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

Date Published: February 13, 2007

Publisher: Public Library of Science

Author(s): Estifanos Biru Shargie, Bernt Lindtjørn, Philip Hopewell

Abstract: BackgroundDefaulting 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 FindingsA 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.ConclusionsDefaulting 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.

Partial Text: As much as untreated tuberculosis (TB) threatens the well being of an individual and
society, defaulting from treatment may increase the risk of drug resistance, relapse, and
death, and may prolong infectiousness [1–3]. In resource-constrained settings where the health care services are not
well developed, delayed presentation for treatment and defaulting from treatment are the two
major challenges that TB programmes face [4]. The idea of direct observation of treatment
(DOT) evolved from the need to improve treatment adherence. However, the role of DOT in
maintaining treatment adherence appears to be surrounded by controversies. Reports from many
countries favour DOT as a key component in the Directly Observed Treatment—Short
Course (DOTS) strategy, a global strategy recommended by the World Health Organization for
the prevention and control of TB [5–7].
Conversely, some randomised controlled studies have failed to establish the superiority of
DOT over the conventional nonobserved treatment in improving treatment adherence
[8,9]. As such, ensuring successful treatment
completion might require addressing multiple factors beyond simple supervision of drug
intake [10–14].

Figure 1 shows the flow of study
participants. A total of 404 new PTB+ patients were registered for treatment
between 1 September 2002 and 30 April 2004. Of these, 82% (n
= 331) were from Hadiya zone and 43% (n =
174) were female patients. A total of 21% (n = 83) of
the patients had treatment follow-up at Hossana Hospital, whereas 43%
(n = 169) and 36% (n =
139) were treated at the health centres and health stations, respectively. A total of 199
patients (49%) volunteered to have HIV testing, of which 12% (25 out
of 199) were positive for HIV. A total of 81 patients (20%) defaulted from
treatment, while 310 (77%) successfully completed treatment; nine
(2.2%) died, one had treatment failure, and three had moved outside the region
and could not be traced. Table 1
presents the baseline characteristics of the study participants.

This study tried to measure the extent and predictors of treatment noncompletion in a
predominantly rural society. A total of one-fifth of the registered PTB+ cases
failed to complete treatment. This finding confirms an earlier study report that documented
a declining trend in default rate from 38% to 18% over a six-year
period from 1994 to 2000 [18]. The default rate in our study is lower compared to previous studies in
some African countries [16,
20–22]. However, it is higher than the
11.6% default rate from DOTS reported in Arsi zone of Ethiopia [17]. Treatment noncompletion is
required to fall below 10% in order to achieve treatment success of
85%, one of the health-related indicators of the Millennium Development Goals