Health Status measurement: an increasingly important outcome evaluation in COPD patients.

In patients with COPD, dyspnea is one of the main activity-limiting symptoms that determine a decrease in patients’ capacity to perform routine daily activities. From the patient’s perspective interference with their health is more important than variables such as pulmonary function tests (PFTs) or arterial blood gas analysis (ABGA) [1, 2]. Furthermore, there is increasing evidence that “Health Status” measures are capable of reflecting a very wide range of effects of COPD. For these reasons Health Status assessment has become an important tool for detecting the impact of many chronic diseases – of use to clinicians, the pharmaceutical industry and policy makers as well. Health Status can only be measured by questionnaires that are designed to quantify and compare different levels of health impairment in a standardised manner [3]. Both generic questionnaires such as the Medical Outcomes Study Short-Form Health Survey (SF36) [4, 5], Sickness Impact Profile (SIP) [6], EuroQoL [7] and disease-specific questionnaires are used in COPD. Among the latter are the St George’s Respiratory Questionnaire (SGRQ) [8], Chronic Respiratory Questionnaire (CRQ) [9], and Maugeri Respiratory Failure Questionnaire (MRF28) [10], which have both discriminative properties (i.e. ability to detect differences in health status among patients at a given moment) and evaluative properties (i.e. ability to detect long term changes in health status within the same group). They also meet criteria for validity, reliability and responsiveness. As COPD is recognised as a chronic irreversible respiratory disease, diverse management guidelines [11–14] have stated as a principal goal the need to provide therapeutic measures which can significantly alleviate symptoms. The most currently used application of Health Status measurement is to assess the effectiveness of different treatments in COPD, and improvement in Health Status has become a goal of new management strategies. For example, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) outlines the importance of health status improvement and symptoms relief as goals of effective COPD management [14]. In addition, the European Agency for the Evaluation of Medicinal Products recommends the inclusion of measures of symptomatic benefit such as the SGRQ along with FEV1 measurement as co-primary endpoints in studies of new medicinal products for the treatment of COPD [15]. To date, numerous clinical trials aimed at detecting the effectiveness of different pharmacological agents have proved the reliability of Health Status assessment as an outcome measure [16]. Recently, clinically worthwhile improvement in Health Status has been shown to last for at least a year with tiotropium, a new long-acting antimuscarinic agent. These improvements in health appear to be accompanied by a reduction in exacerbations [17]. Health Status evaluation can also be used as an outcome parameter in non-pharmacologic interventions, e.g. pulmonary rehabilitation in COPD patients, where Health Status has been shown to improve after implementation of such programs [18, 19]. A novel area of implementation of Health Status measurements is to test the efficacy of preventive initiatives. In Italy, an educational multicentre project on COPD (Edu-Care®) has been designed to test whether a patient education program can improve Health Status by reducing the number of exacerbations and health care resources utilisation. It is a one year controlled study involving 70 pulmonary departments that are enrolling 1800 patients. Another interesting role for Health Status assessment is in predicting outcome, particularly mortality. It has already been shown that Health Status can predict the risk of subsequent hospitalizations [20] and exacerbations [21] of COPD. Now, interim data from the Quality of Life Evaluation and Survival Study (QuESS) [22] suggest that Health Status assessment can detect a worsening in health better than functional parameters and that it is a better predictor of mortality than functional parameters such as FEV1 and exercise performance [23, 24]. Fondazione Salvatore Maugeri, Clinica del Lavoro e della Riabilitazione, IRCCS, Divisione di Pneumologia, Istituto Scientifico di Veruno (NO), Italy and *St George’s Hospital Medical School, Division of Physiological Medicine, Cranmer Terrace, London, UK.