MRC Dyspnoea to predict survival in PH
Research type
Research Study
Full title
MRC Dyspnoea risk stratification in pulmonary hypertension
IRAS ID
313175
Contact name
Martin Johnson
Contact email
Sponsor organisation
NHS National Waiting Times Centre
Duration of Study in the UK
3 years, 0 months, 2 days
Research summary
Summary of Research:
Pulmonary hypertension (PH), when untreated, leads to progressive right ventricular failure and death. Current guidelines advocate the use of risk stratification to predict prognosis and to identify the need for treatment escalation. The World Health Organisation (WHO) Functional Class (FC) is four-point scale and is a predictor of survival. A deterioration in FC is an alarming indicator of disease progression, which should trigger investigation with consideration of treatment intensification. Multiple risk models have been proposed in PH which incorporate WHO FC, including the recent development of the COMPERA 2.0 model. However, all current risk models have their drawbacks, including the need for patients to attend face-to-face and for blood sampling as they include the blood test NT-proBNP.
An alternative non-invasive classification could be the 1988 modified Medical Research Council (mMRC) dyspnoea scale which measures perceived disability arising from breathlessness. This has five scales, giving the potential to allocate WHO FC III patients into additional strata. Respiratory physicians, who in many centres are responsible for the care of PH patients, are better acquainted with this score. Whilst validated in other respiratory conditions such as interstitial lung disease, this scale has not been studied in PH and the association with survival is unknown.
This study therefore aim to assess, in pulmonary hypertension, how each scale of the MRC Dyspnoea scale affects survival and how this model compares to the COMPERA 2.0 model and to WHO functional class for predicting survival.
Summary of Results:
Risk stratification models in pulmonary arterial hypertension (PAH) rely on World Health Organisation Functional Class (WHO FC). A high proportion of patients are classified as WHO FC III, a heterogenous group which limits the stratification abilities of risk models. The Medical Research Council (MRC) Dyspnoea Scale may allow a more precise assessment of functional status and improve current risk models. We investigated the ability of the MRC Dyspnoea Scale to assess survival in PAH and compared performance to WHO FC and the COMPERA 2.0 models. Patients with Idiopathic, Hereditary or Drug‐induced PAH who were diagnosed between 2010 and 2021 were included. The MRC Dyspnoea Scale was retrospectively applied as derived from a combination of patient notes, 6MWD tests results and WHO functional status using a purpose‐designed algorithm. Survival was assessed using Kaplan-Meier analyses, log rank testing and Cox proportional hazard ratios. Model performance was compared with Harrell's C Statistic. Data from 216 patients were retrospectively analyzed. At baseline, of 120 patients classified as WHO FC III, 8% were MRC Dyspnoea Scale 2, 12% Scale 3, 71% Scale 4 and 10% Scale 5. The MRC Dyspnoea Scale performed well compared to the WHO FC and COMPERA models at follow up (respectively, C‐statistic 0.74 vs. 0.69 vs. 0.75). It was possible to use the MRC Dyspnoea Scale to subdivide patients in WHO FC III into groups which had distinct survival estimates. We conclude that at follow‐up, the MRC Dyspnoea Scale may be a valid tool for the assessment of risk stratification in pulmonary arterial hypertension.
REC name
West of Scotland REC 5
REC reference
22/WS/0149
Date of REC Opinion
6 Oct 2022
REC opinion
Favourable Opinion