Daily Pain Is Unrelated to Admission Rate in Adult Patients with Sickle Cell Disease

Sickle cell disease is characterised by frequent episodes of vaso-occlusive pain resulting in frequent health care utilisation and cumulating organ damage. Disease severity is often quantified by the number of hospital admissions. However, sickle cell patients frequently experience episodes of pain without health care utilisation. In the present study, we analysed whether daily self-reported sickle cell pain in adult patients is related to disease severity quantified by frequency of hospital admission or disease severity defined by genotype.

We conducted a prospective cohort study in order to analyse daily pain in adult sickle cell patients in a tertiary teaching hospital in the Netherlands. Patients were divided in having severe (HbSS/HbS-β⁰) or milder (HbSC/HbS-β⁺) disease according to genotype. Daily pain was assessed for a period of 6 months by the use of pain diaries. Pain intensity was measured with different validated pain assessment instruments (Visual Analog Scale (VAS), McGill Pain Questionnaire and Brief Pain Inventory). Daily pain scores were correlated with genotype and frequency of hospital admission.

110 consecutive outpatients with sickle cell disease were approached. 16 patients were excluded for different reasons (pregnancy, unable to fill in a diary or declined participation), 19 patients missed their appointments in the outpatient clinic and 26 patients completed less than a month of their diaries. 49 patients (mean age 33 years (SD 12.6); 67% female) completed at least two month of the diaries (response rate: 65%). No differences in disease severity according to genotype or age were observed between responders/non-responders.

Pain was reported in 18% of the total 5016 patient-days. Overall median pain intensity was 3.6 (VAS). 41% of the patients reported pain in 5% or fewer diary days and 5% of all patients reported pain in more than 95% of the days. The frequency of hospital admission was unrelated to self-reported pain and no difference in daily pain was observed between patients with severe or milder disease according to genotype. Furthermore, lab results (hemoglobin and fetal hemoglobin levels, leukocyte counts, lactate dehydrogenase (LDH) and the presence of alfa-thalassemia) were not associated with daily pain.

Using daily pain diaries, adult sickle cell patients report pain in 18% of their total diary days. Interestingly, our patient population reported less daily pain in comparison to daily pain in adults reported previously (over 50%). Daily pain appeared to be unrelated to disease severity according to genotype or defined by frequency of hospital admission. Our results further stress that daily pain is an important problem in sickle cell patients and appears to be unrelated to the traditional definitions of disease severity.

No relevant conflicts of interest to declare.