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 Table of Contents  
Year : 2020  |  Volume : 9  |  Issue : 3  |  Page : 254-260

Epidemiology and clinical characteristics of tuberculosis in leon bernard tuberculosis unit in algeria

1 L'IFORCE, Faculty of Mathematics, University of Sciences and Technology Houari Boumediene, Algiers, Algeria
2 Health and Hospital Reform Services, Ministry of Health, Population and Hospital Reform, Algiers, Algeria

Date of Submission20-Apr-2020
Date of Decision20-May-2020
Date of Acceptance14-Jun-2020
Date of Web Publication28-Aug-2020

Correspondence Address:
Schehrazad Selmane
L'IFORCE, Faculty of Mathematics, University of Sciences and Technology Houari Boumediene, Algiers
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijmy.ijmy_78_20

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Background: This study aimed at highlighting some demographic and clinical features of tuberculosis (TB) at Leon Bernard TB unit, Algeria. Methods: This was a retrospective and descriptive study based on TB data extracted from TB patient records during 2009–2019 at Leon Bernard TB unit. Results: Of the total 1375 TB patients, 602 (43.8%) had extrapulmonary TB (EPTB), 482 (35.1%) had new sputum smear-positive pulmonary TB (PTB), 42 (3.1%) had sputum smear-negative with culture-positive PTB, and 97 (7%) EPTB patients had concomitant pulmonary involvement. The male-to-female ratio was 1.07. A total of 116 (8.4%) TB relapses were reported with predominance among ETPB cases (54.3%). Lymphadenitis TB was the most common manifestation of EPTB with 301 cases (39.6%), followed by pleural TB with 237 cases (31.2%). The number of bacteriologically not confirmed EPTB was 22.6% more than half (53.3%) of whom were pleural TB. Among patients with new sputum smear-positive PTB, 71.2% were males, whereas the reverse was observed among patients with EPTB where 62.3% were female. Two-third of recorded cases were between 15 and 45 years old. Nearly all children had EPTB (64/69). The results revealed that most of the patients who passed away were affected by PTB (15/18), and the most frequent cmorbidities were diabetes (9/18) and high blood pressure (6/18). Conclusion: Specific attention needs to be given to an examination of the risk factors of PTB among male population and of EPTB among female population and children and to diagnosis of pleural TB and primary PTB.

Keywords: Algeria, epidemiology, extrapulmonary tuberculosis, pulmonary tuberculosis

How to cite this article:
Selmane S, L’Hadj M. Epidemiology and clinical characteristics of tuberculosis in leon bernard tuberculosis unit in algeria. Int J Mycobacteriol 2020;9:254-60

How to cite this URL:
Selmane S, L’Hadj M. Epidemiology and clinical characteristics of tuberculosis in leon bernard tuberculosis unit in algeria. Int J Mycobacteriol [serial online] 2020 [cited 2023 Mar 31];9:254-60. Available from: https://www.ijmyco.org/text.asp?2020/9/3/254/293550

  Introduction Top

Tuberculosis (TB), an infectious bacterial disease with primarily human-to-human transmission, is caused by the tubercle bacillus, Mycobacterium tuberculosis (MTB). The MTB most commonly affects the lungs, causing pulmonary TB (PTB); however, it can reach other organs, causing extrapulmonary TB (EPTB).[1],[2],[3] Despite the fact that TB is a preventable and curable disease, it remains a major global health issue. The disease ranks ninth among the top causes of death worldwide.[4] Approximately 1.7 billion of the world's population was estimated to be latently infected with MTB.[5] Globally, in 2019, an estimated 10 million people fell ill with TB and there were an estimated 1.2 million TB deaths among HIV-negative people in 2018 and an additional 251 000 deaths among HIV-positive people.[4]

Formerly, a country with a high TB prevalence, Algeria was able to join the group of countries with moderate prevalence since the 1980s. Throughout half a century, considerable efforts were made to improve the care, the detection rate of sputum smear-positive PTB cases, and treatment of TB. The incidence per 100,000 inhabitants of PTB declined by 49.1% from 1982 to 2018 and that of EPTB decreased first by 29.5% from 1982 to 1992, and then increased gradually between 1993 and 2018 by 20.8%. Between 1982 and 2000, PTB has been in the lead. In 2001, EPTB cases took over and stayed ahead since.[6],[7],[8]

This study aimed at depicting some key demographic and clinical characteristics of TB in Algeria. To this end, a thorough examination of 1375 medical files of patients treated for TB at Leon Bernard TB unit in Algiers, between 2009 and 2019, was undertaken. The patients' medical records obviously contain more information than those reported by the national TB control program and allow more extensive conclusions to be drawn. To our knowledge, this is the first TB unit-based retrospective study exploring clinical and demographic characteristics of TB and some of the risk factors associated with TB mortality in Algeria.

