Rate and correlates of weight change in Huntington's disease

Objective: To determine the rate and correlates of weight change in a large, well characterised sample of patients with Huntington's disease followed at 44 sites by the Huntington Study Group. Participants and methods: Weight change was assessed in 927 adults with a definite diagnosis of Huntington's disease who were followed prospectively for (mean (SD)) 3.4 (1.4) years. The unified Huntington's disease rating scale was used to assess weight, motor dysfunction (including chorea and dystonia), depressive symptoms, and functional decline. Results: Random effects modelling determined that patients gained an average of 0.11 (1.7) kg/year and their chorea scores increased by 0.36 (0.78) points/year. There were significant but weak relations between weight loss and increasingly severe chorea (r = -0.13), worse baseline motor performance (r = -0.12), less severe baseline depressed mood (r = 0.14), and poorer baseline independence ratings (r = 0.07). Patients who were within 0 to 2 years of symptom onset at the time of the baseline visit gained more weight than those with longer disease duration. Conclusions: Weight loss following symptom onset is not a consistent feature of Huntington's disease. The mechanisms contributing to weight change in this condition are unclear and probably multifactorial. Future studies examining asymptomatic carriers of the mutation could be helpful in identifying incipience of low body weight and may be better suited for identifying clinical correlates of weight loss than studies in symptomatic patients.