is the largest organ in the body and is responsible for many important functions such as processing nutrients, production of essential proteins and removal of toxins. CLD is characterised by scarring and destruction of the liver tissue. Early changes, such as "fatty liver" can progress via inflammation (hepatitis) and scarring (fibrosis) to irreversible damage (cirrhosis). Causes of death from cirrhosis include development of liver failure, brain damage (encephalopathy), catastrophic internal bleeding (oesophageal varices) and also primary liver cancer. Most cases of hepatocellular carcinoma, the commonest primary liver cancer, occur in patients with cirrhosis. In Scotland there was a 52% increase in incidence of primary liver cancer between 1987 and 2006 (from 178 to 345 cancers) 23.
Figure 1: Death rates per 100,000 population (age/sex-standardised, using European Standard Population)
There are a variety of risk factors and diseases that cause chronic liver disease. The three commonest risk factors for CLD are excessive alcohol consumption; blood borne viruses, in particular Hepatitis B and C, and obesity. Metabolic disease ( e.g. haemochromatosis, which causes a build up of iron in the liver) and auto-immune disease, e.g. primary biliary cirrhosis, are relatively rare accounting for less than 2% of all chronic liver disease deaths in 2007 24. The incidence and mortality rates of these metabolic liver diseases appear to have changed little in recent time 25,26.
Alcohol is a potentially toxic and addictive substance. It is rapidly absorbed by the body where it is detoxified by the liver. A rise in the average population consumption of alcohol is closely related to an increase in mortality from CLD27. Additional risk factors include gender (women are more susceptible), a genetic predisposition and concurrent liver disease.
Alcohol consumption in the UK has more than doubled over the past 50 years 28. In Scotland, at least 40% of men and 33% of women are drinking over twice the daily recommended limits 29. Enough alcohol is sold each year in Scotland to allow every adult over 16 to exceed weekly limits 30. Population consumption rises as alcohol becomes more affordable and available, both of which have occurred in Scotland in recent years 1.
'Alcohol consumption in the UK has more than doubled over the past 50 years. In Scotland, at least 40% of men and 33% of women are drinking over twice the daily recommended limits. Enough alcohol is sold each year in Scotland to allow every adult over 16 to exceed weekly limits.'
Eighty-five per cent of deaths from CLD in 2007 in Scotland were due to Alcoholic Liver Disease ( ALD), a rise from 37% in 1979 31. Deaths from ALD have been driving the rapid rise in CLD death rates in Scotland in recent years (Figure 1). As many as two-thirds of deaths from CLD which are not currently attributed to alcohol may actually be due to alcohol use 32,33. In other words, the overwhelming majority of deaths from CLD in Scotland are due to alcohol.
Blood Borne Viruses
The virus that causes Hepatitis C was first identified in 1989. It is highly infectious and is transmitted through blood borne routes, principally by sharing of injecting drug use equipment but also via blood transfusion (prior to instigation of testing of blood donors in 1991) and, rarely, by sexual activity and mother to child transmission.
Diagnosis of Hepatitis C is confirmed by a blood test. Treatment with anti-viral therapy achieves sustained viral clearance in 50-60% of instances 34. There is currently no vaccination for Hepatitis C. One-fifth of those infected with the virus recover spontaneously 35,36 whilst of the remainder who develop chronic Hepatitis C infection, 5-15% will develop cirrhosis over the next 20 years 36.
During 2006, estimates suggested approximately 50,000 people in Scotland are infected with Hepatitis C (about 1% of the population). Of these, three-quarters (37,500) had become chronically infected, the majority of whom (34,300) will have, at some time in the past, injected drugs into their bodies. Less than 40% of those chronically-infected will have had their infection diagnosed. Only 1 in 5 (8,000) chronically-infected individuals had ever been in specialist care and only 1 in 20 (2,000) had received a course of antiviral therapy. It was also estimated that, at the end of 2006, just over 2,000 Hepatitis C infected persons in Scotland were living with cirrhosis and 1,000-1,500 Injecting Drug Users ( IDUs) were becoming infected annually 34,37.
The proportion of liver-related deaths that occurred in HCV-diagnosed individuals increased from 2.8% (1995-1997) to 4.2% (2004-2006) 38. This is likely to be due to high rates of infection in the 1970s and 80s.
The Hepatitis B virus is highly infectious and is transmitted through blood and bodily fluids by unprotected sex; sharing of injecting drug equipment and from mother to child transmission Less than 10% develop chronic infection which in turn can result in CLD. In the UK it has a lower prevalence than Hepatitis C, with 1 in 1,000 people thought to be infected. This contrasts with other parts of the world where up to 1 in 10 people are infected 39,40.
In Scotland there were 475 new reports of Hepatitis B in 2007, up from 375 in 2006 41. Prevalence is higher in certain ethnic groups. A vaccine against Hepatitis B is available, uptake of which has increased in recent years 42. As with Hepatitis C, there is effective drug treatment for established chronic infection.
The proportion of CLD deaths due to Hepatitis B in Scotland cannot be determined from routine mortality data.
Non-alcoholic fatty liver disease ( NAFLD) is a disease of the liver characterised by fatty infiltration with or without inflammation (non-alcohol steatohepatitis or NASH). Previously thought to be benign, it can progress to fibrosis and cirrhosis in 15-20% of patients. It can also result in liver cancer. Development of NASH and fibrosis is associated with obesity, type 2 diabetes, hypertension and high triglycerides 25,26. In European and US studies, NAFLD affects 3-30% of the population, depending on whether blood tests or liver scans are the screening test 43,44,45. Hospital admissions for NAFLD in England and Wales have risen in the past 10 years 26.
