Background: The epidemiological characteristics of chronic inflammatory demyelinating polyneuropathy (CIDP) are still not fully understood.
Methods: The clinical and epidemiological characteristics of CIDP in an Italian population were assessed. All subjects with a diagnosis of demyelinating neuropathy after 1990 in Piemonte and Valle d’Aosta (4,334,225 inhabitants) were considered. The diagnosis of CIDP was based on the AAN research criteria.
Results: One hundred and sixty-five out of the 294 patients found met the diagnostic criteria. The crude prevalence rate was 3.58/100,000 population (95% CI 3.02 to 4.20). At the prevalence day, 76 (49.0%) cases had a definite, 67 (43.2%) a probable, and 12 (7.7%) a possible CIDP; the disability was mild in 105 (67.7%) cases, moderate in 32 (20.6%), and severe in 18 (11.6%). The course was remitting-relapsing in 40 cases (25.8%), chronic progressive in 96 (61.9%), and monophasic in 19 (12.3%). Considering the 95 patients whose disorder presented in the 1995-2001 period, the mean annual crude incidence rate was 0.36/100,000 population (95% CI 0.29 to 0.44), with a men to women rate ratio of 2.3:1. Fourteen cases were affected by diabetes mellitus. In multivariate analysis, factors related to severe disability at the prevalence day were: age>60 years; failure of immunomodulating therapies at the time of diagnosis; worse disability at nadir; and chronic course.
Conclusion: Incidence and prevalence rates of CIDP in Italy are higher than those observed in most previous studies. At prevalence day more than 80% of cases had a mild or moderate disability, indicating either a good response to immunomodulating therapy or a tendency of CIDP to have a mild course in most cases.