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Article Summary
Racial and Ethnic Disparities in Survival in Lung Transplant Candidates with
Idiopathic Pulmonary Fibrosis

Lederer DJ, Caplan-Shaw CE, O'Shea MK, et al. Am J Transplant. 2006;6:398-403.

Discussion

• A retrospective study was done to determine if race and ethnicity were associated with survival in patients with IPF.
• It was found that Black and Hispanic IPF patients referred for lung transplantation have a worse rate of pretransplant survival than White and Asian patients.
• Differences in pulmonary hemodynamics, exercise capacity, and socioeconomic factors were important.
• Exercise capacity and pulmonary hemodynamic alterations indicate that Black and Hispanic patients were sicker at the time of transplantation referral.

Study Design:

• Retrospective cohort study of consecutive IPF patients at single NY center
• Demographic and clinical data collected: Neighborhood characteristics, insurance status, marital status, age, gender, BMI, smoking history
• Physiologic data collected from initial transplant evaluation: spirometry, lung volume, DL_CO, 6MWT, cardiopulmonary exercise testing
• Primary endpoint: time to death from initial evaluation

Results:

• 50 IPF patients identified in cohort:
• 36 White non-Hispanic
• 6 Black non-Hispanic
• 6 White Hispanic
• 2 Asian
• There were no statistical differences between the Black/Hispanic and White/Asian groups in age, sex, BMI, history of smoking, percent enrolled in Medicare or an HMO, forced vital capacity, forced expiratory volume (FEV₁), total lung capacity, DL_CO, or SpO₂ after 6MWT
• Demographic and socioeconomic differences (Black/Hispanic vs White/Asian):
• percent married (33 vs 89, P = 0.0003)
• percent with private insurance (33 vs 76, P = 0.01)
• percent with Medicaid (50 vs 5, P = 0.001)
• neighborhood median household income ($27,000 vs $66,000, P = 0.0001)
• percent neighborhood families below poverty line (29 vs 3, P = 0.001)
• percent neighborhood high school graduates (63 vs 89, P < 0.001)
• Physiologic differences (Black/Hispanic vs White/Asian):
• mPap (27 vs 19 mm Hg, P = 0.03)
• meters walked in 6 minutes (285 vs 406, P = 0.045)
• exercise maximal workload (35 vs 74 watts, P = 0.002)
• anaerobic threshold reached (33 vs 68, P = 0.04)
• SpO₂ during unloaded pedaling (91 vs 95, P = 0.01)
• peak V_E (45 vs 60 L/min, P = 0.03)
• Though the time from evaluation to transplant was not different between the groups, the Black/Hispanic patients were more than 4 times more likely to die while waiting for transplantation (P = 0.05).
• Half of Black/Hispanic were listed for transplantation compared to 81% of White/Asian and of these, 17% Black/Hispanic were transplanted compared with 34% of White/Asian.
• Black/Hispanic patients had a 3-times higher risk of death after adjustment for lung transplantation (HR = 3.3, 95% CI, 1.2-8.9, P = 0.02).
• Black/Hispanic patients had a shorter pretransplant survival time than White/Asian patients. The 2-year survival estimates were 30% and 82%, respectively (P = 0.02).


          Kaplan-Meier survival curve for patients with IPF


• Study limitations:
• Retrospective design
• Single center
• Asians arbitrarily grouped with Whites (only 2 Asian patients)
• Duration of disease and prereferral status not evaluated
• Study period predates new allocation system, which may have an impact on these findings

Implications/Recommendations:

• Multiple factors correlate with risk of death in this retrospective analysis.
• Differences in exercise capacity, pulmonary hemodynamics, and socioeconomic factors appeared to account for some of the differences in survival.
• The main variable examined is race/ethnicity, but access to health services and disease severity at time of evaluation may contribute.
• These factors should be investigated in a prospective, multicenter study.
• Educational initiatives addressing the care of patients with pulmonary fibrosis, including diagnosis, treatment, and transplant referral, should be directed at minority patient populations and the physicians who care for them…timely subspecialist and transplant referral should be made available to patients of all ethnic and racial backgrounds.

Reference

1. Kawut SM, Horn EM, Berekashvili KK, et al. New predictors of outcome in idiopathic pulmonary arterial hypertension. Am J Cardiol. 2005;95:199-203.
2. Fiscella K, Franks P, Gold MR, Clancy CM. Inequality in quality: addressing socioeconomic, racial, and ethnic disparities in health care. JAMA. 2000;283;2579-2584.

Article link

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