Isokinetic muscle strength in long-term IDDM patients in relation to diabetic complications.
The isokinetic muscle strength in 56 IDDM patients with > 20 years of diabetes duration and in their individually sex-, age-, weight-, and height-matched control subjects was assessed. Peak torque of foot dorsal and plantar flexion and knee and wrist extension and flexion was measured. The neuropathic condition was assessed by a neurological disability score, a neuropathy symptom score, nerve conduction studies, and quantitative sensory examination. All results were summed to obtain a neuropathy rank-sum score for each patient. According to their renal albumin excretion, the patients were classified to have normo-, micro-, or macroalbuminuria. In addition, according to their retinal status, patients were classified as having no, simple, or proliferative retinopathy. The IDDM patients had a 21% reduction of muscle strength of both ankle dorsal (P < 1 x 10(-4)) and plantar flexors (P < 0.01), compared with control subjects. A 16% reduction of knee extensors (P < 0.005) and a 17% reduction of knee flexors (P < 0.01) was found. In contrast, muscle strength in wrist flexors and extensors was not significantly reduced (10 and 11%, respectively [NS]). In patients with the most severe weakness, muscle strength of the calf muscles was only 50% of the expected performance. Correlations were found between the neuropathy rank-sum score and the muscle strength of ankle dorsal (r = -0.66, P < 1 x 10(-7)) and plantar flexors (r = -0.51, P < 0.0005), knee extensors (r = -0.51, P < 0.0005) and flexors (r = -0.44, P < 0.005), and wrist flexors (r = -0.41, P < 0.005). No correlation was found for wrist extensors (r = 0). Neither were there any relationships between muscle strength at the ankle and knee and the degree of albuminuria or retinopathy. In conclusion, motor performance is substantially impaired in long-term IDDM patients, and the weakness is related to the presence of neuropathy but not to albuminuria or retinopathy per se.
Andersen
H
H
Department of Neurology, Aarhus University Hospital, Denmark.
Poulsen
P L
PL
Mogensen
C E
CE
Jakobsen
J
J
D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D003930:Diabetic Retinopathy; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009068:Movement; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009431:Neural Conduction; D010465:Perception; D012016:Reference Values; D012044:Regression Analysis; D014732:Vibration; D014955:Wrist Joint / Q000503:physiopathology