The Effect of Diagnostic Delays on the Drop-Out Rate and the Total Delay to Diagnosis of Tuberculosis

Abstract

BackgroundNumerous patient and healthcare system-related delays contribute to the overall delay experienced by patients from onset of TB symptoms to diagnosis and treatment. Such delays are critical as infected individuals remain untreated in the community, providing more opportunities for transmission of the disease and adversely affecting the epidemic.Methodology/Principal FindingsWe present an analysis of the factors that contribute to the overall delay in TB diagnosis and treatment, in a resource-poor setting. Impact on the distribution of diagnostic delay times was assessed for various factors, the sensitivity of the diagnostic method being found to be the most significant. A linear relationship was found between the sensitivity of the test and the predicted mean delay time, with an increase in test sensitivity resulting in a reduced mean delay time and a reduction in the drop-out rate.Conclusions/SignificanceThe results show that in a developing country a number of delay factors, particularly the low sensitivity of the initial sputum smear microscopy test, potentially increase total diagnostic delay times experienced by TB patients significantly. The results reinforce the urgent need for novel diagnostic methods, both for smear positive and negative TB, that are highly sensitive, accessible and point of care, in order to reduce mean delay times.

Rapid Detection of rpoB Gene Mutations Conferring Rifampin Resistance in Mycobacterium tuberculosis

“…Increasing the initial test sensitivity from 35% (microscopy sensitivity for an HIV-positive patient) to 95% (molecular diagnostic approaches) would decrease the mean delay in diagnosis by approximately 25 days and reduce the dropout rate (the proportion of infected individuals who cease seeking medical treatment) by approximately 30% (26). By providing drug resistance information during the initial diagnostic test, the delay to appropriate treatment, a critical factor in reducing mortality attributable to infectious diseases, would be reduced further (22).…”

“…However, delayed initiation of appropriate treatment in suspected MDR TB cases is associated with excess morbidity and nosocomial transmission (39). It has been determined that the main contributor to delay in treatment is poor sensitivity of diagnostic tests (26); the average sensitivity of sputum microscopy is Ͻ60% for immunocompetent patients and lower for HIV infected patients. The frequency of smear-negative disease increases the difficulty of detecting HIV-associated TB as well (33).…”

Tuberculosis in Trinidad a Small Developing Country: Will we Reach the Millennium Development Goal 8 (MDG8) as we Countdown to 2015?

“…[29,30]. Further in most high-burden countries, sputum smear microscopy remains the principal tool for diagnosing active disease; however, operationally, its sensitivity for pulmonary tuberculosis can be as low as 20% [31,32]. The global control of the tuberculosis epidemic is a public health priority [33,34].…”

Diferenças nas características clínicas e epidemiológicas entre os casos notificados por tuberculose na atenção primária e terciária

“…Porém, muitas vezes, alguns casos deixam de ser precocemente diagnosticados e tratados na APS, e passam a ser diagnosticados com atraso nos serviços de urgência e emergência. Esse quadro, além de definir uma grave deficiência no sistema de saúde em relação à atenção primária, traz consequências que, muitas vezes, põem em risco a vida do paciente, uma vez que o atraso no diagnóstico e no início do tratamento aumenta a gravidade da morbimortalidade por TB, bem como o risco de transmissão na comunidade (6,7) . Dessa forma, ocorre uma incapacidade de se controlar essa endemia, possibilitando a perpetuação da cadeia de transmissão (7) .…”

“…Esse quadro, além de definir uma grave deficiência no sistema de saúde em relação à atenção primária, traz consequências que, muitas vezes, põem em risco a vida do paciente, uma vez que o atraso no diagnóstico e no início do tratamento aumenta a gravidade da morbimortalidade por TB, bem como o risco de transmissão na comunidade (6,7) . Dessa forma, ocorre uma incapacidade de se controlar essa endemia, possibilitando a perpetuação da cadeia de transmissão (7) . No município de Vitória-ES, a rede de Atenção Terciária à Saúde (ATS) é uma importante porta de entrada para os pacientes, representando um percentual em torno de 30% dos casos novos notificados.…”