The impact of transition from paper to electronic death records on garbage codes in the Norwegian Cause of Death Registry 2018–2023

Abstract Background In 2018, electronic death certification was gradually introduced in the Norwegian Cause of Death Registry (NCoDR). Electronic certification was made mandatory from 2022. This may have affected the use and pattern of ill-defined death codes, so-called “garbage codes”, reported as the underlying cause of death. This study aimed to assess whether the transition from paper to electronic certification changed the magnitude and pattern of garbage codes in NCoDR. Methods The analyses included all deaths with a registered underlying cause of death in the period 2018–2023 ( n = 248 225). A garbage code was defined according to the definition used by the Global Burden of Disease study. Trends and patterns of garbage codes were assessed and its association with type of certificate (paper/electronic) estimated using a modified Poisson regression model estimating relative risks with 95% confidence interval (CI) adjusting for sex, age at death and place of death. Results In the complete study period, 22.6% of the deaths were registered with a garbage code as the underlying cause of death. The probability of a garbage code was 21% lower in electronic compared to paper certificates (adjusted relative risk 0.79, 95% CI 0.78–0.80). This difference was stable over time and led to an overall decrease in the proportion of garbage codes with increasing use of electronic certifications. The decrease in garbage codes over time was mainly driven by more specific coding. The five most common garbage codes were I50 (Heart failure), J18 (Pneumonia, organism unspecified), I64 (Unspecified stroke), R96 (Other sudden death, cause unknown) and X59 (Accidental exposure to unspecified factor), accounting for more than one third of the garbage codes in the study period. The proportion of all of these, except for I50, were significantly lower in electronic compared to paper certificates, most notably so for J18 and I64. Conclusion The transition from paper to electronic certification led to an improvement in cause of death registration through a reduction in garbage codes, although garbage codes remain a considerable problem. An electronic system can provide guidance and feedback to the certifying physician, thereby providing opportunities for further improvement in data quality.