  Methods Top

TB is classified, according to the handbook on TB control for medical personnel elaborated by the committee of the Algerian national control program, as exclusively PTB, exclusively EPTB, or EPTB with concurrent PTB involvement. PTB was further disaggregated as follows: sputum smear-positive PTB and sputum smear-negative with culture-positive PTB. The sites of EPTB include pleural, lymphadenitis, bone and joint, urogenital, primary, and the remaining sites are recorded in a class named others (including peritoneal and meningeal locations, among others).[6] A TB case is notified bacteriologically confirmed or bacteriologically not confirmed. A bacteriologically confirmed TB case is one from whom the taken biological specimen is positive by smear microscopy, culture, or WHO-endorsed Rapid Diagnostics such as Xpert MTB/RIF.[4],[9] It should be underlined that the diagnosis of EPTB remains a challenging task. Indeed, specimens taken from relatively inaccessible sites are mostly paucibacillary, thus decreasing the sensitivity of diagnostic tests. In that case, various clinical or paraclinical examinations in addition to histopathological findings of lesion sites according to biopsy method help the doctor to set the diagnosis and the patient is notified as bacteriologically not confirmed TB case.

The TB data from 2009 to 2019 used to profile the epidemiology of TB were extracted from the patient medical records at Leon Bernard TB unit in Algiers, Algeria. The overall population covered by this care unit was estimated at 237661 inhabitants in 2019. The extracted data included sex, age, year, month, address, TB classification, and outcome (new case never treated before, relapse, treatment failure, interrupted TB treatment, recovered, TB death, for EPTB, it is mentioned confirmed (P) or not confirmed bacteriologically (NP)). As regards the death cases, their medical files were screened. All patients enrolled in this study received anti-TB treatment.

Data were analyzed, and graphs were generated to recognize trends and outcomes of TB using two software applications: Epi Info (version 7.1.5, freely available at http://www.cdc.gov/epiinfo/) and Microsoft® Office Excel. For qualitative variables, frequencies and percentages were computed, and for the age, the mean, standard deviation (SD), interquartile range (IQR), and confidence interval (CI) were estimated.

This study was approved by the Committee of National Tuberculosis Control Program. The proposal was sent to the Ethics Committee on January 2, 2017. The proposal was approved on February 6, 2017.

  Results Top

This retrospective study was carried out using data retrieved from the patient medical records at Leon Bernard TB unit, Algiers, covering the period from 2009 to 2019. The retrieved demographic and clinical characteristics of TB, from the 1375 patient files accessed, are displayed in [Table 1]. The number of TB cases decreased significantly from 201 cases in 2009 to 77 cases in 2019. The yearly data are well fitted to the linear regression equation y = −11.9x + 196.56 with the coefficient of determination R2 = 0.938, that is, 93.8% of the variance in yearly cases are predictable from this linear regression equation. In 2019, the incidence rate was estimated at 32.4 cases per 100,000 inhabitants. The number of new sputum smear-positive PTB has dropped 74.7%, from 87 cases in 2009 to 22 in 2019 and the number of cases with EPTB has witnessed a decrease of 49.4%, from 79 cases in 2009 to 40 in 2019. Men represented 51.8% (712/1375) of all TB cases. The annual male-to-female ratio peaked at 1.3 in 2009 and in 2013, was the lowest (0.8) in 2019, and in all, it was 1.1.
Table 1: The demographic and clinical characteristics of tuberculosis cases at Leon Bernard tuberculosis unit from 2009 to 2019

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TB affects the individual at all ages of life, as shown in [Figure 1]. Three-quarter of TB patients are aged between 18 and 55. The mean, SD, median, and CI with 95% confidence level, by age group and by localization, are displayed in [Table 2]. Of 5 1-year-old children with TB, four had primary PTB and one had PTB, while the youngest child with EPTB (lymphadenitis TB) was 2 years old. The percentage of children below the age of fifteen did not exceed 5%; likewise, the percentage of elderly aged 65 and over varies, yearly, between 5% and 12%. The population of active age (18–60 years) was the most affected with 79% (1085/1375) of TB cases, of whom 46.5% (504/1085) were female and 53.5% (581/1085) were male. The mean ± SD age of TB cases in this age group was 35.1 ± 11.2 (95% CI 34.4–35.8) and the median (IQR) age was 34 (25–43) years. Among the 1375 TB-diagnosed patients, 602 (43.8%) of patients had EPTB, 482 (35.1%) had a new sputum smear-positive PTB, 42 (3.1%) had sputum smear-negative with culture-positive PTB, 36 (2.6%) with microscopy not done or unknown result, 97 (7.1%) had both EPTB and PTB, and 116 (8.4%) had relapsed TB. The total number of cases of PTB notified and treated was 560 cases, of which 86.1% (482/560) had new sputum smear-positive PTB. The male predominance was observed among new sputum smear-positive PTB-diagnosed patients; indeed, 71.2% (343/482) were male and 28.8% (123/437) were female and this predominance holds for almost all age groups, as shown in [Figure 2], while the reverse was observed among EPTB patients with 62.3% (375/602) of females and 37.7% (227/602) of males. A TB frequency difference by gender is observed in the age groups of 15–24 and 35–44 years, while for the other age groups, it is almost the same [Figure 2].
Figure 1: Age distribution by gender of tuberculosis recorded cases in Leon Bernard tuberculosis unit from 2009 to 2019

