Effects of Biological and Non Biological Agents (Disease Modifying Antirheumatic Drugs) on Bone Mineral Density in a Sample of Rheumatoid Arthritis Patients

BACKGROUND: Osteoporosis is an extra-articular complication of rheuma­toid arthritis that results in increased risk of fractures and associated mor­bidity, mortality, and healthcare costs.

OBJECTIVE: To evaluate changes in bone mineral density in a sample of rheumatoid arthritis (RA) patients on biological (anti tumor necrosis factor (TNF) alpha) and non-biological agent disease modifying antirheumatic drugs (DMARDs).

PATIENTS & METHODS: A cross sectional study enrolled 60 RA patients diagnosed by rheumatologist according to the 2010 American College of Rheumatology/European League Against Rheumatism (2010 ACR/EULAR) classification criteria for RA. Thirty patient on biological agent (anti TNF alpha) and 30 patient on non-biological agent (DMARD). RA disease-related data wincluded disease duration, disease activity score index of 28 joints (DAS 28) and clinical disease activity index (CDAI), functional class, body mass index and treatment history. vitamin D level were measured in both groups. Bone mineral density was measured by dual energy x-ray absorptiometry of hip and lumber spines for patients. A T –score of equal or less than -2.5 standard deviation that of young healthy adults were taken as osteoporotic and scores between -1 to -2.5 standard deviation was taken as osteopenic.

RESULTS: Prevalence of RA patients on biological agent (anti TNF alpha) who had osteoporosis was 1(3%) and 12(40%) were osteopenic, and in patients on non biological (DMARD), Osteoporosis was present in 8(26%) and osteopenia in 13(43%, p= 0.019).Vitamin D level in patient on biological agent (anti TNF alpha) was low in 24(80%) and normal in 6 (20%) patients. While in non biological agent (DMARD) it was low in 13(43.3%) and normal in 17(56.7%) of patients, p=0.003). Patients on biological agent (anti TNF alpha); 15 (50%) patients showed high calcium, 2(6.7%) low phosphorous, and 2(6.7%) high Alkaline phosphatase (ALP) while in patients on non biological agent the results were 10 patients( 33.3%) had high calcium, and 5(16.7%) had high ALP. There was a significant decrease in bone mineral density in RA patients on DMARDS while biological agent (anti TNF alpha) had a role in arrest bone loss in RA patients.

CONCLUSIONS: There was a strong association between types of therapy and reduction of bone mineral density.