Adherence to Long-Term Therapies - Evidence for Action
(2003; 211 pages) View the PDF document
Table of Contents
View the documentPreface
View the documentAcknowledgements
View the documentScientific writers
View the documentIntroduction
View the documentTake-home messages
Open this folder and view contentsSection I - Setting the scene
Open this folder and view contentsSection II - Improving adherence rates: guidance for countries
Close this folderSection III - Disease-Specific Reviews
Open this folder and view contentsChapter VII - Asthma
Open this folder and view contentsChapter VIII - Cancer (Palliative care)
Open this folder and view contentsChapter IX - Depression
Open this folder and view contentsChapter X - Diabetes
Open this folder and view contentsChapter XI - Epilepsy
Open this folder and view contentsChapter XII - Human immunodeficiency virus and acquired immunodeficiency syndrome
Open this folder and view contentsChapter XIII - Hypertension
Open this folder and view contentsChapter XIV - Tobacco smoking cessation
Close this folderChapter XV - Tuberculosis
View the document1. Definition of adherence
View the document2. Factors that influence adherence to treatment
View the document3. Prediction of adherence
View the document4. Strategies to improve adherence to treatment
View the document5. Questions for future research
View the document6. References
Open this folder and view contentsAnnexes
Open this folder and view contentsWhere to find a copy of this book

4. Strategies to improve adherence to treatment

Concurrently with the efforts to improve our understanding of factors affecting adherence to TB treatment, numerous measures have been introduced in different settings in an attempt to improve it (30,31).

A. Classification of interventions

The interventions for improving adherence rates may be classified into the following categories:

• Staff motivation and supervision - includes training and management processes aimed at improving the way in which providers care for patients with tuberculosis.

• Defaulter action - the action to be taken when a patient fails to keep a pre-arranged appointment.

• Prompts - routine reminders for patients to keep pre-arranged appointments.

• Health education - provision of information about tuberculosis and the need to attend for treatment.

• Incentives and reimbursements - money or cash in kind to reimburse the expenses of attending the treatment centre, or to improve the attractiveness of visiting the treatment centre.

• Contracts - agreements (written or verbal) to return for an appointment or course of treatment.

• Peer assistance - people from the same social group helping someone with tuberculosis to return to the health centre by prompting or accompanying him or her.

• Directly observed therapy (DOT) - an identified, trained and supervised agent (health worker, community volunteer or family member) directly monitors patients swallowing their anti-TB drugs (see below).

B. Directly observed treatment as a component of the WHO DOTS strategy

The concept of "entirely supervised administration of medicines", first developed by Wallace Fox in the 1950s (32), is now known as directly observed therapy (DOT).DOT was first adopted in TB drug trials in Madras (India) and Hong Kong as early as the 1960s (33) and is now widely recommended for the control of TB (34 - 36).WHO recommends DOT as one of a range of measures to promote adherence to TB treatment (37).

DOT has always meant much more than "supervised swallowing". Different projects in countries with a high prevalence of TB have shown that removing the socioeconomic barriers to DOT faced by patients increases adherence and cure rates (38,39). In a country where the prevalence of TB is low, such as the United States, DOT programmes are complex and have several components including social support, housing, food tokens and legal measures and are highly cost-effective (35,40).

Since 1991, WHO has promoted the strategy of "directly observed therapy, short course" (now known as the DOTS strategy) (32)."DOTS" is the brand name for a comprehensive technical and management strategy consisting of the following five elements:

- political commitment;

- case detection using sputum microscopy among persons seeking care for prolonged cough;

- standardized short courses of chemotherapy under proper case-management conditions including DOT;

- regular drug supply; and

- a standardized recording and reporting system that allows assessment of individual patients as well as of overall programme performance (41).

C. Evidence for the effectiveness of interventions aimed at improving adherence

Unfortunately, there is a lack of rigorous experimental research on the effects of interventions to promote adherence to TB treatment. Quantitative research asks questions about efficacy and effectiveness. The choice of an appropriate experimental design methodology (whether individual or community randomization) depends on the nature of the intervention under evaluation. Quantitative research should be complemented by in-depth qualitative research to answer questions about why an intervention had an effect in a particular setting.

The extent to which DOT alone and various individual social support measures contribute to adherence is unknown. On the one hand, randomized controlled trials have shown no difference in adherence between TB patients randomly allocated to DOT alone or to self-administered treatment. Two recently published systematic reviews reported 16 randomized trials, of which only half were in countries with a high disease burden (8,49). These reviews showed that DOT alone ("supervised swallowing") did not always promote adherence, and therefore the results do not support the use of this intervention in isolation from the other factors affecting adherence (e.g. good quality of communication between patient and health providers, transport costs and lay health beliefs about TB) (Table 10).

