National Records of Scotland (NRS) analysis found almost three in 10 (28%) of the 63,587 deaths registered in 2021 were considered preventable or treatable, up from 27% in 2020.
The age-standardised rate of avoidable mortality rose to 350 per 100,000 people last year, up by 4% on the previous year.
Covid-19 was a “significant contributor” to avoidable mortality in 2021, with half of the increase in the latest year attributable to coronavirus deaths, NRS said.
The Covid-related avoidable mortality rate increased in 2021 to 35 deaths per 100,000 people, up from 29 per 100,000 in 2020.
The NRS report also found that in the most deprived 20% of areas in Scotland, the rate of avoidable mortality was 4.1 times as large as in the 20% least deprived areas.
Julie Ramsay, NRS head of vital events statistics, said: “Avoidable mortality doesn’t impact everyone equally.
“The rate of avoidable deaths in the most deprived areas was over four times the rate of those in the least deprived areas.”
In 2021, the avoidable mortality rate of those in the 20% most deprived areas was 659 per 100,000 people compared with 161 per 100,000 for those in the 20% least deprived areas.
The report also found that after adjusting for age, avoidable mortality rates among males (434 per 100,000) were 1.6 times as high as among females (272 per 100,000).
Cancers and circulatory diseases were the most common causes of avoidable mortality in 2021, accounting for 28% and 25% of all avoidable deaths respectively.
Alcohol and drug-related avoidable mortality rates increased for the ninth year in a row, with 53 deaths per 100,000 people in 2021.
Avoidable deaths are those which are considered either preventable or treatable through public health or healthcare interventions.
In March this year, the rate of avoidable deaths increased for the first time in two decades, rising 9 per cent to 336 per 100,000 people.
NRS said this increase was mostly due to Covid-19.
Before this the rate had fallen steadily, from 450 in 2001 to 308 in 2019.
The term avoidable mortality is based on an international definition by the Organisation for Economic Co-operation and Development/Eurostat and looks only at deaths under the age of 75.