Scientists say their findings on why many people with tuberculosis (TB) fail to complete their drug regimens could help design better medication regimens and patient support systems, improving treatment outcomes.
Lead researcher Salla Munro, of the South African Medical Research Council, and colleagues in Britain, Norway and South Africa, conducted a review of 44 studies from Africa, Europe, Latin America, North America, and South and East Asia where patients had been asked about their own treatment adherence.
Up to half of all people with TB do not complete their drug treatment and there is a wide range of factors financial, personal and environmental impacting on treatment-taking behaviour, according to the research.
"Adherence to treatment is not simple, and is not only due to patient motivation. A number of factors contribute to this dynamic process," Munro told SciDev.Net.
For example, some patients did not have a way of getting to the health centre to take their drugs, some could not afford the treatment, others were afraid of being scolded by medical staff for missing a dose, and many could not endure the perceived prejudice of having TB or bear the drugs' side-effects.
Current treatment regimens require taking several antibiotics for at least six months. Failure to complete the course can mean that people are infectious for longer, more likely to relapse and die, or become infected with drug resistant TB.
Munro said that their findings "emphasise the need to develop drugs that are able to treat tuberculosis in an even more short term".
"With low rates of adherence, which are not necessarily the patients' fault, drug resistance can be more common," he added.
The study suggests there is a need for more "patient-centred approaches" to treatment that include patients in decisions managing their illness.
There is also a need to pay more attention to obstacles such as poverty and discrimination.
Jeremiah Chakaya, TB specialist and a researcher at the Kenya Medical Research Institute says the research calls for the development of new drugs that are less toxic and taken for a very short duration, and that the findings should act as an "impetus for the pharmaceutical and public sectors for additional funding for research into TB treatment".
TB is a major contributor to the global burden of disease and has received considerable attention in recent years, particularly in low and middle-income countries where it is closely associated with HIV/AIDS.
The study was published last month (24 July) in PLoS Medicine.
PLoS Medicine 4, 238 (2007)
PLoS Medicine doi: 10.1371/journal.pmed.0040238