Impact of Hydroxyurea On Employment Among Patients with Sickle Cell Anemia.
Authors: Ballas Samir K. , Bauserman Robert L , McCarthy William F. , Waclawiw Myron A , Barton Bruce A 
Published: October 2019

Abstract
Abstract 2485
Poster Board II-462

Introduction:
Sickle cell disease (SCD) has a negative impact on education, career development, employment, and work history. Repeated painful crises and chronic complications (leg ulcers, retinopathy, etc.) can limit employment options and interfere with work attendance. Young adults frequently report that their health has interrupted educational plans and prevented their finding a full-time job. The purpose of this study is to examine employment patterns over time among SCD patients enrolled in the Multicenter Study of Hydroxyurea (MSH) in Sickle Cell Anemia, a randomized placebo-controlled double-blind study of whether hydroxyurea (HU) treatment could reduce the rate of painful crises in SCD.

Patients and Methods:
The N=299 adult patients in MSH were recruited from 21 sites across the U.S. and Canada, and were evenly distributed between males and females. Patients were at least 18 years old with a diagnosis of sickle cell anemia and at least 3 painful crises in the year prior to entry. The trial was terminated early due to a beneficial effect of HU on painful crises, but led to an observational follow-up and extension.Patients reported employment status at baseline and at 12, 24, and 36 months in the clinical trial; during the follow-up, employment data was collected in years 1-5 and 7-9. We categorized patients as ‘employed' (working full or part time) or ‘unemployed' (any other response, including unemployed, disabled, in school, retired, etc.). About 90% of all responses in this category were either unemployed or disabled, rather than other options such as in school.We examined employment history in 2 ways. First, changes from baseline to 24 months in the clinical trial (there was little data for 36 months due to the early termination) were categorized as continuous employment, continuous unemployment, shift from employment to unemployment, or from unemployment to employment; chi-square analyses were used to compare groups. Second, using all available data from the trial and follow-up, we calculated cumulative employment for each patient as the proportion of years employed out of all years of available data (up to the maximum possible of 12 years of data). This allowed us to obtain values for all patients despite missing data from some years. Linear regression models were used to compare groups.Employment history was compared between the placebo group and HU treatment responders and nonresponders (responders were defined as patients with % fetal hemoglobin < 15% before treatment and > 15% two years later). Many patients moved from placebo to HU following the clinical trial, but original group assignment was used for analyses because the HU group would have had the earliest and most consistent exposure to HU.

Results:
Descriptive data were suggestive of better employment outcomes for HU responders. During the clinical trial, 41% of responders and 29% of nonresponders were continuously employed or moved to employment. However, differences between responders, nonresponders and placebo patients were not statistically significant (p=.73). Across all years of data, responders were employed in 34% of years, versus about 30% for nonresponders and placebo patients. However, differences between groups were again not statistically significant (p=.71).

Conclusions:
Recurrent episodes of acute and chronic pain are characteristic of SCD. In MSH, HU treatment significantly reduced the rate of painful crises, the need for blood transfusion, and morbidity and mortality. Although some aspects of quality of life improved in this cohort of patients with moderate to severe SCD, employment patterns during the clinical trial and overall proportion of years in employment did not significantly differ. These findings point to two important aspects of HU treatment.First, employment effects may differ with more timely initiation of HU. MSH patients had moderate to severe SCD at enrollment, and some already had related disabilities (such as avascular necrosis) unaffected by HU. Earlier initiation of HU may prevent or delay onset of the most serious SCD complications that can negatively affect employment. Second, data such as those reported here may be of use in counseling young SCD patients regarding employment. The Americans with Disabilities Act defines rights of disabled/impaired persons in the workplace and awareness of this may lessen stress due to fear of losing a job or being unable to find employment.

Disclosures:
No relevant conflicts of interest to declare.