Abstract 160: Comparison of Baseline Characteristics Among World Health Organization Groups in Pulmonary Hypertension
Authors: Neshewat Julian M , Morgan Spencer , Weinstein David , Wasserman Amanda , McDevitt Susanne , Kline-Rogers Eva , McLaughlin Vallerie , Cascino Thomas 
Published: April 2019

Background:
The epidemiology of pulmonary hypertension (PH) is changing with increasing numbers of patients diagnosed with non-group 1 pulmonary arterial hypertension (PAH). The average age of patients diagnosed with PAH is older, and patients are living longer. As a result, patients with PAH frequently have non-PH related comorbidities that make the diagnosis of group 1 PAH challenging. Many patients evaluated for PAH are ultimately diagnosed with non-group 1 PAH, and comorbidities may impact disease progression and treatment response. Understanding presenting clinical characteristics and comorbidities of patients referred to a Pulmonary Hypertension Comprehensive Care Center has the potential to offer insights into the evolving characteristics of patients with PH.

Methods:
In order to better understand the clinical differences between the patients presenting in different WHO groups, several functional assessments were analyzed from the period surrounding their baseline clinic visit. Using 280 newly diagnosed patients from the University of Michigan’s pulmonary hypertension databasethat were either group I, II, III, or multifactorial, the groups’ mean body mass index (BMI), WHO functional class (WHO FC), six-minute hall walk distance (6MW), diffusing capacity for carbon monoxide (DL
CO
), and B-type natriuretic peptide (BNP) were compared. Additionally, the prevalence of ten comorbidities were collated to evaluate differences by etiology: chronic obstructive pulmonary disease, obstructive sleep apnea, interstitial lung disease, diabetes, arrhythmia, hypothyroidism, chronic kidney disease, hypertension, coronary artery disease, and obesity.

Results:
Two hundred and eighty newly diagnosed PH patients were analyzed (Group 1 = 67, Group 2 = 51, Group 3 = 35, multifactorial = 127). All of the comorbidities except for diabetes and thyroid disease yielded statistically significant differences among the WHO groups. Newly diagnosed Group I patients have the lowest mean BMI (27.97,
p
<.001) and number of comorbidities (2.55,
p
<.001), while the multifactorial patients had the most comorbidities (3.95,
p
<.001) and highest average BMI (34.26,
p
<.001). Group III patients had the lowest percent predicted DL
CO
(38.7,
p
<.001) and lowest mean 6MW distance (220.2m,
p
<.05). There were no statistically significant differences among groups for WHO FC, 6MW, and BNP.

Conclusion:
Patients with Group 1 PAH present with lower BMI and fewer comorbid conditions, whereas multifactorial PH patients present with the most comorbidities and highest BMI. The long-term effect of higher BMI and number of comorbidities in multifactorial PH is unknown. Group II and Group III PH patients did not demonstrate statistically significant differences in any of the baseline parameters. Further study including longitudinal follow up and response to treatment is warranted in each of the WHO Groups.