Conference: 2008 International PHA Conference and Scientific Sessions
Release Date: 06.20.2008
Presentation Type: Abstracts
Murugappan M. 1, Taichman D. 2, Williamson T. 3, Sundy R. 1, Byers B. 1, Duncan M. 1, Zheng J. 1, Chakinala M. 1
1. Washington University, St. Louis, MO, USA
2. University of Pennsylvania, Philadelphia, PA, USA
3. Kansas University Medical Center, Kansas City, KS, USA
BACKGROUND: The World Health Organization (WHO) functional classification (FC) scheme is an important assessment in pulmonary arterial hypertension (PAH). Given its subjectivity and variability across graders, a role exists for an accurate, reliable instrument to aid in FC assignment.
METHODS: Enrolled patients at Washington University completed an unencouraged 6 minute walk (6MW) with Borg dyspnea score (BDS) and a novel questionnaire that gauged their daily activity tolerance. Interviewers assigned FC based on routine clinic evaluation while blinded to the questionnaire & 6MW distance (6MWD). One interviewer (MC) as well as two outside pulmonary hypertension specialists (DT and TW) assigned FC based on completed questionnaires, unaware of patient identity & 6MWT results. Intra-grader and inter-grader agreements for FC assignment (I/II vs. III vs. IV) solely based on questionnaires were assessed by weighted Kappa (K). Agreement between FC assignment by interviewer and by questionnaire was also determined in a subset of patients. Relationship between questionnaire-assigned FC assignment and 6MWD was assessed by analysis of variance (ANOVA).
RESULTS: 53 patients were enrolled: 39 females (74%), mean age 49 (±13) yrs, diagnoses (36% Idiopathic PAH, 23% collagen vascular disease, 41% other). Based on interviews, 49% were FC I/II, 38% FC III, and 13% FC IV. 6MWD and BDS significantly differed among these groups [mean 6MWD (ft): 1441 (±237), 1035 (±317), 528 (±155), respectively (p<0.001); mean BDS: 2.7 (±2.2), 5.0 (±2.6), 7.0 (±2.9), respectively (p<0.001)]. Intra-grader agreement for FC, based on questionnaires, among individual physicians was substantial to almost perfect (K =0.75-0.86). Overall inter-grader agreement for FC assignment based on questionnaires was moderate (K = 0.53), while pair-wise agreements between clinicians’ interpretations were moderate to substantial (K = 0.48-0.71). Agreement in principal clinician’s FC assignment between interview and interpretation of questionnaires was moderate (K = 0.58). For each physician, there was a significant relationship between 6MWD and questionnaire-based FC assignments (p<0.001).
CONCLUSION: This pilot study revealed moderate to substantial intra-grader and inter-grader agreement for FC assignment in patients with PAH, based on a novel questionnaire. Inferences of FC assignments based on questionnaires were significantly related to 6MWD, a well-established parameter of functional outcome in PAH. Future studies to further refine and validate the questionnaire are warranted.