Setting: The epidemiology of tuberculosis (TB) among children in the Democratic Republic of Congo (DRC) is not well known. Objective: This study aimed to describe the trends in TB epidemiology among children in the DRC and to compare these trends in children and adults. Design: Data from the National TB program, the WHO Global TB Report, and a demographic survey of health in the DRC were retrospectively analyzed. The study period was from 1995 to 2014. The notification rate, absolute incidence and incidence rate of TB per 100,000 population were reported. Results: In 2014, 12,785 (12.6% of adult cases) TB cases were reported in children and 101,303 in adults. Among children, 3438 (26.89%) had PTB+; 2828 (22.11%) had PTB –; and 6519 (50.98%) had extrapulmonary TB (EPTB). Children under 5 years had a lower reported prevalence of TB (184 cases). The incidence rate per 100,000 population was 10 in children and 181 in adults. The TB incidence decreased between 2010 (11.47) and 2014 (10.46). The proportion of children in overall cases of PTB+ was 4% to 5% in all districts. Conclusion: Caring for childhood TB remains a challenge in the DRC. Improved diagnostic procedures and effective training of providers who care for childhood TB are needed.
Tuberculosis (TB) is an important contributor to maternal and child’s morbidity and mortality [
Indeed, the vision of the “End TB Strategy” is to have a world free of TB by 2035, meaning zero deaths, diseases and suffering due to TB [
Therefore, there is an urgent need to address the lack of epidemiological data on TB in children in high-burden countries and to understand the differences in epidemiology between children and adults; this information could contribute to a reduction in the TB burden.
The present study aimed to describe the trends in childhood TB epidemiology in the DRC and to compare these trends to those in adults.
This study conducted a retrospective analysis of data collected from the WHO Global TB Report and the National Tuberculosis Program (NTP), specifically data concerning the DRC’s districts. The NTP houses the central processing unit for the fight against TB in the DRC. This program is organized into 3 levels of activity: data from the Centers for TB Diagnosis and Treatment (CDST) are sent to provincial coordinating centers for the fight against TB (CPLT) and are then consolidated at the national level. The study period was from 1995 to 2014. Data regarding the notification rates for total TB cases, new TB cases, and cases by form of TB, district, and age group were collected. Children were divided into two groups: children aged 0 - 4 years and those aged 5 - 14 years. District-specific population data were obtained from the 2014 national survey on health demography in the DRC (EDS) [
Data were available from 1995 for new TB case notifications in children and adults, from 1999for new smear-positive pulmonary TB (PTB) cases by age group and sex, and from 2010 for year- and district-specific cases by sex, age and type of TB. These data were collected until 2014. For practical reasons, we used the previous 11-district organization of the DRC for data analysis.
The number of case notifications was defined as the number of cases registered during a given period. TB incidence was calculated using the number of new cases divided by the total population within a reporting area or age group. Rates of notified and incident cases were expressed per 100,000 pop. The rate of detection was defined as the ratio of the number of cases registered during a given period and the number of cases tested during the same period multiplied by 100 [
The number of new cases was defined as the number of cases detected and treated for the first time during a given period. The proportion of pediatric TB cases was defined as the number of cases in children aged 0 to 14 years old divided by the total number of cases [
Cases of smear-positive PTB, smear-negative PTB, and extra pulmonary TB (EPTB) and type of patient (new cases and retreatment) were defined according to the WHO criteria [
Data were collected and analyzed using Excel. The calculation of incidence and the generation of graphs were performed using the same software. Frequencies and average values were reported for the variables of interest. Chi-square test was performed to evaluate the differences in trends between different DRC districts from 2010 to 2014. A p-value < 0.05 was considered statistically significant. Density maps depicting the TB case notification rate per 100,000 pop by DRC district were produced using Geographic Information System software (QGIS), version 1.6. This study was approved by the Ethics Committee of the School of Public Health (Permit Number: ESP/CE/042/2015, part B). The procedures used in the study were in accordance with the recommendations of the Declaration of Helsinki. Informed consent was not obtained from the patients because this was a retrospective study and we worked exclusively with data obtained from documents.
