Determinants of Treatment Adherence Among Smear-Positive Pulmonary Tuberculosis Patients in Southern Ethiopia

Abstract

Background

Defaulting from treatment remains a challenge for most tuberculosis control programmes. It may increase the risk of drug resistance, relapse, death, and prolonged infectiousness. The aim of this study was to determine factors predicting treatment adherence among smear-positive pulmonary tuberculosis patients.

Methods and Findings

A cohort of smear-positive tuberculosis patients diagnosed and registered in Hossana Hospital in southern Ethiopia from 1 September 2002 to 30 April 2004 were prospectively included. Using a structured questionnaire, potential predictor factors for defaulting from treatment were recorded at the beginning of treatment, and patients were followed up until the end of treatment. Default incidence rate was calculated and compared among preregistered risk factors. Of the 404 patients registered for treatment, 81 (20%) defaulted from treatment. A total of 91% (74 of 81) of treatment interruptions occurred during the continuation phase of treatment. On a Cox regression model, distance from home to treatment centre (hazard ratio [HR] = 2.97; p < 0.001), age > 25 y (HR = 1.71; p = 0.02), and necessity to use public transport to get to a treatment centre (HR = 1.59; p = 0.06) were found to be independently associated with defaulting from treatment.

Conclusions

Defaulting due to treatment noncompletion in this study setting is high, and the main determinants appear to be factors related to physical access to a treatment centre. The continuation phase of treatment is the most crucial time for treatment interruption, and future interventions should take this factor into consideration.

Abstract

A prospective cohort study of smear-positive tuberculosis patients at an Ethiopian hospital found treatment default rates to be high; the main factors relate to physical access to the treatment centre.

Editors' Summary

Background.

Tuberculosis (TB) is one of the leading causes of death from infectious disease worldwide, and it kills around 1.7 million people each year. TB can be successfully treated but the treatment course is long (at least six months). In 1995 the World Health Organization set up “DOTS”, an international strategy for TB control. One of the links below explains what DOTS is in more detail. One of the main elements of DOTS involves the use of standard courses of drug treatment, with the recommendation that trained observers watch people take their treatment. These steps should prevent people from failing to complete their course of treatment, and the World Health Organization has set a target level of 85% for treatment success. However, people do often have problems sticking to treatment and the reasons for this are not clearly understood. Factors such as access to care and a person's social and financial situation might affect whether an individual sticks to their prescribed treatment.

Why Was This Study Done?

This study was carried out in Ethiopia, which has been recognized as being in the top 22 countries with the highest burden of tuberculosis. In the region of southern Ethiopia studied, the proportion of patients not completing their treatment has declined from 38% to 18% between 1994 and 2000. However, the World Health Organization's targets have not been met, with 20% of patients currently failing to complete treatment. These researchers wanted, therefore, to identify the factors that play a part in determining whether a patient completes their course of treatment. They hope that once such factors are identified, they could ultimately be overcome with appropriate interventions and the level of treatment success improved.

What Did the Researchers Do and Find?

The researchers carried out a cohort study, in which all patients diagnosed with clinical tuberculosis during a particular period of time at a major regional hospital in southern Ethiopia were included. Patients were followed up throughout their treatment course and then counted as either having defaulted from treatment (if they had been on treatment for at least 4 weeks and then interrupted for at least 8 weeks), or having completed. The researchers carried out interviews with each participant at the start of the study, to collect information on factors which might affect how each participant might stick to their treatment plan. These factors included basic information such as whether the patient was male or female, their age, marital status, educational level and occupation, as well as others including family income, whether their home was rural or urban, and the distance to the treatment centre. Finally, patients who stopped their treatment were asked an open-ended question: “Why did you stop taking TB medication?”

404 patients were included in the study and 20% defaulted, most of these within the first few months of treatment. The researchers found that a number of factors seemed to be linked to an increased chance that the person would default from treatment. These included age (patients over 25 were less likely to complete); living in a rural setting; having a lower level of education; greater distances from home to the treatment centre; the need for transport to get to treatment; and whether the patient was admitted to hospital in a serious condition. When defaulters were questioned about the reasons they did not complete treatment, the main reasons were related to physical access to the treatment clinic—for example that it was too far, they could not afford to get there, or were not able to walk to get treatment.

What Do These Findings Mean?

The proportion of patients failing to complete their tuberculosis treatment here supports the view that the default rate in Ethiopia has been falling over the past two decades; but that it is still higher than that recommended by the World Health Organization. The researchers also found that physical access to treatment poses a significant barrier to completing treatment. In this study 72% of patients were within two hours' walk of the health facility, a much greater proportion than is the case for the general population in that region. These findings suggest that government initiatives will be needed in order to address the problem of access to treatment and therefore improve adherence. New initiatives are underway in Ethiopia to train health service workers who can provide community-based care.

Additional Information

• World Health Organization (WHO) fact sheet on tuberculosis. More detailed information from WHO is available on DOTS, including the five key elements of DOTS

• The US Centers for Disease Control and Prevention has a minisite dedicated to tuberculosis, including a questions-and-answers page

• The Stop TB Partnership was established in 2000 to realize the goal of eliminating TB as a public health problem and, ultimately, to obtain a world free of TB. It comprises a network of international organizations, countries, donors from the public and private sectors, governmental and nongovernmental organizations, and individuals that have expressed an interest in working together to achieve this goal

• Médecins Sans Frontières, an international medical humanitarian organization, has information on its website about its activities in Ethiopia