Background To assess the coding quality of deaths and its impact on elderly unintentional fall mortality.

Methods Using data from the World Health Organization (WHO) Mortality Database, 1990–2019, we calculated number of countries/territories in the database, and proportion of deaths with five types of problematic codes based on the 10th international classification of disease (unspecified deaths, injury deaths with undetermined intent, unspecified unintentional injury, unintentional falls with unspecified mechanism, unintentional falls with unknown occurrence place). We estimated age-adjusted unintentional fall mortality before and after correcting problematic codes.

Results Only 64% (124/194) WHO member states had at least one-year mortality data during 1990–2019. Among the study years when countries/territories possessed mortality data, 80, 53, 51, and 63% had a proportion of unintentional falls with unspecified mechanism over 50% in low-income, lower middle-income, upper middle-income, and high-income countries/territories, respectively; comparable proportions for unintentional falls with unknown occurrence place were 100, 42, 71, and 62%. Among the 94 countries/territories having mortality data, problematic codes caused a relative mortality difference ≥50% in 59 countries/territories (63%). After correcting problematic codes, 5 of 55 countries/territories with data witnessed a reverse in mortality changes between 2005 and 2015. Among the 82 countries/territories with mortality data for 5 or more years, 18 countries/territories (22%) experienced a directional reverse in linear regression coefficient.

Conclusion The availability and coding quality of global elderly unintentional fall mortality data was poor during 1990–2019. Varying coding quality across countries/territories and over time have a substantial impact on mortality estimates and mortality comparisons.