In 2014, a total of 12,785 TB cases were reported in children, and this prevalence was 12.6% of the cases in adults (101,303 adults). Of the cases in children, 3438 (26.89%) were smear-positive PTB (1582 boys and 1856 girls), 2828 (22.11%) were smear-nega- tive PTB, and 6519 (50.98%) were EPTB. The distribution by age showed that 184 children aged 0 - 4 years (99 boys and 85 girls) and 3254 aged 5 - 14 years (1483 boys and 1771 girls) had smear-positive PTB, 1441 children aged 0 - 4 years and 1387 aged 5 - 14 years had smear-negative PTB, and 2251 children aged 0 - 4 years and 4268 aged 5 - 14 years had EPTB (
A total of 75,339 new smear-positive PTB cases (42,735 males and 32,604 females, sex ratio of 1.31) were identified in 2014: 3,438 were children, and 71,901 were adults. The
distribution by age group was as follows: 184 (0.24%) were 0 - 4 years old, 3254 (4.31%) were 5 - 14 years old, 13,638 (18.01%) were 15 - 24 years old, 19,009 (25.23%) were 25 - 34 years old, 16,401 (21.76%) were 35 - 44 years old, 11,813 (15.68%) were 45 - 54 years old, 7256 (9.63%) were 55 - 64 years old, and 3784 (5.02%) were 65 years and older (
In 2014, the overall TB case notification rate was 162/100,000 pop, and the overall incidence was 104/100,000 pop. The incidence rate was 10/100,000 pop in children and 181/100,000 pop in adults. The district-specific distribution of cases among children in the DRC showed that the highest incidence rates were in Bandundu (16/100,000 pop), Maniema (15/100,000 pop) and Katanga (14/100,000 pop). The lowest incidence rates were reported in North Kivu (5/100,000 pop), Bas-Congo and Province Orientale (each 6/100,000 pop). In adults, the highest incidences were observed in Kinshasa, Katanga and Maniema (255, 229 and 213 cases/100,000 pop, respectively), and the lowest incidence was in North Kivu (91/100,000 pop) (
The trends in new TB case notifications in adults and children from 1995 to 2014 are presented in
In children 0 to 15 years old, the number of new case notifications in 1995 was 704,
followed by a decrease from 1996-1997 (520 in 1996 and 580 in 1997) and then an increase to 3438 cases in 2014.
From 2010 to 2014, the incidence rate in children/100,000 pop indicated a decreasing trend: from 11.47 in 2010, to 10.17 in 2011, 8.90 in 2012, 8.28 in 2013, and 10.46 in 2014. This variation was statistically significant (p < 0.01) in DRC overall based on chi-square tests. The five-year trends in case notification among children during the
study period indicated the highest numbers in Kasaï Oriental (3246 in 2010 and 1765 in 2014), Kinshasa (2884 in 2010 and 2075 in 2014), and Katanga (2103 in 2010 and 1,499 in 2014). A progressive reduction in reported cases occurred in almost all districts, Kasaï Occidental in particular (1181 in 2010 and 545 in 2014), with the exception of North Kivu, where the number of reported cases slightly increased (767 in 2010 and 860 in 2014). Detailed data from all districts during the 5-year study period are presented in the in
