Gender and Regional Differences in In-Hospital Mortality in Patients with Sickle Cell Anemia (SCA) in the United States: Results from the Nationwide Inpatient Sample (NIS) 1993-2003.

Background: The purpose of this study was to use the NIS to describe hospital utilization and in-hospital mortality among adults with SCA in the US between 1993-2003.

Methods: The NIS is designed to approximate a 20% stratified sample of U.S. community hospitals. We restricted our analyses to discharge records with ICD-9-CM diagnosis codes 28261 or 28262 (SCA without/with crisis), and where the age was listed as 18 or older. Analyses were conducted using tests of linear combinations of coefficients, χ², and linear and logistic regression.

Results: There were an estimated 705,080 hospitalizations over the time period (mean of 64,098 hospitalizations/year). 54% of all hospitalizations were for females. 50% of the hospitalizations were expected to be paid for by Medicaid. The mean patient age over the time period was 31.3 yrs. The mean patient age increased from 30.3 in 1993 to 32.1 in 2003 (p < 0.001). Mean age over time increased even after adjusting for the gender makeup and hospital region (β=0.162, p < 0.001). There were no gender differences in the median age (30) of patients. Mean length of stay (LOS) was 6.5 days for the time period. LOS decreased from 7.5 days in 1993 to 6.4 days in 2003 (p=0.001). Adult women experienced longer LOS than adult men (6.8 days vs. 6.3 days, p <0.001). This difference remained significant even after controlling for age, time, insurance status, and hospital region (β = 0.49, p<0.001). Mean charges/discharge increased from $16,799 in 1993 to $22,281 in 2003, even after adjusting for inflation (p < 0.001). There were an estimated 4497 in-hospital deaths during the time period (0.64% of hospitalizations). The median age at death was 38. The median age at death increased from 35 in 1993 to 42 in 2003 (p = 0.0061). This was due to an increase in age of death (39) for women (p=0.0052). In men the median age of death (37) did not change over time(p=0.4352). In bivariate analyses of median age at death, women were older than men (39 vs. 37 p=0.0056). A simple logistic regression of deaths over time found no significant trends in the odds of an in-hospital death over the time period. In a multivariate model of death over time patients in the South and the West experienced higher odds of an in-hospital death than patients in the Northeast and Midwest.

Conclusions: Our analysis shows that women with SCA have longer in-hospital LOS than men, and are older in age at death than men. While the median age at death among persons hospitalized with SCA has been increasing since 1993, this increase is seen exclusively in women. There has been no change in longevity in men hospitalized with SCA over the time period studied.