Inaccurate coding of diabetes mortality deaths in Belgrade over time and the redistribution effects

Background

Priority setting and resource allocation in health care use death statistics, which are prone to coding errors. Considering the pathophysiology and death-certification practices, the Global Burden of Disease Study (GBDS) developed a typology of garbage codes (GCs - impossible, unspecified, intermediate, immediate, ill-defined, and unknown causes of death), and redistribution methods. Diabetes mellitus (DM) is a major health threat in the Belgrade population (Serbia). The study presents DM mortality burden in Belgrade before and after the GCs redistribution in 2015 (pre-pandemic) and 2020 (pandemic).

Methods

GC with serious and substantial policy implications (types 1 and 2) were proportionally redistributed to DM mortality (the International Classification of Diseases, ICD-10: E10-14.9) in Belgrade during 2015 and 2020, as advised by the GBDS age-sex group algorithm. The City Institute of Public Health of Belgrade approved access to population data and anonymised individual electronic mortality data.

Results

In 2015, DM accounted for 2.0% (472) of the 23,663 total deaths in Belgrade, including 409 deaths validly coded as DM and 63.3 deaths coded with GCs (Type 1=39.6; Type 2=23.7). In 2020, DM accounted for 3.3% (905) of the total 24,670 deaths, including 755 deaths validly coded as DM and 149.8 deaths coded with GCs (Type 1=103.8; Type 2=46). In 2020, 16.5% of total DM deaths were redistributed, increasing from 13.4% in 2015. The estimated DM mortality rate per 100,000 people in Belgrade before GCs redistribution was 24.3 in 2015 and 44.6 in 2020, and, after redistribution, 28.1 in 2015 and 53.4 in 2020.

Conclusions

The study reveals a near-doubling of DM mortality in the Belgrade population from 2015 to 2020, implying the necessity for improvements in DM management. Given the increase in the share of GCs related to DM mortality, there is an urgent need to train physicians who complete death certificates and to strengthen medical coding practices.

Key messages

• In Belgrade, the capital of Serbia, the mortality rate due to diabetes mellitus nearly doubled over six years, while death coding practices deteriorated during the same period.

• The ability to detect improper coding practices and reassign garbage codes should motivate local initiatives to enhance death certification quality and public health policy.