Early onset dactylitis associated with the occurrence of severe events in children with sickle cell anaemia. The Paediatric Cohort of Guadeloupe (1984-99).

Dactylitis or hand-foot syndrome is related to intravascular sickling and classically occurs around 6 months of life when haemoglobin S levels reach pathological significance. It has been hypothesised as a possible predictive factor of adverse outcome. The objective of this study was to estimate the survival without severe events (acute chest syndrome, stroke or death) according to early occurrence of dactylitis in the sickle cell paediatric cohort of Guadeloupe. The study period was 1 January 1984 to 31 December 1999. Medical data were recorded from birth for children with sickle cell anaemia diagnosed before 6 months of age. The Kaplan-Meier method was used to estimate the severe event-free survival and to draw related curves. We used proportional-hazard modelling to assess the risk of severe events (stroke or acute chest syndrome or death) in children with early dactylitis (before 6 months of age). The study sample comprised 114 children. The incidence [95% confidence interval] of clinical events per 100 child-years were 10.0 [7.63, 13.07] for dactylitis, 0.73 [0.33, 1.62] for stroke, 10.88 [8.35, 14.17] for acute chest syndrome and 1.06 [0.56, 2.05] for death. Thirteen of the 14 children who had dactylitis before 6 months of age had at least one severe event later in life. The median severe event-free survival time was 2.1 [1.6, 2.7] years in children with dactylitis before 6 months compared with 6.3 [4.5, 8.1] years in the other children; P < 0.0005. After adjustment for haemoglobin level <or=7 g/dL (25th percentile), leucocyte count >19 000/mm3 (75th percentile), transfusion before age of one year, acute splenic sequestration before the age of one year, the adjusted hazard ratio of severe event for children with early dactylitis was 2.13 [1.06, 4.40]; P < 0.03. Dactylitis occurring before 6 months of life identifies children at risk of severe complications who should benefit from close management.