The Dilly-DALY of health metrics

The Pandemic led to a data revolution. Newspapers scrambled to make the best-looking charts on statistics like daily hospitalizations, mortality, and recovery rates. Of these stats, mortality rate became the household favorite. Countries were compared based on this metric, and subsequently, health policy was optimized to reduce mortality rates.

But this metric does not come close to capturing the true impact of COVID. People who contracted COVID but did not die did, in fact, suffer from many diseases like pneumonia. The incubation period of these diseases was prolonged in many cases, and many people now live with 'long COVID’. 

Measuring the impact of diseases should include a measure that is not as 'final' as mortality. The ideal metric should be able to capture the disease's disruptive effect, which might not lead to death. 

Let's dissect this idea with a variation of the wannabe philosopher's favorite thought experiment: The trolley problem.

Imagine country A, where everyone who contracts a disease will lose 20 years of their lives. And on the other hand, in country B, where 5 percent of the population who contract a disease will die, the rest would be completely unharmed. Which disease is more threatening, or rather which country would you choose to live in? 

If mortality rate was the only metric in consideration, everyone would choose country A. But, it is improbable that everyone would choose country A in real life. Ergo, there is something remiss with only accounting for mortality rates; it does not reveal true human preferences. Why must then mortality rates be the center of all public health assessments?

So, how can one solve this problem? The answer lies in DALY — Disability-adjusted Life Years. This metric translates the disease's burden to the number of life years lost.

If you are incapacitated due to COVID for a whole month, your DALY due to it would be 1/12th of a year. This a simplified explanation. The metric as formulated by W.H.O includes other factors like disability weight, time discounting, age adjustment.

However, this measure has yet to be adopted by mainstream reporting. The non-inclusion of DALY has led to countries deprioritizing the 'non-mortal' impact of COVID, such as the increase in mental health burden, the loss of schooling, the loss of wages, and thus overall quality of life and well-being. 

It has also painted a wrong picture of countries' performance vis-à-vis handling the Pandemic. Many southeast Asian countries boast about their low COVID mortality rates, which, BTW, is owed to the low age of their population. This chest thumping has allowed these countries to forget about the 'non-mortal' impact or 'scarring' due to the Pandemic. 

Countries in the global north that have high rates of drug abuse have forgotten about the stronghold that substances have over their youth just because they have the means to avert mortalities. Had DALY been the metric of choice, they would realize the true impact of substances; the fall in schooling, increased mental health diseases, and constant relapses. 

To solve a problem, we must first identify it. In that, DALY is a step forward. However, some might contend that focusing on 'non-mortal' metrics will deprioritize mortality rates, leading to an increase in deaths. It is not necessarily true that one type of measure will elude the importance of another. It is more likely that they will reinforce each other. Suppose policymakers seek to improve general well-being, nutrition, and education. In that case, it will lead to lower death rates by way of preparedness, much so in the long run. If metrics like DALY are not popularized, the political leadership will never be fully accountable. Health policy will not improve. 

To know more about the impact of different diseases in terms of DALY, or to measure DALY inequality, have a look at the interactive charts on ourworldindata.org