Flip Flop Flu, WHO Rule 3 & The Blip Of COVID (part 1)
A festive frolic involving a bit of time series modelling of deaths from influenza and pneumonia so that we may see what we once saw
Whilst spaced out on a heady mixture of Covonia for chesty coughs, rum + raw honey toddies and Christmas carols I penned an intermission that included a daft slide. There’s a story behind that slide that you can bone-up on by going back to my original article entitled Flip Flop Flu (part 1). To cut a long story short the WHO decided to annihilate flu and pneumonia deaths back in 1984 - 1992, and again from 2001 onwards by virtue of a change in the coding of death certification known in the business as “rule 3”.
The groggy monkey in me wanted to know what the time series for flu and pneumonia deaths might have looked like if rule 3 had not been permanently implemented in 2001 and, in particular, whether COVID would still have stood out like a sore thumb.
Definitions
We need to start with a couple of definitions and so for this particular bake I chose the nations of England and Wales combined, and I decided to consider causal death. Yes indeed, I’m well aware of the many problems and issues surrounding cause of death coding! These existed in the era before COVID and it was my painstaking job to boss a team about to do this as best we could whilst casenotes were still hot and registrars willing to be grilled.
This landing page of the Office for National Statistics, with the grand title of All Data Related To Deaths is where you need to go with your shopping basket and search phrases such as pneumonia and COVID. A couple of hours later and you’ll be knee-deep in spreadsheets in daily, weekly, monthly and yearly formats that need to be cobbled together to form a coherent spreadsheet for analytical purposes. This is the bit in the movie when the hands of a clock whirl round while a frantic montage of industry is shown over a suitable orchestral score.
When the final bars of music slow us to real time we may sit back in our chair and puff contentedly on a pipe (a liquorice one if we are health conscious) and slam down a neatly engraved spreadsheet for the period 1901 - 2022 with the following goodly columns, backed by a broad smile:
England & Wales Population (mid year estimate)
Registered Births (live)
Registered Deaths
Natural Change (Births – Deaths)
Crude Mortality Rate (Deaths/100k)
Deaths due to influenza and pneumonia
Deaths due to COVID
Let us now get the oven on and start baking some treats!
Christmas Cake
I couldn’t resist kicking-off with all cause crude mortality for the period 1901 – 2022. This is one of those slides that is rather like Christmas cake: there’s all sorts of nuts and fruit in there, along with ale, brandy, egg and grated carrot. Interpretation is difficult because soooo many things have been changing over time, and not just in terms of healthcare and the social sector. We are looking at the kitchen sink; in this instance the kitchen cake: