OBJECTIVES: To evaluate the relationship between pain crisis and life-threatening complications in sickle-cell disease (SCD) patients.

METHODS: A retrospective study was conducted using the Medicaid Analytic Extracts Database from 2009-2013. SCD patients were identified using ICD-9-CM diagnosis codes (282.41-282.42, 282.60-282.69) and first observed SCD diagnosis during the identification period was designated as index date. Patients were required to have continuous Medicaid enrollment for 6-month pre- (baseline) and 12-month post-index period and were followed until earliest occurrence of disenrollment, death, or study end. Patient characteristics, pain crisis, mortality and life-threatening complications were examined. Pain crisis was defined as inpatient stay with a diagnosis of SCD with crisis (ICD-9-CM: 282.42, 282.62, 282.64, 282.69). Cox regression was used to evaluate the relationship between pain crisis and life-threatening complications with pain crisis in the follow-up as a time-dependent covariate.

RESULTS: A total of 20,909 patients were included with a mean age of 17.9 (Standard Deviation=15.2]) years. 65.7% of the patients were black with an average Charlson Comorbidity Index of 0.4. The event rate of inpatient pain crisis (including multiple events per person) was 89.1 in 100 person-years and mortality was 0.5 in 100 person-years. Incidence rates of life-threatening complications in 100 person-years were: acute chest syndrome (5.6), stroke (2.0), pulmonary embolism (0.8), splenic sequestration (0.7), and pulmonary hypertension (0.7). Patients with follow-up pain crisis had higher risk for death (Hazard Ratio[HR]=1.6, 95% Confidence Interval [CI] [1.2, 2.0]) or life-threatening complications such as acute chest syndrome (HR=58.7, 95% CI [50.2, 68.6]), stroke (HR=2.3, 95% CI [1.9, 2.6]), pulmonary embolism (HR=2.8, 95% CI [2.2, 3.6]), splenic sequestration (HR=44.0, 95% CI [30.7, 63.1]) and pulmonary hypertension (HR=4.1, 95% CI [3.1, 5.4]) compared to patients without pain crisis.

CONCLUSIONS: SCD patients had substantial burden of complications, and patients with pain crises had higher risk of other life-threatening complications.