When we talk of health we also need to measure it, because as is often being said in management circles, what gets measured gets done. So when we plan health programs, then we need to find out what the impact of those programs is in terms of improving health indicators.
This is important for national systems to look at how they’re functioning and faring in terms of various health priorities. It’s also important to compare across different countries, over time within countries and across geographies in different countries and sometimes over time in terms of the global trends.
Policymakers will also find it very important not only to use it as a measure of progress, but also for priority setting. Clearly when there are a number of priorities which need to be addressed in terms of different health challenges, and they have to allocate resources, they will have to decide which are the ones which are really the most important in terms of tackling early on and those which can be tackled later on or how to allocate resources across different programs.
The WHO defines health as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.Therefore it s a positive definition, not a negative definition, therefore it goes beyond the absence of disease or infirmity in stating positive attributes of health.
However, it s a holistic definition which is very pleasing but difficult to measure and pin down. So how do we actually measure health? One of the important measures is longevity because as societies advance one expects life expectancy to improve and life to grow longer and longer. So that depends upon when and why people die. And that captures the life expectancy on an average within a country. But as we know, there are wide disparities in life expectancy across different countries. Japan for example has a life expectancy of 83 years, whereas Mozambique has a life expectancy of 53 years and in between we have Sweden at 82, Bangladesh at 70 and Tanzania at 59.
But the important thing to remember is that while we must try and reduce this huge gap in life expectancy as a measure of health across the world, it is quite clear that all the years of life are not lived in good health. So there are some years which are compromised by ill health. And therefore we are also looking at a modified measure of life expectancy which is healthy life expectancy. That means if you remove the amount of years lost due to ill health, by adjusting in some way for the level of ill health and the years lived with ill health and then subtract that from the total life expectancy, then you come to healthy life expectancy. And Japan in this case has 75, which is very good. That means the gap between life expectancy and health life expectancy is not very large.
On the other hand, Mozambique which started off with a low life expectancy has a very low healthy life expectancy of only 37. And the gap therefore is quite substantial of 16 years. That means, even in the shortened life expectancy of Mozambique, several years
are consumed by ill health. So when we re looking at cause of death for example, one of the very important measures in international comparisons, there is an international classification of diseases which was first proposed by William Farr. And now we are in the tenth revision. So different diseases are provided different criteria of diagnosis and then we attribute the cause of death to the most important cause that contributed to death. And then we compare again, across countries as to which are the dominant contributors to death and within in countries too we compare across social groups and we compare across time periods to see whether there are transitions occurring or whether health policies and health programs have had the desired impact.
And some of these are also linked to individual causes of death or age groups or particular types of programs that we are really trying to assess. Like for example, infant mortality rate, child mortality rate, maternal mortality ratio, or disease specific mortality. What is the mortality contributed by cardiovascular diseases as a whole and what is the mortality contributed by coronary heart disease and stroke separately? So we look at all of these in a manner that is disease specific.
And this we gain from different sources of information. Usually countries should have vital registration systems which are quite robust. They should also have very good cause of death certification procedures based on the international classification of diseases. You can t go around classifying death in a very arbitrary manner and then expect good comparison. So you need a standardized method of certifying death and physicians and others who certify death must be trained properly to really adhere to that. Others include hospital records, national and international surveys like demographic health surveillance systems,sample registration systems and so on. Cause of death information is best generated from systems of civil registration and vital statistics. When these systems are either incomplete or dysfunctional and not really reliable in terms of the validity of the information generated or the completeness of information generated, we can still attempt to gain some useful information on births and deaths from other sources. These include demographic surveillance sites, sample registration systems, population censuses and household sample surveys.
None of them give the full information that we can get from civil registration systems. However by supplementing the limited information that they offer with structured verbal autopsy techniques, we ll be able to get additional information which can inform policy and programs even as civil registration systems are being established or strengthened.
In some countries where the vital registration systems and cause of death certification is not very widespread, well established, or reliable, people also undertake techniques known as verbal autopsy. In order to try and send trained people into the community to try and identify deaths which have taken placeand then through a very well structured interview, try and ascertain what the potential causes of death might have been in those cases. And these are usually verified against available medical records or a physician opinion. So there are different ways of ascertaining mortality data.
But we also need to measure morbidity because death is not the only thing that matters in life. Good health matters and therefore living a life in good health without disability is a very important objective in any society. And therefore we have to measure disability or handicap. And therefore we have to first start defining disability. So every disease carries a certain degree of disability. In some cases, very short-lived, in some cases chronic or in some cases, permanent. So we have to try and measure what the durational disability is and what the degree disability is. So in terms of health expectancy measures, we do look at disability measures and there are multiple disability measures that are there for different categories of diseases. But again, we are faced with a challenge of compressing all of this into one or two indicators which capture all of the information. And there we ideally should look for measures that combine mortality and morbidity, particularly for comparisons across countries and comparisons over time within countries.