The trends in the age and gender distribution of new smear-positive PTB cases during 1999-2014 indicated that the highest TB incidence occurred in the 25- to 34-year-old age group, followed by the 35- to 44-year-old and 15- to 24-year-old age groups (
From 2010 to 2014, the proportion of TB notification rates in children in terms of the overall TB cases ranged between 10 and 15%. The lowest proportion of children was
DISTRICT | 2010 | 2011 | 2012 | 2013 | 2014 |
---|---|---|---|---|---|
BANDUNDU | 28.88 | 28.60 | 24.02 | 31.70 | 19.65 |
BAS CONGO | 19.84 | 16.27 | 16.36 | 27.14 | 16.30 |
EQUATEUR | 29.87 | 28.02 | 24.52 | 22.51 | 18.52 |
KASAÏ OCCIDENTAL | 49.92 | 49.01 | 44.32 | 30.83 | 17.65 |
KASAÏ ORIENTAL | 116.82 | 99.76 | 85.80 | 56.25 | 45.00 |
KATANGA | 45.69 | 45.38 | 39.05 | 39.72 | 31.74 |
KINSHASA | 68.93 | 63.30 | 55.17 | 90.77 | 70.36 |
MANIEMA | 64.57 | 75.38 | 61.74 | 55.96 | 36.28 |
NORTHKIVU | 30.98 | 27.45 | 25.10 | 29.54 | 32.41 |
SOUTHKIVU | 33.40 | 30.84 | 28.00 | 27.24 | 27.14 |
PROVINCE ORIENTALE | 32.26 | 24.72 | 28.61 | 26.27 | 19.67 |
DRC | 46.90 | 43.12 | 38.47 | 39.29 | 30.93 |
0 - 14 | 15 - 24 | 25 - 34 | 35 - 44 | 45 - 54 | 55 - 64 | ≥65 | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
M | F | M | F | M | F | M | F | M | F | M | F | M | F | |
1999 | 474 | 708 | 4061 | 4472 | 5886 | 4991 | 4191 | 3117 | 2250 | 1725 | 1279 | 836 | 626 | 305 |
2000 | 485 | 718 | 4042 | 4418 | 5822 | 5135 | 4147 | 3304 | 2544 | 1719 | 1291 | 853 | 601 | 351 |
2001 | 581 | 842 | 4651 | 4922 | 6794 | 5586 | 4817 | 3704 | 2876 | 2057 | 1384 | 1042 | 724 | 470 |
2002 | 649 | 874 | 4965 | 5378 | 7414 | 6230 | 4994 | 3939 | 3065 | 2262 | 1388 | 1055 | 791 | 476 |
2003 | 853 | 1233 | 5886 | 6630 | 8426 | 7711 | 6194 | 4827 | 3776 | 2866 | 1836 | 1457 | 1046 | 592 |
2004 | 1201 | 1682 | 7057 | 7662 | 9560 | 8623 | 7134 | 5542 | 4426 | 3439 | 2355 | 1855 | 1226 | 720 |
2005 | 1320 | 1694 | 6661 | 7550 | 9800 | 8487 | 7571 | 5825 | 5017 | 3894 | 2631 | 2049 | 1499 | 951 |
2006 | 1122 | 1517 | 6391 | 7236 | 9486 | 8522 | 7321 | 5621 | 5011 | 3762 | 2657 | 2019 | 1504 | 975 |
2007 | 1343 | 1842 | 6485 | 7130 | 9548 | 8415 | 7925 | 5939 | 5341 | 4127 | 2801 | 2352 | 1752 | 1099 |
2008 | 1495 | 1811 | 6497 | 7304 | 9888 | 8895 | 8452 | 6293 | 5706 | 4064 | 3121 | 2516 | 1686 | 1212 |
2009 | 1556 | 1940 | 6993 | 7362 | 10037 | 9191 | 8746 | 6586 | 6316 | 4757 | 3401 | 2669 | 1827 | 1325 |
2010 | 1707 | 1987 | 6859 | 7199 | 10412 | 9120 | 9134 | 6721 | 6464 | 4579 | 3641 | 2612 | 1907 | 1311 |
2011 | 1579 | 1800 | 6640 | 6802 | 9872 | 8742 | 8932 | 6541 | 6415 | 4537 | 3584 | 2671 | 1911 | 1295 |
2012 | 1439 | 1699 | 6612 | 6598 | 10274 | 8406 | 9361 | 6471 | 6612 | 4131 | 3698 | 2625 | 1941 | 1257 |
2013 | 1380 | 1706 | 6776 | 6376 | 10218 | 8352 | 9280 | 6472 | 6587 | 4402 | 3841 | 2551 | 2016 | 1263 |
2014 | 1582 | 1856 | 7098 | 6540 | 10540 | 8469 | 9771 | 6630 | 7123 | 4690 | 4294 | 2972 | 2337 | 1447 |
identified in Bas-Congo (7%), and the highest rates were observed in Kasaï Oriental (17%), Maniema and North Kivu (each 15%).
