Is the Rule of Halves framework relevant for diabetes care in Copenhagen today? A register-based cross-sectional study

OBJECTIVE: The study aimed at analysing whether the ‘Rule of Halves’ framework applies for diabetes care in the Danish healthcare system with high levels of accessibility and equity. The Rule of Halves states that only one-half of people with a particular chronic condition are diagnosed; one-half of those diagnosed get treatment, and one-half of treated achieve desired therapeutic goals. DESIGN: The analysis is cross sectional based on available surveys, register data and clinical databases covering the adult population in Copenhagen. We analysed five levels of prevention and care including behavioural risk factors and biomarkers, prevalence of diagnosed and undiagnosed diabetes as well as how many received care according to guidelines and achieved relevant outcomes. SETTING: The study population is Copenhagen City with a population of 550 000 with 21 500 prevalent cases of diabetes. While the registers used cover the whole population, the surveys include 750 cases and the biobank data 365 cases. OUTCOME MEASURES: Outcome measures are for each level of analysis: the prevalence of high-risk individuals, prevalence of undiagnosed and diagnosed diabetes, proportion receiving treatment and proportion achieving quality and treatment targets. RESULTS: We found that the ‘Rule of Halves’ framework raises relevant questions on how diabetes care works in a specific population, but the actual proportions found in Copenhagen are far from halves. Our analyses showed that 74% are diagnosed and among those who are 90% are receiving care. 40%–60% have achieved target levels of treatment in terms of HbA1c level and lipid levels. 80% have received eye and foot examinations in the last 2 years. 11% have retinopathy and 25% have macrovascular complications. CONCLUSION: Copenhagen is doing much better than halves, when it comes to diagnosis and providing treatment, whereas the Rule of Halves still prevails when it comes to treatment targets. There is thus still room for improvement.