Materials and Methods
We describe an 11-year retrospective cohort study performed at the Gudalur Adivasi Hospital. We analyzed the data of all patients with a diagnosis of SCD, who were followed up at the Hospital and community Area Centers from January 2008 to December 2018.
The Association for Health and Welfare in the Nilgiris (ASHWINI), a charitable non -governmental organization, was established in 1990 in the Gudalur Valley, a remote part of the Nilgiri hills of Tamilnadu in Southern India, to work with the marginalized and displaced aboriginals living there. ASHWINI’s Board consists of aboriginal members with a physician serving in an advisory capacity. ASHWINI trained aboriginals as nurses, pharmacists, laboratory technicians, community health workers, paramedics, accountants, etc. and set up a Comprehensive Health System comprising of 200 village-based health workers, eight primary care Area Centers each manned by two trained aboriginal nurses, and a 50 bed well equipped secondary hospital, the Gudalur Adivasi Hospital (GAH).11
This population of 18,506 individuals is made up of four distinct aboriginal groups: Paniya (58%), Betta Kurumba (22%), Kattunayakan (13%), and Mullu Kurumba (7%), classified by the Government of India as Particularly Vulnerable Groups (formerly Primitive Tribal Groups).
The SCD program was started in 1997 with the establishment of the hemoglobin electrophoresis diagnostic facility. In 2004, with the support of the Government of Tamil Nadu, the program was greatly enhanced. Screening for SCD was started in this population in the villages, Area Centers, and GAH as a standard of care, using the sodium metabisulfite sickle cell preparation test. Positive samples underwent cellulose acetate electrophoresis to be differentiated into HbAS, Sickle Cell Trait (SCT) and HbSS, SCD
In Dec 2011, neonatal screening for SCD by High Performance Liquid Chromatography (HPLC) performed by an accredited laboratory (Neogens Lab, Bangalore) was initiated at GAH.
In this cohort of patients diagnosed with SCD, a standardized bundle of SCD care, termed “comprehensive care” was delivered, inclusive of counseling, healthcare review either at the Area Centers or GAH, multivitamins, iron, and analgesics. From 2005, prophylactic penicillin until 5 years of age was offered; symptomatic patients and those with a history of admissions in crisis were started on 5 hydroxyurea (5HU) at 10 mg/kg body weight with monthly and later, when this dosage was found to be safe, three monthly monitoring of the white blood cell count. In 2011 the polysaccharide pneumococcal vaccine was introduced, as this was not part of the National Immunization Program, and administered at the age of 2 years and penicillin discontinued.
We reviewed hospital medical records of SCD patients who died in the hospital and extracted the details of demography and mortality including sex, age, genotype, date of death, and their causes. The data of the patients with missing hospital records and deaths outside the hospital were collected utilizing World Health Organization verbal autopsy (WHO VA 2016)12 questionnaire from close associates of the deceased and a semi-structured questionnaire added to get a clear understanding of the causes which lead to death, using the Anderson Newman behavioral model of health service use, social-ecological and social autopsy models.13,14  No post mortem autopsies were performed.
We investigated the age of death in the general aboriginal population during the study period. Of note, the accurate age of older adults in the aboriginal population was difficult to determine because of the absence of formal registration of births before 1990 in this remote region, even though the compulsory registration of births and deaths was introduced by the Government of India in 1969.15 Thus the lack of birth certificates and varied self-reporting of age by illiterate aboriginals could lead to uncertainty about the accurate age of the older individuals. The age of death in this group was determined using the village census list. However, the age of the younger people was accurate as it was taken from their birth records with the Unique Id numbers.
The study was approved by the ASHWINI institutional review board