From 2010 to 2014, the trends in TB forms suggested a very large gap between the number of cases reported in children and adults. The proportion of children in overall cases of smear-positive PTB was 4% to 5% in all districts. Nearly a third (26% to 33%) of smear-negative PTB cases occurred in children, and approximately half (50% - 55%) of EPTB cases were in children. The 5-year trends showed a decrease in cases in both adults and children (
The present study was the first to analyze the epidemiologic trends in childhood TB in the DRC and to compare them to the trends in overall cases and in adults.
The main results of this study showed an overall difference between children and adults in the trends in TB epidemiology. In children, the incidence of TB in 2014 was 10/100,000 pop. This rate varied between 5 and 16/100,000 pop in specific DRC districts. Cases in children represented approximately 9.6% of the overall incident TB cases and 5.5% of the incidence in adults. The incidence in the DRC districts showed a de- creasing trend from 2010 to 2013. Additionally, in adults, the trends in new TB case notifications showed a decrease from 13,365 to 12,662 cases from 1995 to 1997; this de-
crease was followed by a slight increase from 1998 to 2000 and a substantial increase from 2002 to 2005, doubling the number of reported cases to reach 62,024 in 2005. The number of cases reported in 2014 was 5.4 times higher than in 1995 in adults and 4.7 times higher in children (
In the DRC, the gap in the incidence between children and adults and the low incidence in children were likely due to an underestimation of TB cases in children; a similar underestimation has previously been indicated worldwide, particularly in countries with limited resources [
The decrease in TB incidence suggests better control of the disease in these countries. In areas with a high burden of TB, although we would expect an increase in TB incidence, our findings showed a slight variation in children, likely because of the challenges managing TB in children in these countries [
Country and study period | Incidence in children/ 100,000 pop | Notification in children/year | Proportion of TB cases in children | Trends | Authors |
---|---|---|---|---|---|
Denmark 2000-2009 | 1.9 (2009) | 323 cases (2009) | 7.6% (2009) | ↓ incidence 4.1/100,000 in 2000 1.9/100,000 in 2009 | Hatleberg CI et al., 2014 [ |
Greece 2000-2009 | 5.37 (2009) | 321 cases | No significant difference (p = 0.194) | Syridou G et al., 2012 [ | |
Spain 2005-2009 | 8.1 (2009) | 2690 cases (2009) | 6.76% (2009) | ↓ incidence in children and adults Children (y = 0.15x + 7.8) Adults (y = −2.8x + 20.2) | Elena Rodriguez et al., 2012 [ |
Kosovo and the Balkans 2012 | 39 Kosovo 7.5 Slovenia 13 Albania 20 Serbia 83 Romania | Xhevat Kurhasani et al., 2014 [ | |||
Brazil (Sao Paulo) 2001-2005 2006-2010 | 3.23 2.13 | 2881 cases 2513 cases | Venancio TS et al., 2014 [ | ||
Australia 2003-2012 | 538 cases | 4.6% | Teo SS et al., 2015 [ | ||
Israel 1999-2010 | 1.05 (2010) | 405 cases (2010) | 8.4% (2010) | Mor Z et al., 2013 [ | |
Ethiopia, (Sidama Zone) 2003-2012 | 4656 cases (2012) | 13% (2012) | No variations overall However, ↑ in incidence from 2010 to 2011 | Dangissoet al., 2015 [ | |
Benin (Cotonou) 2009-2011 | 13 (2011) | 73 (2011) | 4.9% (2011) | ↑ incidence in children 13.2/100,000 in 2009 13.8/100,000 in 2011 | Ade S et al., 2013 [ |
The DRC 1995-2014 | 10 (2014) | 3438 cases | 12% (2010-2013) | ↓ incidence in children 11.47/100,000 in 2010 10.46/100,000 in 2014 | Present study |
the Global Fund and its partners to enable a better coverage of activities in the country and a better detection of cases [
Approximately 30% - 40% of close contacts are estimated to be infected at the time of diagnosis for each identified case of TB [
Regarding the incidence in DRC districts, in general, the most affected districts were Kasaï Oriental, Kasaï Occidental and Katanga, probably because of the influx in population to the mining zones in these areas, resulting in a high rate of TB transmission in mining camps. Subsequently, from 2010-2011, the NTP increased the number of CDSTs in these districts, and a decrease in the TB case notification rate has been observed in recent years.
