Longer hospital stay is associated with higher rates of tuberculosis-related morbidity and mortality within 12 months after discharge in a referral hospital in Sub-Saharan Africa

Abstract

Background: Nosocomial transmission of pulmonary tuberculosis (PTB) is a problem in resource-limited settings. However, the degree of TB exposure and the intermediate- and long-term morbidity and mortality of hospital-associated TB is unclear. In this study we determined: 1) the nature, patterns and intensity of TB exposure occurring in the context of current TB cohorting practices in medical centre with a high prevalence of TB and HIV; 2) the one-year TB incidence after discharge; and 3) one-year TB-related mortality after hospital discharge.

Methods: Factors leading to nosocomial TB exposure were collected daily over a 3-month period. Patients were followed for 1-year after discharge. TB incidence and mortality were calculated and logistic regression was used to determine the factors associated with TB incidence and mortality during follow up.

Results: 1,094 patients were admitted to the medical wards between May 01 and July 31, 2010. HIV was confirmed in 690/1,094 (63.1%) of them. A total of 215/1,094 (19.7%) patients were diagnosed with PTB and 178/1,094 (16.3%) patients died during the course of their hospitalization; 12/178 (6.7%) patients died from TB-related complications. Of the 896 (83.7%) discharged patients, 41 (4.6%) [corrected] were diagnosed with TB during the year of follow up. Overall, 123/896 (14%) patients died during the follow up period, of whom 26/123 (21%) died from TB. [corrected] One-year TB incidence rate and TB-associated mortality were associated with the number of days that the patient remained hospitalized, the number of days spent in the cohorting bay (regardless of whether the patient was eventually diagnosed with TB or not), and the number and proximity to TB index cases. There was no difference in the performance of each of these 3 measurements of nosocomial TB exposure for the prediction of one-year TB incidence.

Conclusion: Substantial TB exposure, particularly among HIV-infected patients, occurs in nosocomial settings despite implementation of cohorting measures. Nosocomial TB exposure is strongly associated with one-year TB incidence and TB-related mortality. Further studies are needed to identify strategies to reduce such exposure among susceptible patients.

Figure 1

Shows the schematic distribution of the bays and the tuberculosis cohorting bay within the medical ward. Position and number of windows, fans and doors are represented as well. Each ward (male and female) is divided in 5, 10-bed bays (6). (1) Each bay has 5 windows and (2) 2 ceiling fans. (3) Beds are organized in two lines of 5 beds each, located on in front of the other. (4) Double doors are located at each extreme of the ward. (5) Traditionally, sickest patients are located in the bay in front of the nurse station. (7) The most distant bay, located next to the main back door is used as the TB cohorting bay.