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Table 2: Descriptive statistics of tuberculosis data by category and by age group

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Figure 2: Tuberculosis, extrapulmonary tuberculosis, and pulmonary tuberculosis cases stratified by age group and gender at Leon Bernard tuberculosis unit from 2009 to 2019

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Many TB localizations are reported, but two of them predominate and account for 70.8% (538/760) of EPTB cases. The lymphadenitis involvement is largely predominant with 39.6% (301 cases) of cases, followed by pleural involvement with 31.2% (237 cases). More detailed gender and localization breakdowns are given in [Table 1] and in [Figure 3]. In men, it is the pleural TB that comes first with 44.6% (127/285), then lymphadenitis with 31.6% (90/285), followed by other with 9.1% (26/285), whereas in women, the most frequent forms are lymphadenitis with 44.4% (211/475), pleural with 23.2% (110/475), other with 17.5% (83/475), and bone and joint with 6.1% (29/475). The percentage of bacteriologically confirmed EPTB was 77.4% (569/735). An in-depth analysis shows that the confirmatory diagnosis of pleural TB and primary TB remains challenging; the confirmed diagnosis was reached in 138 of 237 patients (61.1%) with pleural TB and 16 of 44 patients (36.4%) with primary TB. Three-quarter of pleural TB cases occurred in the age group of 18–50 years and 41% of primary TB cases were children under 14 years old. A total of 116 (8.4%) TB relapses was reported. Among the relapsed cases, the proportion of females was 52.6% (61/116). The proportion with EPTB and new sputum smear-positive PTB were 54.3% (63/116) and 41.4% (48/116), respectively. The mean ± SD age for all relapse cases was 39.4 ± 16.8 (95% CI 36.3–42.5), the median age was 39 years, and the mode age was 39 years. Children represented 4.3% (5/116), and the age group of 15–64 years accounted for 88.8% (103/116) of all relapse cases.
Figure 3: Extrapulmonary tuberculosis recorded cases stratified by localization and gender at Leon Bernard tuberculosis unit from 2009 to 2019

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TB breaks out throughout the year with a more or less regular distribution. [Figure 4] shows the monthly time series of the numbers of all TB cases, sputum smear-positive PTB, and EPTB cases registered from 2009 to 2019. A regressive evolution over the past 11 years is observed with a peak of recorded cases (201 cases) in 2009. The seasonal evolution of all TB cases and EPTB (respectively, PTB) shows that the maximum number of cases is diagnosed during the period which runs from May to July.
Figure 4: The monthly trend of tuberculosis all cases, smear-positive pulmonary tuberculosis, extrapulmonary tuberculosis at Leon Bernard tuberculosis unit from 2009 to 2019

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Of the 18 reported cases of death among reported TB patients between 2009 and 2019, 13 patients had a new sputum smear-positive PTB, two patients had PTB with negative microscopy, and three patients had pleural TB. The male-to-female ratio was 1.25 (10 males and 8 females). Seven patients were aged between 55 and 63 years and 11 patients were over 70 years, of which more than half were over 80 years. One-third of the cases had been hospitalized at the pneumology department for a short period not exceeding 1 week before starting their treatment. After the beginning of treatment, there were three patients who died less than a month later, 12 patients between 1 month and 3 months later, and three patients a few days before completing their treatment. The cause of death for most of these cases was related to comorbidities: diabetes in nine patients, high blood pressure in six patients, interstitial pulmonary fibrosis has been reported in two patients, and cancer in two patients. Three sputum smear-positive PTB cases, successfully treated, relapsed with the same type of TB: 18 months after for the first case, 20 months after for the second case, and 55 years after for the third case.