The distribution of smear-positive PTB cases showed an increase by age, particularly in those aged 15 - 44 years (peak in 24- to 34-year-olds), corresponding to the period of increased social and sexual activity. A study previously conducted in the DRC with children from 0 to 15 years old also reported an increase in the number of cases with age [
The low number of new smear-positive PTB cases in children can be explained by a slight increase in case detection during the 5 study years. This observation differed from findings previously reported in developed countries, where PTB was the most frequently identified clinical form of TB [
The observations by district showed a decreased number of smear-positive PTB cases in Katanga; however, the number of smear-negative PTB and EPTB cases increased. This trend indicated fewer cases of bacteriologically confirmed TB and more clinically diagnosed cases, which could likely be explained by the conflict between tribes in this district that occurred in the last years of the study. In the Bandundu district, a continuous increase in the rate of new smear-positive PTB cases in children was observed. The intervention of several partners in this district’s various health programs could have contributed to the improvement observed in the rate of detection. Partner support has had a major impact on disease control in the DRC, particularly in conflict zones such as the east districts, where war has raged for several years.
This study is the first to describe the epidemiological profile of TB in the DRC. Another strength of the study was the description of the epidemiologic trends in childhood TB, as this understanding can contribute to a better control of the disease by the application of new strategies.
Some limitations should be acknowledged; few data were available for more specific age groups of children, and this scarcity may have limited some understanding of the TB trends in subgroups of children. Additionally, there are potential biases inherent to retrospective studies. Some specific data were not available before 2010, and this lack of data limited some analyses. The difficulty in diagnosing TB from sputum in young children, particularly the difficulty in obtaining expectorate samples or gastric aspirates, the low sensitivity of the scoring system, and the difficulty confirming smear-negative cases based on clinical signs and chest X-rays could also be considered limitations of this study.
In 2014, the incidence of TB among children in the DRC was 10/100,000 pop. The proportion of children with TB was approximately 12% of total cases. The highest incidence occurred in the Bandundu district (16/100,000 pop). Globally, an increase in new TB case notifications in adults and children was observed from 1995 to 2014, but a decrease in notification rate occurred in children in 2014. These findings showed that childhood TB remains a challenge in the DRC. The rate of TB notification remains low compared with the rates targeted by the WHO. The identification of BK must be performed on all suspected TB cases. Control efforts should be increased to achieve the rate of TB infection recommended by the WHO and WHO guidelines for children. Specific strategies must be implemented to improve the diagnosis, monitoring, and reporting of cases, especially in children.
The authors thank Professor Nadia Ait Khaled for her substantial contribution to the drafting of this paper; the NTP and Dr. Brian Bakoko for supplying the data necessary to conduct this study; and the WHO for the regular publications of epidemiological reports, from which the data necessary for this study were obtained. We also thank Nicole Anshambi and Lisiara Robert for their help collecting the data. The primary author developed the project, collected the data and drafted the manuscript. There are no conflicts of interest.
Loukia, A., Joseph, S.D., Zacharie, K., Gertrude, L., Kapay, K. and Patrick, K.K. (2016) Trends in Tuberculosis Epidemiology among Children in the Democratic Republic of Congo. Journal of Tuberculosis Research, 4, 235-248. http://dx.doi.org/10.4236/jtr.2016.44026