QoL was assessed by the use of SF-36 forms. The SF-36 is a short-form health survey that has been proven to be valid and reliable in the black population [15] . It has been previously used to determine QoL in adults with SCD [16] . Briefly, it yields eight different scales (physical functioning, role limitations due to physical problems, role limitations due to emotional problems, social functioning, mental health, vitality, bodily pain, and general health perceptions) of functional health and well-being as well as psychometrically based physical and mental health summary measures. The SF-36 is a generic measure, which is not age, disease, or treatment specific. Accordingly, the SF-36 has proven to be useful in surveys of general and specific populations, comparing the relative burden of diseases [7] . All patients were asked to complete this questionnaire during a routine outpatient visit. All scale scores are linearly converted to a 0-100 scale, with higher scores indicating higher levels of functioning or well-being. We analyzed the scores of our study population and compared the data with the scores of the general healthy Dutch population [7] .