This study was conducted in Lubumbashi. It is the economic capital of the DR Congo; it is also the capital of the province of Haut-Katanga. Moreover, it is the second most populous city of the DR Congo. Its population would be around 2 million inhabitants according to the latest estimates, with an area of 747 km². Its density is 2391 habitants/km².

In DR Congo, tuberculosis control is the mission of the National Tuberculosis Control Program (NTP). In order to achieve its various objectives, the NTP recommends an integrated approach to tuberculosis control activities in primary health care structures in line with the strategy for strengthening the health system.

The structure that ensures the diagnosis and treatment of tuberculosis patients is called the Tuberculosis Diagnosis and Treatment Center (TDTC). The TDTC is the functional unit of the NTP. The TDTC is equipped with diagnostic tools (a microscope with immersion lens, rapid diagnostic tests, etc.) endorsed by the WHO, and has trained medical personnel. A sample of the sputum smears collected by the TDTCs is also regularly monitored by the higher level according to the national strategy in this area.

Some TDTCs are equipped with XPERT MTB/Rif machines depending on their strategic location and the number of suspected multiresistant (MR) cases surroundings.

Screening and treatment are free. The drug supply and other inputs to tuberculosis control are subsidized.

The data were collected after all of the TDTCs of Lubumbashi, 22 centers.

This is a descriptive cross-sectional study, which was conducted from 1st January 2013 to 31st December 2015, a 3 years period.

Our target population is children under 15 years of age, living in Lubumbashi.

・ Size sample: 8699 tuberculosis cases were collected during the period of our study, including 717 children having constituted our sample.

・ Sample type: we proceeded to a convenience sampling, according with inclusion criteria below.

・ Inclusion criteria: we have included children from 0 to 14 years diagnosed and treated for tuberculosis. The diagnosis of tuberculosis was based on NTP guide criteria in conformity with WHO recommendations for TB in children. The following elements were researched: a significant Keith Edwards score [7] with at least one paraclinic criterion suggestive of tuberculosis: a positive Ziehl test, an evocative X-ray, a positive intradermoreaction, a positive serology or a positive culture of Koch Bacillus.

・ Non-inclusion criteria: patients with incomplete study parameters were excluded from the study.

The following socio-demographic parameters were collected for each child: age in months, sex and commune of provenance.

Apart from weight, elements of anamnesis and clinical examination were collected, the HIV status and the evolution especially.

We have carried out the technique of documentary review to carry out the collection of our data. It was based on the follow-up records and the registers of the patients as drawn up in the different TDTCs.

For the evaluation of nutritional status, the usual material used to perform anthropometry was used, namely a Salter® scale with accuracy to 100 mg for weight gain.

HIV serology was made with a rapid screening test (Determine®) confirmed by a 2^nd discriminative test (Unigold®).

・ The determination of the nutritional status’s is made based on the following indicators: weight and age, allowing the calculation of Z-score Weight for Age to indicate global malnutrition.

The calculation of Z-score is based on the following formula:

Z-score= (Measured value - Average value in the reference population)/ Standard deviation of the reference population.

In this study, the Z-score calculation used the ENA software (Emergency Nutrition Assessment) 2007 Version, based on NCHS curves. Nutritional status was classified as follows: normal nutritional status (Z-score greater than or equal to −1.00), mild malnutrition (Z-score between −2.00 to −1.01), moderate malnutrition (Z-score between −3.00 to −2.01) and severe malnutrition (Z-score less than −3.00) [8] .

・ The encoding of data was made using Excel 2013 software on Windows 2013.

・ The processing of data was made by using Epi-Info 7 (2013), to generate statistical tests. So was calculated the mean with standard deviation, and the median. When association is performed between two or more parameters, Odds-ratio was generated, with a 95% confidence interval. The p-value signification level is <5%.

Respect for the anonymity of patients was respected. The administrative authorizations required for the completion of the data collection were duly obtained.

It should be recognized that the nutritional status assessment was not extended to the Weigh- f-height and height-for-age Z-scores, which could have highlighted acute malnutrition and chronic malnutrition, respectively. This is related to the fact that the examination of the patient, often summarized in several TDCTs, forgets to mention the size. The Z-score Weight-for-Age used here is

the reflection of the underweight alone, hence global malnutrition.

Our study population constitutes 8.2% of the total tuberculosis population monitored in Lubumbashi. This is a high frequency, but it falls within the thresholds of the figures presented in other studies in sub-Saharan Africa, between 6% and 39%. These figures reflect the precarious living conditions of the population, but probably also the result of the high rate of HIV infection, including tuberculosis can be a corollary [9] [10] [11] [12] .

In comparison, we know that in developed countries tuberculosis is essentially an adult pathology; an 8-year Taiwan study that found 0.85% of tuberculosis cases in children compared to cases diagnosed in adults [13] .

In terms of socio-demographic parameters, most of the patients came from the city of Lubumbashi (91.4%). There is no significant difference in the distribution of cases in relation to sex, with the sex ratio being 0.9.

According to the EDS II report in the DRC, about 23% of children under five are underweight and 7% in severe form. These proportions are significantly higher than those expected in a healthy and well-nourished population (2.3% and 0.1%, respectively) [14] . In our study, the prevalence of underweight (<−2 z-score) was 20.8%, of which 8.4% was severely malnourished (<−3 z-score). This is supplementary to the nutritional status of the general Congolese population.

Nevertheless, there is evidence of greater risk in patients with a precarious nutritional status to develop tuberculosis. One study highlights the role of vitamin D receptors, influencing the immune response to respiratory infections in malnourished children, particularly in tuberculosis. This also suggests the wider need to supplement these tuberculous children with micronutrients and macronutrients [4] [15] . However, this option is neither explicit nor systematic in the national program for the management of tuberculosis patients in DR Congo.

The first factor highlighted as significantly associated with the nutritional status of malnourished is age. Age less than 60 months is associated with a significantly more deleterious nutritional status than age greater than 60 months. In DR Congo, the risk of developing underweight is increased by 5 years (21% of the population at this age) and is already present even in infants younger than 6 months (10% of infants ) [14] . This underlines the urgent need to integrate nutritional management into anti-tuberculosis treatment in children in general.

Second, it has been shown that poor nutritional status is significantly associated with positive HIV serology. HIV leads to immunodeficiency, on which tuberculosis finds a propitious ground for development. At the same time, HIV immunodeficiency is itself responsible for a more or less sensitive alteration in the nutritional status of patients. In addition, both malnutrition and HIV negatively influence the risk of developing tuberculosis and the outcome of treatment due to deterioration of the immune defenses mediated by T lymphocytes, hence the association between HIV-TB co-infection and poor nutritional status [16] [17] [18] .

Finally, a more favorable outcome was significantly associated with good nutritional status (p < 0.001; OR = 12, CI 8.0 - 18.9). Indeed, it is widely recognized that nutrition is an important underbody to the immune response. Malnutrition alone or associated with other pathologies (especially tuberculosis) is one of the leading causes of infant mortality in sub-Saharan Africa [4] [19] . Thus, improving the nutritional status of tuberculous malnourished children would be beneficial in improving their prognosis.