The patients’ profiles in this study are compatible with those described in the literature, with a predominance of homozygous disease (SS), female sex, non-white individuals, and young individuals [9, 12, 13]. However, most patients in this study reported a low frequency of pain crises, which is different from that reported in previous studies [9, 14, 15].
Platt and colleagues has suggested that people with SCD with HbF values > 8% have a higher survival rate , which may indicate a better prognosis for our patients, but with cumulative damage to the osteoarticular system.
The bone is the second most affected organ by SCD after the spleen . We found 140 osteoarticular lesions in our cohort (mean: 2.61/participant). However, 20% participants did not present any radiographic lesions.
Previous studies have evaluated osteoarticular involvement in patients with SCD in the acute phase. However, our study evaluated lesions in patients on a steady-state fasis, which explains the low incidence of infectious and inflammatory changes, which were highly prevalent in past studies [17,18,19], and a high incidence of OA and ON.
The main sites of bone involvement were the spine, followed by the femur and the shoulders and the most frequent changes were ON, followed by OA, as classically described .
The prevalence of ON in people with SCA ranges from 3.2 to 26.7% [19,20,21,22]. In our study, this complication affected approximately one-third of the patients. However, like other studies, we observed that the prevalence of ON increases with age, which may be a consequence of recurrent episodes of bone infarctions. Globally, SCD is probably the most common cause of avascular necrosis that most commonly affecting the femoral and humeral heads .
Patients with SCD may develop OA, usually secondary to ON, which progresses to OA in 86% patients when not properly treated [24, 25]. These data justify the high prevalence of this type of lesion verified in the evaluation of patients in an outpatient setting on a steady-state basis.
The occurrence of radiographic alterations did not present a statistically significant association with sex, skin, age, number, and intensity of pain attacks; however, we observed that despite the higher percentage of individuals without radiographic lesions in the young group, painful crises were of high intensity in this group. In the group of people with ≥5 injuries, the majority were adults and females. Radiographic changes are secondary to injuries suffered by patients throughout their lives, which may explain the higher incidence of young patients among those without identifiable radiographic injuries and adults with a higher incidence of radiographic damage.
Individuals who regularly used HU had a lower incidence of multiple lesions than those who did not use it, statistically significant result.
Treatment with HU is associated with a significant reduction in the incidence of hospitalization, acute chest crisis, stroke, and vaso-occlusive crises, however, the impact of the use of this drug on the prevention and treatment of chronic osteoarticular lesions needs further investigation.
There is only one study published thus far regarding the osteoarticular alterations of SCD, which has cited high-dose HU significantly reduced the incidence of ON in white and non-white patients aged > 18 years with ßS/ßS and ßS/ß + treated for 10 years .
A review article on the role of HU in SCD describes the importance of this medication in reducing the morbidity and mortality in these individuals . Because of the effects of HU in reducing the sickling of red blood cells, elevating HbF, reducing oxidative stress and vaso-occlusive crisis consequently, we infer that HU also has a positive impact on osteoarticular lesions, as reinforced by the findings of the present study.
SCD is a disease that has a great impact on the osteoarticular system of affected patients, which can lead to functional limitations and low quality of life, requiring special care by a health team. Until new drugs are available, HU should always be considered an important therapeutic option in patients with SCD.
The main limitations of the study were the small sample size, its heterogeneity, the limitation in the recording of data in medical records, and the difficulty in performing some tests in our hospital.
Future studies with a larger sample, including other hemoglobinopathies, control group and nuclear magnetic resonance exams may bring further clarifications on this topic.