Socioeconomic status affects pulmonary hypertension disease severity at time of first evaluation

A low socioeconomic status (SES) has been linked to disproportionate access to health care in many diseases, leading to worse disease severity at initial presentation. There is a paucity of these data in the pulmonary hypertension (PHTN) population. We studied the association of SES, as measured by zip code-based median annual household income, with World Health Organization functional class (WHO-FC) at time of first evaluation in PHTN patients. All patients evaluated at our center with a right heart catheterization revealing a mean pulmonary artery pressure of ≥25 mmHg within 12 months of initial evaluation were considered for the study. Demographics, WHO-FC, and zip codes were obtained from retrospective chart analysis. The 2010 US census was used to obtain zip code-based annual median income. The income groups were divided into quartiles. Patients were categorized by their WHO-FC and zip code-derived median income. Similar analyses were conducted for pulmonary arterial hypertension (PAH) patients. Survival was estimated with the Kaplan-Meier method. Data were analyzed in SAS, and P < 0.05 was considered significant. There were 228 PHTN patients (70 [30.7%] male, 158 [69.3%] female). As median income decreased, the FC at presentation increased, signifying higher disease severity (Spearman correlation: r = -0.161, P < 0.0515). This association between median income groups and WHO-FC at initial evaluation was significant (χ(2) test: P < 0.0168). There were 116 PAH patients (32 [27.6%] male, 84 [72.4%] female). There was again a negative relationship between income and initial FC (Spearman correlation: r = -0.0307, P < 0.0007). A lower SES was associated with worse disease, as measured by WHO-FC.