It may be one of the causes. Sure it does guide one's attention towards this pandemic. Though there can be other factors as well.
1- As far as I have seen on the database of WHO, more than 20,000 people die each year in Italy during 2012-15 of lower respiratory tract infections.
2- The almost same figure is for Iran.
But Dr Sb, each year, we loose 70,000 People just because of TB. So, it will be pretty much a thin chance that BCG has been playing its part in lower mortality rates in certain countries.
There can be problems on the other side of having improper data and/or diagnosis.
I still think that there is a correlation between the comorbidity and covid-19
and I doubt that the data from Italy is grossly misleading.
COVID-19, just like many other pathogens remain dormant in 80% of the cases.
Just like 95% of the population will test positive for Pseudomonas. But rarely it flourishes into a malady.
I think that a person dying because of cancer and does also test positive for corona virus does not mean that we shall count his death because of coronavirus, which is basically done in Italy to over inflate the statistics.
The death should be counted in cancer's account.
Diabetes in general population can have a correlation with the COVID-19 related deaths, as the natural immunity in diabetics is suppressed and their antibodies are usually either not there or are very weak.