Scotland has the highest level of obesity in the western world, second only to the United States. It was estimated, in 2003, that 22% of men and 24% women (nearly 1 in 4) of the Scottish population were obese ( BMI >30). Furthermore, the trends in obesity are very worrying with a 46% rise between 1995 and 2003. Obesity is also commoner in children and 18% of boys and 14% of girls age 2-15 are obese 46.
'It was estimated, in 2003, that 22% of men and 24% women (nearly 1 in 4) of the Scottish population were obese ( BMI >30). Furthermore, the trends in obesity are very worrying with a 46% rise between 1995 and 2003.'
Deaths from NAFLD have risen in Scotland from 3 in 1979 to 40 in 2007 47.
Treatment of Chronic Liver Disease
Liver disease is often symptomless or 'silent' and freqently does not present until irreversible. Mortality rates after hospital admission are high and have shown little improvement in the past 30 years 48. Medical interventions can prevent or treat complications such as screening and treating oesophageal varices; radiological treatment of small liver tumours and corticosteroids for severe alcoholic hepatitis but these have a limited effect on mortality overall. Surgical intervention through liver transplantation offers a life-saving treatment with survival figures of 75% at 5 years 49. Approximately 60 patients per year receive liver transplants in Scotland, ALD being the commonest reason. These only save a small proportion of deaths from ALD as many fail to stop drinking, normally a pre-requisite for surgery. Liver transplantation is costly and is limited by the number of donor organs. Scotland has one of the lowest organ donation rates in Europe and at present 1 in 4 patients listed for liver transplant die before an organ becomes available. The commitment by the Scottish Government to fully fund the recommendations of the UK Organ Donation Task Force, which will introduce measures aiming to increase the donation rate by 50% over the next 5 years, is welcome.
Action to Reduce Mortality from CLD
Action on Alcohol
Although treatment of established CLD can save lives, public health policies are the most effective way to reverse the upward trend of deaths from CLD. An epidemic of alcohol misuse is driving the current rise in CLD mortality. This needs to be urgently addressed and with a response proportionate to the scale of the problem. Two other epidemics, of Hepatitis C and obesity, unless tackled now will further increase deaths from CLD. Each will necessitate tailored approaches but these should be multi-faceted, encompassing preventative, harm reduction and early intervention measures as well as treatment and support. It should also be recognised that those with CLD may be exposed to multiple risk factors ( e.g. Hepatitis C and alcohol) with consequential worsening of their disease 50.
Tackling health inequalities is a top priority in improving the health of Scotland 51. Those in disadvantaged communities are 16 times more likely to die from CLD than those in more affluent areas and this gap has been widening over the past 20 years 52 (Figure 2).
Figure 2: Deprivation and Chronic Liver Disease
Source: Leyland et al., 2007
The exact reasons as to why Scotland in particular has experienced such a rapid increase in ALD since the early 90s is not entirely clear. One notable difference from the rest of the UK is that Scottish licensing laws were liberalised in 1976. Another factor is demonstrated in a recent analysis of sales figures which has shown that, in the past 3 years, adults in Scotland drank nearly 2 litres more pure alcohol per person per year than people in England and Wales. It is known what works in policy terms. The most effective alcohol policy includes measures directed at the population as a whole as well as targeted interventions for those at risk 54. This approach has been set out by the Scottish Government in the recent consultation Changing Scotland's Relationship with Alcohol with the express aim of reducing the alcohol consumption of the overall population 19. It includes measures to tackle price and availability as well as detection and intervention for those consuming alcohol at hazardous levels. These have been shown to be the most effective in reducing alcohol related harm 55,56,57. The Scottish Government is already investing some £100 million over the next 3 years in an ongoing nationwide programme to deliver screening and brief interventions for those drinking excessively. The Government will publish its next steps on tackling alcohol misuse early next year.
Action on Viral Hepatitis
Hepatitis B and C share similar transmission routes so there will be interventions common to both. The commonest route is through injecting drug use. Efforts to reduce drug use in general must continue as well as encouragement of drug users into treatment and support. The recently published drug strategy sets out the government's renewed focus and action 58. Harm reduction initiatives to reduce the spread of infection through injecting behaviours (such as needle exchange) and encouragement and support for safe sex are essential. Given the large number of people infected with Hepatitis C but not yet identified, it is vital that screening and testing are implemented with treatment and support of those newly diagnosed with Hepatitis C. This action will reduce the future level of death and disability due to Hepatitis C in Scotland. Phase II of the Hepatitis C Action Plan was published in 2008 funded by £43 million over the next three years 34. Although prevalence of Hepatitis B in Scotland is currently low, increasing immigration from areas with higher prevalence will need careful consideration as to whether universal vaccination should be implemented.
Action on Non-alcoholic Fatty Liver Disease
Healthy Eating, Active Living was published in June 2008. It is an action plan to improve diet, encourage greater physical activity and help tackle obesity with an additional £40 million over the next 3 years 59. Interventions are aimed across the whole population but with emphasis on the early years and those at increased risk of health inequalities. A new national target has been set to reduce the rate of increase in the proportion of children that are overweight by 2018. This is supported by the delivery of healthy weight interventions by Health Boards to overweight children between ages 5-15.
Scotland is experiencing one of the fastest growing rates of chronic liver disease mortality in the world. Recent rises are predominantly due to alcohol misuse. Urgent and radical action is needed and is being taken to address this. But two other epidemics, that of Hepatitis C and obesity, unless similarly tackled will add further to the burden of CLD in future years and increase health inequalities. Treatment of CLD is costly and of limited impact on mortality overall. About one thousand people a year die from CLD in Scotland. Most of these deaths are preventable. Without urgent action there will be many more.
'Scotland is experiencing one of the fastest growing rates of chronic liver disease mortality in the world. Recent rises are predominantly due to alcohol misuse. Urgent and radical action is needed and is being taken to address this.'