Prevalence and determinants of osteoporosis in Congolese patients with axial rheumatism: a cross-sectional hospital-based study.

Introduction: osteoporosis seems to be uncommon in sub-Saharan Africa. The aim of this study was to determine prevalence and determinants of osteoporosis in Congolese outpatients attending rheumatology consultation for axial rheumatism in Kinshasa, Democratic Republic of the Congo.

Methods: a cross-sectional hospital-based study from January to December 2018 among outpatients received for axial rheumatism in 8 hospitals of Kinshasa. The parameters of interest were age, sex, body mass index (BMI), alcoholism, smoking, physical activity, sunlight exposure, intake of dairy products, the notion of personal or parental fracture, a bone mineral density (BMD) and a phosphocalcic metabolism. The BMD was measured by using the dual energy X-ray absorptiométry. Serum level of calcium, Vitamin D, phosphore and parathormon were determined to assess the phosphocalcic metabolism. Osteoporosis was defined by a T-Score ≤ -2.5 SD. Standard statistical tests were used to analyze the results.

Results: ninety patients (75 women and 15 men) were included. Their mean age was 63.5 ± 12.2 years. Low back pain 71.1% (n=63) was the main symptom. The rate of patients with osteoporosis, osteopenia, and normal bone density was 34.4% (n=31), 43.9% (n=44), and 16.7% (n=15) respectively. Pathological bone fractures were not noted. Ageing (aOR: 1.31, IC95%: 1.11-1.54; p=0.002), smoking (aOR: 14.65, IC95%: 1.38-156.1; p=0.045) and non-obese status (aOR: 32.3, IC95% 1.50-696; p=0.032) were identified as determinants of osteoporosis.

Conclusion: in the present study, osteoporosis is common in Congolese patients with axial pain and is more frequent in women. Its determinants are ageing, smoking and non-obese status.