The effect of diagnostic criteria on dementia prevalence – A population-based study from Gothenburg, Sweden

• Published in: The American journal of geriatric psychiatry 2024-02, Vol.32 (2), p.230-243
• Main Authors: Wetterberg, Hanna, Najar, Jenna, Sterner, Therese Rydberg, Kern, Silke, Skoog, Ingmar
• Format: Article
• Language: English
• Subjects: Algorithms; Bias; Cross-Sectional Studies; Dementia; Dementia - diagnosis; Dementia - epidemiology; Dementia - psychology; Diagnosing; Diagnostic and Statistical Manual of Mental Disorders; Geriatrics; Geriatrik; Humans; International Classification of Diseases; Medicin och hälsovetenskap; Prevalence; Sweden - epidemiology
• ISSN: 1064-7481; 1545-7214; 1545-7214
• DOI: 10.1016/j.jagp.2023.08.018

•What is the primary question addressed by this study? How does the use of different diagnostic criteria (DSM-III-R, DSM-IV, DSM-5, ICD-10 and ICD-11) influence the prevalence of dementia among a population-based sample of octogenarians?•What is the main finding of this study? The ICD-11 yielded the highest prevalence of dementia and ICD-10 the lowest. The agreement between the different criteria was overall high, with the highest being between the most recent editions: ICD-11 and DSM-5.•What is the meaning of the finding? The choice of diagnostic criteria has large effects on the estimated prevalence of dementia, and comparing estimates based on different criteria should be performed cautiously. To examine how the use of different diagnostic criteria (DSM-III-R, DSM-IV, DSM-5, ICD-10 and ICD-11) influence the reported prevalence of dementia. Two cross-sectional population-based studies of systematically selected 85-year olds in Gothenburg, Sweden, (N=774), were examined in comprehensive health examinations including comprehensive neurocognitive examinations. Five algorithms based on the diagnostic criteria in the DSM-III-R, DSM-IV, DSM-5, ICD-10, and ICD-11 were created, including 105 different variables that were operationalized in different ways to match the criteria of each classification system. ICD-11 yielded the highest prevalence of dementia (36.4%), followed by DSM-5 (32.9%), DSM-IV (30.7%), the clinical consensus DSM-III-R diagnosis (26.7%), DSM-III-R (21.4%), and ICD-10 (20.5%). The agreement between the DSM-5 and the ICD-11 was κ = 0.9. All other kappa values ranged between 0.6-0.9. The choice of diagnostic criteria has large effects on the estimated prevalence of dementia. We found that the recent editions, the DSM-5 and ICD-11, gave a higher prevalence of dementia than older editions. We also show that the attempts to harmonize DSM and ICD and has in part been successful, however, there are still differences between the systems.