Myopathy in the elderly: evaluation of the histopathologic spectrum and the accuracy of clinical diagnosis.

We undertook a retrospective clinicopathologic study to ascertain the spectrum of histopathologic muscle biopsy changes in the elderly thought to have a myopathy, and to determine the accuracy of clinical diagnosis of myopathy in the elderly compared with a younger control population. We compared muscle histology and case histories, as well as EMG and creatine kinase (CK) data, obtained over 10 years from 77 consecutive patients aged 65 years or older (75 +/- 6, mean +/- SD; group 1) with those from 104 patients aged 30 to 50 years (group 2). Prominent myopathic features were present in 42% (group 1) versus 51% (group 2) of all biopsies. Neurogenic changes (17% versus 9%, p < 0.04) and type II fiber atrophy (22% versus 6%, p < 0.0005) were more common in the elderly, whereas normal findings tended to be less frequent (19% versus 35%). In at least 68% of patients in both groups with the histologic diagnosis of myopathy, either the CK was elevated or the EMG was consistent with that diagnosis. Our study indicates that (1) the spectrum of histopathologic changes in the two groups differs because of a higher frequency of neurogenic change and type II atrophy in the elderly, and (2) the accuracy of clinical diagnosis of myopathy in the elderly approximates that in a younger population.