Cluster analysis of symptoms in pulmonary arterial hypertension: a pilot study

Background: Pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary artery pressures leading to right heart failure and death. Aims: The aim of this study was to use cluster analysis to describe the symptom profile in PAH and differences in the health outcomes of health status, health-related quality of life (HRQoL) and psychological states in the cluster groups. Methods: A cross-sectional descriptive design was used. A convenience sample completed a socio-demographic and clinical data form, a PAH Symptom Severity and Interference Scale, the Medical Outcomes Study Short Form (SF-36), the United States Cambridge Pulmonary Hypertension Outcome Review (US CAMPHOR) and the Short Form of the Profile of Mood States (POMS). Results: Of the 151participants, the mean age was 53.5 +/- 15.1 with the majority female (n = 128, 85%). Fifty-eight (41%) were disabled and 67 (44%) were Functional Class IV. The most prevalent symptoms were shortness of breath with exertion (n = 149, 99%) and fatigue (n = 144, 93%). Three clusters emerged: Cluster 1 diffuse symptoms (n = 93), Cluster 2 severe cardiopulmonary symptoms (n = 32) and Cluster 3 moderate cardiopulmonary symptoms (n = 26). Overall, on the SF-36 the participants had poor general health, reduced physical function, role physical, vitality, and a low composite score for physical health. On the POMS the sample had limited vigor and increased fatigue. Cluster 2 Severe Cardiopulmonary Symptoms had worse SF-36, US CAMPHOR and POMS scores than the other cluster groups. Conclusions: Patients with PAH are experiencing a constellation of symptoms that are interfering with their life and emerging clusters were present.