Incidence of ICD-Based Diagnoses of Alcohol-Related Disorders and Diseases from Swedish Nationwide Registers and Suggestions for Coding

Abstract

Aim

To improve consistency between register studies in Sweden and ensure valid comparisons of possible changes in alcohol-related disorders and diseases (ARDDs) over time, we propose a definition of ARDDs. Based on this definition, we examined Sweden’s incidence rates of ARDDs from 1970 to 2018 in non-primary healthcare settings (inpatient and outpatient).

Methods

Swedish Society of Epidemiology members were invited to give feedback on the International Classification of Disease (ICD) codes with a potential link to alcohol use. We then calculated age-standardised and age-specific incidence of ARDDs over time according to the National Patient Register, and the lifetime prevalence of ARDDs diagnosed in adults alive in Sweden on Dec 31, 2018.

Results

Sweden’s estimated incidence of ARDDs increased substantially after introducing the new ICD-9 codes in 1987. In the past 10 years (2009–2018), the incidence of ARDDs has been stable (males: 110/100,000 person-years, females: 49/100,000 person-years). Requiring at least two ICD records for diagnosed ARDDs led to a somewhat lower incidence of ARDDs (males: 71 per 100,000 person-years, females: 29 per 100,000 person-years). In Sweden, the lifetime prevalence of diagnosed ARDDs in adults on Dec 31, 2018, was 1.9% (95% CI=1.9–1.9).

Conclusion

In this nationwide study, we found an incidence of ARDDs of 50–100/100,000 person-years. In 2018, 1 in 52 adults in Sweden had been diagnosed with ARDDs in the National Patient Register.

Keywords:

• alcohol
• alcohol use disorder
• alcohol-related disease
• alcohol drinking
• drug use
• ethanol

Acknowledgments

We are grateful to the Swedish Society of Epidemiology for providing help in distributing the web questionnaire.

Key Notes

• Alcohol-related disorders and diseases (ARDDs) are common but epidemiological research on ARDDs is hampered by a lack of consensus on definitions.

• Through a web questionnaire, followed by group discussions, we systematically developed and agreed on a definition for epidemiological research on ARDDs using International Classification of Disease (ICD) codes in nationwide registers linked to high alcohol consumption.

• The incidence of ARDDs has been stable over the past 10 years. One in 52 adults in Sweden has been diagnosed with ARDDs in national registers.

Abbreviations

ARDDs, alcohol-related disorders and diseases; ICD, International Classification of Disease; NPR, National Patient Register.

Disclosure

Andrea Johansson Capusan reports personal fees from Camurus, Indivior, and Lundbeck, outside the submitted work. Fredrik Nyberg reports being an employee of AstraZeneca until 30 September 2019, outside the submitted work. Jonas F Ludvigsson reports coordinating a study on behalf of the Swedish IBD quality register (SWIBREG); this study has received funding from Janssen corporation. The authors report no other potential conflicts of interest for this work.

Additional information

Funding

The study did not receive any external funding.