De Maeyer J., Vanderplasschen W., Broekaert E.
International Journal of Drug Policy: 2010, 21, p. 364–380.
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The first systematic review of research on the quality of life of opiate users finds this generally improves once they enter substitute prescribing treatments, but that few studies have assessed what counts as a good life from the point of view of the patient.
Summary Despite a shift from objective to more subjective outcome measures in both general and mental health care, attention to consumers' perspectives is still limited in the field of addiction research. Typically, evaluation studies start from a unilateral focus based on the norms and values of society, instead of basing their measures on drug users' experiences. In particular, until the 1990s addiction research gave only limited attention to quality of life, though since 2000 interest has grown extensively, mainly in respect of opiate users, associated with the recognition that substance misuse is a chronic, relapsing disorder which may have negative consequences for various life domains. This is the first systematic review of this new literature on the quality of life of opiate users.
The concept of 'quality of life' is vague and inconsistently used. Often terms like 'health status' and 'health-related quality of life' are mistakenly treated as synonymous with quality of life. 'Health-related quality of life' measures the extent to which a disease impedes everyday functioning. Frequently used in general medicine to demonstrate the absence of pathology, it is very different from quality of life as a positive subjective experience of well-being and satisfaction with life. Rather than a fixed and universal concept, several authors have demonstrated the importance of the individual's own ideas of what for them constitutes a good or bad quality of life.
Consequently, this review distinguishes between health-related quality of life on the one hand, and subjective quality of life on the other. Additionally, quality of life can be measured generically in ways applicable to any group in society, or tailored to a specific population, disease, function or problem, and the assessment instrument can deliver one global score or produce sub-scores for different aspects or 'domains' of quality of life.
Articles published before 2009 were included in the review if they assessed and reported the quality of life (health-related or subjective) of opiate dependent individuals using a quantitative measure completed by the clients themselves. In all 38 studies published between 1993 and 2008 and using 15 instruments to measure quality of life met these criteria.
Most of the 38 studies measured quality of life as part of a study of the effectiveness of substitute prescribing programmes. Eleven instead or also compared the quality of life of opiate users with a a non-opiate using population, and eight observed the long-term impact of substitution treatment on quality of life. Generally generic scales were used rather than those tailored to opiate users.
Compared to people not using opiates, opiate-dependent individuals both at the start of and during treatment generally report a significantly lower health-related quality of life, most obviously in respect of their social functioning, physical and emotional role limitations, general health, and mental health.
In the 16 studies which followed up substitute prescribing patients, at treatment entry patients usually reported poor subjective and health-related quality of life, including emotional problems and difficulties sleeping. However, compared with patients on long-term medication for other chronic illnesses such as diabetes or schizophrenia, substitute prescribing patients evidenced comparable or even greater improvements in health-related quality of life after a period in treatment. Subjective quality of life also typically improves significantly in various domains during the first months of treatment. Later during the stabilisation phase of treatment, quality of life may regress somewhat (but not to treatment entry levels), perhaps as patients experience difficulties in fulfilling their (often high) expectations.
Nine studies compared the quality of life and/or (in six) changes in the quality of life of patients in methadone versus other kinds of substitute prescribing programmes. Measures of health-related quality of life were no different but there were differences in subjective quality of life, suggesting that this construct distinguishes better between types of substitute treatments. In respect of the five relevant comparisons between methadone and buprenorphine, even these differences were confined to certain early periods of treatment; in the longer term there were substantial and equivalent improvements in the quality of life in patients whether on methadone or another substitute medication. Across the three studies of slow-release oral morphine, the impact on subjective quality of life was unclear and improvements might be less than in methadone or buprenorphine treatment. The single study (a randomised controlled trial) comparing heroin prescribing with methadone found that after nine months health-related quality of life had improved to about the same degree.
Among the other possible influences on quality of life investigated by the studies, no clear relationship was found between health-related quality of life and use of specific substances, or the amount, duration and frequency of use. Almost all the studies which found a negative association between drug use and quality of life used a health-related quality of life measure; little information was available on links with other life domains such as family relations, leisure time, social participation, and housing.
Several studies assessed relationships between quality of life and treatment length, dose, or concomitant heroin use. One found that compared to other patients, those who had started treatment using relatively more heroin or had been prescribed higher doses of methadone had a worse overall health-related quality of life 12 months after starting treatment, though no such relationship was found with 'on top' use of heroin during treatment. But another study found no association between subjective quality of life and methadone dosage. This study also found no link with number of prior treatments nor the duration of the current treatment. Two studies found that patients who had been able successfully to leave methadone treatment subsequently had a better quality of life than those who remained in treatment.
Based on this review of 38 articles, both subjective and health-related quality of life are relatively poor among opiate-dependent individuals compared with the general population and people with various other medical illnesses. This may be because opiate user are usually sampled at the start of treatment when quality has yet to improve, and also because those who seek treatment do so while in crisis or because their lives and/or health have deteriorated. Opiate dependent individuals who choose not to enter treatment may have a higher quality of life. The implication is that treatment services must address psychiatric and psychological problems as well as addiction.
Generally, substitution treatment seemed to have a positive effect on quality of life, especially during the first months of treatment, perhaps as the crisis or symptoms which precipitated treatment entry recede. Though they may fall back a little, the observed improvements persist over a long-term period. The influence of drug use itself on quality of life remains unclear, but excessive drinking has been found to be related to a low health-related quality of life. Other aspects of life (eg, emotional, social, and physical status) probably have a bigger impact on quality of life than current drug use, indicating that treatment services should have a broader objectives than abstinence.
One of the most important reasons given by methadone clients for entering treatment is to improve their satisfaction with life. Drug use is not always the reason why people seek treatment, but rather problems in other life domains. Measuring subjective quality of life can broaden our view beyond the direct consequences of drug dependence and physical and mental health, to aspects of life which really matter to clients. Drug users do not primarily associate quality of life with health, but rather with social inclusion and self-determination. Measuring health-related quality of life is valuable, but the wrong construct if the focus is on quality of life as experienced by the client. 'Having no physical or psychological limitations' is not the same as having a high quality of life. Beyond health-related issues, factors such as self-esteem, life goals, and social participation have a great impact on subjective well-being.
Rather than instruments tailored to drug using populations, generally studies have used generic scales to measure quality of life, scales perhaps less sensitive the impact of treatment and of different treatments. Also just one study incorporated the client's perspective on the importance of different aspects of quality of life. More such studies might pave the way to a more empowering approach in addiction treatment and research. Multidimensional scales measuring different aspects of what for the client is a good life are preferable to one-dimensional approaches which do not incorporate the client's perspective. Whatever scales are used, they will not affect treatment unless they are embedded in clinical practice as one way services assess their patients' needs and progress and the adequacy of the service.
commentary Some of the same authors have conducted an in-depth study of what for a sample of opiate dependent patients and former patients in Belgium constitutes a high quality of life and the role of methadone treatment in promoting or impeding a 'good life'.
To make it easier to search for this and other quality of life studies, in its free-text search facility Findings treats 'quality of life' as a single phrase, avoiding the retrieval of studies which simply have these three words in the text, but not as a single phrase. Enter the words 'quality of life' (without the quotation marks) in the 'ALL of these words' box to search for studies related to this concept. Add other words (eg, heroin) to narrow the search.
In particular see this Findings analysis of quality of life as an outcome measure and the background notes which document studies showing that quality of life is poorly related to conventional outcome measures such as abstinence.
Last revised 27 October 2011. First uploaded 27 October 2011
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