Results
Between Sept. 1997 and Dec. 2018, 13,144 individuals were screened for sickle cell disease in the community and the hospital. Of those screened, 1102 (8.4%) were found to have SCT, and 149 (1.1%) to have SCD.  Of the 149 SCD patients, eight had died before Jan 2008, leaving a cohort of 141 aboriginals with SCD at the end of Dec. 2018.
As of Dec 2018, out of a total of 1,400 newborns screened, 239 (17.1%) were found to have SCT and 16 (1.1 %) to have SCD. Thus, the total cohort studied in this retrospective analysis from Jan 2008 to Dec 2018 was 157, the diagnosis of SCD was confirmed by either hemoglobin electrophoresis or HPLC. (Table1)
Fifty-one percent of the cohort was female. The majority of the patients with SCD were from the Paniya tribe 63.7%, with 17.8% from the Mullu Kurumba tribe, 10.8% from the Betta Kurumba tribe, and 8.3% from the Kattunayakan tribe.
The overall crude mortality rate was 14% (22/157) or 140 per 1000 population. All 22 deaths were from the Paniya tribe with a mortality rate of 22.2% (22/99) or 222 per 1000 Paniya population. (Table 2).
In the cohort of SCD patients who died, the median age of death was 24.5 years; in females 20.5 years and males 27 years.
Seventy percent of the deaths were in the 6-29 age group, 45% of deaths being in the 19-29 age group, followed by 25% in the 6-18 age group. There were no deaths in the 0-5 age group. Despite the comprehensive care package, none of the SCD children <5 years age took prophylactic penicillin, as the mothers were reluctant to administer the antibiotic to their apparently healthy babies. Even with the availability of the polysaccharide pneumococcal vaccine free of cost outside the National Immunization Program, they had not received it. Their intake of iron and multivitamins was also inconsistent.
More deaths 59.1% (13/22) occurred among the males with SCD.   Hospital deaths accounted for 54.5% (12/22) of deaths and the remaining deaths occurred at home (45.5%). A total of 12 deaths were reviewed by verbal autopsy. All causes of death were attributed to the sequelae of SCD. There were no deaths attributable to accidents or suicides. The causes of death were acute chest syndrome 31.8%, severe anemia 22.7%, sepsis 18.2%, pregnancy-related 9.1%, acute abdomen 9.1%, dehydration 4.6%, and stroke 4.6% (Table 3).
The annual mortality rate per 100 sickle cell disease population was 4.3 in 2008 and 0.7 at the end of the study period in 2018. Between 2008 and 2018, the mortality rate was variable, but the overall rate has been trending down (Figure 1).
During the study period, 1771 individuals from the non-SCD aboriginal population died; the mortality rate was 9.6% and the median age of death was 55 years. The ten commonest causes of deaths were stroke (12.8%), suicides (10.8%), cardiovascular diseases (10.5%), cancer (10.1%), old age-related (9.8%), < 5 years (8.2%), unknown (6.8%), trauma (accidents/homicide/alcohol-related violence) (6.1%), COPD/asthma (3.7%) and acute gastroenteritis (3%).