Background Given the rarity of Huntington’s disease (HD), large cohort studies are warranted to better understand the clinical burden of disease in routine clinical practice.

Aims To describe the incidence of clinical events in patients with HD compared with a matched cohort from the general population, and to describe differences between adult- and juvenile-onset HD.

Methods This was a nationwide cohort study linking data from the Swedish National Patient Registry, Prescription Drug Registry, and Cause of Death Registry. Patients of all ages with a first diagnosis of HD (ICD-10: G10) from 2002–2018 were included and matched 1:4 (on age and sex) to a control cohort without HD. Incidence rate ratios (IRRs) and 95% confidence intervals (CI) approximated the relative risk of clinical events occurring in patients with HD vs controls after first HD diagnosis. Incidence rates (IRs) of cases were compared in those aged < 20 years (juvenile-onset) or ≥ 20 years (adult-onset) at first diagnosis.

Results Overall, 1,492 patients with HD were matched to 5,946 controls. Median age at first diagnosis was 56 years (range: 0–96; 50% female; median follow-up: 8 years). Most outcomes were higher in patients with HD vs controls, with the greatest difference for (IRR [95%CI]): acute psychiatric episodes (14.4 [13.6–15.2]), subdural haematoma (7.5 [7.1–7.9]), communication and speech problems (6.4 [6.1–6.8]), depression (6 [5.7–6.4]), obsessive compulsive disorder (5.7 [5.4–6.0]) and anxiety disorders (4.4 [4.2–4.7]) (table 1). IRs for all studied clinical events were higher in adult-onset (N=1,447) vs juvenile-onset HD (N=45), except for epilepsy, asthma, gastrointestinal events, meningitis, and acute respiratory symptoms.

Conclusions This nationwide study demonstrates considerable disease burden in HD compared with the general population. Juvenile-onset HD have higher incidence of some clinical events when compared with adult-onset HD.

Study sponsored by F. Hoffmann-La Roche Ltd.