Comparing pandemic death rates in Italy with UK

There is much media attention directed to the Covid19 deaths recorded in hospitals. As the weeks have passed, the headline figures have shown Covid19 deaths in UK hospitals exceeding those of Italy. I hope to show that comparisons of this kind are not possible.

The weakness in the comparison is it is only possible to compare one country with another if the underlying metric is universal. Not every person dying during the pandemic, in either country, has had a nasal swab. This renders comparisons of the Covid19 deaths in separate populations impossible.

However deaths from all causes are recorded with considerable accuracy. It is therefore possible to measure the excess deaths by comparing the mortality rates in each country with a 5 year average for the same period. Covid19 deaths in hospital are recorded so we do have a fairly accurate start point. These data are based on the six weeks following the first recorded Covid death.

The Italian population is approximately 10% smaller than in the UK; The statistics allow for this. Looking at the chart, we can see the pandemic, excess deaths (2020 rates minus the 5 year average) are greater in Italy than the UK. However is this significant? The chi-squared statistic which measures significance is 283.93, degrees of freedom = 1 and the all important p < 0.0001. This means the difference between the Italy and UK results is highly significant. However chi-squared does not gives us the magnitude or the direction. For this we need the odds ratio.

The odds ratio is 1.13 (CI: 1.11 – 1.14) which means the odds of dying from any cause in Italy in the 6 weeks from the first Covid19 death were 1.13 greater than in the UK. This is very different from headline figures and can be explained by swab testing not being universal.

Summary
I provide this analysis not to promote international comparisons but to debunk them. We cannot in the midst of the pandemic make any useful comparisons. This can only be done after we have eradicated the global infection. The time for meaningful analysis will come.


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