The responsiveness and validity of the CAMPHOR Utility Index

¹ Galen Research, Enterprise House, Manchester Science Park, Lloyd Street North, Manchester, M15 6SE, UK
² Galen Research, Enterprise House, Manchester Science Park, Lloyd Street North, Manchester, M15 6SE, UK; and School of Psychology, University of Central Lancashire, Preston, PR1 2HE, UK
³ Pulmonary Vascular Disease Unit. Papworth Hospital NHS Trust, Papworth Everard, Cambridgeshire, CB3 8RE, UK
⁴ Dept of Cardiology, Royal Free Hospital, Pond Street, London, NW3 2QG
⁵ Dept of Cardiology, Hammersmith hospital, Du Cane Road, London, W12 OHS
⁶ Actelion pharmaceuticals UK, BSI Building 13th Floor, 389 Chiswick High Road, London, W4 4AL

^* To whom correspondence should be addressed. E-mail: david_meads{at}hotmail.com.

	Abstract

Validate, determine the Mininal Important Difference (MID) and responsiveness of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) Utility Index, a new tool enabling cost utility analyses.

CAMPHOR, 6 Minute Walk Test (6MWT) and NYHA data from three centres for 869 PH patients (545 [63%] female; Mean age=56.6 [±15.4]) were analysed. Utility was correlated with 6MWT and calculated by NYHA class to assess validity. Effect sizes were calculated for those with two CAMPHOR assessments. Distribution and anchor-based MIDs were calculated. Analyses were run on patients receiving Bosentan to determine whether those remaining in NYHA class III after treatment improved.

The Utility Index distinguished between adjacent NYHA classes and correlated .0.49 with 6MWT. CAMPHOR subscales and Utility were as responsive as 6MWT (effect sizes ranged 0.31–0.69 for CAMPHOR and 0.16–0.34 for 6MWT). Within-group MID for the Utility Index was estimated to be approximately 0.09. Patients remaining in NYHA class III on average experienced a statistically significant improvement (CAMPHOR Utility Index and functioning) that exceeded the MID.

The CAMPHOR Utility Index is valid and responsive to change. Patients can experience significant and important improvements even if they do not improve on traditional outcomes such as NYHA functional class.