In the region of Lagos, neither prenatal nor neonatal screening for sickle cell anaemia is offered. So the age at which children are diagnosed with sickle cell anaemia has been unknown so far. Also, haemoglobin genotype determination is not performed on a routine basis; it is only done if requested by child’s caregivers or healthcare providers.
Early diagnosis of sickle cell anaemia is very important because many complications can be prevented by early diagnosis and treatment as well as by education of the parents on complications requiring immediate care. Newborn screening for sickle cell disease in California, USA, has shown that screening, coupled with extensive follow-up, reduces mortality.19, 20
Improved survival of screened babies has also been confirmed by the Jamaican cohort study that showed a reduction of early causes of death such as acute splenic sequestration, pneumococcal septicemia, aplastic crisis, and acute chest syndromes.24
The age at which diagnosis of sickle cell anaemia was made had a wide range and standard deviation for two reasons – absence of a routine screening programme for the diagnosis and the fact that there is no specific age at which manifestations attract attention of parents/guardians. Nearly three quarters of our subjects were diagnosed before the age of three while more than 10% were diagnosed after their fifth birthday. It is plausible that a number of factors, particularly social and health circumstances could have contributed to earlier diagnosis of some of our children. In the absence of a routine screening program, diagnosis is often made when patients show up with suggestive clinical features. Early diagnosis may in turn depend on health-seeking attitude of caregivers among other factors. In any case, the establishment of a routine screening programme which could be prenatal, neonatal or tied to child welfare services like immunization would significantly reduce the number of children with delayed diagnosis for any reason. The major limitation of our report is that we do not know the circumstances under which the diagnosis was made in individual subjects. If for instance, diagnoses were mostly made because the children presented with suggestive history or physical findings, differences in type and severity of initial presenting features would explain differences in age at diagnosis. If on the other hand, the parents requested the tests, health–seeking behaviour would be called to question. If the children had visited hospital and/or had blood tests a number of times before the diagnosis, lack of a surveillance system that would demand routine haemoglobin genotype screening would be at fault.
The present study showed that the overall mean age at diagnosis of study subjects was significantly higher among female subjects than male subjects. The explanation for the different pattern in females and males may be because male is more prone to sickle cell crisis as they are more exposed to known precipitating factors.25
Lack of significant difference emerged on stratification according to age-groups. It is possible that the lower numbers attendant upon such stratification was responsible for the loss of significance.
The study also revealed that an upper socioeconomic stratum was associated with younger age at diagnosis of sickle cell anaemia. This finding is consistent with that of Brown et al26
in Ibadan. It is logic to argue that upper socioeconomic stratum implies that there is better access to health care by such families as well as privilege to health information.
It is straightforward that a routine screening at some point is imperative in Lagos. This may be done prenatally, in the neonatal period or sometime in the first year of life using DNA analysis or Agar gel electrophoresis respectively. Some workers27
have reported screening in the first year of life through infant welfare clinics and well baby clinics e.g. during the measles immunization visit at nine months as a viable approach in developing countries with limited resources.