  Discussion Top

TB remains a health issue in Algeria. In 2018, 7032 (respectively, 16,025) of 23,057 patients with TB had PTB (respectively, EPTB). The incidence of EPTB has steadily increased from 12.5 in 1993 to 38.5 in 2018, while PTB has steadily decreased from 21.3 in 1993 to 16.9 in 2018. EPTB is contributing to the burden of TB in Algeria and in many other countries. Unfortunately, EPTB is not granted specific attention in TB National Control Program and even in TB international control strategies.[10],[11] Some studies indicated that the rise in EPTB could be attributed to zoonotic TB caused by Mycobacterium bovis that spreads from animal to human and results in EPTB, and therefore, a better veterinary control should be surmised in EPTB control to reach both protection of animals and human.[18],[19]

To profile and highlight the epidemiological factors associated with TB in Algeria, a statistical inference approach was used. To this end, the analysis of the data extracted from the patients' medical records at Leon Bernard TB unit in Algiers, Algeria, was performed. From this retrospective data-driven study over 11 years from January 1, 2009, to December 31, 2019, on a sample of 1375 patients with TB, the frequency distribution of TB by age, gender, and sites was examined. The PTB ratio was significantly higher in men, whereas the reverse was observed in the EPTB ratio, which was significantly higher in women. Indeed, the male-to-female ratio of EPTB was 0.6, whereas this ratio for new sputum smear-positive PTB was 2.6. A predominance of EPTB cases was confirmed likewise the observed trend at the national level.[8] This finding is in line with studies conducted in Turkey and Brazil.[12],[13] The lymphadenitis involvement was largely predominant followed by pleural involvement. Similar conclusions have been established in studies conducted in other countries.[14],[15] More women than men were affected by EPTB, while the reverse was observed for PTB. This sex difference in the incidence rates of EPTB and PTB is consistent with other studies.[16],[17] Another striking finding in this study is that children < 15 years old were affected much more with EPTB than PTB; 64 against 5 cases with boy-to-girl ratio 0.8 (30/39). Lymphadenitis TB was the most common manifestation in children with 31 cases, followed by primary TB with 18 cases. This finding is consistent with studies conducted in Europe.[16]

It is worth noting that of 522 patients with exclusively EPTB, the diagnosis has not been bacteriologically confirmed for 116 of them. It might be noted here that the reported percentage of a confirmed diagnosis of EPTB cases varies largely from one country to another and depends on the prevalence of TB. As a matter of fact, for instance, in Europe, it varies from 10% (in Romania) to 80% (in Sweden).[10] The EPTB poses a real problem in terms of accurate diagnosis owing to the diversity of symptoms, and it is often cited as a challenge. It is clear that the diagnosis of EPTB without microbiological confirmation may result in overdiagnosis. The bacteriological confirmation remains challenging. Indeed, just to mention a number of reasons, it is not always easy to obtain an adequate sample for confirmation, the specimens are paucibacillary by nature, affected organs are difficult to access, the lack of an efficient sample processing technique universally applicable on all types of extrapulmonary samples, the paraclinical examinations, and often expensive without providing confirmation. Raising awareness of physicians about guidelines for the diagnosis and treatment of EPTB may result in more timely and adequate diagnosis. Moreover, there is a need for seeking the sure way to confirm that a patient is EPTB affected in the case where the bacteriological confirmation is not possible. The diagnosis of EPTB requires further attention of academic researchers. The more elaborated database could guide and advance research on more accurate diagnosis.

Although this study yielded some TB feature insights, it has some limitations. Indeed, our study included only patients admitted to one TB unit out of 200 TB units spread throughout the Algerian territory, meaning that the outcomes may not reflect the true picture of the TB profile of the country. Furthermore, we reviewed data over 11 years, which may have an impact on the reliability of the outcomes. It has also been assumed that the TB-related deaths were comorbidities-related deaths; autopsies were not done to confirm these prognoses. Identifying real risk factors could pave the way to reducing TB-related death by early recognition of patients at risk for death and a better and adequate follow-up.

  Conclusion Top

The analysis revealed that EPTB was more prevalent among women, while PTB was more prevalent among men. Children under the age of 15 years are most likely to be infected with EPTB. Focusing on PTB among the male population and EPTB among the female population and children to document the epidemiology in Algeria and to examine the risk factors, the diagnostic modalities, the treatment strategies, and the outcomes to carry out preventive and control measures are recommended. Diagnosing EPTB remains challenging; the bacteriological confirmation is not always possible for pleural TB and primary PTB, as emphasized in this study. The refinement of diagnostic facilities is therefore essential for early recognition and better treatment of EPTB cases. The study outcomes should guide surveillance of TB control to enhance existing measures by identifying the deficiencies while defining the corrective measures and the means to implement them at the district level. The file review revealed also the need to enrich the designed demographic and clinical questionnaire for TB patients to contribute to the enhancement and the management of patients and in the identification of risk factors.

Although the EPTB is contributing to the burden of TB and this since 1993, it does not receive specific attention in the control strategy. To achieve a better protection of both animals and human, specific attention needs to be given zoonotic TB caused by M. bovis that spreads from animal to human and results in EPTB.


The authors would like to sincerely thank Mr. Khellaf, the medical supervisor of Leon Bernard TB unit, for his appreciated support during the data collection.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1], [Table 2]

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