This was a documentary and descriptive study extending from January 1, 2014 to June 1, 2017 carried out simultaneously at the University Clinics of Kinshasa (CUK), at the General Reference Hospital of Kinshasa (HGRK), at the BIAMBA Marie MUTOMBO (HBMM); all domiciled in Kinshasa. The choice of these institutions was justified by their respective capacities to manage COPD cases. We included the files of patients over 18 years old, followed on an outpatient basis for COPD with chronic respiratory symptoms (cough, expectoration, dyspnoea) and diagnosed with COPD with spirometry (an FEV1/FVC ratio < 70% before and after administration of 400 μg of inhaled salbutamol). Pregnant women, asthmatics and atopic subjects were excluded from our sample. The recruitment method was exhaustive as long as the inclusion and exclusion criteria were met.

Data were extracted from medical records and collected on an anonymized survey form written for the purposes of the study. Sociodemographic, clinical, functional and radiological data were collected. The socio-demographic and clinical data concerned age, sex, chronic cough, dyspnea, expectoration, tobacco risk factors, domestic and occupational pollution, tuberculosis sequelae; comorbidities diabetes, cardiovascular pathology, interstitial lung disease, cardiovascular and pulmonary pathology.

The smoker was defined as a subject who had active tobacco intoxication at the time of diagnosis, the ex-smoker having not stopped active intoxication for at least 1 (one) year. The degree of tobacco intoxication was assessed in packs/year. The others are considered non-smokers or exposed to passive smoking.

Spirometry was performed outside of any acute episode with the Spiro doc from the medical manufacturer International Research (MIR) using a pre-calibrated single-use turbine. The acceptability and reproducibility criteria recommended by the ATS and the European Respiratory Society (ERS) were met. The different ventilatory variables measured included: the forced expiratory volume in the first second (FEV1), the forced vital capacity (FVC), the median expiratory flow rate at 25% - 75% of the vital capacity (FEMM 25 - 75), and the ratio FEV1/FVC [7] .

Comorbidities refer to all other conditions found in patients in this series. Bubble is hyperclarity with thin and clear wall measuring 1cm or more. Dilation of the pulmonary artery: a diameter of the common trunk of the pulmonary artery greater than 28.6 mm (predicts the presence of pulmonary arterial hypertension). Dilatation of the bronchi: when the bronchial eye is larger in diameter than the vascular eye. Thoracic distension: it is deduced respectively from the low position of the diaphragm (right hemi-diaphragm below the 7th rib), from the flattening of the diaphragm and from the increase in the retro-sternal clear space on the profile (greater than 2, 5 cm).

Increase in lung height: when the distance from the diaphragmatic dome to the top of the lung reaches 30 cm. Reduction of cardiac diameter: when the cardiac silhouette is verticalized, while its transverse diameter measures less than 11.5 cm on the frontal chest X-ray. Thickening of the bronchial walls: the walls of the bronchioles are not visible under physiological conditions. But in case of thickening they can now be seen in the form of clear rings contiguous to their satellite arteries. Centrilobular emphysema: this refers to the presence of hypodense, well-defined lesions measuring less than 1 cm and often located at the apex. Panlobular emphysema: corresponds to a localized destruction of the respiratory bronchioles, of basal topography.

Expiratory trapping: corresponds to the reduction of the diaphragmatic stroke on the chest X-ray taken during expiration. Normally the amplitude of the diaphragm under physiological conditions is 1.5 cm.

Pulmonary vascular changes: these relate to the scarcity of vessels in the periphery, while there is a dilation of the proximal arteries. The distortion can sometimes be so pronounced that the lung appears peripherally avascular.

Pulmonary arterial hypertension: said of a right interlobar artery measuring more than 16 cm in diameter or a left pulmonary artery exceeding 18 mm in diameter.

COPD CT phenotype includes respectively:

• predominantly emphysematous involvement (better seen on CT);

• the predominant attack of the airways (made up of micronodules, thickening and irregularity of the bronchial walls;

• mixed damage, combining the two varieties described above.

Saber sheath trachea: corresponds to a narrowing of the frontal diameter of the intrathoracic trachea in favor of a compensatory increase in the sagittal diameter of the viscus measured at the same level.

Data were collected in Excel, and analysis was done with Statistical Package for Social Sciences (SPSS) software for Windows version 23.0 (SPSS Inc., Chicago, IL). The qualitative variables were represented in the form of counts and proportions. Continuous variables were summarized on average with standard deviation (SD) when the distribution was normal, and where appropriate they were represented by their median (interquartile range). The chi-square test and the exact probability of filing were used for the comparison of the proportions, and Student’s t-test was used for comparison of means. A difference was considered statistically significant if p < 0.05.

Patient data was anonymized with a unique code assigned to each patient and then recoded for analysis. The work was presented and approved by the Medical Ethics Committee of the University of Goma at No. UNIGOM/CEM/11/2022.

The proportions of aging varied unequally and very significantly (p < 0.001) between men and women. Aging was observed in all women followed by men with aging and men without aging (Figure 1).

The proportions of men were comparable (p = 0.211) to that of women between the different health structures: 65.3% (n = 62), 20% (n = 19) and 14.7% (n = 14) respectively observed at CUK, HGRK and HBMM. There was no significant association (P = 0.406) of the proportions of exposure to domestic and/or occupational pollution between aging (32.6% n = 31) and young-adult status (24% n = 6) (Figure 1).

The proportions of allergy, comorbidities and types of comorbidities were similar (p < 0.05) between aging and the young-adult state (Table 1).

We note that the proportion of thoracic distension (p = 0.022), the pulmonary vascular modification (p = 0.001), the rail image (p = 0.009) and the trachea in the sheath (p = 0.017) were significantly higher in the elderly compared to young adults (Table 2).

It was noted that the proportions of bronchial parietal thickening (p = 0.011), bronchial dilation (p = 0.015) were significantly higher in aging compared to young adults (Table 3).