Low usage of hydroxyurea is a major obstacle towards optimized care for SCD in Sub-Saharan Africa. Here, we show for the first time in Tanzania that perceived susceptibility, severity, and threat of SCD complications among caregivers predicted hydroxyurea usage among their children with SCD who have unrestricted access to hydroxyurea through health insurance. Furthermore, we show that caring for children with SCD aged below 5 years of age and being attended at lower-level healthcare facilities were associated with low SCD threat perception. These findings have implications for public health measures aimed at speeding up the usage of hydroxyurea among children with SCD in Sub-Saharan Africa.
The perceived threat of illness is influenced by a person’s socio-demographics and economic status (18). However, there is a paucity of literature on SCD threat perception. In our study, the proportion of caregivers with high SCD threat perception was 61%. The age of the SCD child was found to influence the caregiver’s perception of the threat of SCD. Caregivers of under-fives with SCD had the lowest perceived threat scores. This is similar to other studies where it has been noted that the longer the duration of chronic illness, the higher the perception of the threat of the illness (23). Caregivers of older children had lived longer with the children and therefore, they may have experienced more negative consequences of the disease and understand the disease better than caregivers of younger children with chronic diseases (29, 30).
In our study, caregivers who attended at National hospitals (MNH Upanga and Mloganzila), the top referral hospitals in the country, had higher threat perception than caregivers who attended the regional referral hospitals (Amana and Temeke RRH). Even though medical specialists were available in all four hospitals, the differences in threat perceptions among caregivers may be caused by the difference in qualifications among other healthcare providers involved in the care of patients with SCD such as medical doctors and nurses, and the SCD education provided in these hospitals. Unlike Amana and Temeke RRH, MNH is a super-specialized teaching hospital and its SCD clinics are run by hematologists, hematology trainees, and nurses with vast experience in the provision of health education to patients and caregivers of SCD individuals. It was noted that SCD education was often provided by nurses in the patients’ waiting area before patients and their caregivers were attended by doctors. Additionally, healthcare providers in regional referral hospitals in Dar es Salaam were found to have inadequate knowledge of SCD and its management in 2021(35) Health education has been found to improve caregivers' and patients’ perceptions of diseases (36). Further, MNH is the National referral hospital, therefore the majority of SCD patients who attended clinics at MNH were likely to have been referred from other regional hospitals due to having acquired major SCD complications at one point. Experience of disease complications acts as a reminder of how the patients are susceptible to complications and associated effects of the disease to patients and caregivers (18).
We also found that the majority (222/229) of caregivers who perceived the threat of SCD as higher reported the use of HU among their children whereas the majority (104/145) of caregivers with lower threat scores reported their children not using HU. We found that children of caregivers with high SCD threat perception were 3.4 times more likely to use HU compared to children of caregivers with low SCD threat perception (IRR 3.4, 95% CI 2.7–4.5, p-value < 0.001). Higher perceived threat of SCD complications indicates a greater perceived need for treatment, hence the higher rate of hydroxyurea use. This is similar to other studies that have shown that high disease threat perception is associated with preventive behaviours to either avoid the acquisition of the disease or use prescribed medications to prevent getting complications related to the disease (28, 37–40). Over 50% of participants did not have adequate knowledge of SCD. This was shown by caregivers who did not perceive that a child with SCD is at risk of acquiring severe SCD complications, SCD having long-lasting complications or SCD being associated with fatal complications. Inadequate SCD knowledge and negative perceptions towards SCD such as believing that patients with SCD have shorter lives and therefore there is no need to treat or invest on them, have been mentioned in several studies as barriers to HU use (6, 17, 41). To increase the uptake of medication among patients with chronic diseases such as SCD, it is advised to provide adequate education to both patients and caregivers about the disease and the role of the prescribed medication in the management of the disease. Adequate SCD knowledge is associated with correct SCD threat perception, improved medication usage for SCD management, and overall improved quality of life among SCD patients (25, 26, 42, 43).
Although there was no statistically significant difference in threat scores among caregivers with different levels of education, we observed that caregivers who had at least a primary-level education had higher perceived threat scores (median scores above 540) than caregivers who did not have formal education (median 387). Other studies have shown that education levels influence the threat perception of diseases (23). The lack of association between caregivers’ education level and SCD threat perception in our study may be caused by the exclusion of caregivers of uninsured children with SCD. Health insurance subscription is influenced by education level and socioeconomic status (44). Therefore, the exclusion of caregivers of uninsured children with SCD possibly led to the exclusion of a significant number of caregivers with low or no formal education and low SCD threat perception. We excluded these participants to control other factors that may limit access to HU among study participants. In this study, the majority of caregivers were women (85.6%). Biological mothers constituted 72% of caregivers of children with SCD. We observed that mothers had consistently higher scores of perceived susceptibility, perceived severity, and perceived threat of SCD complications than fathers of children with SCD. However, the difference was not statistically significant. Women had a better understanding and correct perception of SCD because most often they are the primary caregivers of children and individuals with illnesses as has been observed in other studies (45, 46).
In conclusion, the age of the SCD child and the hospital where the child attends have shown a strong association with caregivers’ perception of susceptibility, perceived severity, and perceived threat of SCD complications, and these perceptions are associated with the use of HU among children with SCD attending SCD clinics in Dar es Salaam, Tanzania. We recommend the provision of health education on SCD to caregivers to improve their knowledge and promote accurate understanding of the potential adverse consequences of SCD, and at the same time promoting other aims such as access to affordable health insurance and sufficient availability of HU and thus improve the use of hydroxyurea among children with SCD in similar settings in Sub-Saharan Africa.
Study limitations.
A strength of this study was that we enrolled caregivers of health-insured children with SCD who attended public SCD clinics in Dar es Salaam where hydroxyurea was available, and therefore, we managed to control other factors that limit access to hydroxyurea such as high cost and unavailability of HU. This allowed us to study the effects of the perceived threat of SCD disease on HU usage in the absence of these major known HU use restrictions in SSA. On the other hand, we did not enquire about the presence of comorbidities unrelated to SCD and the number of people in households with chronic illnesses which could further explain the level of disease threat perception among caregivers with SCD children and potentially be another predictor of HU use. Therefore, the results are applicable to patients with access to HU such as health-insured patients, able to afford medication expenses or receive HU free of charge. However, it is important to note that the predictors could be different among other groups of patients with SCD who do not share the same access to HU.