Recurrence in tuberculosis: relapse or reinfection?

Lambert, Marie‐Laurence; Hasker, Epco; Deun, Armand Van; Roberfroid, Dominique; Boelaert, Marleen; Stuyft, Patrick Van der

doi:10.1016/s1473-3099(03)00607-8

Cited by 194 publications

(189 citation statements)

References 25 publications

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“…Reinfection (van Rie et al 1999) or multiple infection (Richardson et al 2002) has been shown to be an important phenomenon in TB dynamics and occurs in both high-and low-incidence societies (Richardson et al 2002;Lambert et al 2003;Behr 2004;Chiang & Riley 2005;Rodrigues et al 2007). Intuitively, one may expect that reinfection would be lower in lowincidence (e.g.…”

Section: Discussionmentioning

confidence: 99%

Tuberculosis reinfection rate as a proportion of total infection rate correlates with the logarithm of the incidence rate: a mathematical model

Uys

Helden

Hargrove

2008

J. R. Soc. Interface.

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In a significant number of instances, an episode of tuberculosis can be attributed to a reinfection event. Because reinfection is more likely in high incidence regions than in regions of low incidence, more tuberculosis (TB) cases due to reinfection could be expected in highincidence regions than in low-incidence regions. Empirical data from regions with various incidence rates appear to confirm the conjecture that, in fact, the incidence rate due to reinfection only, as a proportion of all cases, correlates with the logarithm of the incidence rate, rather than with the incidence rate itself. A theoretical model that supports this conjecture is presented. A Markov model was used to obtain a relationship between incidence and reinfection rates. It was assumed in this model that the rate of reinfection is a multiple, r (the reinfection factor), of the rate of first-time infection, l. The results obtained show a relationship between the proportion of cases due to reinfection and the rate of incidence that is approximately logarithmic for a range of values of the incidence rate typical of those observed in communities across the globe. A value of r is determined such that the relationship between the proportion of cases due to reinfection and the logarithm of the incidence rate closely correlates with empirical data. From a purely theoretical investigation, it is shown that a simple relationship can be expected between the logarithm of the incidence rates and the proportions of cases due to reinfection after a prior episode of TB. This relationship is sustained by a rate of reinfection that is higher than the rate of first-time infection and this latter consideration underscores the great importance of monitoring recovered TB cases for repeat disease episodes, especially in regions where TB incidence is high. Awareness of this may assist in attempts to control the epidemic.

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Section: Discussionmentioning

confidence: 99%

Tuberculosis reinfection rate as a proportion of total infection rate correlates with the logarithm of the incidence rate: a mathematical model

Uys

Helden

Hargrove

2008

J. R. Soc. Interface.

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“…TB relapse can occur due to endogenous reactivation or exogenous re-infection, 12 conditions that are clinically indistinguishable 13 but can be differentiated by genotyping techniques. [12][13][14] In areas of low TB incidence, relapse is usually due to endogenous reactivation.…”

Section: Discussionmentioning

confidence: 99%

“…[12][13][14] In areas of low TB incidence, relapse is usually due to endogenous reactivation. [15][16][17] In areas of high TB incidence, however, the incidence of relapse attributed to re-infection can reach 75%.…”

Section: Discussionmentioning

confidence: 99%

A nested case-control study on relapse predictors among tuberculosis patients treated in Yemen's NTCP

Anaam

Ibrahim

Serouri

et al. 2012

public health action

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high relative relapse rate (RRR) of 6-11% between 1995 and 2009, exceeding the acceptable norm (<5%). [3][4][5] The present study was designed to measure the actual relapse rate and to identify associated risk factors. METHODS Study designA prospective nested case-control study was conducted to identify risk factors for relapse among TB patients. At the end of the follow-up period (28 February 2010), all those who relapsed within 12 months after completion of treatment were identifi ed from the tuberculosis registry. For each confi rmed relapse case, four control subjects were randomly selected from among patients who had successfully completed the initial phase of treatment and had not relapsed. Sampling was performed using the Statistical Package for the Social Sciences sampling procedure (Base 7.4 for Windows, SPSS Inc, Chicago, IL, USA). Study area and populationThe study was conducted at health centres with TB units throughout the 10 governorates of Yemen: Metropolitan, Amran, Aden, Taiz, Al-Hodeida, Hajjah, Ibb, Dhamar, Hadramout and Mareb. The study population was a cohort of smear-positive pulmonary TB (PTB) patients registered for DOTS-based treatment between July 2007 and June 2008. Patients who had completed treatment, were considered cured and were aged ⩾15 years were included as subjects, while all patients with smearnegative PTB and extra-pulmonary TB (EPTB), children aged <15 years and adult patients receiving other treatment regimens were excluded. SamplingThe calculation of the sample size for determining factors contributing to relapse was based on a balanced design for simple logistic regression with a binary covariate (X ). 6 In this method, the proportion (B) of the sample (X = 1) was assumed to be 0.5. The event rates P 1 and P 2 are 0.05 (X = 0) and 0.1 (X = 1), respectively. The power of the study was set at 80%, while the two-tailed type I error was assumed to be 5%. The sample size required to detect a change in probability (Y = 1) from a baseline value of 0.05 to 0.1 was 862 patients. Adjusting for the variance infl ation factor, a total sample size of 880 was needed for multiple logistic regression. Based on the required sample size and the number of patients available according to the previous years' statistics, it was decided that recruitment of all patients within the timeframe July 2007 to June 2008 would provide an adequate sample size. Results: A relapse rate of 5.7% was found. Multivariate logistic regression analysis showed that unemployment, smoking, presence of cavitations, weight gain, weight loss, non-adherence during the continuation phase and diabetes were significantly associated with relapse (P < 0.05). Interna onal Union Against Tuberculosis and Lung Disease Conclusion:Relapse rates can be reduced by ensuring that patients take their treatment regularly and are counselled effectively to stop smoking. Reinforcing the implementation of the DOTS strategy and strengthening the anti-smoking campaigns are important actions. Action to help unemployed patients, including free...

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“…Conversely, one study carried out in Karinga Malawi, concluded that HIV increases the rate of recurrent TB by increasing the rate of reinfection disease (Crampin et al, 2010). Other authors reviewed different studies on recurrence and argued that, apart from extreme situations, the problem of recurrence due to reinfection has few implications for TB-control programmes (Lambert et al, 2003).…”

Section: Recurrent Tuberculosis: Relapse or Reinfection?mentioning

confidence: 99%