Peripheral autonomic impairment in sickle cell anaemia (SCA)

Impairment of autonomic nervous system seems underestimated in SCA. To assess the prevalence of sudomotor dysfunction in SCA patients, and to identify relevant associated clinical/biological phenotypes. A total of 90 adult homozygous SCA patients–exclusively sub-Saharan-African-native–referred to our centre for a routine-follow-up were included. Clinical and biological data were collected as well as electrochemical skin conduction (ESC) measurements using Sudoscan®. A total of 34 healthy subjects with the same ethnic origin and matched for age, gender and BMI, were enrolled for ESC comparison. Among SCA patients, median age was 29.3 years, 51% were males. Neither overweight nor hypertension was reported. Mean Haemoglobin, reticulocyte-count, bilirubin and lactate-dehydrogenase was respectively of 8.9 ± 1.5 g/dL, 242 ± 122,109/L, 49.5 ± 34.7 μmol/L and 467 ± 169 IU/L. Percentage of glomerular hyperfiltration, micro and macroalbuminuria was respectively of 31.4%, 31% and 26.2%. ESC values for both hands (HESC) and feet (FESC) were significantly reduced in SCA patients compared to controls (P < 0.0001), with ESC measures below normal values in 61% of patients (HESC < 60 μSiemens and/or FESC < 70 μSiemens). Among SCA population, FESC values were negatively associated with age (P < 0.0001) and albumin-creatinine-ratio (P = 0.02), and positively with Haemoglobin (P = 0.03) and estimated-glomerular-filtration-rate (P < 0.0001). However, after adjustment with multivariate regression, FESC remained associated with only age and Haemoglobin (b = −1.14, P = 0.0001 and b = 3.6, P = 0.03 respectively). Sudomotor dysfunction is an underdiagnosed frequent event in SCA patients. Its quantification could be of potential interest to assess the magnitude of peripheral autonomic impairment and/or microvascular lesions.