Analysis of seasonal variation of sickle cell disease with crisis and associated complication in the United States from 2011 to 2019. Free

Introduction: While the clinical burden of sickle cell disease (SCD) is well recognized, observations suggests that environmental factors, including seasonal changes, may influence the frequency and severity of sickle cell crises. Understanding the temporal patterns of SCD-related crises and associated hospitalizations can provide critical insight into triggers, inform patient management strategies, and improve resource allocation.

Methods: This study examined seasonal variations in sickle cell disease with crisis across U.S. hospitals from 2011 to 2019, based on hospital type, size, and geographic region, using the Nationwide Inpatient Sample (NIS). The study population included adults aged 18 and older with a primary discharge diagnosis of sickle cell disease and with crisis of acute chest syndrome, splenic sequestration (ICD codes). Statistical analyses were performed using Stata version 15.1. Discharge weights accounted for the NIS sampling design, with a p-value of <0.05 considered statistically significant.

Results: We identified 175,537 patient discharge records with a diagnosis of SCD during the study period. The majority were African American (93.0%), aged 18–44 years (86.2%), with slight female predominance (55.5%).

Seasonal distribution of discharges was roughly equal and approximately equal proportions of discharges (about 25%) were recorded during each of the four seasons of the year.Hospitalization rates per 1,000,000 population ranged from 4.1± 0.1 in February to 4.8± 0.1 in January, with highest admissions from October to March, but seasonal hospitalization averages did not differ significantly (ANOVA p = 0.9198), and no trend was observed over time (p = 0.7345).

Although, complication rates peaked in June and July, but the seasonal complication rates in winter, spring, summer, and fall were without significant variation (36.1% ± 7.62, 36.7% ± 7.91, 36.9% ± 8.10, and 35.7% ± 8.67% respectively) (ANOVA p = 0.9883). However, a significant overall decline in complications was observed over time from 2011 to 2019 (p < 0.001). Similarly, a significant downward mortality rate trend was noted over time (p < 0.001), though seasonal differences in mortality odds were not statistically significant.

Lastly, subgroup analysis did show seasonal associations for specific complications, including increased odds of splenic sequestration, and DVT in summer, lower odds of acute chest syndrome during fall and bacterial pneumonia during summer.

Conclusion: From 2011 to 2019, there was no significant seasonal variation in overall hospitalization among adults with Sickle Cell Disease in crisis. However, several specific complications exhibited seasonal patterns, particularly during summer months. Notably, mortality rates showed downward trend, indicating improvements in disease recognition and management over last decade. Further research is needed to understand the underlying factors contributing to these variations and improve patient outcomes.