So disability adjusted life expectancy has been something that was proposed in the World Health report of year 2000. And now it s called Healthy Life Expectancy. If you assess the nature of disability, attach some weights to it, estimate the number of years lived with that particular disability which could vary actually in terms of its severity across those years, but ultimately calculate the cumulative loss of healthy life years because of the disability and subtract that from the overall life expectancy, then you get healthy life expectancy. So this measures the equivalent number of years expected to be lived in full health.
Now there is another measure that has come in to play, particularly through the global burden of disease project. This was first introduced into global health in the year 1994. This was again to capture the combined burden imposed by premature mortality and prolonged disability as a summative measure. It combines the years of life lost due to premature death and the years lived with disability weighted for the degree of disability. And therefore it subtracts the amount of life lost because of that weighted disability. And this again has become an important measure though it has become a little controversial sometimes by saying that it s a bit of an ageist measure and then it sets too much premium on years of life lost and substantially overweighs certain categories of death and disease over others. But nevertheless it s a useful measure for global comparison.
At the same time, there are other estimates that have come in in terms of measuring health gaps. Years of life lost. This is estimated on a population basis, compared to potential maximum life expectancy, which in this case is Japan. Then we also look at years lived with disability. These are all subcomponent measures of the DALYs. These all go into the calculation of disability adjusted life year lost. So the years lived with disability, they estimated on a population basis the number of cases with that particular condition must be multiplied by the average duration of the disease and a weight factor that reflects the severity of the disease on a scale from zero, which is perfect health to one which is death.
The global burden of disease studies as I said, first started in 1990. They were published in the first version in 1994 and subsequently they have been revised extensively in 2010 and are going to be also periodically revised. And currently the Institute for Health Metrics and Evaluation in the University of Washington-Seattle is now leading this effort. And they do comparisons of global burden of disease across different countries and groups of countries using the disability adjusted life years. This has had an unprecedented scale and effort going into this, of looking at multiple data sources and compressing that all into a measure that provides for global comparison. It does give a global picture of progress and the status of health which is not available presently through any other source because most of the other measures fall short either in terms of measurement of disability or being very disease specific or particular age specific.
But it also is an important measure for highlighting emerging focus areas and improvements in health. For example, in 1994, when the first global burden of disease study came in, people were surprised to note that many of the low and middle income countries already had very advanced epidemics of non-communicable diseases where there was a lot of premature mortality and a lot of disability. And until the calculations of disability adjusted life year loss was done, mental health did not emerge as a very major factor in global health. So the DALYs calculated for all of these were a great contribution in helping us to re-prioritize some of our public health interventions.
But there are some justifiable criticisms. There are always issues raised on the quality of data available from different countries and ultimately whatever is the summative measure is dependent upon the quality of the data and the extrapolations made. And again, there is a little criticism that this is an ageist measure and this weighting system also is sometimes controversial. The amount of weights attached by patients, by physicians and by people who are healthy tend to vary. And therefore we re not sure which the actual weight to be utilized is. The DALYs and the global burden of disease are supposed to be guides to resource allocation, but they do not always account for differentials in resource availability.
Remember, sometimes you have to take equity also into consideration. You have to take affordability issues into consideration. And there are multiple other factors that go into policymaking. Nevertheless, for prioritizing public health action and to some extent resource allocation, the GBD is useful indeed. We understand that measuring disease burdens is a complex activity but a very important activity. It s an evolving process. We are still gathering knowledge about what are the best methods of assessing disease and the disease burdens and measuring health free from disease but global health requires these metrics for decision-making, for comparison and for advancing our progress to adequately prioritized public health programs.
But we also recognize that health now must be positioned fairly effectively in the broader developmental context. It can t be seen in isolation from other developmental activities, including the whole area of sustainable development which is now coming to the fore in the United Nations. So there are some of the indices that are coming up in which health forms a part of a broader development index. Dissatisfied with the gross domestic product as an indicator of economic progress, Stiglitz, Sen and Fitoussi who are very major international economists developed what is known as a well-being index which captures multiple areas including environment, education, poverty reduction, health, among several others. And therefore this is a composite index. There is a multidimensional poverty index developed at Oxford which looks at health, education and living standards and measures poverty in multiple dimensions, including the lack of health. There is a social progress index that s currently under development which looks at basic human needs, foundations of well-being, opportunity and brings in some of the environmental concerns as well.
So as we move towards the sustainable development goals we need to definitely improve our measures of health, but we also need to see how we can coalesce those measures with other developmental indicators to get an idea of what a healthy society should be in all dimensions.