The aim of a study was to determine whether the clinical characteristics and electrodiagnostic classification of nerve injury, and response to treatment differed in patients diagnosed with chronic inflammatory demyelinating polyneuropathy ( CIDP ) with and without diabetes.
CIDP patients with diabetes ( CIDP+DM ) ( n = 67 ) and without diabetes ( CIDP-DM ) ( n = 67 ) underwent clinical examination and nerve conduction studies ( NCS ).
CIDP-DM patients were selected using age and gender matching with the existing CIDP+DM cohort.
Patients treated with immunotherapies were classified as responders ( R ) ( n = 46 ) or non-responders ( NR ) ( n = 54 ) based on clinical response to treatment.
CIDP+DM subjects had more severe neuropathy based on higher lower limb vibration potential thresholds ( VPT ) ( p = 0.004 ), higher Toronto Clinical Neuropathy Score ( TCNS ) ( p = 0.0009 ), more proximal weakness ( p = 0.03 ), more gait abnormality ( p = 0.03 ) and more abnormal nerve conduction studies.
CIDP+DM subjects had more abnormal sural nerve conduction studies with lower sural sensory nerve action potential amplitudes ( 2.4±3.0 microV, 6.6±6.0 microV, p less than 0.0001 ) and slower sural nerve conduction velocities ( 38.6±5.4 m/s, 41.0±5.3 m/s, p = 0.04 ).
CIDP-DM subjects were more likely to receive immune therapies ( 93% vs 57%, p less than or equal to 0.0001 ), despite no significant differences in treatment responder rates ( p = 0.71 ).
Patients who responded to therapy had shorter duration of CIDP than non-responders ( 8.0±6.0 years vs 11.9±7.6 years, p = 0.004 ).
The clinical phenotype and electrophysiological profile of CIDP patients differs according to the presence or absence of diabetes.
Despite CIDP+DM patients having more severe clinical and electrophysiological neuropathy, they are less likely to receive disease-modifying / specific therapy, yet have similar response rates to treatment as those without diabetes. Specifically, the duration of neuropathy, not diabetes status, was associated with treatment response. ( Xagena )
Dunnigan SK et al, PloS One 2014; 9(2):e89344