Introduction

Top Abstract Introduction Methods Results Discussion References

Clinical trials and similar forms of evaluative study should incorporate the patient's perspective of outcome.¹ For complete assessment of the benefits of an intervention it is essential to provide evidence of the impact on the patient in terms of health status and health related quality of life. These terms refer to experiences of illness such as pain, fatigue, and disability and also broader aspects of the individual's physical, emotional, and social wellbeing. ^{2 3} Unlike conventional medical indicators, these broader impacts of illness and treatment need, wherever possible, to be assessed and reported by the patient.

Several reviews have criticised researchers for their failure to use appropriate measures of health related quality of life in evaluations purporting to address the impact of interventions by assessing outcomes of concern to patients.^3-7 We undertook an extensive review to describe the extent to which patient assessed outcome measures have been developed and applied and examined whether such instruments are available for all aspects of clinical research.

	Methods

Top Abstract Introduction Methods Results Discussion References

Search strategyWe retrieved reports relating to the development and evaluation of patient assessed measures. We based our search terms on terminology applicable to the development and evaluation of patient assessed health outcomes and terminology used in structured reviews. ^{3 8} We searched the following from their inception to 2000: AMED, Biological Abstracts, British Nursing Index, Cinahl, Econlit, Embase, Medline, PAIS International, PsycInfo, Royal College of Nursing database, Sigle, and Sociological Abstracts.

Assessment of reportsThe inclusion criteria comprised the development and testing of patient assessed measures including aspects of health status and quality of life, summary items, and symptoms. We excluded reports that related solely to the use of measures. We assessed the reports for the different types of measure (box) and specialties using a classification based on that used in a review of quality of life measures within randomised clinical trials, supplementing where necessary.²

	Results

Top Abstract Introduction Methods Results Discussion References

Search strategy
After we removed duplicates the initial download from the electronic databases produced 23 042 records. Of these, 3921 (17%) met the inclusion criteria and reported on the development and testing of patient assessed measures of health outcome. The 3921 reports cited 1275 identifiable measures. The number of reports increased from 144 new records in 1990 to 650 in 1999 (figure). At the time of our search the databases were incomplete for 2000. 

View larger version (23K): [in this window] [in a new window]   Number of reports for four main types of measure by year

There was considerable overlap between the types of measure because a large number report the concurrent validation of measures. Most (1819) reported the development and evaluation of measures specific for a disease or population; 865 reported generic measures; 690 reported dimension specific measures; 409 reported utility measures; and 62 reported individualised measures (see bmj.com).

The largest number of evaluations were for rheumatology and musculoskeletal medicine, cancer, and older people; these three accounted for 31% of the 3921 reports. Mental health, neurological diseases, paediatrics-child health, and respiratory diseases were the only other specialties that accounted for more than 5% of records each. There were also a large number of reports (6%) for generic and utility measures that have been evaluated within general populations (for more detail see bmj.com).

The arthritis impact measurement scales,¹⁴ health assessment questionnaire,¹⁵ and European Organisation for Research into the Treatment of Cancer quality of life questionnaire (EORTC QLQ-C30)¹⁶ were the three disease specific measures reported most frequently (table). However it was the generic measures, including the SF-36,¹¹ sickness impact profile,¹⁷ and Nottingham health profile¹⁸ that had undergone the largest number of evaluations. These three measures accounted for 16% of the total number of reports; they have been evaluated across numerous patient populations and have been translated into several languages. Population norms are also widely available for these measures. Of the utility measures, the EuroQol¹³ and health utilities index¹⁹ have undergone the largest number of evaluations.

	Discussion

Top Abstract Introduction Methods Results Discussion References

The application of patient assessed measures of health outcome has become increasingly important to evaluation of health care.¹ We have shown considerable growth in the production of measures to support this trend. Growth has not been consistent across specialties or health problems and has been concentrated around the development of measures specific for diseases or populations.

Selection of measures
The different types of measure are all potentially useful for evaluating health outcomes from the perspective of the individual patient, and there are now multiple measures available within these individual categories. Those wishing to select a measure for a specific application face quite a daunting task. Although there is some evidence for the standardisation of generic measures with a few measures achieving widespread application, this is not the case for disease specific measures. For many patient populations there are several specific measures. It is perhaps not surprising that there is evidence of a lack of consistency in the selection of measures for clinical trials which hinders comparisons between studies.² In a study of 67 clinical trials, 48 were found to use 62 different existing measures and 13 reported new measures.²

The selection of measures can be informed through primary research that compares measures against recommended criteria,³ recommendations based on expert consensus, and structured reviews that assess the evidence for different measures. The concurrent evaluation of measures within primary research typically involves the comparative evaluation of reliability, validity, and responsiveness. Recommendations have been produced for the use of patient assessed measures in rheumatoid arthritis and back pain. ^{20 21} Our search strategy identified 314 reviews of instruments. The quality of the reviews was variable with just 47 using the words comprehensive, structured, or systematic within the title or abstract. Most reviews compared measures for reliability, validity, and responsiveness to change. However several other important considerations relating to the selection of patient assessed measures have been described, ^{3 22} the most pertinent being the relevance of the content of a measure to the proposed application.

Conclusions
The huge growth in the number of patient assessed measures of health outcome has obvious benefits in terms of the availability of measures for specific populations. However, potential users require guidance particularly when faced with multiple measures. Structured reviews together with recommendations based on patient and professional consensus are required for the effective application of measures. Concurrent evaluation can also help to determine the most suitable measure for a particular application. Finally, researchers should undertake comprehensive literature searches to ascertain whether a suitable measure is available before they decide to develop a new one.