title: Prognosis and prognostic factors in sporadic inclusion body myositis.
abstract: OBJECTIVE
  To describe the course of change in muscle strength sporadic inclusion body myositis (IBM) patients.
  
  
  METHODS
  We have studied a cohort of 66 IBM pateints using a hand-held dynamometer.
  
  
  RESULTS
  Follow-up during a mean of 61.1 months showed a deterioration of on average -0.79% per month. The 'natural course' without immunosuppressive treatment (IS), analyzed in 43 patients (mean 46.4 months) was mean -1.03% per month. Loss of muscle power was most rapid in knee extension -1.12% (P < 0.001 when compared with elbow flexion, elbow extension and hip flexion). There was a tendency towards a more rapid decline in males than females and over the first 5 years after onset, while the level of serum creatine kinase (CK), age, or region affected at onset did not predict the prognosis. The mean change during periods with any IS treatment was -0.76% per month which was significantly lower compared to the total of untreated periods -1.03% (P < 0.05). Patients (n = 13) treated with mykofenolatmofetil showed a better prognosis of -0.67% per month (P < 0.05). In this group elbow flexion and extension and hip flexion showed a positive response, while knee extension was seemingly unaffected.
  
  
  CONCLUSIONS
  There is a mean of 1% loss in power per month in the untreated IBM patient - the rate of loss was greater in the quadriceps muscle and in untreated compared with IS-treated patients.
authors.affiliation: Clinical Neuroscience and Physiology, Section of Neurology, Sahlgrenska Neuromuscular Center, Sahlgrenska University Hospital, Gothenburg, Sweden. christopher.lindberg@vgregion.se
authors.forename: C
authors.initials: C
authors.lastname: Lindberg
authors.forename: A
authors.initials: A
authors.lastname: Oldfors
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018908:Muscle Weakness / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology*; D018979:Myositis, Inclusion Body / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology*