The nature of case-mix coding may well be impacting on the data used to estimate drug-related excess mortality in the USA. Using annual death rates for 1999–2016 stratified by state, sex, five-year age group, and cause of death, researchers have modelled the relationship between drug-coded mortality and mortality from other causes. For people aged 15–64 living in the USA, the estimated number of drug-associated deaths in 2016 (141,695) was 2.2 times the number of drug-coded deaths (63,000). The researchers suggest that in the absence of drug use, the probability of dying between ages 15 and 65 would have continued to decline after 2010 among men (to 15% in 2016) and would have remained at a low level (10%) among women, meaning that that an additional 3.9% of men and 1.8% of women died between ages 15 and 65 in 2016 because of drug use. Drug-associated mortality in the US is thought to be roughly double that implied by drug-coded deaths alone – both illicit drugs and misused medicines are contributing. See the study here