Table 10 Factors affecting adherence to treatment for tuberculosis and interventions for improving it, listed by the five dimensions and the interventions used to improve adherence


Factors affecting adherence

Interventions to improve adherence

Socioeconomic-related factors

(-) Lack of effective social support networks and unstable living circumstances (12); culture and lay beliefs about illness and treatment (10,17); ethnicity, gender and age (13); high cost of medication; high cost of transport; criminal justice involvement; involvement in drug dealing

Assessment of social needs, social support, housing, food tokens and legal measures (35,40,41); providing transport to treatment setting; peer assistance; mobilization of community-based organizations; optimizing the cooperation between services

Health care team/health system-related factors

(-) Poorly developed health services; inadequate relationship between health care provider and patient; health care providers who are untrained, overworked, inadequately supervised or unsupported in their tasks (20); inability to predict potentially nonadherent patients (21)

(+) Good relationship between patient and physician (19); availability of expertise; links with patient support systems; flexibility in the hours of operation of treatment centers

Uninterrupted ready availability of information; flexibility in available treatment; training and management processes that aim to improve the way providers care for patients with tuberculosis; management of disease and treatment in conjunction with the patients; multidisciplinary care; intensive staff supervision (42); training in adherence monitoring; DOTS strategy (32)

Condition-related factors

(-) Asymptomatic patients; drug use; altered mental states caused by substance abuse; depression and psychological stress

(+) Knowledge about TB (16)

Education on use of medications (43); provision of information about tuberculosis and the need to attend for treatment

Therapy-related factors

(-) Complex treatment regimen; adverse effects of treatment; toxicity (18)

Education on use of medications; adherence education; tailor treatment to needs of patients at risk of nonadherence; agreements (written or verbal) to return for an appointment or course of treatment; continuous monitoring and reassessment of treatment

Patient-related factors

(-) Forgetfulness; drug abuse, depression; psychological stress

(+) Belief in the efficacy of treatment (16); motivation (24)

Therapeutic relationship; mutual goal-setting; memory aids and reminders; incentives and/or reinforcements (44,45); reminder letters (46), telephone reminders (47) or home visits (48) for patients who default on clinic attendance


DOT, Directly observed therapy; TB, tuberculosis; (+) factors having a positive effect on adherence; (-) factors having a negative effect on adherence.

On the other hand, programmatic studies of the effectiveness of the DOTS strategy have shown high rates of treatment success (2,50 - 52). In practice, the trial design necessary to properly evaluate the contribution of DOT alone to the effectiveness of the overall DOTS strategy requires assessment of the social aspects of patient support that surround DOT (as "supervised swallowing").The outcomes of programmatic evaluations of the effectiveness of implementation of the DOTS strategy better reflect the social, behavioural and economic factors related to the patient, the health care services and characteristics of treatment.

Many other interventions have been found to significantly improve adherence. One study found that reminder letters sent to patients who failed to attend clinic, appeared to be of benefit even when patients were illiterate (46). Another study reported that home visits by a health worker, though more labour-intensive, may be more effective than reminder letters for ensuring that defaulters complete their treatment (48).Yet another study showed that prospective telephone reminders are useful for helping people to keep scheduled appointments (47). Such studies are often location-specific and therefore often produce results that cannot be generalized. For example, studies demonstrating the benefit of telephone and mail reminders are of little relevance in many of the countries with a high prevalence of TB because most patients do not have telephones or mail boxes.

Although one trial found that assistance by a lay health worker increased adherence to a first appointment (44), a subsequent study showed no impact on completion of preventive therapy at 6 months (53). Studies in the USA have suggested that monetary incentives are an effective method for improving adherence. Appointment-keeping was significantly improved in homeless men (44) and in drug users (45) by offering US $5 in payment for returning to a clinic for TB evaluation, but the results of a study of offering monetary incentives to people recently discharged from prison were inconclusive, partly due to its small size (54).

The evidence for an independent effect of health education on adherence of patients to treatment is weak. One trial did suggest some benefit (55) but the design of this study was flawed because individuals receiving health education were contacted or seen every 3 months, whereas those in the control group were seen only at the end of the study period. The relative contributions of health education and increased attention in this study are therefore hard to separate. A trial to examine the impact of intensive education and counselling on patients with active TB did, however, find a trend towards increased treatment completion rates for the patients who received intensive education and counselling compared with those who received routine care (43). The study by Morisky and colleagues (56), lent no support to the authors' claims for the benefit of health education as the results were confounded by the effects of a monetary incentive used in tandem with the educational intervention. In a more recent trial that has helped to disaggregate these effects (45) health education alone was found to be no better than routine case management for improving appointment-keeping and the impact of education combined with a monetary incentive was indistinguishable from that of the monetary incentive alone.

Finally, an intervention directed at clinic staff rather than patients was studied. Patients attending clinics in which staff were closely supervised were more likely to complete treatment than those attending clinics where there was only routine supervision of staff (42).

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