In individuals with the disorder, disease duration may range from approximately 10 years up to 25 years or more.

All the patients enrolled in the study had been recently diagnosed with SSc and their disease duration was between 1 month and 1 year.

This difference between mean disease durations in the two groups was statistically significant (p<0.01).

The median disease duration was 8 (range 0.5-33) years.

Fifteen patients had colectomy for failed medical treatment after a mean of 15.6 years (range 9-32) disease duration.

Moreover, prevalence of dementia increases in relation to disease duration, going up to 80%.

Risk factors for increased dystonia in patients with Huntington's disease include long disease duration and use of antidopaminergic medication.

The amount of calcification is often related to disease duration.